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ARTICLES BY F. L. Brown PE FAINT SUBJECTS CLIPPED FROM TRADE MAGAZINES OH IN REPRINT OR PAMPHLET FORM iqzS'yo \%0 OLI3EPM3S AND REPRINTS OP ARTICLES ON PAINT SUBJECTS BY P. L. Brown* PROM TRADE MAGAZINES 1, The Role of Paint A Varnish in Pood Conservation, AMERICAN PAINT JOURNAL Aug, 1925 2, How Protective Coatings Retard Moisture Qhangea in Wood, YATES^AMERKAN QUALITY $. How to Prevent Decay Whan Building ofWbdd; BUILDINGS CONSTRUCTION A MAJiTTlNANCE 1926 4. Woof Finishing - A Gianoa Ahead, MECHANICAL ENGINEERING, Mid-November 1926 5. Why Wooden Buildiaga-Need Paint Protection, FAOTORT, October 1927 i* 6. Principles for Testing Paint on Wood, HARDWARE DEALERS MAGAZINE November 1927 7, Some Cannes of Blistering and Peeling of Paint on House Sidingj AMERICAN PAINT & VARNISH MPRS, ASSOC., Cir* 317, Cetobe# li!?27 8, Why Some Wood Surfaces Hold Phi'at Longer Than Others/LEAFLET 62 U.S.D.A. 1930 9,-HoW Properties of Wood Determine the Service Givenby Exterior Paint Coatings, . AiBRIOAN PAINT jOURNAL April 7#' 195 10. Developments in the Stabilization of Paint lag Practise for Wood, TRANSACTIONS . AMERICAN SOCIETY OF MECHANICAL ENGINEERS, 3|SdptS$bSr l951 11. Painting of Wood, SOUTHERN CYPRESS MANUFACTURERS' ASSOC., I931 12. News ittm* WtSC<SlN SnTN JOURNAL* February 22, 1951 15. Priming Coat Reductions for Painting New Wood Surfaces, AMER. PAINT & VARM.MFRS. tiff ' Circ. 445* OIL PAINT ia DRUG HEPTR., PAINT OIL & CHEM.REV. Nov. 1933 14. Painting Characterist ics of Wood* LECTURE TO NEW ENGLAND PAINT & VARNISH J PRODUCTION CLUB, 1933 ipp 15. %6, Testing House Durability of Paints for Durability, JOUR, CHEMICAL EDUCATION September 1933 Paint on Loaglaaf' & Shortleaf Pine, SOUTHERN LUMBERMAN February 1935 it 17. Painting Exterior Woodwork, PAOIFE! PURCHASER February 1954 , 18. oat Reductions for Paint id New Wood Surfaces, AMER* PAINT JOUR, Dee. 1934 19. Durability of Paint oh Wood Treated with Zinc Chloride, AMER. WOOD-PRESERVERS ,life...20 ASSOC. 1954 A Trouble-Shooter's View of the Gamble in House Paint, PAINT OIL & OHEM. REV. Oct. 1935 V;.2i Don't Let Faulty Painting Jobs Steal Public Confidence!, CANADIAN PAINT & VARNISH is 22 MAGAZINE September 1935 Stingy Paint Application Often a Danger, NATIONAL PAINTERS MAGAZINE August 1935 - 23. Repainting Old, Paint-Thursty Surfaces, PAINT OIL & CHEMICAL REVIEW May 1935 m 24. Repainting Paint-Neglected Frants Houses, NATIONAL PAINTERS MAGAZINE Apr.-June 1935 25* The- Preservative Treatment and Staining of Shingles, WISCONSIN CARPENTER AND ii BUILDER (date T-) 26. How Painters Can Prevent Painting Complaints, NATIONAL PAINTERS MAG. M rch-June 1936 27. PAintlng and Finishing Wood, WOOD HANDBOOK OF FOREST PRODUCTS LABTT. (about 1936?) 28* Some Interesting Facts About Paint Complaints, PACIFIC RETAIL LUMBERMAN Vol. IV, No. 1 29. Wf House Paint for a Planned Maintenance Program, PACIFIC PURCHASER February 1937 50. Painting Problems - What are They Today, RAILWAY ENGINEERING & MAMTENANCE Feb. 1937 JX. Have you a Paint Maintenance Program?, THE AMERICAN HOME April 1957 32. The Fading of Painted Surfaces, RAILWAY ENGINEERING & MAINTENANCE September I937 53 The Effect of Climatic Differences on the Behavior of House Paint, PACIFIC PURCHASER February 1938 54. Wood and Paint* THE DECORATOR (London) March 1938 35. Classification Of House Paints as a Guide to the Study of Formulation* DRUGS* OILS AND PAINTS March 1938 36, What Can Be Done to Make Paint Maintenance More Successful, AMER. PAINT J. Mar. 1938 also in PAINT, OIL & CHEMICAL REVIEW Apr, 1938 57. When and How to Paint Homes and Farm Building, WISCONSIN CARPENTER & BUILDER 1948 58. Effective Floor Finishes, BUILDINGS & BUILDING MANAGEMENT sJun* 1939 39. Painting your House, AMERICAN FORESTS May 1939 40. An Open Letter from Dr* Browne , NATIONAL PAINT BULLETIN May 1939 . 41. Some Painting Problems and the Answers, NATIONAL REAL ESTATE JOURNAL .Sept. 1939 42. Classification of House and Barn Paints, U.S.D.A. TECHNICAL BULLETIN 8o4 Jan. 1942 43. The Right Paint for Your Job, SUCCESSFUL FARMING May 1941 44. Durability of Paint Jobs Studied., MICHIGAN ARCHITECT & ENGINEER Aug. 1941 45. painting Army Buildings, U.S. ARMY, OFFICE CHIEF OF ENGINEERS L($# N41698.01 1 i : r- V ; iD?'; ansi: , ' r- :: ; . fi . 46; Somes 18&ige Tou Should Know About Postwar House'Faints, RATIONAL HEAL . -ESTATB &BUILDINGJOUHHAX* March to May 1946- 47* Taintere From You* Taint Farm, SUCCESSFUL FARMING Sept* 1946 48 Wood Properties end Faint Durability, U.S.E.A. MISCELLANEOUS PUBLICATION 629 49. Painting the Bam* HOARD'S DAIRYMAN July 1948 50. FORMAN FORD AND 00. ANNOUNCES,GRADE 1 HOUSE. ANDBAHN PAINTS, from J. , THE MISSISSIPPI VALLEY LUMBERMAN January 1949 51. A Standard of Quality for Faint; BUILDINSS AS BUILDINC MANAGEMNT Mar. 1949 also in WESTERN BUILD INC March 1949 52. House Paint and Outdoor Furniture* WOOD WORKING DIGEST April 1949 * 55. How to Use Natutl#d0d Fiaiahes, NATIONAL HEAL ESTATE AND BUILDING JOURNAL November 1951 , 54. Natural Finishes for Exterior Wood, ARCHITECTURAL RECORD February 1952 55. FPL,Studies Natural Finishes* WISCONSOT STATE JOURNAL September 26*1952 56. Weed Siding.Left toWeather Naturally, ARCHITECTURAL pCORD Kov. 1952 57. Selection of Durable Exterior White House Paint, HOUSING RESEARCH Mar*?1955- 58. Teats proys Painting Too Often May Cause Trouble, WISCONSIN STATE JOURNAL March 7* 1954 . -, 59; lOiear Finiahea for Exteriora of Houses, AMERICAN PAINT JOURNAL May 1954 : 60, Wood Siding* How to Install It, Paint It,- Care for It* U.SjS.A* HOME AND , ... - , . GAfU^N>aULETNOw 1956 . . 61. Wood Siding Left to Weather .Naturally, SOUTHERN LUMBERMAN December I960 *; V ! - 77:,.;.- - ** s " ' f 0.. f7 7'... FLB 000773 THE ROLE OF PAINT and VARNISH IN WOOD CONSERVATION By DR. F. L. BROWNE U. S. Forest Products Laboratory Madison, Wisconsin Reprinted From AMERICAN PAINT JOURNAL August 24,1925 Ame r ic a n p a in t j o u r n a l c o mp a n y Publishers ot American Paint Journal American Paint and Oil Dealer American Painter and Decorator ' 3Y13 WASHINGTON AVE., ST. LOUIS, MO. N41698.02 FLB +A r 0 _ 1 q P 1 0 q t J Xu r q 1 , s t . 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WoS w ^o p ao ow^a .VSi *- 'S ^ 1 D,-tf:5 so {? rt eS ? .*3 Wf <* \ **.** m 3b ^ir *** M, . 7v r; ig-M M S tl Si A* I fH fjj $5fc 15*: : IP* Hj| S|f H Hi *|8i MUtlll lli )H? tv ci i&* v- >*,j mm^ ^ w i I* Si llSfi; : >; ||e SS^ ::fHS*' 'Uptf* FLB 000777 "I'S'2 s| go g2'3 S-.2 | a 0 2 ?laS|&ra^--s`G| g 'S'g 80S : iZo-'3g Hiiagso> ^ a,** o o < itn1i*S4 2*a'u.S'S3 I'fSa3lmoato sg o <y XS fi ,_ * 4*i**2 II &ft ^ rl ri`ews'2jj?sfeo}*l-*1 s"a .31 'i!JH5"2 5rj*aan?*^5"QsQ SJs3 ^^ saO-'-wg,,s5*tSs--*>, !a ,, 8a -Sa! .5?a3|"|`g3g *3a2 r: . s u 's.a g .5 s- .5 2 2 ,1, t-i *2 w --Xfgl.*-"asi$ *3s 2,gj 2-s Is ~!g aS'gaaAfgi-Sg.a^ Srtj 4) h wOO^r*p!jg<SS-***[2 _S.S g-* 4> |OSQ |<** V|a1o f** 48 X ^ D > 4J X c; y g1 or~ .-rrtfl* i?-2 *O^*'2a;-w<3sCs*M*i?8Vu3*,-2Cr5i31,;S.>3*> ?| arf I aS ill-9 Sft> cC B02 slip Pf 4) I* <sft a,a &g^ iPi 4saJc. > Oi t#. fe msRw-..a.Q2o1P>^*a^O+3*',*Os- jA*.S.o6sp0>*.^32aS^a3g&O45e2) _!5PsScfc-j;'?lJSSSa2O5S*3aoU" --^I.dT2r' *^TiMc?32t1-sv"'5fgt"<,'^spr|, ^ s a g a 8sa|s'?-s s"5i 2-gl " .0 a ? -3 . * "MS> ^JATs1'wWS> Io,, S^sag"v-S2lSs-s"l.t-?'Ss5'a5s& .a _3 a '0o'~S *^'Sg*|3"|!& S'C|&fc* Si)3 3*'9-E? '-SS&23 tsf*i-lj,f-*<-lu> ,J"3ooB ^sysi5C9s32i .*OjfMe rrgto>}o& t/3 W s *J +j V2 FLB 000778 ft. FLB 000779 fFigure 9. Decay Due to Moisture Seeping Under Column. _____ Figure to. Decay Due to Moisture from Leaking Do r~)i : .' ' ' ............'.. ...... ..' V . ..................... ' '..' ....."...r.:."... /i 12 A+ 0 _ 1 q P1 >+ JX <q 1 , s t . Louts decay was the result. In the program for the conservation In so far as the paint coating re- of our timber supply, paint and var iants the absorption of vain water and nish provide the most effective anti- dampness by wood in structures it dote for weathering. Unfortunately a tends to keep the. moisture content of great many people still fail to realize the wood below the point necessary the time economy of keeping buildings for the development of decay. But well protected with paint and var- mauy structural conditions are likely nish; in fact, in certain sections of to occur in which water can obtain ac- the country, a very large proportion cess to the woodthrough parts which of the less pretentious dwellings arc are not painted. Inmany cases the not painted even when new, presum- subsequent drying out of the wood ably from a mistaken idea of money can take place only through the ex- saving. There is need for further eduposed painted surfaces, and the paint national work to encourage better coating tends to keep the moisture practice. content high and thus favors decay. On the other hand, someone is be lt would frequently help matters if easibnaliy found trying to use paint some/ of the concealed ^ surfaces sub* f o gave a non-durable wood employed ject to contact with rain water were in a place Where conditions make de parted'during erection, but end-graih cay almost a certainty. This is un wood is difficult to paint, and the la- fortunate from the standpoint of both bor /factor must always be taken into fhe paint manufacturer and the cOuaecount, Ttcpainting of such-places is: servatibnist, because when disaster | , usually impossible, it.Would probably results the disappointed user is likely be found more practical to improve to discount the value of paint as a the methods of construction in such a protection for wood, forgetting that way as to avoid crevices and pockets when employed in its proper held as likely to retain rain water and, where a protection against weathering it is they cannot be avoided altogether, to remarkably effective and adds very try to provide for quick re-evapora- materially to the service life of lumber, tion. FLB 000780 i'nr Woodworkers and Timbermen dmhAtim t2u ( 9ow protective Q Ilf c^Coisture (Changes in By .F. L. B X q O WRITES a promi moisture takes place between nent chemist, giving "The structure of wood is largely fibrous. Free wood and the air with which it concrete expression to water or moisture in the wood is probably located is in contact unless the wood a widespread popular between the fibers. This water forces the happens to have that particular misconception of the relation between change in moisture t ontent and swelling or shrink ing of wood. Persons holding fibers apart. As the water dries out, the fibers come closer together, producing contraction (shrinking) moisture content which is in equilibrium with the prevail ing humidity and temperature of the air. In general the hu that theory usually think of midity and air temperature wood as a "porous" material, much like a sponge, with constantly are changing, however, and the moisture con the water moving in and out through the cavities. If tent of the wood tries to keep in step. For that reason the "pores" of dry wood are filled with some such sub wood in service is usually subject to a certain amount of stance as paraffin or linseed oil, they believe that moisture variation in moisture content from time to time and hence movement and consequently swelling or shrinking can be "works." Fortunately the "working" is small enough so completely prevented. that it proves troublesome only in special uses of wood So deeply rooted is this ancient craftsman's tradition where the dimensions must be held constant to a high that a mere technical man criticises it with a good deal or degree of precision. diffidence. Yet it is dearly in contradiction to easily The way to stop the shrinking and swelling of wood demonstrable facts of everyday experience, and it proves is to interpose between the wood and the air a continuous misleading when practical means for minimizing the swell film of impermeable substance. Filling the wood cavities ing and shrinking of wood are being sought. For. the with oil or wax will not suffice if the wood substance it truth is that the moisture responsible for the "working" self is still in contact with.air, because hygroscopic mois of wood is not at all the free water held in cavities visible ture can move through the wood substance and does not under the microscope and that mere plugging of such need to enter through "pores." Protective coatings openings with oils or waxes does not suffice to prevent rather than impregnation treatments should therefore either moisture absorption or swelling of dry wood. prove the best means of retarding moisture changes. Water is held in green wood in two different ways. As Practice in fact confirms that conclusion. Wood which an illustration, let us suppose that we have a board weigh has been thoroughly impregnated with paraffin, but with ing two pounds of which one pound is "bone dry" wood the surfaces wiped clean after treatment, still absorbs and one pound is water. Of that one p.ound of water moisture from damp air only slightly less rapidly than does something like 73 per cent exists as free water partly filling the untreated wood. But if, instead of impregnating, a cavities in the wood which can be made visible by putting substantial coating of paraffin is applied to all surfaces of the wood under a powerful microscope. During the the! wood, moisture is taken up only slowly. Similar re proper kiln drying or air seasoning of the board, the free sults are obtained with oils. Treatments with non-drying moisture is removed without change in its dimensions. oils or mere impregnation with linseed oil are compara At-a certain stage of the drying known as the fiber satura tively ineffective; but as soon as a substantial coating of tion point, the wood cavities are empty of free water, drying oil is obtained, the rate of absorption of moisture but the board still contains perhaps .27 pound of hygro is materially retarded. scopic moisture held, not in "pores," but in intimate The U. S. Forest Products Laboratory for a number of association with the wood substance itself--dissolved in years has been .studying the effectiveness of protective the lignin and cellulose, if you please. coatings in retarding the absorption of hygroscopic mois There is nothing mysterious about the hygroscopic ture fay wood. Their method of testing is as follows: moisture of wood. Other common substances behave Birch test panels are prepared and seasoned in a room at quite similarly. Take bread, for example. Fresh bread 60 per cent relative humidity and 80 degrees Fahrenheit, contains hygroscopic moisture so necessary that we use Some of the panels then are coated on ail surfaces with waxed wrapping paper to conserve it in the loaf. Stale the paints or varnishes being studied. Others are left un- bread or bard toast is more nearly bone dry, is shrunken, coated. The panels are next weighed and placed in a and has different physical properties. But it is readily chamber at 95 to 100 per cent relative humidity and 80 observable that the moisture in a slice of fresh bread is not degrees Fahrenheit for two weeks, after which they are free water in the cavities. Fill the cavities by dipping weighed again. The coated panels absorb less moisture the bread in water and soggy bread is obtained. than the unfcoated ones, the difference being the amount As our board passes the fiber saturation point during of moisture excluded by presence of the coating. This drying, it begins to shrink, and shrinkage continues as difference, divided by the absorption by the uncoated long as hygroscopic moisture is being removed. In com panels, with the quotient expressed in percentage, is a mercial practice it is not usually desirable to remove all measure of the effectiveness of the coating and is defined the moisture, so that "dry" wood still contains a con as its "efficiency," siderable and a variable amount of hygroscopic moisture. The accompanying illustration gives the efficiencies of Such necessarily must be the case, because interchange of several types of protective coatings. The results are at N41698.03 FLB 000781 Yates-American Quality MOISTURE RESISTANCE OF COATINGS '""I-- - ^-- . . " . variance with some other time-honored traditions of the paint trade. Linseed oil, for example, is much less resistant to the passage of moisture than is com monly supposed. A long-oil spar var nish is,much more effective, and a shortoil rubbing varnish is very efficient. To be sure, rubbing varnish is Suitable only for indoor use because it does not last long out of doors. (It should be noted that the data refer to the moisture ex cluding efficiency of the coatings only and tell nothing whatever about their durability.) Evidently the resin com ponent of the varnish rather than the oil is the effective constituent in exclud ing moisture. In line with that conclu sion we find that shellac, the film of which consists entirely of resin and wax, is very efficient. So are asphalt and pitch paints. It is noteworthy also that the gums present in cellulose lacquers are more important in preventing moisture movement than is the nitrocellulose, be cause bronzing liquid, which is nitro cellulose solution alone, is somewhat less efficient than linseed oil. The addition of mineral pigments to clear vehicles adds greatly to the mois ture-excluding efficiency of the coatings. Compare oil paint with linseed oil, enamel with spar varnish, and cellulose enamel with cellulose lacquer. Alumi num powder used as a paint pigment is especially remarkable and gives coatings in several types of vehicle which are more effective than any of the more common paints and varnishes. The reason probably lies in the peculiar property aluminum powder has in the "leafing out" of paint liquids, so that it forms a more or less continuous metallic coating over the wood, much like the scaLes on a fish. When aluminum leaf is glued over the wood, using varnish for the glue, the nearest approach to com plete exclusion of moisture so far dis covered is attained. Government Reports Now Available Gives The Advantages and Uses of End-Matched Soft Wood The Subcommittee of the National Committee on Wood Utilization has prepared a report on the uses and ad vantages of End-Matched Soft Wood Lumber. Readers of this magazine will no doubt be interested to know that this report is now available in pamphlet form to anyone requesting it. The need for conservation in the pre paring of wood products for market is being impressed, more and more every day, upon the general public and espe cially manufacturers. End-matching of soft wood lumber is a great forward step in this direction and the government, in an effort to further this practice, is mak ing exhausting researAes. These re searches cover every possible phase of the practice from the manufacture to the nailing of the end-matched lumber ip the home or office. Upon the committee making these investigations are some of the most prominent men in woodwork ing manufacture, in architecture and in building associations. Their report, now ready for distribu tion, covers a description of the endmatched process, the strength factor of the end-matched joints, the many uses for end-matched lumber, its advantages to the consumer, the distributor and the manufacturer and end-matched Lumber as a" potential export item. This report should be interesting and particularly valuable to every one en gaged in lumber manufacture. It may be obtained from the Superintendent of Documents, Government Printing Of fice, Washington, D. C. The price is five cents per copy. FLB I Construction and Maintenance Kit the manager who looks ahead to"that ideal plant"and the manager on the alert for improvements in presentfaciliti.es 111; How to Prevent Decay When Building of Wood By F. L. BROWNE U, S. FOREST PRODUCTS LABORATORY, MADISON, WISCONSIN LATHERING, in itself, is essary to start a fungus colony, thus Decay, or rot, except in cases of K enough to ruin a structure. exposing the building to its second It is the inevitable result enemy, rot. This whole cycle can be of denying wooden structures adfoeqreusattaelled by the prevention of weath long-continued neglect, is usually the result of unsuitable design of the struc ture. When discovered in wood in protection by faint. ering - that is, by the simple expedient service, it may b.e difficult, if not im It is not sufficient to apply a coat of applying paint to the exposed-and possible, to arrest without making of bnght paint when the structure is readily accessible surfaces and renew serious alterations. It lurks in dark fiist erected In time the paint wears ing the coatings as they wear out. corners, at low, damp levels, and in away until it no longer shields the concealed spaces. The most effective surface of the wood from the rapid steps against decay must be taken dur fluctuaiions in moisture content caused ing or even before the erection of the by atmospheric changes. After that, building. Wood rots only if it is kept general dilapidation is not long in at a moisture content favorable to f. coming First the wood roughens. Then it checks and cracks, white warp ing and c upping set in, and. boards fungus growth for relatively long periods. When subjected merely to alternate wetting' and drying by di begin to pull away from their nail rect exposure to weather conditions in fastening1-. the United States, wood does not The wind takes a. strong hand in usually become moist enough or re the work of destruction, and a way main so long enough to harbor wood- is opened in the once weather-tight rotting fungi, structure loi raiti-water to obtain ac When rot is found in frame con cess to leicsses from which it cannot e.tsdv evaporate. Eventually the ac cumulation of moisture in such a manner ma\ supply the dampness nec END-GRAIN EXPOSURE Though kept painted, this post de cayed because moisture had easy ac cess through the end-grain. struction, some such factors as the following can be found responsible for keeping the wood in contact with moisture for abnormally long periods: ,J IiV i ii'ffir fpit 1M "W"!m > "wir-wiwwtaywgipyw IDEAL CONDITIONS FOR DECAY Uni-Liiit (.o;u 11u; dmvnspoul is causing the decay of this CMwiilen 'ill, which rests on the damp ground. Tile decay is spi ending into tile painted woodwork above. ww**,, DILAPIDATION THROUGH WEATHERING On this siding, where the paint has worn away, checking, splitting, and warping are at work, and boards are be ginning to pull away from their nail fastenings. N41698.04 FLB 000783 1, Stringers or sills are laid directly upon the ground. 2, Although the stringers or sills may be raised a certain distance above the ground, the space between the floor and the ground is enclosed by brick or masonry, without allowing enough opening to provide thorough ventila tion, 3. Although raised above the ground, with ample ventilation pro vided underneath, the sills and joists are supported on wooden piles or posts in contact with the ground. Under these conditions dry-rot fungi may start in the piles and may proceed through the sills and joists into the rest of the structure. Dry-rot fungi possess their own method of conduct ing the water necessary for their activities. 4, Leaky plumbing or downspouts or sweating water pipes keep the wood in contact with water for long periods. This is especially disastrous if the water reaches the wood through con cealed surfaces and, to escape, must pass through the board to evaporate from painted surfaces. 5. Construction is such as to afford crevices into which rain-water can work its way and be retained in por tions of the wood far from surfaces from which evaporation can take place. Window sills and bottom rails of sash, when made of sap-WQpd, occasionally rot. Posts or columns of non-durable woods or containing much sap-wood are quite likely to decay because the water working its way underneath is drawn up very readily from end-grain surfaces, 6. The building is used for manu facturing purposes of such a nature that the air within is saturated with moisture all or most of the time. Near the roof and outside walls, where con densation may result through cooling by outside temperatures, decay is especially likely to be encountered. Protective measures against decay in wooden structures, in the order of their desirability, include: 1. Avoiding the use of wood as far as possible in places where it may be exposed to moisture continuously or for fairly long periods. 2. Providing ample ventilation in air spaces enclosed by wooden walls in which the air would otherwise be damp and stagnant. 3. Designing all joints and junctions between wooden pieces in such a way that there will be no possibility of rain water working into crevices and being "pocketed," especially where water will come into contact with end-grain wood. 4. Selecting only the heart-wood of durable species ior use in cases where provisions i, 2, and 3 Cannot be met, 5. Preserving the wood against decay by treatment, preferably by impregnation, with a material poison ous to fungi, such as coal-tar creosote, zinc chloride, or sodium fluoride. From the practical point of view, paint and varnish cannot be considered preservatives for wood against decay.* In the first place, it is not customary and Would generally be impracticable to keep paint on the hidden surfaces of wood likely to be continuously in contact with ground moisture or seep age, In the second place, such coat ings merely retard the absorption of moisture and do not prevent it' so that wood, even though painted, if ex posed constantly to dampness, will be come moist enough to decay. In the third place, assuming that a coat of paint is an absolute safeguard against fungus infection (which experiments seem to show is not the case), wood during its long journey from forest to sawmill, to lumber-yard, and finally in to construction, has been exposed to infection so constantly that spores are bound to be present on all surfaces, and decay is a certainty once conditions be come favorable to fungus development. *Wbat About "Save the Surface and Yon Save All"? So general has been the acceptance of the role of paint and varnish in prevent ing the deterioration of wood, as well as of other surfaces, that Dr. Browne's dis tinction between weathering and decay and his statement as to the limitations of paint in preventing the latter, may come as a surprise to many readers of F1 _ Xy . Dr. H. A. Gardner, Director of the In stitute of Paint and Varnish Research, takes the position that "to the average reader the word decay connotes the pass ing of a material from a sound or perfect state to weakness or dissolution--the roughening and the raising- of the 'grain, the checking of the surface, the splinter ing, and other obvious signs of decay in lumber; the corrosion of metal; the dis integration of the surface of cement; and similar defects. It is generally admitted that paint will prevent these defects and therefore it is called a preservative agent or an agent against decay. Therefore the slogan `Save the Surface and You . Save All.' " In that phase of "decay" which Dr. Browne terms "weathering," he gives paint full credit. His article does not by any means belittle the supreme impor tance of paint as a protective agent in its rightful place. ft does point out that with Wooden structures, the correct form of construc tion and protection against moisture should accompany any sound program of preservation by paint. THE EDITORS S' >YlrH)j^ 0i4 J/d it SijUs /;?2{lxJ2A>vh^ 'M4cl^J($2'J P Wood Finishing--A Glance Ahead Wood Finishing as an Art, a Science, and a Branch of Engineering--Technical Knowledge of Wood the Foundation of Wood-Finishing Engineering--Need for Methods of Measuring Service Value of Finishes s By F. L. BROWNER MADISON, WIS. ROM time immemorial the prophet has been granted a cer Ftain license in speculation, a certain freedom from the con straint of hard-and-fast detail, in order that the essential the lines of future progress in wood finishing as an art. It is desirable, however, to emphasize the fact that the artistic con sideration is a vital part of the wood-finishing problem, and that accuracy of his general forecast may not be too greatly obscurwedhile it is likely to be affected by changes in technology, the engi i- by petty discrepancies in particulars. Sufficient if the seer can neer as such is not competent to advise upon it. The special predict the victor in the battle without setting forth in full the talents of the artist, not always combined with those of the engineer ebb and flow of the action; or, to change the simile, if he can fore or chemist, are required. tell the direction of movement of the market during the nest There are those who feel that the art of wood finishing has been month without specifying, say, for the top quotation on Steel even more seriously neglected than its technology, and that the Common. In assuming the robe of soothsayer with respect to tendency in recent years has been away from rather than in the the future of wood finishing, then, the author bespeaks the tra direction of a better balance between these two aspects of the sub ditional indulgence with regard to specific details in the hope that ject. At least two factors probably have tended to discourage a consideration of general principles will be of interest and value artistic originality in wood finishing--the dominance of manu at this time when wood-finishing practices are being subjected to facturing considerations over esthetic values, and the craftsman's critical scrutiny. monopoly of finishing knowledge. That wood-finishing methods are undergoing something of a The first factor is well illustrated by the prevalence of very dark revolution at the present time is obvious enough. The spray gun shades in walnut and mahogany furniture, dictated in all proba displaced the brush only a few years ago, and nitrocellulose lacquers bility by the circumstance that it is easier to disguise birch and gum i . challenged the supremacy of oleoresinous varnishes still more in combination with the more expensive woods when such finishes recently. Other new materials are being developed and still are employed than when using the more attractive lighter shades. more radical changes in methods of application are likely to appear. When fashion swung to the other extreme during the recent vogue But even more significant of the movement now under way is the of French walnut, the attempt to use the darker-colored wood fact that the A.S.M.E., in giving a special place on the program by bleaching led to a good deal of trouble and produced some to the subject of wood finishing, recognizes that the time has come finishes that left a good deal to be desired from the point of view when certain phases of it, at least, must be placed under the charge of beauty. of men having the specialized technical training of the engineer The importance of the second factor tending to discourage Ill rather than be entrusted entirely to the craftsman. artistic originality in wood finishing is manifest. Since the crafts However, ip our enthusiasm to apply our technical knowledge man is concerned primarily with the routine of production, he to the solution of the Wood-finishing problem we may make the naturally tends toward standardizing his work with as few materials serious, blunder of thinking it a technical problem exclusively. and operations as possible, and opposing the introduction of new It will be well to keep in mind that the technical aspect, though effects and new technic. For obvious reasons he is likely to take undoubtedly of primary importance, may prove in the long run sides with the engineer against the designer in the conflict between to be more easily dealt with than other features. In fact, there convenient production and artistic expression. When he alone are a goodly number of executives in the woodworking industries possesses the knowledge of what can be done in the way of finishing who would maintain that the problem is wholly one of foreman and how to do it, as has been the ease all too frequently in the training, and that if one could find a satisfactory substitute for woodworking industries, the designer's efforts are very narrowly the old apprenticeship system, capable of providing craftsmen circumscribed. It is much like asking an artist to paint with three as competent as the good-old-timers are reputed to have been, or four prepared paints of unknown composition which he is for there would be no need of calling in the aid of the technical man bidden to mix or alter in any way, A talented artist no doubt at all. So, before going to the other extreme, we should consider could produce an excellent picture, but he will probably turn to a carefully how much of the burden of his finishing difficulties we more, flexible vehicle for expression. Similarly, higher standards dare premise to take from the executive's shoulders. of beauty in wood finishing are not likely to be achieved until the " HWoon F0 q 0 AQ0 q13 1 q 7 designer is freed from thraldom to the craftsman. To produce that result the technical man will have to devise adequate means of Wood finishing is at once an art, a craft, and a branch of engi measuring the adaptability of the available materials and de neering. It will always require skilled workmanship, esthetic scribing the results with different procedures. The choosing of IIf appreciation, and technical knowledge. In the easy-going times when small manufacturing establishments were the order of the proper finishing operations and the selection of necessary materials is then properly as much a,` part of design as the specifications day, it was possible for the craftsman to assume the entire re for the woods and dimensions of the various parts. sponsibility; but as the woodworking industries became more There are, as a matter of fast, signs of a rebellion against medi complex and more highly specialized the traditional policy of ocrity in wood finishes. As the lumber associations improve their leaving it all to the finisher has been productive of more and more merchandising methods they are emphasizing the finishing possi worry for the executive, until at the present time in many lines bilities of their woods. The mahogany and walnut interests urge the finishing room probably gives rise to more exasperating diffi shades that bring out the beauty of their woods more clearly, the culties than any other division of the operations. In looking groups interested in maple are centering their advertising upon for ways of improving the situation it is important to keep in the new light brown and gray finishes for it, the gum producers mind that the problem has three sides, and that new develop would like to popularize distinctive finishes, and even some of the ments on the technical side have an important bearing on the softwood interests are devoting much attention to the develop other two. ment of appropriate finishes. Now that the radio is competing This is neither the place nor is the author the one to discuss with the automobile for the attention of the public, it seems rea 1 Chemist, U- S. Forest Products Laboratory. Contributed by the Wood Industries Division for presentation at the Annual Meeting, New York, December 6 to 9, 1926, of TQ A+ 0 _ 1 q Socisrr X~ M E _ Q1 q 0 _ 1 q3 0 q . All papers are subject to revision. sonable to suppose that people will again be at home enough to heed the broadcast clamor of the lumbermen and demand beauty in the finish of their furniture and woodwork even as they do in their cars ! 1286 N41698.05 FLB MlD-NOVEMBfiJJ, 1926 MECHANICAL ENGINEERING 1285 There will alwayS\be at large scattered fue^xiemand, which, can be wet best by solid njeJL s It would not be advisablqto attemntdo carbonise 500,000,000 tons of soft coal until the couiba^was prepared to absorb the by products. This question seems 3>tind up with the problem of automotive-fuel supply, and tj/gtwo msiyQje worked out together to a happy solution. One of the best features about carbonized fueNis that it would automatically solve the part of our smoke problem'that is most difficult oif control---the human element. Providing a foolproof fuel that could be\hoveled helter-sheltar into any kind of a fire pot without any precaution, would remove the last barrier to a realization of our dream of smjdkeless cities. None of these things aregqmgto come overnight. At the proper time, depending on ecoaomic^anditions, the fuel interests and tech nologists will meet the s)tuauon\In the meantime we should not. relax our efforts along present linevas it is by these efforts that the field will be prepared fpr more radie&k measures. FLB 000786 IVL_ -NX +<< , 1926 r< MECHANICAL ENGINEERING `"'T ,~ 1287 WXX F C0 q 0 Q0 q13 1 1 ~t The wood-finishing craftsman has been traditionally jealous of the intrusion of the uninitiated, especially the engineer and chemist, into his secrets, and the technical man in return has continually increased the complexity of the subject by perforce introducing new materials, new methods of application, and even new woods, each departure from the good old-fashioned way bringing with it a whole new set of special precautions to be learned if disaster is to be avoided. Unfortunately, that rivalry has resulted in placing altogether top much emphasis upon cook-book formulas of magic concoctions. Both craftsman and chemist have Wasted too much time in the vain search for a philosopher's stone of wood finishing. As a matter of fact, to obtain a given effect there are usually a dozen different methods, any one of which will give excellent results if skilfully applied, but no one of which will produce a really first-class job unless handled with skill and good judgment. The craftsman's place in wood finishing is assured not by the secret formulas which he thinks he possesses but by his mastery of the materials with which he works. Technical progress has a Way of making more rather than less demand upon his ability. It is more difficult to apply smooth, uniform coats by means of the spray gun than with the brush, and the care and operation of the new tool are more intricate. Nitrocellulose lacquers are even more capricious than varnish, and require closer attention to avoid getting into trouble. Not only are the newer materials and methods increasingly complex, but their very multitude in itself adds to the craftsman's burden by making it necessary for him to familiarize himself with the peculiarities of many different products. A generation ago the finisher needed to understand the use of a few dozen materials, whereas today he must be able to handle several score. While the demands upon the craftsman have been growing more exacting, social forces too familiar to need mention here have combined to make it more difficult for industry to obtain skilful wood finishers in sufficient numbers. Much attention has been paid to the problem of finding a satisfactory substitute for the obsolete apprenticeship system, but thus far without much success.' There seems to be a* tendency for the woodworking industries to look for help from outside--from the schools or even from governmental bureaus--but it seems to the author that the problem is such a Vital one to industry that its solution must be sought from within. Even with the excellent training in engi neering subjects now furnished by the universities, some industries find it worth while to provide their own special schools for graduates entering their employ. But whatever the answer to this question may be, it is sufficient for present purposes to recognize that the training of craftsmen is a major portion of the wood-finishing problem which is not likely to be solved by developments of a purely technical nature but on the contrary may be rendered more acute. WXX F0 q 0 B EQ0 q13 1 1 q _ Q X~ q3 0 q 0 q3 Although the engineer is not the only expert whose special talents will be required to solve the wood-finishing problem, there can be no question that he must be called upon for an exceedingly im portant contribution. It so happens that the technical man whose attention, is drawn to wood finishing is very likely to approach the subject from the direction of the paint and varnish industries rather than from the side of the woodworker, and therefore to look upon wood finishing as a branch of paint science. The reason is not far to seek. Wood-finishing materials are commonly regarded as "chem icals" requiring the special knowledge of the chemist to understand them; the chemist, although sometimes thus enlisted in the paint and varnish industries, is practically unknown in woodworking. As there are plenty of unsolved problems in the chemistry of paint and varnish to keep the technical men of that industry too busy to learn about Wood, the development of such technical knowl edge of wood finishing as now exists has been decidedly one-sided. As a matter of fact, wood-finishing engineering should have its foundation in wood science rather than in paint science. Compli cated and imperfectly understood as our finishing materials are, the Wood is still more complex and even less understood. Troubles in wood finishing probably arise far more often as a result of the peculiarities of wood than of those of the finishing materials. The characteristics of wood can be controlled only within very narrow Emits, and as timber supplies become less abundant it is more difficult to choose woods for their ease of finishing alone. The finishing materials, on the other hand, are nearly all manufactured products or could be replaced by manufactured products, and therefore can be altered more nearly at will to suit conditions imposed by the wood. The ideal in wood finishing, therefore, is most likely to be achieved when we start with a thorough knowl edge of wood properties and select materials and methods in con formity with them rather than by trying to modify wood properties to suit finishing methods. ' If wood science is the foundation of wood-finishing engineering, then the latter is surely in its infancy, for our technical knowledge of wood is woefully inadequate. Long accustomed to dealing with wood, the average man does not realize how little is really known about it. Incorrect explanations of common observations And even statements of "facts" that are "not so" are accepted without question by engineers and chemists as well as by laymen. Haw ley2 has exposed a group of such fallacies. His list is representa tive, not exhaustive. Even such an. apparently simple question as "how does moisture escape from a piece of wood during drying?" cannot be answered satisfactorily at the present time.3 The obviously incorrect statement that the shrinkage of wood during drying is due to the removal of free water from the "pores" of the wood appears in print with discouraging regularity. Until we are in a frame of mind to answer such questions less glibly and more thoughtfully, it will be inopportune to try to explain such interesting facts of wood finishing as: 1 The effectiveness of shellac as an undercoat in comparison with other spirit varnishes, oil varnishes, and laequeis. 2 The difference in. the amount of dyestuff requited to stain wood a given color with a water or alcohol stainand with an oil stain. 3 The lighter color given to the suinmerwood of a softwood as compared with the springwood when using an oil stain, despite the apparently deeper penetration into the summerwood. 4 The property of a wood which the finisher calls "suction" and the paint technologist calls "absorption," and which seems to bear no relation to the ease with whieh the wood can be impreg nated with chemicals. 5 The ease with which some oils and resins in woods work their way through paint and varnish coatings, apparently without rupturing them. Q The development of such exasperating finislung-room troubles as varnish "shrinkage," "pinholing," and "blooming." 7 The apparent development of a third dimension or "depth" in a wood surface when shellacked, varnished, or lacquered. Spectacular developments sueh as the widespread adoption of laequer during the last few years are likely to mislead us into thinking that the important technical advances in wood finishing are to be sought in radically new materials and new methods. Undoubtedly many valuable nqw inventions will be made as the subject of wood finishing receives more adequate technical study, but it is the author's belief that even more profitable results can be expected from the better utilization of existing methods and materials which will result from, a painstaking study of the funda mentals. Already there-, is a vast accumulation of empirical knowledge, much of it rendered mysterious by an overgrowth of fanciful theory. If the information is subjected to the cold scrutiny of systematic research and every theory examined with a vigorous skepticism, it should be possible to separate facts from fancies and to organize a body of knowledge that will form the real basis of a wood-finishing engineering. One of the first problems for the future in wood-finishing engi neering is the development of tests for measuring results. This is practically a virgin field, because heretofore very little has been accomplished except to finish sample panels and pass judgment upon them by visual inspection. For example, such a property of a varnished surface as "depth" should be susceptible of mea surement by a suitable instrument. The trained eye of the ex- z Seventeen Fallacies about Wood, News Edition of Industrial and Engineering Chemistry, vol. 3, no. 15, Aug. 10, 192$, p. 5. 3 See The Movement of Moisture with Reference to Timber Seasoning, (British) Forest Products Research Technical Paper No. 1. 1288 MECHANICAL ENGINEERING . VX . 48, No. 11a perienced finisher seems to be very sensitive to it, but a mechanical "eye" of some kind is essential for a technical study of the property. With proper tools at his command for measuring this and every other significant factor, the engineer would be in a position, to determine precisely how much each step and each variation con tributes to or detracts from the finishing process as a whole. The need of adequate tests for evaluating finishes will probably be felt most keenly in its relation to the selection of finishing materials. Every purchaser of such products has realized the difficulty in choosing intelligently among the many brands offered to him. Usually price and the reputation of the manufacturer are taken as the only available index of quality, and the most common method of testing is the hazardous one of using a trial shipment. Attempts to adopt other test methods as the basis of selection have been made often enough but have usually proved abortive. Trying to borrow the test methods of the chemists of the paint and varnish industries is the most common reason for the failure of the woodworker's efforts to test materials. The varnish chemist, for example, finds a viscosity test very useful as a routine method of control of the uniformity of successive batches of the same varnish; but it does not follow that the viscosity test alone will tell the purchaser which one of several varnishes is most suitable for his use. Again, there is a natural tendency toward the as sumption that a chemical analysis of a material gives all necessary information about it. But when the consumer tries to purchasefinishing materials on the basis of a chemical analysis he finds himself at once at loggerheads with the makers on the ground that he is attempting an unwarranted intrusion into their trade secretsWhether the varnish-makers' argument is valid or not, the wood worker will usually find that knowing the formula of a material will not help him much in determining what it will do. Manufacturers of wood-finishing materials in the past have not found it necessary to devise methods of measuring the servicevalue of their products, and they are not likely to spend much time in that direction unless the woodworkers themselves lead the way. The author recalls the experience of one large factory which was greatly troubled with varnish printing during shipment of their furniture. 1110 problem was turned over to an engineer who- soon devised a test requiring no more elaborate apparatus than some wood panels, some kraft paper, a few weights, and a comer of the factory cellar where temperature and humidity remained constant. When purchases of varnish were made in accordancewith the findings of this test the printing troubles were eliminated. It is true that much more time and ingenuity will be required to work out practicable testing systems covering all the require ments of many finishing materials, but where a serious effort is made to do so it is likely to be generously rewarded. / FLB 000788 ioV/Hmctuj PAINTING and FINISHING To protect from the weather, to please the eye,to ,, reflection-whatever the use,paints and finishes for Eoth product and plant must fee wisely selected and properly applied Why Wooden Buildings Need Paint Protection By F. L. BROWN, Ph. D, FOREST PRODUCTS LABORATORY, MADISON, WISCONSIN " "'>(OOD paint costs nothing," says an old Dutch proverb, V_M expressing epigrammaticalLy the wide-spread belief that savings re sult from painting which, exceed in value the expense of applying it. It is not the present purpose to examine that statement from the accountant's point of view as it applies to wooden buildings. It will be worth while, how ever, to call attention to some of the ways in which paint maintenance is indispensable to the really satisfactory service of exposed woodwork. The first manifestation of weathering in wood exposed without paint protec tion is "grain-raising." The smoothly planed surface, essential to the archi tectural effect for which wood house siding, trim, and window-frames are usually employed, becomes rough and corrugated. In the softwoods such as the pines, cedars, firs, hemlocks, and spruces, the summerwood {the darkercolored part of the wood which deline ates the "grain") becomes raised up in WHAT WEATHER DOES Bran siding that lias seen nearly 70 years of service. Most of the dam age is done in the first few years. relief above the surrounding springwood. In the hardwoods like poplar, basswood, gum, and cottonwood the relief pattern is not so systematic-in stead, individual wood fibers thrust out from the surface, making it "fuzzy," The cause of grain-raising can be demonstrated very easily. It is merely necessary to wet the surface of a board and let it dry out again, simulating the action of rain and sun. One such treatment roughens the surface sensi bly and repetition intensifies the effect. The'probable explanation is that some parts of a piece of wood swell more than others when wet. The summerwood, of the conifers especially, which may he much more dense than the springwood, probably swells more. In ternal stresses are therefore set up in the wood as it takes up moisture, and distortion of the wood structure takes place. On drying back to the original moisture content the former shape is not resumed exactly because of a per manent "set." This characteristic of i i f AN OUTDOOR LABORATORY FOR TESTING DURABILITY Various kinds of wood, painted and unpainted, are exposed to die weather under .similar conditions on this test fence of the Government Forest Products Labora tory at Madison. The effects of weathering can he accurately determined. for OCTOBER. 1927 ONE COAT IS NOT ENOUGH One coat of blade paint produced the desired appearance, but did not pre vent capping of the board. 655 N41698.06 FLB oK acquiring permanent set readilYls well known, being turned to practical ad vantage in steam bending. / Some softwoods may develop "loose grain" as well as raised grain. One edge of the summerwood band comes loose from the neighboring springwood and curls up, leaving a projecting knife-edge of thin wood to splinter and present a jagged surface, dangerous to handle. The edge of the summerwood band whiph comes loose is always the one marking the end of one year's growdr of the tree from which the board came. The difficulty is much mofe serious on "flat-grain" (plain sawed) than on "edge-grain" (quarter 4awed) boards. Practical lumbermen say that the development of loose grain on weathering is prevented by turning the board so that the side exposed is the one that was nearest the bark of the log from which it was cut, A few experiments at the Forest Products Laboratory are inclined to confirm that statement. The next stage in the weathering of most woods is surface checking. Us- Painting the plant interior; has meant a7time of delays and inconvenience. .Often v^no'fe departments were held up- production at a standsfi11--vunti1 naihters were through. Now the DeVilbiss Sp/ay-painting/System enables you to paint without any of this. / One man with a DeVilbiss spipy gun works five times as fast as a brush painter. He is/spon finished and out of the way. He requires less scaffolding. He leaves no drips nor spatters to clean up. And the speed of this painting oper ation saves 80% ,6f your/labor cost. But convenience an& the 80,% labor saving are but part of what you gain by painting tpe DeVilbiss way. The DeVilbiss sprayed-coat is smoother of surface add more evert of, thickness. It reaches every comer and crevice. It hgs twice the hiding power of a brushed coat. You will find it interesting and profitable no know more about these and other advantage/ that modern factories are gaining from paint ing with the DeVilbiss System. A wordVfrom you will promptly bring additional facts. Address-- \ THE DeVIL^ISS CO., 250 Phillips Avd^ TOLEDO, OHIO N*wyYffrkIt --FPbh3il>adetlph]uia ---ChicBgo---Detroit --Indianapoli*--San Frnaoncisicco Piitaltur*fc - Hreiaad --Cincinnati -Milwaukee -- Misnwpolit --S< Loois --- Windsor, Octlario / Yourmanufactured product can be finishedbetter and at lower cost with DeVilbiss spray-finishing equipment. Let us mail you further particulars. \IW\V PAINT PROTECTS One rear's weathering raised the grain and corrugated the 'unpainted board (right) .\ The same Wood painted shows only brush marks. -tl- jer, tem WEATHER CHECKS Deft, a test panel after a few weeks' exposure. Right, the same spot (iden tified by cross) after one year. The . cracks run deep.- \ 656 FACTORY, the MAGAZINE oj MANAGEMENT, FLB ualiy the checks are So small at first ' outer portion have finally become great that it requires careful searching to enough to bend or twist the whole find them, but as time goes on they board. Of course thin boards cup Wliy Wooden Buildings Need Pain l Protection become conspicuous jygjjg^^Tbey ( sooner than thick boards of the same may eventually beeonl|f*ibqjie cracks j kind of wood, and there is much varia (Continued from pi,je MO) running all the Way through the boards. tion between woods in the tendency the roofs and walls uf lr inn- bondings As Would be expected, checks are likely ij toward cupping. breaks down their fire resistance and to be most serious near the ends of The "working" of the wood with increases the fue h irard. boards, and, where boards are rather fluctuating weather conditions tends The rough surf a 0/4 0r, a hi short -as may sometimes be true of1 to pull nails loose. They may actu ment for firebrand.' mil >m tin are siding between two adjacent windows - ! such end checks may split an ocea-1 sional board in two. j Checking results from the continued * ally be withdrawn much as though the board were operating as the claw of a hammer. Fastenings may also come loose because nail holes tend to be a chance to tali li ilrl ( upped .>nd warped bo irtls offer two sides instead of one to the combined attack of heat and advancing flames, ami li i- J.i >vn*'d operation of the same forces responsi- , come centers for the development of wall surface, instead of deflecting the ble for grain-raising.. It can be pro- deep cracks, especially when the nails hot draft rising from tl hit {i,n,ii are near the ends of the board. it in a measure to use ti i ,[>ue lie Prolonged weathering results in the tween siding and sheathing as a flue slow wearing away of the wood at the to encourage combustion. surface. For example, old signs with Decay due to the attack .u u n painted letters on an unpainted back is not a normal hazard of the wooden ground are occasionally found with building, as has been pointed out in the wood under the letters in relief F1 _ Xpy for May, 1026 (page 882). through the wearing away of the back However, weathering and neglect may ground. occasionally open the way to decay by permitting an ess of rain-water Does Wood Ever Last without Paiut Protection? through loosened siding to interior parts of tb structure whence it cannot readily escape. LOOSE GRAIN The weathering of unprotected wood The whole series of events taking proceeds rapidly in its early stages. place in exposed Woodwork and its A short exposure of 'unprotected wood raises the grain beyond repair. Flat grain (center) suffers more than end grain (below). Within a few weeks the grain raises and checking begins. By the end of a year the surface may be badly serious consequences can be pievented completely by adequate paint main tenance if the building has been prop duced artificially bypepeatedly wetting roughened and checked, and cupping the surface of a board and drying it out again rapidly. When it is consid- i ered that superficially wood absorbs j may have started. The original yel low or brown color of the wood changes to gray, which with some woods may water rather easily, while moisture moves very slowly through the deeper layers, it is evident that such alternate wetting and drying of the surface causes an outer layer of the board to be drab but with others may have a pleasing silvery sheen. The further progress of weathering, however, is very slow, at least if the lumber is of substantial thickness, say S/8-inch or more. "work'' against the relatively constant . interior. The internal stresses introi duce a cumulative "compression set" j in the surface layer of the wood - that I is, the outer layer of the board tends Even granting that well-built wood en structures might be maintained without the use off paint until they be come obsolete, there are serious practi I to shrink continuously in the direction cal objections to leaving them un- of the width of the board. Such stress painted. Moreover, once a building es are usually relieved, in part at least, has become badly weathered it can be by checking. properly painted only at comparatively Woods differ greatly in the extent of; great expense, if at all. Again, the checking when exposed to weather. / shaggy, splintery surface of weathered erly designed and constructed. Coated wood absorbs moisture or dries out so much more slowly than bare wood that .inequalities of moisture content do not develop within the boards, and in con sequence the wood near the surface does not struggle against that in the interior until it tears itself to pieces. By means of paint, siding can be kept smooth, flat, and snugly fastened, giv ing a tight wail effective against wind and rain, resistant to the spread of fire, add amenable to decorative treatment,, It Is Dangerous to Neglect Painting The early stages of weathering, grain-raising, checking, and cupping, can be inhibited only by the use of Some woods develop few checks even ; on prolonged weathering. Others check quickly. Flat-grain boards of any wood, which suffer more severely from loose grain, also weather-check more seriously than edge-grain boards. The greater swelling and shrinking of wood I in the tangential than in the radial di wood is undesirable on those parts of a structure likely to be touched with the hands. In the second place, weathering, by cupping the siding and tearing it away from fastenings, loosens the structure until it affords less satisfactory shelter against the elements. paint or other protective coating. Once the paint is seriously neglected, an im portant part of the original value of the lumber is permanently lost. ' Furthermore, the attempt to main tain without painting is also dangerous because of the related temptation to keep putting off necessary repairs. The rection would lead ns to predict as Then again, new or painted wood, act of painting involves a minute sur much. j in pieces of substantial. size or in tight vey of the structure, p>- udically re As weathering continues and a thick er layer of wood becomes affected, nip ping or warping of the board begins. The internal stresses in the weathered walls, does not take lire readily. It burns slowly, and usually will not con tinue to burn unless the fire has ob tained some headway in the building. Weathering of peated, at a time whf the owner is prepared to take act' .1. Paint there fore has an "insgrv.lon value" which should not be oyf Rooked. RY, the MAGAZINE of MANAGEMENT, TORY, the MAG|; INE of MANAGEMENT, jpKY, the MAGAZINE of MANAGEMENT, Hf FLB V" / y' e Yoiir lirimciples for or&'U. . {(} Testing Paint 1m fj;Vi on Wooc^ As Protection Against Weathering 1 IN spite of the fact. that protection of The tests included exposure orwood the wood is universally considered as panels coated similarly on all surfaces to one of tire primary reasons for painting (1) 60 per cent, relative humidity for 2 exterior woodwork, no serious effort has weeks; (2) 95 to 100 per cent relativeh heretofore been made to determine experi humidity for 2 weeks; (3) 60 per cent mentally how long coatings of paint con relative humidity again for 2 weeks; (4) tinue to protect wood against deterioration, outdoor exposure facing south for 6 according to F. L. Browiie, chemist in weeks. The last stqp secures the actual the Forest Service, United States Depart weathering, while the second step provides ment of Agriculture. the means for measuring the absorption^f relied; tresspasser- and losses! premises.It! Link Fence hundreds o throughout Easily insta maintained, Fence gives; , The sturdy mesh illusti ior its long Unpainted softwood, exposed for one year, shows a "washboard" effect from swelling and shrinkage. The smoother surface (the irregularities arc brush marks), an a similar board, was given three coats of paint and the same exposure. Mr. Browne recently analyzed the re sults of a series of tests on the durability of paint coatings, some of which have been under way as long .as six years. A. more convenient and rapid technic embodying the principles determined in these tests is now being developed in the laboratory. Paint coatings protect wood against weathering by retarding the exchange of moisture between-; die. wood and air. Their durability as protective coatings can be measured by observing their effectiveness in retarding the absorption of moisture from saturated air by painted wood panels. The time when a paint coating first begins to chalk, or to expose the wood through cracking, is not always an indication that the paint is no longer effective. water as a result. Steps 1 and 3 merely return the specimens to a standard mois ture content before their reexposure to the conditions of the other two parts of the cycle- By weighing the panels before and after exposure to the 95 to 100 .per cent, humidity, the amount of moisture ab sorbed could be determined. Previous tests, says Mr. Browne, have been prone to ignore such evidence of wood weathering as wood checks, loose grain, cupping, warping, and loosening of nail fastenings, on the ground that they are "wood defects" rather than "paint de fects." As a matter of fact-,, defective paint may often be responsible for bring ing about, in some .measure, what are thought to be defects in the wood. lelving in Wood [Shelving tisn't any ct to the oor busire-instal- rugged h bakedftructure storage ---b .-r - - . __ experi enced layout engineer to assist you in your storage problems. Send for the book ^Saving with Shelving." Nowisagood time toinvemgatethebenefits ofthisorm.oiptcprrtymsdrance.Leiusshow youhow economical,dependableAmeri can Chain Link Femre can cut down plant maintenance costs {or you--hov/it can giv<t you security tharno other protection offers. AletteraddreSE^atoourChicagoOfficewill ,, bringiullinSorrmrion. Noobligation loyou. ^ '1 + 0 _ 1 q 0 ~ q _ _ X+ 1 q 7 South Dca^omStreet - Chicago, Illinois Factory: Ubertyville, RL MERICAN CHAIN LINK ufacturersofSuperiorWireFence forover25 years TQ G q 1 F0 XX~0 q 3 GX . - Youngstown, Ohio Canadian Plant: Toronto 1 Brancht&and .dealers in.altprincipal cities GFAllstoelLine: Safes Filing Cabinets - * Sectioned Cases Desks Tabiesl . ^Shelving Transfer Gases Storage Cabinets Document Files Supplies]? easier'With SHELVING --~ Attach tills coupon to . Rwn ~ ~~ ''A," THE GENERAL FIREPROOFING CO., Yeancsloem, Ohio Please have an experienced layout engineer rail. 1~1 Please send book "Saving with Shelving." Name_______ i.', . ___ _______ _________ Address .......__________ _______________ ____ ________ ____ ____ ,.__ ________ City---------.................... ....... ................. ;------ -------State -------------- far OCTOBER, 1927 705 FLB IxtjMMx 9k I f > ? i ' \Jo 2i 4ma ^\ . ULkti k] SOME CAUSES Off DEISTEPING AND PEELING Of PAINT ON HOUSE SIDING Revised, March 1933 U*S No. R6 Uq 0 !"1 " ! DEPARfMfeNT X~ 1 3 #0 _ $%$# FOREST SERVICE FOREST PRODUCTS LABORATORY Madison, Wisconsin in Cooperation with the University of Wisconsin N41698.07 FLB 000793 SOME CAUSES OP BLISTERING Mil PMlfe Off PAINT 01 HOUSE SIDING % r. i. mourn Senior Chemi st Introduction Whenever paint coatings on wooden walls of houses fail un reasonably soon, say in less than two years after they have been applied, the failure is almost always due to certain circumstances called, for convenience, 11 abnormal conditions of exposure.11 ffailure under such conditions is not a question of the kind of wood upon which the coating is applied, the quality of the paint, or the craftsmanship of the painter. The staff of the forest Products Laboratory has observed the troubles in question on all of the kinds of wood commonly used for house siding, with paints of all the varieties generally accepted as of first quality as well as with cheap paints, and rarely has there been any possibility that poor, workmanship on the part of the painter was responsible. The fault lies in the abnormal conditions of exposure, and the only certain cure is to search out the abnormal conditions and change them into normal ones. Attempts to overcome difficulties of this kind by using special priming paints, special paints,,special liquids, or unusual amounts of liquids for thinning ordinary paint are, in the writer's opinion, of very doubtful merit, ho sound structure can be reared on a faulty foundation. The most common form of paint failure under abnormal con ditions of exposure is that known as blistering and peeling. The failure, however, sometimes appears in other forms that at first glance do not seem at all related to paint blistering, such as paint scaling, &X'7 kinds of discoloration of coatings, and blue stain in the wood beneath the coating. Sometimes blistering and peeling occur along with the other defects. All such troubles with painted wood may well be discussed together because of their common origin. & Present information about the effects of abnormal oonditions of exposure upon paint coatings is basgd chiefly upon |p I" f ''ll'' ,ji j R6 .'I :.i!H FLB 000794 examinations of ocoupied buildings which have given trouble. The staff of the Forest Products laboratory has been called as consultants in such cases for many years. In addition a limited amount of laboratory experimentation lias been done with miniature "houses" warmed and humidiiied inside and set out of doors during cold weather. Many, characteristic paint defects have thus been reproduced under partially controlled conditions. Much more study will be needed before the mechanism of paint blistering and the allied defects are really understood* but the general nature of the practical conditions that commonly give rise to abnormal conditions of exposure is now reasonably well established.A Most cases of paint trouble due to abnormal conditions that have been brought to the attention of the Forest Products Laboratory have been on widely scattered houses whose neighbors experienced no such difficulties. Many of them have been cheaply built houses, but on the other hand many have been relatively expensive houses on which every effort seems to have been expended to build properly. Occasion ally, however, early paint failure caused by abnormal conditions occurs on a large majority of the houses built in some one community under the Supervision of a single organization, either as a speculative building enterprise or as an employee housing plan. Losses .incurred because of abnormal conditions in one large development of this kind are estimated by the construction company at more than a million dollars in 8 years. It is evident, therefore, that our present general knowledge of abnormally early paint failure does not suffice to prevent very large losses because of it and that much more specific information about the building of houses with Certainty that; such trouble will not be experienced is badly needed. i-This mimeograph, emphasizing the'necessity of avoiding the abnormal conditions if trouble from blistering and related defects is to be avoided, was issued first in May 1927, and later summarized in Circular 317 of the Scientific Section, American Paint & Varnish Manufacturers' Association, October 1937,. Since then Otto fi. Ksrtwig of the West Coast Lumbermen's Association has studied more than 1/500 houses on which such difficulties have arisen and has materi ally extended the knowledge of the dot.ail-s of construction in which the fault often lies. His observations, well illustrated by photo graphs, were published in 1929 in Circular Mo. 355 of the Scientific Section, American Paint & Varnish Manufacturers' Association, 2201 Hew York Ave., M,. W., Washington, D. C. E6 -3- FLB 000795 Circumstances that Have Been Observed to Cause Abnormal Conditions of E()X sure In practice, abnormal conditions of exposure almost always involve, as an essentia;! factor, the access of large amounts of moisture to the unpainted sides of the "boards. The conditions are greatly aggravated when the tenperature on the unpainted side is materially higher than that on the painted side, as is"the case on the outside walls of heated "buildings during cold weather. Causes of abnormal exposure conditions that have been observed re peatedly may be classed as follows: Type A.--lain water seeping through leaky joints left by poor car penter work or faulty design. 1, Poor fitting between siding and corner, boards,between siding and casings of doors or Windows, and between siding and drip caps over window and door headers or sills beneath such open ings. 2, Joints in window frames forced open to permit swollen sash to move freely. When the sill and head of the window frame are housed into the jamb, this is an easy way to make the sash move freely, but it leaves an opening to admit water. If the jamb is housed into the sill and head, the joint cannot be forced open in this way. 3. Omission of metal flashing or its in correct installation, -over doors and windows or at the junction between porch, or dormer roof and side wall or chimney. 4. Incorrect junction between shingle side wall ahd water table where the Tipper part of the side wall is shingled and the lower part sided. This junction should either be protected by metal flashing or the shingles lapped over the water table carefully to see that no openings are left through which rain water can gain entrance. 5. Seepage into the joint between porch column and plinth block or porch floor. i' 6. Leaking roof's, gave troughs, or down spouts when so located that the water gains access to the interior of the side walls." - R6 -3- 7. frozen gutters failing to carry off the water from snow melting on the roof and letting it hack up beneath, the shingles to gain access to the interior of the side walls, ' Abnormal exposure conditions of Type A may occur- on either heated or unheated buildings and, with the exception of No. 7, in any climate. However, heating the interior of the building during cold weather tends to aggravate the resulting difficulties with paint coatings. The only sure remedy is to locate the leaky joints and repair them until they are water tight. Type B.--Moisture originating within the building and carried by air circulating within the hollow outside walls. When moisture laden air comes in contact with surfaces at sufficiently lower temperature, water condenses. 1. Attempting to hasten the drying of wet plaster or other building moisture by heating the interior of a building under construction without adequate circulation to carry off the moisture laden air. New buildings should be dried by circu lating fresh air through windows and doors. Marked difference in temperature between interior and exterior permits water to distil from plaster to sheathing and siding through the hollow side walls. By leaving temporary openings at the top and bottom of the air spaces between studding, enough circu lation through the side walls can be insured to prevent such action while the building dries, 2. Designing parts of buildings in such a way that stagnant air spaces are enclosed by wood walls within which the air may become moist and -warmer than the outside air. Porches built beyond the foundation with skirting extending down to the ground and no provision for ventilating the enclosed air space are common causes of trouble. Hollow ornamental walls extending beyond the foundation and hollow columns with leaky joints admitting rain water at the bottom require Ventilation. 3. Lack of ventilation in unused attics. During cold weather water may condense beneath the cold roof and drain.down toward the cornice. If the top course of siding is placed below the frieze board the water is directed between siding and sheathing* Coming directly in contact with the backs of the painted clapboards. FLB 000797 '4. Failure to secure a water-tight "basement. Building in soil that is not adequately drained and using "basement walls and floors that are not waterproofed may result in a damp basement and a circulation of the moist, air through the hollow side walls of the building to condense behind the siding. Plumbing leaks left uncorrected may also produce this result. 5. Activities within the building that humidify the air. The bathrooms and kitchens of duellings tend to show blistering and peeling of paint from their outside walls sooner than other rooms. , Frame "buildings, originally designed as dwellings, when used for purposes like laundering often give rise to severe blistering and.peeling of paint. Horse stables at country clubs when built with hollow frame walls like those of dwell ings instead of the more usual barn, construction, are sources of trouble unless the walls are provided with louvers for ventilation. The channels of circulation for air within the hollow exterior walls of frame buildings are controlling factors in abnormal exposure conditions. The subject has not yet been studied carefully and-much remains to be learned about it. In general the direction of movement of air enclosed in the spce between lath and plaster on one side and sheathing and siding on the other is upward along the warmer side and downward along the colder one. hen the building is being heated dur ing cold weather, the warmer side is the lath and plaster so that the upward air current moves along that side until it meets an obstruction, which may be a plate or a fire stop, where the-air current is deflected and starts downward along the colder sheathing and siding side. This downward current of air is likely to circulate through the joists in the sheathing and building paper (even though waterproof building paper is used) and to pass out between boards of siding. The escape of air between clapboards may be helped or hindered by wind blowing on the outside wall according to the angle at which the wind strikes the wall. In cold weather the temperature at the back of the siding where air is escaping may easily be below the dew point even though the air may have had a low relative humidity when it first entered the holJLow' ^ide-wall .fr<m-the. interior of the building. Thus air chilled from f0 F. begins to deposit its moisture as water or~ice at 32 if the initial relative humidity was 25 percent, at 15 if the initial relative humidity was 11 percent, and at 1G if the initial relative humidity was 5 percent. Since the coldest surfaces in the side wall with - which the circulating air may come in contact Q 6 _5- FLB ' are offered, by the back of the siding and the front of the building paper, these are often the points at which condensation sets in. The amount of the condensation will depend upon the mount of circulation ; and will naturally be greatest near the points in the side wall where the upward current of air is deflected by ar.window frame, plate,, or fire stop so that the air starts its downward course along the sheathing and siding side of the wall. The effects on paint coatings of condensation of moisture behind the siding are commonly found most marked on the parts of the walls corresponding to the points of de flect Ion of the air currents. The fact that the effects of moisture condensation are often most marked near fire stops should not be regarded as an argument against the inclusion of fire stops in frame buildings, fire stops are desirable, often necessary. Their omission in a building in which trouble from moisture condensation was experienced would not necessarily overcome the difficulty, though it might shift the location of its most marked development. Forms of Paint Failure Under Abnormal Conditions Failure under abnormal conditions may appear as blistering, peeling, or scaling, in which the coating is removed bodily from the wood, or'as a discoloration, which mars the appearance of the coating. The discoloration may be due to substances leached from the wood by water, substances carried by water from other places within the structure, or hlue-stain fungi growing in sapwood beneath the paint coating. Blistering. Feeling, and Scaling The characteristic form in which paint coatings fail under abnormal conditions is blistering and peeling or scaling. Blistering always precedes peeling, though the trouble often escapes notice or fails to arouse anxiety until the peeling is well Tinder way. From thfip shape it. is obvious that blisters are due to a fluid pressure beneath the coating forcing it away from the surface.1 When observed soon after their formation, blisters are sometimes found tn be hollow, sometimes filled with Water, but if the blistering conditions continue they always become filled with water. If the wood is of a kind that certains colored substances, soluble in water the water in paint blisters is colored with them. j Sometimes water soluble extracts from- the wood do not become highly colored until they break through the coating and come freely in contact with air. Deposits of such substances over paint blisters i often look like resin exuding from the wood. HS 6- - $::: FLB 000799 The mechanism of the movement of water through wood and the development of pressure behind paint coatings is still obscure, but the following considerations are helpful in gaining an understanding of tho sort of forces that aro at work: From half to moro than threefourths of the volume of a piece of dry wood is air that is enclosed in the cavities of the wood. Ordinarily this air remains at atmos pheric pressure because the cavities communicate with each other and with the surface through the openings in the pit membranes, but as soon as the wood becomes wet and there is free water in the cavities, the minute openings in the pit membranes become covered with films of water which can be dislodged only by high pressures. It has been shown that pressures of approximately 20 to 40 kilograms per square centimeter are required to force air through wot wood. Once wood begins to hold free water, thereforo, its enclosed air is effectively trapped and the pressure acting on the air may rise above that of the atmosphere. Increase in pressure in the trappod air may be occasioned by ripe in temperature, by evaporation of some of the free water, or by displacement of air by further, amounts of free water. While still turgid or filled with water, paint blisters can be broken easily and the coating peeled off though it does not necessarily peel of its own accord. As the abnormal conditions give way to normal conditions and the wood dries, the blisters often shrink back into place so completely that the coating may seem to be as sound as ever. The good apr>earance is deceiving, however, for a few months exposure under normal conditions may lead to scaling. Since the coating is now thoroughly dry and somewhat aged it is no longer tough and pliable, but is hard and fragile, so that the failure is of a sort easily confused with paint scaling under normal exposure. If often happens that scaling is the first sign of failure that comes to the houseowner's notice because the stage of blister ing occurred during cold weather when he did not inspect the painted surfaces very carefully. In scaling, the pieces of paint coating that become de tached may include the entire thickness of the coating so that the wood beneath is left quite bare, or the separation may take place between coats of paint, leaving the oldest coats still in place. In general, intercoat scaling is most likely to be encountered on repainted surfaces, the newer coats scaling from the older ones, though it is occasionally seen on surfaces painted for the first time, especially if the first coat of paint differs markedly in composition from the others or if the first coat was allowed an exceptionally long time to dry before applying the others. The susceptibility of paint coatings to blistering and the size of the blisters formed vary materially with a number of factors of which one of the most important is the age of the coating. Coatings blister most easily soon after they have been applied and H6 FLB hardened. At that- age,the coatings are very pliable and the bListers formed are likely to be numerous but small in size and sharply rounded. If,the Coating has time to age and become less pliable before abnormal moisture conditions arise it does not blister as quickly and the blisters are less numerous but larger in size and less sharply rounded. Blisters have been observed that were many inches across and the coatings could be peeled off in strips several yards in length# .Coatings that, reach an advanced age before abnormal moisture conditions arise become too hard, and unyielding to bulge out into rounded shapes recognizable as blisters, but their grip upon the wood may nevertheless be broken so that failure promptly takes place by cracking and scaling# Very old coatings that are chalking or checking deeply or cracking badly do not seem to fail in the manner characteristic of abnormal moisture conditions; it may be that they are too readily permeable to vapors for pres sure to develop beneath them, or perhaps they do so fail, but the failure is indistinguishable from paint flaking or scaling under normal conditions of exposure. Paint mixed with a high,ratio of pigment to linseed oil, which is accomplished practically by substituting turpentine for part of the linseed oil (not by merely adding turpentine), is more resistant to blistering and finally forms fewer, though larger blisters than similar paint mixed rich in linseed oil# It is good practice to mix paint rich in pigment because it improv es the appearance of the coating and makes it last longer. Substitution o.f bodied linseed oil or of some kinds of varnish for part of the linseed oil in paint also increases the resistance, of coatings to blistering. The addition of varnish to paint by paint users, however, is not to be recommended without competent technical advice in the selection of .the varnish because most varnishes are uhsuited for such use. The most resistant paint to blistering so far tested at the Forest Products Laboratory is linseed oil paint made with pure basic carbonate white lead, mixed with a high ratio of pigment to linseed oil, and allowed to age several months before subjecting it to abnormal moisture conditions. Moreover on houses painted with white lead paint that have been brought to the Laboratory's attention because of abnormal ipoisture conditions the complaint has been about discoloration more often than about blistering or peeling." It must be emphasized that, although the composition of the paint does affect the ease and form of blistering, all good paints are subject to failure under abnormal moisture conditions so that the only certain remedy for such troubles is removal of the faulty conditions. The kind of wood painted is likewise of little* practical significance as far as paint blistering is concerned. The Labora tory has seen badly blistered paint on all kinds of- wood commonly -16 FLB 000801 used in. building and has made paint `blister experimentally on 'dll woods that it has tested. fib differences have been found between wood species in the case of blistering or in the form of the blisters. Within any species, however, some boards or parts of boards seem notably less subject to blistering than others. In general paint blisters more readily over heartwood than it does over sapwood under the conditions that usually prevail on houses, but under other conditions that have been realized in laboratory experiments blis tering occurs more readily over sapwood. On houses it seems probable that the boards most resistant to blistering are the ones through which air and liquids can move most easily so that there is, least likelihood of building up pressure behind paint coatings. Discoloration of Faint with Extractives from the Wood Some woods widely used for house construction contain water-soluble materials that are strongly colored. Abnormal conditions may bring these substances to the painted surf ace to stain the coating. Discoloration commonly accompanies blistering and peeling on such woods, but discoloration may occur without blistering or blistering without discoloration, depending upon the sort of abnormal conditions pre vailing and the resistance of the coating to blistering. Thus when water from a leaking roof or condensation in the attic drains down back of the siding to find its way out between clapboards, discolora tion without blistering often results. If the paint is of a kind that resists blistering or has reached an age at which it does not blister easily there may be discoloration without blistering. Again, the trouble may not be noticed until the blisters have shrunk back into place and only the discoloration remains. On the other hand, if the abnormal conditions do not continue long enough for much water to pass through the boards to the painted surface, blisters may result that contain little or no water and there may be no staining, long continued or severe abnormal conditions generally produce both dis coloration and blistering. The kind of paint and the painting methods have no bearing upon discoloration as far as is now known. The stain is a deposition of foreign material upon or within the paint coating, not a product of reaction with substances in the paint. It has been found iii practice with paints of all kinds. There is no evidence that the danger of discoloration is increased by following such practices as two-coat' painting on new wood, adding more than the customary amount of paint drier, reducing the time of drying between coats to a minimum, or using so-called 11 sealers" or ''reinforcing oils,'* although these practices are open to serious objection for other reasons. The recom mendation has sometimes been made that more than the usual proportion of thinner be used in the priming coat for the woods containing watersoluble, colored substances, or that special thinners like benzol H6 -9- ill w FLB 000802 Blistering arid discoloration of white lead paint (lower panel) and of a high-grade prepared paint (upper panel) pro duced in Laboratory experiments on "miniature houses." FLB 000803 Paint scaling within a year after painting, caused by condensation of moisture behind the siding during the winter season when the interior of the house was kept warm. 2ivT20Zcl&F or toluol be used in place of turpentine, tut sued suggestions are not well founded because the offending materials are not resins and are soluble in water rather than in paint thinners. Furthermore, the excessive use of thinners on the woods in question is bad practice because they belong to the class for which any departure from the standard proportions for the priming coat should be in the direction of more oil rather than of more thinner. Only woods containing generous amounts of colored extractives soluble in water are subject to discoloration by extracted materials. Of the woods widely used for the exterior of buildings, redwood and western red cedar are of this class. That fact should not be regarded , as a disadvantage for the two woods under consideration because ab normal conditions will give trouble of one kind or another on any wood. Moreover, the water-soluble extractives of redwood and Western red cedar give them desirable properties, for the durability of their heartwoods. against decay is known to reside in the extractives present. Under normal conditions of exposure both woods hold paint coatings especially well and there is good evidence that the extractives exert a favorable influence on the life of the coatings, Discoloration of paint with extractives from redwood and Western red cedar , is usually more marked on some boards than on others,; . In part this may be due to differences in the amount of extractives in the boards or to their concentration near the surfaces of the boards during drying, but it probably is due still more largely to details in the construction of the house that make the abnormal con ditions more pronounced in some spots than in others. For example, both blistering and discoloration tend, to occur near windows or doors or just outside of plates or fire stops in the house walls. Discoloration with Substances Carried by Water from other Parts of the Building Abnormal conditions of a kind that permit water to seep out between clapboards and run over the painted surface are likely to pro duce discoloration even on woods other than redwood or western red cedar because the water may leach colored substances from building paper or composition shingles, or may carry dirt and deposit it upon the painted surface in irregular patches. Discoloration by Blue-Stain Fungi Growing in Sapwo od Certain fungi grow .in moist sUpwood of practically all species of wood and stain it dark blue or black. The defect is known m r -10- FLB 000805 as "bins stain. Like all other fungi, Hue stain organisms can grow only in moist wood. When infected wood dries the fungi stop growing and remain dormant, though the discoloration persists. Sapwood that has become blue stained during seasoning may be painted without danger of the stain coming through the paint, provided that the wood subsequently remains ^dry. But if abnormal conditions arise so that the wood again becomes wet the organisms begin to grow once more and will penetrate through the coating, bringing the stain into view. The fact that a piece of sapwood is bright before painting does not prove that it will not blue stain if the wood later becomes wet because it may be infected even though the fungi have not developed far enough to reveal the color, There is no evidence that the composition of the paint has any influence on the facility with which blue stain penetrates the coating under conditions permitting the fungi to grow. * i Blue stain may occur in the sapWood of any species. A few species with naturally durable heartwood contain no sapwood in the highest grade in which the lumber is sold in commerce. In'all but the highest grade of these species and in all grades of other woods, there may be some sapwood. The proportion of the boards of comparable grade in different species in which sapwood may be present varies widely be cause some kinds of trees contain more sapwood than others in the parts of the logs from which the select grades of lumber are cut. Blue stain coming through paint may be distinguished from mold and lichen growing on the coating itself by the fact that blue stain is confined to the areas immediately 'Over 'Sapwood and the color is revealed deeply imbedded in the Wood when the coating's, s scratched' away with a penknife. N41698.08 FLB 000807 WHY SOME WOOD SURFACES HOLD PAINT LONGER THAN OTHERS **By F. h. BQX , Senior Chemist, Forest Products Laboratory,1 Forest Service The impression has long prevailed that outside house paints must be mixed according to the kind of wood to be coated. Experimental study with the normal exterior exposure of painted softwoods--that is, wood cut from evergreen or coniferous trees--proves these tradi tional recommendations to be unnecessarily complicated. The painter need not change the composition of his priming-coat mixture for different softwoods; on the contrary, he may as well adopt a single formula for mixing the priming coat. To be sure, the paint when so applied will not last equally long on all woods, but the differences are not reduced materially by any practicable adjustment of the pro portions of paint, oil, and thinner or of the kind of thinner in the priming coat. Where abnormal conditions arise under which moisture in large amounts gains access to the backs of painted boards, paint coatings may fail by blistering and peeling or may be discolored with watersoluble materials leached from tne wood. Paint trouble resulting from these abnormal conditions is not confined to any species of wood. Such trouble can be prevented only by discovering the source of the unusual amounts of moisture and removing it. Painting Characteristics Depend on Wood Texture and Density The painting characteristics of a board depend primarily upon the amount and distribution of summer wood in it. Summer wood is the dense, horny, dark-colored portion of the annual-growth ring, formed in the tree late in the growing season. It is made up of wood cells with very thick walls and small cavities and is in this sense much less porous than the spring wood, which is composed of cells with thin walls and correspondingly large cavities. Although liquids move more x-eadily through the dense summer wood and paint oils are found to penetrate more deeply there, paint coatings do not seem to secure so firm an anchorage on summer wood as they do on spring wood; as a result, coatings exposed to normal conditions of weathering fail by flaking from the summer wood, leaving it bare while the spring wood remains apparently well covered. All native softwoods contain both summer wood and spring wood, but the proportions vary in different woods and in different boards of the same wood. There is, in fact, a greater variation in painting charac teristics between the spring wood and summer wood in a single board than there is between average boaids of different woods. The density, or weight per unit volume, of a softwood board measures roughly its ability to hold paint coatings because boards are heavy or light according as they contain much or little summer wood. However, if a board has many annual-growth rings per inch it may have the summer wood confined to narrow bands and yet be moderately heavy. (Fig. 1.) Such boards hold paint far better than boards of equal weight cut from more rapidly grown trees, in which the summer wood is present necessarily in wide bands. 1 Maintained at Madison, Wis., in cooperation with the University of Wisconsin. Selecting Wood for Painting Characteristics The following methods help in selecting the kind, of wood that f, holds paint coatings most satisfactorily. S1 By Species t';- Since woods are marketed by species, this method is easier to follow but less effective and less economical than the other methods. In the Forest Products Eaboratory's tests, the cedars, cypress, and red wood held paint best, and ^northern white pine, west ern white pine, and sugar pine did almost as well. With southern yellow pine and Douglas fir, which are , abundantly available woods whose high strength makes them especially suitable for building construction, to gether with western larch, serious flaking of the coat ings from the summer wood occurred sooner than with the other species tested. Western yellow pine, white fir, the hemlocks, and the +,F0 X l.--Painting characteristics depend on wood texture and density. Boards A and B hold p'aint well, boards C and X> poorly. Be neath each board is placed a small piece ent from the end and turned so that the annual growth rings can be seen on the end-grained surface. Board A had 38 annual rings per inch of radius of the log and at 6 per cent moisture content weighed 25 pounds per cubic foot; B had 27 rings and weighed SO pounds; C had 6 rings and weighed 30 pounds; D had 15 rings and weighed 46 pounds spruces fell between the white pine group and the southern yellow pine-Douglas fir group. By Density and Texture The wood of many species varies greatly in density and texture and therefore in painting characteristics. Thus, for example, when light, narrow-ringed boards are found in southern yellow jpine or Douglas fir, they hold paint about as well as the wide-ringed boards of cypress, and light, narrow-ringed boards of western yellow pine behave like the white pines. Density and texture therefore afford the most satisfactory basis for selecting the best wood to paint, wherever it proves practicable to 'apply them. By Grade Knots and pitch play a large part in the grading of lumber. Since they give trouble in painting, the select grades of lumber, which permit few defects, are more Satisfactory to paint than the common grades. Knots in the pines, both white and yellow pines, seem to be more objectionable from the point of view of painting than sound knots in woods like the cedars, the hemlocks, white fir, d and larch. By Kina of Gram. Is it jh be er in Edge-grained boards hold paint far better than fiat-grained boards. (Fig. 2.) This is because the bands of summer wood in the edge-grained boards are cut in such a manner that they are as narrow as possible.' Among flat-grained boards, those surfaced and painted on the bark side (the side nearer the bark of the log) are more satisfactory . to paint than those turned pith side out because there is.less danger of the "grain shelling out." "(Fig. 3.) Even some woods that hold paint best may give difficulty with grain shell ing under these circumstances. like method 2, selection by the kind i FLB 000809 of gram is difficult to apply to the purchase of many lands of lum ber because only lumber cut from very large trees can be economi cally segregated according to such classifications. Southern Exposure Is Hardest on Paint Although the buyer of lumber in small quantities can seldom con fine his purchases to the kinds of material that give best paint service, nevertheless he can sometimes distribute bis lumber to best advantage among the various parts of his building. Some parts are more conspicuous or more severely exposed to the weather than others and the best lumber may be placed there. Paint wears out most rapidly where it is most directly F0 3 -.2.....-^-Edge grain holds paint better than fiat grain: A, Flat-grained panel showing failure of paint oyer summer-wood bands ; B, edge^grained exposed to sunlight, and the time for repainting panel in a better condition than the flat-grained panel, bat disintegration of paint over summerwood bands IS shown. This panel is of the same species of wood, paint, .and age of paint coating as A the entire building is de termined by the part on which the paint fails first. As a rule this is the south side, though local conditions, such as the shading by trees and neighboring buildings, may alter conditions greatly. When to Repaint Repainting should not be put off until the old coating has flaked badly and much bare wood is exposed. The old coating serves as the foundation for the new one, and if it is badly chipped and Broken, customary methods of re painting do not secure a first-class appearance and a durable repaint job. Very often coatings fail to give adequate protection against weathering long before they flake notice ably, This is especially true of flat-grained boards of some species that hold paint well because of their low content of summer wood. Conspicuous wood checks or cracks show clearly, that the wood- is no longer receiving suffi cient proteotion even F0 3 /1 3.--^Flat-grained boards surfaced and painted on the side nearer the bark of the I02 are more satisfactory to paint than thtise turned with the pith side out: A, Flat-graihed board painted on the bark side showing a satisfactory coating; B,. flat-grained board painted on the . pith side showing paint failure as a restilt of the grain shelliiig out. This panel is of the same species of wood, paint, and age of paint coating as A though the coating is ap parently intact. Repainting neither heals nor entirely conceals weathering damage that has become conspicuous, but if the wood is repainted, promptly when minute wood cheeks begin to appear, it can be protected from weathering indefinitely. - U. S. GOVERNMENT PRtJJTIMG OPFlCEi 1030 i For sale by the Superintendent of Documents, Washington, D. C, - -; - ' - - Trice 5 cert 4 | FLB 000810 C&4-4 How Properties of Wood Determine the Service Given by Exterior Paint Coatings By F. L. Browne Senior Chemist, Forest Products Laboratory, Madison, Wis. S4NT makers have long recognized that exterior house paints made in accordance with the best technical standards of the industry vary widely In the service they will give on wood surfaces of different kinds, even though the painter applies them skillfully. However, there has been much uncer tainty about the kinds of wood surfaces on which paint fails soonest and what jran be done about It. Study of the painting characteristics of woods at the Potest Produets laboratory for more than six years has revealed the proper^ ti&sl of wood that have most influence on paint behavior. The study indicates the direction in which improvement should be sought. The findings can be presented here to best advantage by first describing certain characteristics 5f Wood and then discussing their bear ing on paint service. Classifications of Lumber by Species -Dumber is cut from trees of many different species and the grouping by species or closely related species is re tained in merchandising because in general each species has more or less characteristic average properties and (lads uses accordingly. A sharp dis tinction ig made in practice between hardwood lumber, which comes from deciduous trees, and the softwood lum ber from evergreen trees. Only soft woods need be considered here because the lumber used for the exterior of buildings is almost entirely of that kind. In: choosing lumber for a particular purpose, let us say house siding, paintablUty is only One of a number of factors to be considered, and not neces sarily the most important one. Ability to stay in place, ease of working and of nailing, durability, cheapness and <i variability in the desired pattern must be given consideration varying with circumstances. No wood excels in all respects and none in common use is deficient iu all of them. Within each species there is a con siderable range in properties, not only in lumber cut in different forest regions, lmt also in that from neighboring trees <>r even from different parts of the name tree. Consequently there is much overlapping in properties between spe cies; for Instance, dry western yellow llne Is usually heavier than redwood and lighter than Douglas fir, but the lightest boards of pine weigh less than the heaviest ones of redwood and the heaviest boards of pine outweigh the lightest ones of fir. The painting char* acteristics depend largely upon such properties as density and therefore vary widely within species. From the tech nical point of view it is far more con venient in discussing painting charac teristics to classify the Woods according to their properties rather than by <pecies, but the classification by species >uust be considered also as long as wood 11 bought and sold that way. Classifications by Grade In commerce, lumber of each Species Is subdivided into grades on the basis of the number and size of defects ap pearing on the surface of the boards. The highest grade admits only boards of clear lumber practically free from defects. Several of the higher grades are known collectively as the select grades; they contain only "lumber of good appearance and finishing quali ties'* and are the ones most likely to be used where painting is important. The common grades permit more defects and usually go into concealed parts of struc tures or are remanufactured, the de fects being largely cut out. The defects that have most influence on painting characteristics are knots, pitch packets, pitch streaks, piteh, and loose grain. Classifications by Grain Wood has an oriented fibrous struc ture, that is, it has grain. Most of the fibers in a board are arranged parallel to the long axis of the tree or log from which the board is cut. Surfaces cut at right angles to the axis of the log cut through most of the fibers trans versely and are known as end-gTain surfaces. Only the ends of boards pre sent end-grain surfaces. A series of rough, concentric rings can be seen on the end of a log. They are the annual growth rings, one of which marks each year of the tree's life. Each annual ring in a softwood, or coniferous tree, consists of a soft, light-colored part termed the spring- woo$, and a horny, dark-colored part termed the summerwood. If the prin cipal surfaces of a board He in planes that run approximately radially to the annual rings they are edge-grain sur faces and the board is an edge-grain board. Both surfaces of an edge-grain board are practically alike. If the prin cipal surfaces of the board He in planes approximately tangent to the annual rings they are flat-grain surfaces and the board is a flat-grain board. The two surfaces of a flat-grain board differ in important characteristics that wifi be pointed out later; the side that Was nearer the bark of the log is the bark side, the other the pith side. Lumber cut mostly from relatively small trees consists predominantly of flat-grain boards. In cutting lumber from large trees that yield a high pro portion of clear lumber it is possible to turn out a predominance of edgegrain boards and to sell edge-grain lumber separately from mixed edge and flat-grain. Heartwood and Sapwood In many species the older wood nearer the center of the tree differs in color and in content of certain Chemicals from the wood nearer the bark of the tree. The former is the heartwood, the latter the sapwood. Heartwood is usually less readily permeable to liquids than sapwood, often much more durable against decay, and is immune from blue stain fungi. Select grades of lumber come from the outer parts of the log and therefore include much of the sapwood. Some species contain so little sapwood that there is little of it in clear commercial lumber, but other species contain much sapwood. In general there is more sap- wood in lumber from small trees than from older and larger trees of the same species. Microscopic Structure of Wood The painting characteristics of wood are profoundly influenced by its poros ity; from one-half to more than threefourths of the volume of dry wood is air Figure 1.--illustrating the influence of ring width and density on the behuvior of paint coatings. The boards are all of the same species of wood, but Board A is both light hi weight and narrow-ringed; Board t) is heavy and wide-ringed; Boards B and C are equal in density, but Board B is nai'i'ow-ringed while Board G is wide-ringed. N41698.09 -y-C FLB 00081: apace. Wood structure is cellular, not labyrinthine, SO that the porosity is more nearly like that ot the honeycomb, in which there is no communication be tween cells, than like that of a heap of marbles or a bundle of rods, in which there is unobstructed, though much in voluted passageway throughout the en tire volume of enclosed air space. The cellular elements of softwood structure consist very largely of tracheids, which are long, narrow tubes running vertically in the tree. They are roughly from 2 to 4 mm. long by less than 0.93 mm. wide. There are also shorter elements, termed the ray cells, which run along radii of the tree trunk and at right angles to the tracheids. , Tracheids and ray cells are not merely bundled together; they are firmly em bedded in a continuous matrix, the middle lamella, so that there are no spaces between elements through which liquids may move. The air enclosed in wood is mostly enclosed within the tracheids and wood cells. These cavi ties are not completely isolated from each other as to a honeycomb, however, because their walls are penetrated by small Pits, covered by membranes, in which there are ultramicroscopic open ings about 0,0000? mm. in diameter, large enough to permit liquids to pass slowly, but far too small to admit paint pigments. In the pines, spruces, larches, and Douglas fir, there are scattered through the structure certain long channels, called resin ducts, running both ver tically and -.radially. These afford long, relatively large passageways provided that they are not obstructed with resin. The true firs, hemlocks, cedars, cy press and redwood do not normally have such resin ducts. Springwood and Summerwood The reason Why the annual growth rings are readily distinguishable in wood is clearly revealed In the microstructure because the tracheids of the springwood and summerwood differ strikingly from each other. In springwood the tracheids are roughly square in cross section, with" thin walls and large voids; in summerwood the tracheids are flattened and have thick wails with small, thin voids. The en closed air space in springwood occupies roughly SO per cent of the total volume While in .summerwood it amounts to somewhere near 40 per cent. Although summerWpod has only half the capacity for holding liquids that springwood has, nevertheless liquids move through it much more readily than they do through springwood. Pieces of Wood differ widely in the width of their annual rings, usually ex pressed as number of rings per radial inch, and in the proportion of springwood and summerwood to each annual ring. If the tree grew rapidly, the annual rings are wide. A high ratio of summerwood to springwood makes wood heavy and strong. Ring Width and pro portion of summerwood are the most important determining factors to paint- ability. Chemical Composition of Wood The principal substances out of which the cellular structure of wood is built are probably identical in chemical com position in all woods and the propor tions in which they occur vary only slightly between species, between springwood and summerwood, and be tween sapwood and heartwood. These chemicals will be spoken of collectively as wood substance. Wood substance consists principally of cellulose and lignin. Cellulose is a very complex carbohydrate, essentially a polymer of sugar. Into which it can be resoved by hydrolysis, lignin is a very complex organic material, possibly aromatic in character, whose molecular structure is still a matter of speculation and which is very likely to prove a mixture of compounds rather than a pure substance. The walls of the wood cells are made of the cellulose, which is present to thread-like fibrils Woven together to spirals Inclined more or less to the long axis of the cell. Part of the lignin is interspersed in this celluiosic fabric where it fills in the chinks between threads more or less completely. The rest of the lignin forms the middle lamella which is the matrix in which the wood ceils are embedded. Swelling of Wood Substance Wood substance Is a typical elastic jelly. It is not soluble In ordinary sol vents and Ip inert toward linseed oil, turpentine, petroleum oils, and benzene. Many liquids are imbibed by wood sub stance which cause it to swell, and dif fuse through it. Water is the most important of these liquids; others in clude methanol, ethanol, acetone, and some of the esters used as solvents or plasticizers for nitrocellulose lacquers. Wood substance imbibes and is swollen by these substances hot only on contact with the liquids themselves but from contact with the vapors. The amount imbibed and the extent of the resulting swelling vary with the nature of the liquid or vapor and with the partial pressure of the vapor in the surround ings. Thus there is a definite equi librium moisture content for wood sub stance at each relative humidity and temperature. Probably there is also a corresponding swelling equilibrium for wood substance also, but in practice what we observe is the change in dimensions of a piece of wood, not the swelling of the Wood substance itself. Only a fraction of the total swelling expresses itself in a change to dimen sions of the piece as a whole because much of it is absorbed in plastic de formation within the wood structure. As a result, both the magnitude of the gross change in volume and the amount of radial and tangential swelling (longitudinal swelling is small) vary markedly With the manner in which the change in moisture content is brought about as Well as with the difference between initial and final moisture con tent. Still more important is the fact that such behavior as warping, cupping, checking, and Weathering of wood de pend more upon the manner in Which changes in moisture content and in swelling take place thin they do upon the amount of the changes concerned. Paint Coatings, therefore, exercise a marked influence upon such behavior of wood even though they may not prevent change to moisture content from taking place. Extractives in Wood Besides wood substance, wood con tains extraneous constituents which can be removed fairly easily by extraction with suitable solvents. These extrac tives are variable in nature and In amount, differing not only between species, but between different parts of the same tree. The extractives are conveniently classified into those soluble in organic liquids like ether and those soluble in water. The ether-soluble extractive of longleaf and slash pines is a resin contain ing the volatile oil turpentine, which consists mostly of terpene hydrocarbons, and the non-volatile substance rosin, which consists largely of abietie acid. The other pines and Douglas fir con tain resins of similar composition. Other softwoods contain such resins only in small amounts if at all, except When they occur to local deposits In the tree like pitch pockets. Western red cedar, redwood, the .true firs, hem locks, spruces, and larches ordinarily contain only small amounts of ether- soluble extractives. Port Orford cedar, eastern red cedar, Alaska cedar, and Cypress contain characteristic oils solu ble in ether but quite different in chem ical nature, lacking an acidic substance analogous to rosin. It is known that heartwood and sapwood may differ materially in the amount and particularly in the compo sition of the extractive present. It is nQt known whether there is more or less extractive present, in summerwood as compared with springwood. The water-soluble extractives include tannins and other complex organic sub stances of an aromatic nature, some of them highly colored; carbohydrates; or ganic acids like formic, acetic, and their homologs; traces of organic nitrogen compounds, and mineral constituents of wood ash. The amount and nature of these extractives vary widely between heartwood and sapwood and, in some species at least, in the heartwood from different parts of the same tree. Dur ing the drying of wood, under some circumstances, these extractives may tend to concentrate at the surfaces. Object of Painting Wood The painting characteristics of wood must be considered with due regard for the object for which wood is painted. Painting is done to secure and maintain a desired appearance on surfaces ex posed to view. There are at least three factors in appearance, namely, color, texture, and line. Exterior wood sur faces must be kept painted wherever color With smooth texture and straight, snug lines are desired; they may be kept varnished where the natural wood color and grain together with smooth texture and snug lines are wanted; they may be Jcept stained or thinly paipted where Color with rough texture and broken lines are preferred; and they may be left without surface treatment where the neutral color, shaggy texture, and irregular lines of weather-beaten Wood give the effect selected. In gen eral, architectural considerations dic tate that different patterns of. lumber be used according to the effect desired. Thus siding nailed with the planed side out is almost always painted when any pretense of keeping up appearances is made, bat if nailed sawed side out <r If shingles are used, the surface is rarely painted and may either be stained or left to weather naturally. In considering painting, therefore, we are striving to maintain a colored, opaque coating intact, . presenting a smooth surface, ' with . straight, .snug fines. The- .effect is marred if the smooth wood surface , is permitted to check badly or roughen by weathering, for ordinary painting does not restore a surface with smooth texture, Dike- FLB warping:, cupping, and loosening of tH* boards must be prevented if snug lines axe to be retained. The paint coating must therefore protect the wood against weathering to keep up the de sired appearance. Influence of Wood Properties During Application of Paint The first coat of paint applied to new wood is very largely consumed in filling the voids, leaving a level, nou- absorptlve surface on which subsequent applications can build a coating. How ever, even though one-half to three- fourths of the volume of wood is void, a comparatively small amount of paint Is required for priming it. A plaster wall takes two or three times as much paint as wood. The cellular structure of wood in contrast to the granular structure of plaster accounts for the difference, because in wood, penetration beyond the voids in those ceils cut open In making the surface can take place only through the very fine openings in the pit membranes. End-grain wood surfaces consume much more paint than edge or flat-grain surfaces because the long trachelds stand at right angles to them. How ever, not much end-grain wood need be painted. There is little if any differ ence in the consumption of paint be tween edge and flat-grain surfaces. Light wood, with its greater content of voids, consumes measurably more paint than heavy wood, though the dif ference is not much greater than the individual variation between painters in applying paint and it is largely com pensated if the customary recommenda tion is followed of mixing the priming coat relatively richer in turpentine than in Linseed oil for heavy woods than for light ones. Undoubtedly there would be a marked difference in spreading rate of paint between springwood and summerwood if we had the two kinds of surfaces to paint separately. The liquids of paint penetrate more deeply into wood than do the pigments, as can be proved by adding an oil- soluble red dye to the paint before application and later examining the depth to which the red color pene trates. The ratio of solids to liquids In the paint remaining at the surface is thereby upset, so that a paint that dries with a glossy film on glass or metal, dries with a dull film on wood. Judged toy the effect on gloss, more oil is thus filtered off in springwood than in summerwood, but penetration Is found to be deeper in summerwood. The paradox is not mysterious, for the void capacity of summerwood is only half that of springwood. Penetration of oil as deeply as pos sible has long been held desirable in painting wood. There seems to be no good reason for so believing, however, because paint fails soonest on the summerwood. Into which oil penetrates deepest. Extractives present In cypress and redwood tend to retard the drying of some paints on these woods, especially in the presence of much moisture or low temperatures. T&ie fact is of no serious practical import, for experiment proves that coatings applied to these woods under conditions giving pro nounced retardation of drying cannot be distinguished in later exposure from coatings applied under good drying con ditions. From the point of view of theory, however, the fact is prooablj significant, for these woods are among those upon which paint coatings last longest even when they have rather wide bands of summerwood. Normal and Abnormal Conditions of Exposure In considering the behavior of paint coatings on wood, sharp distinction must be drawn between normal and abnormal conditions of exposure. Un der normal conditions moisture in large Chart 1.--Representing for the differ ent woods the average time elapsed before repainting was needed to main tain (a) the integrity of the coating, (b) adequate protection against wood weathering. For each species the upper half of each bar represents flat-grain panels, the lower half edge-grain panels, except that for eastern hemlock only flat-grain panels were tested. The whole length of the bar, that is, the solid plus the cross-hatching, represents the time for repainting' when coating integrity only is comidered; the solid part alone represents the time for repainting when protection of the wood is considered also. amounts gains access only to the painted surface for short times during wet weather. Under abnormal condi tions much moisture gains access to the backs of the painted board, usually for fairly long intervals. The results of abnormal conditions will not be dis cussed here; it need only he said in passing that trouble from abnormal conditions may bir'experienced with any kind of paint, on any kind of wood, and may arise very early In the coating's history. The failure may take one or more of several forms. The coating may blister and peel, forms which are easily recognized, or it may scale, a form which Is often hard to distinguish from scaling under normal conditions with some paints. The coating may be come discolored with water-soluble ex tractives from the wood or with dirt and stains carried by the water from other sources within the structure. The coating may become discolored by blue stain fungi growing In sapwood, and finally, under prolonged or repeated exposure to abnormal conditions, the wood beneath the coating may rot. Early Part of Normal Exposure Not Influenced by Wood Under normal conditions of exposure the behavior of paint coatings during i he early part of their service life is not materially influenced by the kind of wood surface upon which they are ap plied. The rate of loss in gloss, the collection of dirt, the development of chalking and fading, the time when paint checking begins, and the dis tinctive pattern, of the checking depend upon the kind of paint, the climate. the local conditions of exposure, and perhaps to some extent upon the man ner of application, but they are not influenced to any important extent by the wood. By way of exception to this gener alization it may be said that occasion ally chalking and fading proceed more rapidly over springwood than over sum merwood, so that the grain of the wood Is revealed by the appearance of the coating over it. Such behavior Is here regarded as due to inadequate priming and, therefore, to poor craftsmanship in painting, because well-painted sur faces do not so behave. Further excep tion may be made of loose grain appear ing on flat-grain boards that are turned pith side out, which will be discussed later. The nature of the wood surface be gins to influence the behavior of coat ings when they reach the point In their deterioration at which they no longer protect the wood adequately against weathering and when they begin to dis integrate by crumbling, flaking, or scaling, leaving parts of the wood sur face bare. From this point on, under present painting practices, it may fairly be said that the kind of wood surface rather than the composition of the paint dominates the behavior of the coating and determines when repainting is in order. Influence of Wood on Ultimate Failure of Coatings Paints as we now use them fall ulti mately either by (1) inadequately protecting the wood so that it begins to weather, check, cup, warp, or pull away from fastenings, or (2) crumbling, flaking or scaling, leaving parts of the Chart <2.--The relation between re painting time and weight of dry wood in the panels tested for the different species. The key to the number is given Chart 1. wood bare.. Aa' would be expected, the wood surfaces on which failure by in adequacy of protection is first noticed are the surfaces having the greatest tendency to develop weathering defects. Failure of the coating to remain intact starts over the summerwood and a stage la usually reached, if the exposure con tinues long enough, when all the sum merwood is bare while the springwood remains covered. The amount and dis- FLB 000813 tributton of summerwood is, therefore, the predominant influence in failure of the coating to remain intact. Influence of Species Chart 1 summarizes the results by species of an extensive series of field tests by the Forest Products Labora tory. Two kinds of paint were used, for each of which a separate tabulation is made. There Is far more difference in the life of coatings of the same kind of paint on different woods than be tween the two paints on any wood. The woods are divided into four groups on the basis of the results in this test: I, those woods on which paint protected and remained intact longest; XI, those on which it remained intact but failed sooner in protection than was found for Group I woods; HI, those on which paint failed in both protection and integrity sooner than on Group I woods; IV, those on which paint failed soonest, especially in integrity. Density and Bigg Width Chart 2 shows that the classification by species follows fairly closely the average density of the species. A stiil closer parallel would he brought out if the chart could show ring width as well as density in their bearing on the results. The photograph, Figure 1, illustrates how ring width modifies density in determining coating integrity. The four boards shown are all flat grain and of the same species of wood. They were taken from paint test panels and planed to remove the remnants of the coatings arid reveal the nature of the surface. Boards A and B held paint well, boards C and U poorly. Board A is both light in weight and narrowringed; Board D is heavy and wide- ringed. Boards B and C are equal in density, but B is narrow-ringed while C is wide-ringed. As already pointed out, there is much variation within many species in dens ity and ring width and it follows that there is a corresponding variation in painting characteristics. Density and ring width consequently are a far more precise guide to paintability than species, hut woods are bought and sold by species and not by density and ring width. Direction of Grain Chart 1 shows that edge-grain boards are far superior to flat-grain boards, both because they require less protec tion against weathering and because they display their summerwood in nar row lines rather than in flaring areas and hence hold coatings intact longer. The bark side of flat-grain boards is far superior to the pith side in many species because there is a tendency for the grain to shell out on the pith side. This is a form of wood weathering, against which paint should, theoretical ly, afford, protection. In practice, how ever, paint as we now use it proves inadequate. Flat-grain boards should therefore be turned bark side out. Influence of Grade Knots are objectionable in painted surfaces because they do not remain perfectly concealed, either because they do no.t remain level with the rest of the surface, because they sometimes cause the coating over them to turn yellow, because the Wood of the knot may crack, or because the paint may scale over the knot. Pitch pockets and pitch streaks lead to objectionable exudation of pitch through coatings. For these reasons high-grade lumber of any spe cies is better for painting than the lower grades. Influence of Extractives The position of cypress and redwood in Charts 1 and 2 seems to be more favorable than their density and ring width would predict. It has already been mentioned that these woods con tain extractives that retard drying un der certain circumstances and it is plausible to consider these substances as inhibitors of oxidation exercising a favorable influence on the maintenance of coating integrity. A careful examination of Chart 1 shows that woods containing a resin rially prolongs the life of the coating both in protective power and integrity, but the Ultimate failure takes place by flaking from the summerwood just as it does when the paints are applied in the customary fashion. The Forest Products Laboratory has also tried a number of supposedly harmful painting practices, such as painting wood at high moisture content (.not containing free water, however), painting in humid atmospheres and in the absence of sunlight and allowing short times for drying between coats. The results seem to indicate that the bad effects of such factors in paint application have been greatly exagger ated. Problem for Future Research The variability in behavior of paint coatings on wood surfaces of different kinds is the wood-painting problem that must be solved before consumers of paint and of lumber can be given better paint service. To some extent selection of lumber in accordance with its painting characteristics can be practiced but improvement in this direction is limited by the facts that in choosing wood for any purpose other factors must be considered besides paintability and that most of our avail able lumber supply is of the kinds that contain much summerwood. Further more, second-growth woods are likely to be less desirable in respect to painting than the virgin stands, because the trees will usually be grown more rapidly and Chart 3.---Illustrating the influence of climate on the behavior of paint coat ings. Each bar is divided into four parts representing respectively, begin ning with the upper part, the behavior of coatings on woods of Group I, Group II, Group III, and Group IV. The whole length of the bar, that is the solid plus the cross-hatching, represents .the -aver age time elapsed before repainting was needed when coating integrity, alone was considered; the solid part represents the time for repainting when protection of the wood was considered also. will be cut younger. It is conceivable that some means of treating lumber to improve its painting characteristics may be invented, but there is no reason for regarding that point of attack On the problem as particularly hopeful. Im proved paint or painting technique seems much more likely to furnish the solution. A coating that would endure indefi nitely is probably a vain objective and perhaps not an altogether desirable one, for most people would like to change their scheme of decoration once in a While. The ideal coating for wood, with an oil-soluble acid like rosin com however, ought to remain an adequate pare with the other woods more favor protective agent against wood weather ably in maintenance of coating integrity ing until its appearance is so changed for white lead paint than in integrity that repainting is clearly necessary and for lead and zinc paint. This is in line it ought to wear down uniformly over with the familiar evidence that paints summerwood and springwood alike, be containing zinc oxide are adversely ing firmly anchored to all parts of the affected by acids present in linseed oil. wood when repainting is done. Flaking Influence of Climate from suifimerwood should be unknown. Chart 3 shows that climate profound With such a paint, all wood surfaces ly influences the durability of paint would give equally satisfactory paint aoatlngs, as has long been realized, but service. the differences between woods remain : The attainment of an ideal paint of much the same. However, the amount this kind is an ambitious but by no of difference between woods of the four means unpromising objective. As we classes is less in the more humid cli see it, the problem is one of securing mates than It is in the drier ones. firmer and more permanent adhesion Influence of Paint Composition between coatings and wood. Probably The .Forest Products Laboratory has at present aged coatings cling to wood tried various expedients in priming-coat by mechanical embedding in the rough procedure that have been recommended surface, much as plaster grips lath. for obtaining better results on wood sur Summerwood, with its low void volume faces containing much summerwood. The ahd very small voids, offers an uncer proportions of turpentine and linseed tain support for adhesion of that kind, oil in the priming coat have been al A true adhesion between wood sub tered greatly, thinners like benzol have stance and the matrix of the paint been used in place of turpentine, and coating is called for. Glue sticks to special priming-coat paints have bee* summerwood, why cannot paint be used. Ail but one of these expedients made to do so' The Forest Products have either failed to alter the behavior Laboratory proposes to seek true ad of the coatings or have led to earlier hesion between paint Coatings and Wood loss of coating integrity. Aluminum and invites the co-operation of the paint used as a priming coat under technical men of the paint industry in white lead or lead and zinc paint mate that quest. I r-r* <r /}a th*f,5"3 k/> / 93| in the Stabilization of Practice for Wood By F. L. BROWNE,1 MADISON, WIS. 'Wm y >r ie 0ue he .flitid ne ago ^od, is< hei iged and. over , be^ the afcVng iown, rfapes paint Painting practice is changing from a craft to a part of engineering. The Forest Products Laboratory has tested the painting characteristics of softwoods. The tests in cluded edge-grain and flat-grain hoards, light woods consisting mostly of spring-wood and heavy woods with wide bands of summer-wood, white lead and prepared paint, various combinations of paint, linseed oil, thinner, and drier for the priming coat, and aluminum paint as ;:a first coat. Conditions of dryness and of humidity entered into the tests. The basic factors responsible for the chief uncertainties of paint behavior were studied, : and the way is pointed for a possible stabilization of painting practice for wood through further research. kAINTlNG practice is in course of transition from a craft to a part of engineering. Cl)2 The breakdown of the apprenticeship system, the multi plication of new materials available for painting, the increasing variety of the sur faces to be painted, the accelerating tempo of building and manufacturing operations, and the rising standards of acceptable service have overwhelmed the oldfashioned painter. However, the engineer is not^ yet fully prepared for his new re sponsibilities because the background of technical data on paint ing practice is fragmentary and largely unreliable, and means of measuring the serviceableness of paint coatings is' lacking A specification for a durable exterior paint finish cannot be written willi the same assurance of success that is possible in designing a structure to carry a given maximum load. Quality in a paint job is judged primarily by the costliness of the material! and the labor of applying them rather than by dependable yardsticks of performance. linder the circumstances it is not surprising that painting practice is far from stabilized. Many kinds of paint are sold for similar uses, and opinions about their relative merits differ bewijderingly. Details of applying paint vary widely. New woodwork is sometimes painted with two coats, sometimes l8mior Chemist, Forest Products Laboratory, maintained at M1 H0 +Q0 , Wis-, by the Forest Service, IT. S. Department of Agricul ture, m cooperation with the University of Wiscbnsin. Dr. Browne a ued the staff of the Forest Products Laboratory in 1918, when he ctuMsul in developing water-resistant, glues, particularly for use in rut rut When investigations of wood finishing were begun in 1922, he v i, pi iced in direct charge of the experiments. He is a graduate of flit, rouse in chemistry at Cornell University and obtained the Jot tor u p at the University of Wisconsin in colloid chemistry. He !* f mi mbi r of the American Chemical Society and of the Society "f hignii XI, a fellow of the American, Association for the Advahce- mi"U- of hi rence, and an assistant editor of Chemical Abstracts. ' Iho numbers in parentheses throughout the paper refer to the Lrtii of References at the end, ^ I or pre entation at the Fifth National Wood Industries Meeting, 2 3 4..an. Fork, N. Y., Oct. 16 and 17, 1930, of T < A+ S0 _ 1 q X_ 0 y 5t>P \fj ruAtucAX. Eq X Q< < . All papers are subject to revision. mu Statements and opinions advanced in papers are to be uh- ncrUfjod as individual expressions of their authors, an'd not those of the Ninety. with three. Admixtures of oil, thinner, and drier are variously recommended. There is uncertainty about the limitations of weather, condition of the surface, and drying time between coats within which painting may be done safely. When paint jobs turn out unsatisfactorily, the cause of failure is frequently difficult to determine. All too frequently coatings give way soon after they have been applied, even though conscientious efforts were made to do first-class work,' When reasonable length of ser vice is attained, it is difficult to determine when a coating ceases to function properly and requires renewal. Opinions then differ about the way to prepare the surface for repainting and how to repaint it. A major source of confusion about painting practice for ex terior woodwork arises from the marked variation in durability of coatings on different kinds of wood. The fact has long been recognized, but statements about the kinds of wood that give good or bad service and what should be done about it have been strikingly contradictory. Some have thought that certain woods are inherently lacking in paintability and should not be used in places where painting is important. Others have held that each kind of wood requires an appropriate adjustment of the proportions of pigment, oil, and thinner in the priming coat, but the formulas for each kind of wood have never been stated definitely* that being left to the painter's judgment. Still others have maintained that for some woods the turpentine in the primer should be replaced by volatile liquids of greater solvent power. Many special priming paints have been proposed for use on woods upon which paints fail soonest. 6FX 78 9 :P X _ ;< = > =?L1 <X 1 X T @A@ To provide reliable information about such moot questions the Forest Products Laboratory in 1924 began an experimental study of the painting characteristics of softwoods. (2) Test fences were established at 11 places in the United States repre senting a great range in climates.^ On the fences, panels of'18 species of softwoods were'exposed and painted. In general, at every station there were four panels of each species,- two made with flat-grain boards and two with edge-grain boards. Of these one panel -of flat-grain and one of edge-grain boards were painted with three coats of white-lead-paste paint and the other two panels with three coats of lead and zinc prepared paint. ............ In the 1924 tests no attempt was made to adjust the propor tions of pigment, oil, and thinner in the priming coat according to the kind of wood painted. All woods were painted in exactly the same way. The mixtures of whitedead-paste paint were: BPaste white lead (92 per^ent pigment), lb. :.. P1 linseedoit, ga!....,:v.... Turpentine, gal........... .......... ............... Paint drier, pt........ .............. ................................... First coat 100 4 2 1 Second Third coat coat . 100 - 100 11/1 ; 3l/2 1*/V : 1 1 ... 1 The: lead and zinc prepared paint consisted of: Pigment, 64 per cent by weight, composed of: Per cent by weight . Basic carbonate white lead............... ........................... 60 Zinc oxide.... -......................................... 30 Asbestine............................. .......................................... 10 N41698.1 FLB 000815 2 TRANSACTIONS OF THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS Vehicle, 36 per cent fay weight, composed of: Raw linseed oil......................................................... Turpentine..................... Liquid drier....................................... Par cent fay weight 90 >5 S For the priming coat V/t pants of raw linseed oil and 2 pints of turpentine were added to a gallon of this paint. For the second coat 2`/a pints of turpentine were added to a gallon- For the third coat the paint was applied without any addition. All test stations were visited at least once each year by the same inspector. During the first year or so the appearance of the paint coatings changed materially. (8) The gloss faded, the white surfaces became dirty, then the coatings began to disintegrate at the surface in the form of a fine powder and some of the dirt became dislodged, and finally the coatings began to check in fine, presumably superficial fissures. There were inter esting differences in appearance between coatings of the two kinds of paint and between the different exposure stations, but the kind of wood beneath the coating had very little effect upon its appearance. However, as the tests continued, other changes set in that varied markedly with the kind of wood. These changes were of two .sorts; namely, in the integrity of the coat ing, and in that of the wood itself. Sometimes deep slits de veloped in the coating at the edge of Which the coating curled up and broke off in little pieces, laying the wood beneath bare. Sometimes paint cheeks finally bec ame deep, interlacing cracks, and little areas of coating outlined by the cracks fell off bodily, leaving the wood bare. Such changes were recorded as de ficiencies in the integrity of the coating. But sometimes checks opened in the wood where otherwise the coating seemed to be intact. Such changes were recorded as inadequate protection by the coating against wood weathering. CD ER t s X~ Q 1924 T FGF y'- The most important faGts revealed by the 1924 tests were the following: (4) Summer-Wood and .Spring-Wood. The variable behavior of paint coatings on the softwoods is due primarily to difference in behavior on summer-wood and spring-wood. Failure of aged coatings in integrity usually begins over summer-wood long before it sets in over the neighboring spring-wood, and there fore failure in coating integrity proceeds most rapidly on boards that contain the greatest amount of summer-wood. Summer-wood is the harder, darker-colored part of the annual growth ring in the wood. Structurally it differs from spring.wood in that the wood cells are flattened and have thicker walls and smaller cavities than the wood cells in spring-wood. Sum mer-wood is roughly three times as heavy as spring-wood. Ex perience in impregnating Wood with liquids proves that the heavy summer-wood is more easily and deeply penetrated by liquids than the light spring-wood. Experiment proves that the Eqirids in oil paint follow the same,general rule and penetrate more deeply into summer-wood than they do into spring-wood, although there has long been a contrary impression among painters. The pigments of oil paint are too large to penetrate beyond the cavities of those wood cells that were cut open in forming the surface of the hoard. Like other liquids, resins exude more easily from summer-wood than they do from springwood, but there is no evidence that summer-wood actually contains more resin than spring-wood. Aged coatings apparently do not adhere to wood substances as glue does, but cling to the wood by a mechanical embedding of the paint in the open cell cavities at the surface, much as plaster clings to lath. Summer-wood, with its small cavities, furnishes inadequate anchorage so that small pieces of aged coating easily become detached and fall off. However, if the band of summer-wood is very narrow, the little pieces of coat ing may retain sufficient grip in the spring-wood on either side to remain in place, arching over the summer-wood. Some Woods Require More Effective Protection Than Others. A second factor causing variable behavior of coatings on soft woods is the fact that some woods require more adequate paint protection to prevent wood-cheeking, which is the first sign of Wood weathering. (5) Test panels were often observed in which the wood had begun to cheek although the coating other wise seemed to remain intact. The woods on which this hap pened were the kinds that quickly develop conspicuous checks and cracks when exposed to the weather without paint protec tion, Frequently the wood checks became centers from which failure of the coating in integrity progressed, Edge-Grain and Flat-Grain Boards. Coatings' remain in tact longer on edge-grain boards than they do on flat-grain boards of otherwise similar wood. The difference in behavior is accounted for by the disposition of summer-wood at the sur faces of the two kinds of boards. Since the surface of an edgegrain board lies roughly in a plane along a radius of the tree, the bands of summer-wood are reduced to the narrowest width possible. The surface of a flat-grain hoard, on the other hand, is in a plane approximately tangent to some of the growth rings of the tree, so .that the bands of summer-wood at the surface of the board may flare out into large areas. Edge-grain boards weather-check less easily than flat-grain boards, doubtless because they swell and shrink less in width, and therefore coatings continue to furnish sufficient protection longer on the edge-grain boards. Bark Side and Pith Side of Flat-Grain Boards. One Side of a flat-grain board is always nearer the bark and the other nearer the pith of the tree from whieh it was cut. The bark side makes a better surface for painting than the pith side. On the pith side of some boards the summer-wood of one annual ring may separate from the spring-wood of the next ring and curl upward in a sharp, easily splintered edge. Paint coatings are often unable to prevent such grain shelling, and consequently the coating may be badly disrupted. Density and Ring Width. Since summer-wood is much heavier than spring-wood, the density of a, piece of softwood is a fairly good measure of the proportion of summer-wood in it and there fore of its painting characteristics. Paint fails sooner on heavy boards, because they contain more summer-wood than light ones. However, another factor must also be considered---namely, the width of the annual"growth rings (usually recorded as the number of rings per radial inch- of the log). When the growth rings are narrow (many rings per inch), there may be a fairly high proportion of summer-wood, and yet the bands may be narrow. Such woo'd holds paint better than wood of equal or slightly lower density in which the growth rings, and conse quently the bands of summer-wood, are wide. The lumber of many Species varies widely in density and in ring width, and the painting characteristics vary correspond ingly. Any classification of species with respect to painting characteristics is therefore a rough approximation at best andinvolves much overlapping; that is, light, narrow-ringed boards of a given species may be superior, from the point of view of painting, to heavy or-wide-ringed boards of species assigned higher positions in the classification. In general, edge-grain boards of any species are as good 6r better for painting than flat-grain boards of the species assigned to the next higher elass. Subject to these reservations,, the softwoods were classified for painting characteristics on the basis of the 1924 tests as set forth in Table I, which lists also the relative amounts of the species cut into lumber in 1927. WOOD INDUSTRIES 3 l,timber Grade and Knots. The principal defects that form the basis for grading lumber are disadvantageous from the point of view of painting. Coatings over knots often discolor, crack, and full off, and the wood of the knots checks conspicuously. Piirh often exudes through coatings over pitch pockets, pitch streaks, or pitehy wood. Low-grade lumber is therefore less it-mule for painting than high-grade lumber of the same species unless the low-grade lumber is remanufactured in such jjl way that the defects are cut out. Even then the advantage may still lie with the high-grade Lumber, because as a rule the high-grade lumber is cut from the outer portions of the log where the growth rings are usually narrower than they are nearer tnc center of the log. ;rain ivior suridgetree, ridtli land, rings rfac grain ridth, jetion R !1 ' it iit JH^ e of a nearer makes e pith g maj .pward i often ;ly the fif flg heavic i & fairiv ltheiei heavy bt ones. nameh. 1 as the growl h a fairiv may tie squal in i coit-e- 111 itlH JH y and m xespqnd- tllll J| painting best aud id board-' f view of assign! d it it dge-gr.iin ting th in ;her class. ssified loi sts as -i f n its of 1 In' i't H II J K L M1 < 0 _ 1 0 ~0 _ 1 N O PN P Q R ST U V W X< H an1 _ 0 0 _1 q Q 0 Xqo p w o o d s ~X 1 qq 1 X _ 10 q 0 Xq X~ 0 q3 Q WOODS AS LUMBER Percentage of Y ZClrASSIFICATION, USING U. S. FOREST SERVICE CX++Xq B , N1 q X 1 q0 _ 1 1 + all Softwood lumber cut ua 1927 Croup 1--Woods on which coatings served longest, both in integrity and >h protection: Cedar, Alaska; Ckamaecyparis nootkalensis............. ) Cedar, Port Orford; Ckamaecyparis lawsottiana..................> Cedar, Western red; Thuja plicata........................ -..............) Cypress, Southern; Taxodium dis.Uchum................................ Redwood; Sequoia semPervirens.......... .................................. 1 2 2 Group 2 Woods on which coatings failed in protection sooner than on woods of Group I; Fine, Northern white; Pinws sirobus............ j pute. Western white; Pinus monlicola................................ ) Pine, sugar; Pinus lamberliana. ................................ .. * ' 1 tp I--Woods on which coatings failed in both integrity and protection sooner than on woods of Group 1: I ir, white; Abies concc&or......... ................................................ Hemlock, Eastern; Tsuga canadensis......................................> Hemlock, Western; Tsuga keterophylla............... ............ ...... j pine, Western yellow; Pinus ponder&sa................................ Spruce, Eastern; picea spp.............................................. 1 bpaice, Sitka; Picea sitchensis.............................................. ) 1 7 10 TM (Voup 4--Woods on which coatings failed soonest, especially . in integrity: l/uuglas.fir; Pseudoisuga taxifclia........................ ............ -- L,irch, Western; Larix occidentalis............. ................. ......... Pine, Southern yellow; Pinus spp......... ................................. 30 I 38 Heartwvod and Sapwood. Few. differences^ in the behavior of coatings on heartwood and sapwood have been observed so far. In the few cases that have occurred, the advantage has some! imes been with the heartwood and at other times with the sapwood. Extractive Substances Characteristic of Species. Although the primary cause of variation in the behavior of coatings on dif ferent species is found in the amount and distribution of summerwood, a factor of secondary importance is the presence in certain woods of characteristic substances that can be separated from the woods by extraction with suitable solvents. Thus cypress aud redwood each contain a substanee peculiar to the species that, affects the behavior of paint. When paint is applied to either of these woods while they are wet with water, the coat^ihgs will not harden until the moisture content has been reduced to i reasonable amount. On the other hand, coatings cling to the summer-wood of redwood and cypress .somewhat longer than they do to the summer-wood of most other species. It seems likely that the extractives in redwood and cypress have a favorable effect on the durability of coatings. All pines contain rosin or a similar oil-soluble acidie substance, l'ree organic acids in linseed oh are known to be harmful to paints containing zinc oxide, but not so harmful to straight white-lead paint. It was therefore to be expected that the lead and zinc paint would not prove quite so durable on the pines ns it did on otter woods of similar density and ring width, hut that no such differences between pines and other woods should be observed in the case of the straight white-lead paint. The results of the tests confirmed this expectation. Results in Different Climates. The same classification of the woods was found to apply in all climates, but the extent of varia tion differed materially. In climates where there are long periods of extreme dryness, failure of coatings by sloughing bodily from summer-wood takes place most rapidly and most characteristically. Such conditions accentuate the discrepan cies in behavior on different woods. Where the humidity rarely falls very low, coatings cling longer to the summer-wood, the paint itself has more chance to disintegrate or wear away, and the difference between species is somewhat less marked. Of the two paints used in the tests, one proved distinctly superior to the other on all woods in arid climates, but just as definitely inferior on all woods in the warm, humid climate of Florida. In the intermediate climates one paint often proved the more durable on the pines, while the other lasted longer on woods other than the pines. TQ 1925 [P 0 [+ T \]\ A second series of tests was started in 1925 to determine how far the durability of coatings on woods containing much summerwood can be improved by altering the proportions of pigment, oil, and thinner in the priming coat, by replacing turpentine with special solvents, or by using special priming paints. The test panels were divided into two halves, of Which one was painted by the standard procedure followed previously in the 1924 tests, while the other half was painted by one of the special procedures to be studied. Thus comparison of new and -old procedure could always be made on the same boards. The Woods studied in 1925 were Southern yellow pine, Douglas fir, Western larch, Western yellow pine, Eastern hemlock, Western hemlock, and Southern cypress. ft ^_^Re s u l t s o p t h e 1925 T The following results were obtained iin the 1925 tests: (6) Proportions of Oil and Thinner in the Primer. In spite of the old and widely accepted tradition that the durability of paint coatings on woods containing much summer-wood can be improved by mixing the priming coat with more than the usual amount of turpentine (and correspondingly less oil and pigment), the tests proved that the priming-coat proportions have very little effect upon the serviceableness of the coatings, If the comparisons had not been made on the same boards, no dif ferences at all would have been detected. As it was, the dura bility' of the coatings with turpentine-rich primers Was judged slightly inferior to that with' the standard primer; clearly the comparisons between species made in the 1924 tests would not have been altered in`any way by changing the proportions of the priming-coat ingredients. The result of these experiments is reasonable. Thinning with turpentine is usually recommended in the belief that deeper penetration of the paint oils will secure firmer adhesion of the coating. However, penetration to begin with is deeper in sum mer-wood, from which coating come loose "first, than it is in spring-wood, to wlteh coatings cling longer. The theory is therefore discredited at the outset. ; Special Solvents as Raimi Thinnsrs. Replacement of turpen tine with volatile liquids that are better solvents for the oils and resins in spine woods has been recommended as a means of improving paint service. Three series of experiments have been made by the Forest Products Laboratory to test the theory. The volatile liquids included gum spirits turpentine, steamdistilled turpentine, destructively distilled turpentine, turpen tine oxidized by bubbling air through it, petroleum distillates ranging in volatility from gasoline to kerosene, petroleum dis tillates from four types of crude oil, benzol, and coal tar naphtha. FLB 000817 \ 4 TRANSACTIONS OF THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS Tests were made on Southern yellow pine, cypress, and Eastern hemlock. The effects of varying the volatile liquid were in all cases so slight that they can be of interest only from the point of view of theory. None of the liquids gave better results than turpen tine on any wood. There were indications that oxidized tur pentine added slightly to the durability of the coatings. The beneficial effect of turpentine must therefore be attributed to the nonvolatile residue left when turpentine evaporates in the presence of oxygen or to a desirable alteration in the drying of linseed oil in the presehce of the turpentine product. Special Priming Paints. Five special priming paints were studied in the 1925 series of tests. Of these two had very little effect on the behavior of the coatings and two proved definitely harmful to the durability. The fifth primer, aluminum paint, materially retarded the loosening and detachment of coatings from summer-wood and thereby prolonged the life of coatings Fie. 1 hO~~ Q ` a ` ba cd e f gCQ1 1 _ 0 F P C F0 _ 1 0 X~ 1 1 0 q X1 0 q 3 < 1 0 q 3 i j h k l lS ++ -W .B EXX 1 q Q q ~0 _ 0 1 ~~ _ AX~ +0 q + m m n o p qP R S B0 + 0 q 1 0 q 3 _ Q Q1 0 Xr (The left-hand part of the panel, marked A, was painted according to .the usual procedure of applying three coats of prepared paint, of which the first contained a little extra linseed oil and turpentine.. 'The right-hand part of the pane!.'marked B, received first a priming coat of aluminum paint, followed by exactly the same second and third coats of paint that were ^ applied on A.) on woods containing much summer-wood. Fig. \ illustrates the improvement in paint service brought about by priming with aluminum paint. ' Aluminum priming paint (7) is made by. adding polished aluminum bronze powder- to a suitable liquid just before it is to be applied. From. llA to 2 lb. of the powder is stirred into the liquid; grinding in a paint mill is neither necessary nor desirable. The liquid should be either a kettle-bodied linseed oil thinned to suitable viscosity with paint thinner and drier or a long oil spar varnish (at least 80 gal. of oil per 100 lb. of resin). Ordinary spar varnish may be mixed with boiled oil, but the cost is likely to be greater. Aluminum priming paint must be thoroughly dry before the top coat of. paint are applied over it. Other priming paints or priming procedures have been sug gested in recent years. Some of them are being tested by the Forest Products Laboratory ox by paint manufacturers. (8) r sA<q X +1 t u v wx y z{ {E1 P1 0 q . F1 0 H Xq X Much uncertainty about painting practice has arisen in the past because paints that give excellent service when exposed on test feriees sometimes fail in an unreasonably short time, perhaps within a year, when applied On houses. Within the last few years observations by the Forest Products Laboratory (9) and by the West Coast Lumbermen's Association (10) have shown that such difficulties are due neither to faulty paint nor to de fective lumber, but are caused by improper methods of drying the budding moisture in hew buildings, errors in designing the structure, faulty construction, or unusual conditions of occu pation. The essential factor is water 'gaining access to the bqck of the painted boards either through leaking joints of one kind or another or by condensation from moist air coming in contact with the backs of the boards during cold weather. Many details that frequently prove sources of trouble have been described. The only sure cure for such ills lies in preventing ac cess of water to the backs of the painted hoards. No paints now on the market are proof against moisture failures of this kind, and no woods are immune to them. |}CXq _ 0 Xq Studies in recent years have contributed largely to the stabili sation of painting practice for wood by removing much of the mystery and vague speculation that has beclouded the subject and also by setting forth clearly the basic factors responsible ipr the chief uncertainties of paint behavior. The durability of coatings on different softwoods varies widely because aged coatings do not adhere satisfactorily to summerwood and the amount and distribution of summer-wood in soft woods ranges between wide limits. To a limited extent paint service may be improved by selecting, for purposes where paint ing is important, woods that are light and have only narrow bands of summer-wood. However, painting is usually only one of many considerations in choosing a wood, and other re quirements often dictate the selection of woods with wide bands of summer-wood. Furthermore, Table 1 indicates that by far the greater part of the available lumber supply is of kinds that contain prominent summer-wood. The woods with wide summer-wood bands can be improved for painting purposes by cutting them as far as possible so that edge-grain surfaces are exposed for painting. The flat-grain boards should be surfaced so that the bark side rather than the pith side is exposed. Further improvement in paint service on woods containing much summer-wood is not to be sought in special proportioning of the oil and thinner in the priming coat or in choosing unusual volatile liquids. The painter may remain free to employ these variables to facilitate application. Thus he may vary the pro portion of thinner to control the consistency and spreading rate o the paint. The durability of paint coatings on woods with wide bands of summer-wood can be increased by priming them with a properly made aluminum paint, given ample time to dry. Abnormally early failures of coatings are not due to the paint nor to the wood, but rather to unhealthy moisture conditions which must be cured before acceptable service can be expected. However, after full advantage has been taken Of the fore going means of improvementj painting practice for wood still falls short qf the standards that engineers expect of the ma terials with which they work. Failure of coatings by bodily detachment from the wood, leaving the surface bare, is inherently unsatisfactory because it leaves a part of the Wood temporarily unprotected, presents a difficult surface for repainting, and affords an insecure foundation for the new coating. The ideal coating would wear away evenly and remain continuous and firmly adherent until" the need for repainting becomes clearly apparent in lack of *opacity. A real stabilization of painting practice for wood cannot be reached until this ideal is achieved through research. ~ ' L0 RX~ ~ q _ (L) Browne, F.L., "Wood Finishing, a Chance Ahead," Mechanieal Engineering, 48, 1288 (1926), (2) Browne, F. L., "Wood Finishing Studies of the Forest Products Laboratory," Proceedings, Scientific Section, Amer. Paint .and Tar nish Mfra. Assn., Circular 184, p. 278 (1923). Browne, F. L., "The Painting Characteristics of Different Kinds of Wood," ibid., Circular 219, p. 175 (1924). ! i A' ; FLB 000818 WOOD in d u s t r ie s * . Browne, r I,, "The Painting Characteristics of Woods, II, tte&hlta After Two Years' Exposure," ibid., circular 290, p. 202 jBrowne, F. L., "Procedure XJsed by the Forest Products -'tobowtory for Evaluating Paint Service on Wood," Proceedings, <rHni*r Society for Testing Materials (1930). ' - ti) Browne, F. L., "Properties of Wood That Determine the ' gervwe Given by Exterior Paint Coatings," Official Digest, Federa- 'b&'in of Paint and Varnish production Clubs, no. 95, p. 106 (1930); ~ Jnff Paint Journal, April 7. 1930, p. 22; Paint, Oil and Chemical ' Arrets, Mar. 2(1, 1930, p: 9,, {g, urowno, F. X., "Paint and the First Stages in the Weathering v iif W mid," Proceedings, Scientific Section, Amer. Paint and Varnish ^ * Mfr5-. Assn , Cm ular 238, p. 289 (1925). U; V 1 efl) Browne, P L., "Effect of Priming-Coat Reduction and Special Primers Upon Paint Service on Different Woods," Industrial and Engineering Chemistry, August, 1930, (7) Edwards, J. D,, and Wray, R. I., "Protecting Wood With Aluminum Paint," Industrial and Engineering Chemistry, 19, 975 ' (1927). (8) Gardner, H. A., Proceedings, Scientific Section, Amer. Paint and Varnish Mfrs. Assn., Circular 231, p. 234 (1925); 281, p. Ill (1926); 314, p. 432 (1927). (9) Browne, F. L., "Some Causes of Blistering and Peeling of Paint on House Siding," Proceedings, Scientific Section, Amer. Paint and Varnish Manufacturers Association, Circular 317, p. 480 (1927). (10) Hartwig, O. R., "Causes of Paint Failure on Sidewalls," ibid., Circular 355, p. 742 (1929). _________ * .4 t*n Hjl 1** A \ l h' in olir FLB X. PAINTING OF WOOD ex t e n s iv e experiments by the (government and Some Wood Surfaces Hold Paint Longer Than by independent paint experts have shown Others," has summarised the most important facts ' conclusively that cypress lends itself excel upon which the successful paint surface depends; lently to painting with the types of linseed oil "The painting characteristics of a board depend paints commonly used for painting houses. Paint primarily upon the amount and distribution of should be applied to cypress in exactly the same summer wood in if. Summer wood is the dense, way that it is commonly applied to other soft woods. homy, dark-colored portion of the annual growth No special kinds of paint, no unusual proportion ring, formed in the tree late in the growing season. ing of paint ingredients, no special paint fhinners, It is made np of wood cells with very thick walls and and no departures from customary painting prac small cavities and is in this sense much less porous tices are required. than the spring wood, which is composed of cells Until within comparatively recent times, most with thin walls and correspondingly large cavities. Although liquids move more readily through the the chemical composition of the paint and very dense Rummer wood and paint oils are found to little, if any, attention was paid to the character penetrate more deeply there, paint coatings do not istics of die wood surface to which the paint was to seem to secure so firm an anchorage on summer be applied. Within recent years, many investiga wood as they do on spring wood; as a result, coatings tions have been carried out, in which the character exposed to normal conditions of weathering fail by * of the wood surface has been considered just as much as the paint applied to the surface. Notable the spring wood remains apparently well covered. B among these investigations were those initiated in All native softwoods contain both summer wood and 1924 by the U. S. Forest Products Laboratory. A spring wood, but the proportions vary in different large number of test fences were erected in various woods and in different boards of the same wood. parts of the United States consisting of several thou There is in fact a greater variation in painting char sand test panels. All commercial softwoods were acteristics between the spring wood and summer included in these tests. Comparatively few paints woodin a single board than there is between average were used in these tests because the influence of the boards of different woods. paintcompositiononthe durability ofthe paint coat "The density or weight per unit volume of a soft ing is reasonably well understood from other tests. wood board measures roughly its ability to hold On this account, most of die panels in these tests paint coatings because hoards are heavy or light ac were tested with two paints, white lead paste paint cording as they contain much orlittle summerwood. ami a typical prepared paint, containing white However, if a hoard has many annual growth rings lead, zinc oxide and asbestine. From the results of per inch, it may have the summer wood confined to the Use of these two paints and the existing knowl narrow hands and yet be moderately heavy. Such edge of paint composition the behavior of most boards hold paint far better than boards of equal house paints can be evaluated. weight cut from more rapidly grown trees, in which the summer wood is present necessarily in wide WOOD PROPERTIES THAT AFFECT hands." PAINT DURABILITY PAINT CHARACTERISTICS OF All wood should be in the air dry condition be fore it is painted. Paint applied to green wood may DIFFERENT SPECIES OF WOOD blister and peel or, if that does not happen, the The experiments of the' Forest Products Labor coating may crack in an objectionable manner atory, which is maintained by the U. S. Government known as alligatoring, which is due to insufficient drying of the pwniing.com. Moisture retards the at Madison, Vis., resulted in the following classifi cation of softwoods by species: drying of paint, especially so on cypress and red wood, which contain characteristic chemicals that impede oxidation of linseed oil. On dry cypress Woods on which the paint remained intact and tarnished adequate protection the longest. paint dries normally and the chemicals exert a fav orable influence on the durability of the coating by hindering the ultimate Oxidation of the oil that causes final paint failure. Group 1 Cedar, Alaska. Cedar, Port Orford. Cedar, western red. Cypress, Southern. Redwood! Ordinarily the nature of the wood painted does not affect the behavior of the paint coating for at least a year or two after the paint has been applied. Ultimately the coating fads, of course, and it does so at an earlier age on some kinds of woods than on others. GroupS Woods that the paint eoaUnga foiled to protect against weathering as long a! they did die woods of group 1 even though the paint coatings re mained intact about as long. Pine, northern white. F. L. Browne, in the U. S. Dept. Agriculture Leaflet No. 62 of September, 1930, entitled "Why Pine, western white; Pine, sugar. [341 N41698.11 FLB 000820 cross-section of the pores and indirectly on the direc- tion of grain of the wood. As an approximation, it qay be assumed that the porosity of the wood is tersely proportional to the resistance*, No islandartlof porosity has been established for the deter mination of quality of the separators. The. figures given in Table 7 are for separators of the Wpe used in starting and lighting batteries. The separators had 16 ribs and 17 dots. The thick ness of thesbackweb was 0.052 inch; the thickness over the rin^0.085 inch; and the mean thickness 0.063 inch, Atkof these separators had received the same treatment."-*. Those interested in a farther study of this problem are also referred to a recent paper of the U. S. Bureau of Standards entitled "Measurement of Electrical Resistanceand Mechanical Strength of Storage-Battery Separators," by C. L. Snyder, Tech nologic paper of the Bureiui of Standards, No. 271. TABLE 7 Resistance of Storage Battery Separators Each figure is the mean of observations on four samples each hind. The separators were allowed to stand for 23 in sulphuric acid of L280 sp. gr. before being measured, resistances are expressed as the resistance per square im surface in the electrolyte of specific gravity 1.280 at Wood Cut Cherry................ Basswood.................... Redwood.......... .............. Redwood................... Cedar............................ Cedar........................... Sit.................................... Cypress............... Rotary Rotary Rotary Sawn Rotary Sawn Rotary Rotary Resistance in Owns Per Sq. Inch / Pm- dm2 0.042 / 0.054 / 0.084/ 0o..0o6jf?t 0.$57 0/116 fl.124 0.0027 0.0035 0.0054 0.0041 0.0054 0.0037 0,0075 0.0080 IX. HEAT INSULATING VALUE OF CYPRESS WOOD I s is used for a good fbany purposes need hardly be given ideradon in estimating where the factor of heat conductivity is of its conductivity. significant. Cypress is particularly adapted on account of its decay resistance, ease oArorking, FABLE8 etc., to uses for fireless cookers, ice-cream took vats, refrigerator rooms, incubators, etc. It is therefore of interest to know something of its heat condi Heat Conductivity of Wood and Various Other Materials at/Ordinary Temperatures* ing properties in comparison with other materials. `"Wood conducts heat comparatively slowly. This is one of the principal properties that makes lumber desirable for building material, furniture, handles, refrigerators and fireless cookers, A wooden wall allows much less heat to pass through it than an iron, concrete, brick, or stone wall of the same thick ness and under the same conditions. /"The rate at which heat passes through dry wood . / / Substance Number of calories of heat which pass from one face to theopposite faceof 1 cubic centimeter of the material within 1 second of time when the dif ference in fhe.temperature of thetwo faces is 1 degree Centigrade ^depends upon the direction of the fibers and upon the density. Wood conducts from two to three times Ct as much heat along the fibers as across the fibers, /ATsWbeislltobsoapradpe..r... other conditions being the same. 0.00006 0.000164 0.00017 0.00029 0.00081 "Dense woods conduct beat more readily than 0.0022 0.000106 light woods because in light woods a larger volume is occupied by air spaces, and air is a poorer eon- / ductor of heat than wood substance (cell walls}/ f. Therefore for fireiess cookers, ice-cream container, and other articles requiring good insulation, as fight a wood as is practical should be used."* / Cypress is one of the lighter woods and its heat conductivity is correspondingly low,/namely 0.00023. The following table* gives the^heat con ductivity of wood and various other materials at ordinary temperature. / Investigations are now in progress' dealing with some of the details of heat conductivity by various Concrete, cinder . Concrete, stone . Cprfcboard, pore Cotton, firmly packed .................... ... Flaxlinum, vegetable fibers firrl^ and flexible...., Glass, window ............. Granite .......................................... Hair felt 0.00010 0.000113 0.0025 0.0053 0.000085 0.000102 0.144 6-0047 to 0.0056 Insulite Iron, wrought ............ Limestone and marble Idnofelt, vegetable fibers between Iayera\f paper, soft and flexible ,........ Pulp board, stiff pasteboard Sand, white dry ................... 0.000103 0.60015 0.00093 0.0055 6.00012 0.00186 BFBCaoiyrlpxs,rwaed.osr.osy.d,...a...c.....r....Wo.....s....o.s.....o.....f.WSSd..i...b?..aa...a..en.w...t.dr.ed...s...ru...t...o.s.....nt.....e......,........d....r...y.. .........0...1..2. 0.90 0.46 Along fiber ..................... 0.00012 86 Spe0o0c..i0ofi0Mcohtgpf r9avity1 species of wood. While these have not gs yet pro gressed very far they already indicate the following: Greenheart ................................... .... Gum, red, across fiber (b)...... Along fiber (b)....... 1.08 0.50 0.50 0.00112 0.00016 * 0.00044 First --- Relation between jmoisture content and Lignnm-vitae ................................ Mahogany .......... 1.16 0.55 0.00060 0.00031 to 0.H conductivity. It is of course recognized that the higher the moisture content of wood the greater its Maple, hard............... Pine, white................. Virginia .................. 0.71 0.60 0.55 0.00038 0.60027 0.00033 conductivity. Recent tests indicate that the amount of moisture present rather than the percentage pres ent is the influential factor. Pine, across fiber (c)................... Along fiber (c) \............ Oak ........ Oak ................................................... Poplar, yellow ............ *. ... 0.61 0.65 0.58 0.00010 0.00030 0.00035 0.00058 0.00041 Second---Presence of knots. Indications are that the percentage of knots ordinarily present in lumber Wool, pure, loosed packed .. 0.00009 * From Smithsonian Physical Tables except (b) which are given as "satin walnut" by Barratt, T., 'Thermal Conductivity," Proceedings Physical Society of London, vol. 27, 1914; and (c) which are taken The Properties and Uses of Wood, by Arthur Koehler, p. 67, .1924. from Duff's, A. W. "Textbook of physics," 1910. 33] FLB 000821 amt Illl rf' u i'.'t \ r*vs ; Groap S Woods from which the paint coatings flaked more rapidly than from the Woods of groups 1 and 2 and which paint coatings failed to protect as Jong as they did die Woods of group 1. Fir, white (and other true firs). Hemlock, eastern and western. Pine, western yellow. Spruce, eastern and sitlca. ' Group d Woods from which the paint coatings flaked most rapidly. Douglas fir. Larch, western. Pine, southern yellow; The classification by species is somewhat of a rougb approximation because there is a wide varia tion within most of tbe species in the painting characteristics of different types of boards. Thus tbebetter types of boards sawn from woods in Group 4 paint as well as the poorer boards sawn from the woods in Group 3 and the better boards sawn from Group 3 woods are as satisfactory as the poorest one from Groups 1 or 2. The grouping by species gives the average results that may be expected from these species as they are customarily bought and used. If the better types of boards within a species areselect ed, the behavior of paint coatings on them may be more satisfactory than the average rating of the species. Edge grain boards are decidedly better for paint ing than fiat grain boards of the Same species, par my; ticularly in the woods of Groups 3 and 4. Paint mKu r." Coatings remain intact longer on edge grain than.on flat grain boards and edge grain boards require less feting. * Flat grain boards paint better on the bark side than on the pith side. Thebark and pith sides may be distinguished by the curve of the annual growth rings, seen on the end of the board. The rings are convex toward the bark side. If the grain of the wood becomes loose and shells Up it almost always does this on tbe pith side and rarely on the bark side, which makes the pith side less desirable for painting than the bark tide. Tins loosening of tire Iain on the pith side may cause early flaking of 1 c paint coating. Raised grain is also more notice able on the pith tide than on the bark tide. Boards of high grade within any species, paint to better advantage than hoards of low grade, for the Teason that such defects as knots, pitch pockets, ||: and pitch streaks prove difficultto handle. Over K |||p knots in the white and yellow pines, the paint coat ing often tarns yellow and sloughs off-leaving the S *V, knots exposed. Knots in cypress, the cedars, red si wood, the true firs, the hemlocks^ the spruces and larch, seldom cause the paint coating to turn yellow or slough off, but the knots are difficult to conceal Hud sometimes crack; Pitch pockets and pitch SgsfSts Streaks often cause the paint coating to crack and IC4* ar its appearance by exuding resin. Pitch pockets $ *\VA ould be chiseled out to remove all resinous sub stances and then be filled with putty. if 'When the factory or shop grades are used and the defects such as knots, pitch pockets, etc., are re moved by remanufacture, it is natural that many paint troubles are also removed, but the fact remains that the dear wood remaining is often less desirable for painting than the wood contained in the select grades as these shop Or factory grades come from that part of the log nearer die pith of the tree where the wood grew faster and where it is less uni form in texture. The woods of Groups 1 and 2 are the softwoods of light weight, uniform texture or both. The woods of Group 4 are heavy and uneven in texture. The Woods of Group 3 are either moderately heavy or uneven in texture. These two properties of wood, density and texture, afford an excellent means by which the painting characteristics may be judged. The reason for this is that early failure of the paint coating such as flaking, always begins over the bands of summer wood, particularly if they are wide, and the amount of summer wood determines the density of the wood. SAPWOOD AND HEARTWOOD Under ordinary circumstances, there is very little if any difference in the behavior of paint oyer sapwood and heartwood. If the unprotected surfaces of the hoards come in contact with water for long periods, however, the paint may fail over the sapwood sooner than over the heartwood. In most types of construction such conditions can be avoid ed, hat if water or continued moisture cannot he kept out, the heartwood of one of the durable species. Such as cypress, should be used to prevent early decay of the Wood. CHARACTERISTICS OF DURABLE PAINT Inasmuch as the authorities differ widely about the relative merits of the several kinds of house paints on the market, it is safe to say that each has its advantages and disadvantages as compared with the others and the choice between them mast re main, to a large extent, a matter of personal opinion. Most experts will agree with tbe few general prin cipals which follow- - The moat durable paints are dark in color. Pure -iron oxide red paint and black paint made with one of the carbon blacks are the most durable of all. The yellow, red and brown paints made with na tural earth pigments in which the color is due chiefly to iron oxide, or paints made with artificial iron pigments are vety durable, as are also paints made with chrome yellow, chrome green and Prus sian blue. Even the best white paints are much less durable titan these deeply colored paints. Paints of light color made by tinting white paint with the deeply colored pigments are intermediate in dur ability. White paints owe their whiteness and opacity to one or more ofthe following opaque pigments: basic carbonate white lead, basic sulphate white lead, tine Oxide, leaded tine oxide, titanox, or lithopone. [l 1 'l < J . FLB 00082 Besides these white and the colored pigments, many paints contain so-called inert pigments which lack opacity. Common inert pigments are: asbestine (magnesium silicate), silicia, barytes blanc fixe (barium sulfate) , china clay (kaolin) and whiting. Moderate amounts of inert pigments often serve use ful purposes in paints, hut white or light colored paints containing large amounts of them are cheap paints and are either deficient in opacity or else limited in the amount of surface that a gallon of paint will cover. In paint, as in Itunher, the price paid may be indicative of die service which wul he rendered. The liquid in a good honse paint is at least fourfifths pure linseed oil. It contains at most only a trace of water and no varnish, except that blame, dark bine, or dark green paint may contain some good varnish. The following rules will serve as a rough guide in choosing paints for quality, assum ing that the paints compared are of the same color and reduced to proper consistency for application of a final coat. 1. Choose the paint containing the highest pro portion of pigment to liquid, if possible determining the proportions by volume because the proportion by weight is somewhat less reliable. 2. If they are white or tinted paints choose the one containing the highest proportion of opaque white pigments. If a deeply colored paint, choose the one containing the highest proportion of iron oxide, carbon black, chrome yellow', chrome green or prnssian bine. White lead is the oldest of the opaque white pig ments and is the only one commonly used Without mixing with other opaque white pigments. Straight white lead paint chalks deeply and doughs from summer wood in very small flakes. If repainting is 4eferred until much summer wood is left bare white ,4ead paint leaves a surface more easily covered smoothly with new paint than other pigment mix tures. Paints containing zinc oxide and white lead usually do not chalk as deeply, fade less in color, and may not become as hadly soiled with dirt. If repainted before there is much flaking from sum mer wood they offer a less absorptive surface on which a smooth glossy coating can be restored with a single coating instead of two coats, but if repaint ing is deferred until much summer wood is bare, such paints leave a rougher surface because the flakes of coating that fall off are larger. In extreme cases, the old coating may have to be removed be fore repainting- Paints containing titanox and zinc oxide in suitable proportions are very opaque, chalk superficially, hold their color well, and remain rela tively free from dirt. Lithopone is cheaper than the other opaque pigments and, in combination with zinc oxide and inert pigments, can be made into very serviceable paint. In localities where the climate is ordinarily very dry for at least a part of the year, straight white lead paint is more durable than mixtures of white lead and zinc oxide. In humid southern climates snch as the south Atlantic and Gulf Coasts, mixtures of zinc oxide and white lead outlast straight white lead paint. Ih moderate climates like New England and the middle Atlantic states, all paints jure more dur able and there is little difference in durability be tween straight white lead and mixtures of white lead and zinc oxide, provided that the amount of zinc oxide is not more than half that of the white lead by weight. Paints are sold in the farm of paste, semi-paste or prepared paints. Prepared paints contain the proper amounts of liquids and drier for application as finish coats and are sold in white and many colors. Paste and semi-paste paints are usually white or one of the deep colors and mast be reduced with linseed oil, volatile thinner and often some drier added before they are ready to apply. To make paint of light color, some of the deeply colored paints must he thinned and added to the white base paint in suitable amounts and colors. Paste and semi-paste paints have the important advantage over prepared paints in that the painter can alter the proportions of pigment, oil, and thinner over wider limits and is therefore able to mix priming coat and body coat paints that are not easily obtain able with prepared paint. RECOMMENDED PRACTICES FOR PAINTING WOOD Lumber for exterior construction should be in an air dry condition before it is delivered on the job. After receipt, it should be so handled that it will remain in that condition until used. Lumber piles should be raised above the ground, providing ven tilation underneath and the piles should he kept covered as protection from rain. Exterior lumber should not be stored in a heated building where it may become too dry. After erection, dressed lumber should be painted promptly. The best moisture content of lumber for painting is roughly from 12 to 18 per cent. If the surface of the lumber.becomes wet with rain or otherwise, it should be allowed to Standardpractice calls for three coats of paint on new wood surfaces. Paint purchased in the form of semi-paste should he mixed according to the following formulas: 'First Coat Second Coat Third Coat Semi-paste paint, gallons 111 Raw linseed oil, quarts. 4 1 1% Turpentine, quarts .... 2(4 1% % Faint drier, pints........... % (4 % Boiled linseed oil may he used instead of raw linseed oil, in which case only half the indicated amount of drier should he added. If the semi-paste paint already contains the drier, use raw linseed oil and do not add any more drier. White lead paste paint is sold by weight instead of by volume and in the forms of soft paste (semi-paste) and of heavy paste, which contains less oil. One gallon of soft paste white lead weighs 30.8 pounds and should be mixed with the amounts of liquids given in the formulas. To mix heavy paste white lead, take 28,4 pounds, add 1% quarts of raw linseed oik and then add the liquids given in the formulas. To make tinted paints starting with white paste paints, mix white paint according to these formulas, then thin the accessary kinds of deeply colored pig ment pastes (colors ground in oil) with a little turpentine and add them to the white paint in the required amounts to give the desired color. Ordin arily only a small amount of colored pigment is necessary. 361 FLB 000823 Jffew woodwork is sometimes painted with two of three coats. When skilfully done, satis factory reBolts may be obtained, but the practice It not generally recommended. Thicker coats must bo applied and therefore the mixtures should he ma<tp. as follows: First Coat Second Coat Serai-paste paint, gaflons............. 1 I Raw linseed oil, quarts................. 2 2Vz ^Siipcntine, quarts ........ .. 1% % Paint drier, pints .............. . %% Jf prepared paint is purchased, three coats should always be applied to new woodwork because pre pared paint is designed for such use. For the prim ing coat, 2 pints of linseed oil and 1 pint of turpen tine should he added to a gallon of prepared paint. For second coat add 1 pint of turpentine to a gallon of paint. The paint is already correctly mixed for third coat. Repainting should be done before flaking of the old coating from summerwood goes very far and before wood checking due to insufficient protection has advanced to any great extent. When repaint ing is done at the proper time, one coat is often all that is necessary and, if the old paint contained zinc oxide, one coat is often all that is desirable. It should be mixed according to the instructions already given for third coat paint on new wood work. When the old coating is very absorptive or when repainting has been deferred until there is much bare summerwood, two coats are needed which may be mixed as follows: First Coat Semi-paste paint, gallons............... 1 Raw linseed oil, quarts, ................. 114 Turpentine, quarts ....................... 214 Taint drier,pints ................... % Second Coat 1 2% % % The foregoing formulas are suitable for painting all softwoods. Recommendations are often made to use special thinners in place of turpentine or to change the proportions of oil and turpentine greatly in mixing the priming coat for some Woods. Investigations at the Forest Products Laboratory prove that such alterations do not improve and, if carried too far, impair the durability of paint coat ings. SOME REASONS FOR SO-CALLED PAINT FAILURES A choice of those species that take and hold paint better will overcome some of the difficulties of paint failure, but the conditions governing the use of lumber and paint are more responsible for unreasonably early failures of the paint to either protect or continuously beautify, than are the ma terials themselves. Probably the chief cause of early paint failure is moisture. More than any one thing and probably any combination of other causes excessive moisture either on or in the wood to be painted, or moisture coming from within the house. Or from poorly drained surroundings, causes the greatest number of so-called paint failures. Moisture within a house will seek an outlet when humidity of the outside air is lower than inside. This moist are, if allowed to find its way out through the side walls, will certainly cause trouble for the out side paint. The paint may peel, blister or in other ways destroy the continuity of the paint coating. This moisture may be present in the house from natural continuous sources or may be caused by attempts to quickly dry out the plaster in newly com structed houses, thus driving the moisture through the puttide walls. The basementmay contain moisture which comes in through poorly built walls or floors. It need not be visible to the eye, but if moisture stands in the soil around or under the walls or floor of a poorly constructed basement, this moisture will surely find its way upward and be absorbed by the various materials used in the house construction and later be given off through the walls canting trouble to the outside paint. After a survey of some 1,500 houses of all types by a competent authority, a very substantial per centage of paint failures was traced to these sources and could have been prevented by proper caution. The various causes of paint troubles on the outside of house walls all deal with excessive moisture from one source or another, except where the paint it self is at fault and this latter condition is more rare than is usually considered. It is only necessary to adopt such type of con struction as will prevent moisture from getting into the basement and also provide proper ventilation of the side walls and attic to allow of the passage of this moisture to the outside air, by other means than through the walls. If daring construction and the drying out of the plaster, sufficient time and ventila tion is provided, very little trouble, if any, will develop on fihe outside painted Walls. Some of the modem types of house construction bring about tighter and tighter wall construction, thus blocking up aR air passages through which moisture might find an outlet to the attic and escape through the wooden shingles, if the house is for tunate enough to have this time-proved roof cover ing. The present emphasis on the value of insulating materials to prevent heat losses brings about a type of construction that leaves few, if any, channels through which moisture can easily find an outlet and it must therefore he absorbed by the walls and thus pass to the outside air, either through the paint or by pushing the paint off to form an opening. Circular No. 317, October, 1927, of the American Paint and Varnish Manufacturers Association, by Henry A. Gardner, entitled "Painting Defects on Wood Surfaces, Their Cause and Cure," lists most causes of paint failures both from moisture and f*om improper application of the paint. A study of this pamphlet is recommended. SUMMARY The foregoing deals with fundamental facts relat ing to the painting of wood surfaces. All of it applies to the painting of cypres.s. Careful atten tion to the principles discussed will result in success ful painting. Good construction, durable paint, and skilful craftsmanship in application are most economical in the long run. Nowhere will the original investment pay better than in the painting of wood surfaces. [37] sb FLB mBmmm 4 **-,*> PWo Twenty-Two WmmBSmSmmmmmmm {/ * MjfoostuJkto\ Committees Agree to Drop! $33,700 Laboratory Re quest for Durabiftty MMMKKKKKKMKm Extensive research work of the Foreat Products laboratory for im proving tbo adhesive quality ot "jjaihis to malic them last, from 15 to JC.IH Oil demi'llls )l llly.p . hia In -1 tf-Mpm ll !>' liela; i d Iim.lU'l! of $39,700 cut from the- laboratory ap- Hprietions for jieyt year which the II inn-fi ., >.' i.iim'i'l r mil e Monday. Appropriations of $526,000 for maintaining tlw regular work of the , laboratory next rear were the same iii tli ' u Hi mo aml'f i . piiip'-ii inn*. rerjai-iort w-ro ial.-nd- d to speed 'up three proposed re- H-oirfiF, of tie laliiMiituiv. 'llith amount had been recommended by 'the federal budget bureau and. had .been added to the agricultural de partment appropriations bill, * The budget bureau had approved '' $13,000 to continue the experiments to i nil, l ii -'l l-*|,link 'iMlnn'ii* for wood, $10,000 to improve the i-.it or t... Q0 in fi 11 e biiildiiii s ini! fti-Hi t. rir'i-ti ilioiw ii jinnoi* the lasting qualities of paints on linns* funds 1 I " h MISO oUlf I1t HI I It l II - l Bsed to approve this fund at the .III w* II* WomUi lull (ill irniH*'. i r Ii t lh i li ll to I'i'ud' ti ' e , items. The conferees for the house * refused to accept the senate amend- '`meni'eiifl the ' senate"'conferees agreed to recede. ' To make a paint job last from 15 to 20 yoavs instead of the present 'imorth'ot trom three to seven years ,ii the purpose-lop which the taborv f-tory asked $8,700 of the proposed' 'a Idition-U appropriations Experiments of Dr. F. D. Browne, senior chemist, of the Forest Prod ucts' laboratory, have shown thaf the irregular wearing of paint coats on the outside of dwellings is. due pi bn,' iii rn Hie di-fi {Million or spring and lumber. summer wood in the t & wKsi'e*^' Whiko Jobs T,ast ... m A ICC Ti o*'o ,n*pe,tb,s fliaho0r,t1afndr,,y, ,, tnm|i| Hmoii ' ifiinmd Vot ost"utnim"n*ieet.r'1wTMWnh' nei"fnlhtchTisf-P *. if manufacturers eal WM$h mfli^,r 3t$0S how kUawJf .*.wtnhiach12wtioll 2m0 aykeearsa.- p'anit ioh ,iaa1Mj ' owners all over the eountrl completed which will make the average grad9eas ,0oItts t0mtahn&ufsaucmtumreedl 1111*&'*Zot&Td 83 th9y d0 t0 tbe N41698.12 Pi iming-Goat Reductions for Painting New Wood Surfaces .' By Dr. F. L. Browne pNir txpv,me tsts with winch , ' * tfeis iVp'Hf is coticoi m-d w*'re dc- scribed in d-fail in a first progrr-s / uli'i' i 1 n t . i n li of the Scientific Scrnon, American 0193.1), iiiiil jiv second,,ipraj>cs,-^rc ' ,,`ninftlUs' sen ice was published in the Official Digest of flic Federation! t'l J*um ard Varnish Production QWbs; -3lo.' 127/ pageflOfiS H932).' * *s to -.how how far tin scuutable of the fence and there u> some fail lire in intcnty of the lead ini /ire paint on a few tret areas on the not th side Although it i of interest to report the present status of the tests it this turn tin committee cannot em phasize too stionglj that (he studv is still far from cimiplcti nid that diawing conclusions fiom the pres enr indications. Future develop ments might make it necessary to h r i i i 1 n | * r tab i tions that cruid be made now, Onlci r.i Jintii] j iiluie on the Foui Woods tin1 prnjortion of pigment, lnnacd liakina of the com mgs of all ihter |e<6l paint, lo discover th,0 oplimurr|| . pruning-coat reduction, and to drterjS `IHtrip whether the priming- coaS >u}i h< icdueCd iliffi i cully morel to the natmc nt tin sjttwo xl type- of white paint Ins now pjo grossed far enough to reveal dis tinct ddfeicnc.es between the four woods in the iate at which failure or coatings bv flaking from the mid t tl ii g bath iw c it an 1 rnrec-coa.1 painting into considia-| ttOn the lieh verc rti idt on Nrtr lh le l (< i-t fiiluic m leclwot 1 oul> siiglilH more failiui on mi of Jnisfci! oil paint -wire need JI m ,-i^AijHy^J.jMmpMi^. pmt^. -iksyw weril wiule lent paint, i load aid >tcl phiiit, ami a titanox and ainr cctlai, distinctly more failure an whiti pme iiul by fu the gieitcsl amoiiui of failure on Not way pine. With white lead paint, white pine '-Oea'd-fire) paint' Painting v/uli an aluminum primer made with a llakrliti \irn 'h vihnlc m, iKo +0 eluded ind to di ti rninn win Hi, i tin .effort of this prnnii is to be ittub ittjjtl to the aluminum or to the ear 1tt*h Hint white tmmeiT inuli with tin lw i paint i tint nuns zinc oxide and i je nils with flu pattil con tainun; no while lead, white pine fall ch <r to NIcuvis pint than to cc dai and rctlwood d Since tip second piosueas icporl tile Toic t Product*- Tishorat >r\ the eumimltcc hi- met to lnsput {see feu example fedeution of We in September, 1933. The coat-| Official Digest, No. 9t, page 106 niR9 were 20 months old at the last# [1930]). The data of Table f, winch iisjjvthon 11 il inf of sortu eif tne gives avoiagc values for ceitnin , if y?jjif e, I| physical piopcrtie.s of (Ire hoaids ^>anit bar. he-guu on the -mil h +0 _I0 || with t> hieli thc_ tc-t pan. 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JS-a C 0 cd 'G0.-Cf8t43 ^-0 gH-g-B ^8' a-8 _O, mu oGJ 4u4 tGi'dw yu ' .3cd+ a ft ucu.2o 55 5'j '3 o dcu .CSu ftx3u<dwC4j-2xf^tt.1 4**h o'-*-* G 'S<d =fCt 4-4 O 4X ^w2 cGd .tSd -G^ u JG S,S"aftr f gi p-S 2 ft 42n*itiit G O ^ sI' If- 44P3_| -..-t-4 4^3 Ot -^o"5j2 CTT3-l 5 -8 0 .20 '2'S _ U:!;8. X u ll g ftS - B8 sJ8.S I wl 3G.G cd ^ ft 4 ssls,,e-s I g'5 5 3 `gfc-ga 'dJ P4 H4-4 jTf?t 45$J2, rCc.atu 2Cf*tU4jWos3l Mtc*ou a522, cw 38 fc.^4 8 (4 6 a* <* f. *>J .-* N.U3 00.(34 SSS*Z^ f,t C(MOcr-ait!ONOirO4 5s|-; H frtip2 'o''a>. XtiPZ FLB 000827 FLB 000828 Painting Characteristics of Wood Dr.. F. L. Browne, Forest products Laboratory, Madison, Wie. jHH THE Forest Products Laboratory Within each species there is a $gtthas been studying the painting siderahle range in properties, Tft characteristics of soft woods since only in lumber cut in different fortSt 1924. Experiments were conducted regions, but also in that from ncign% by exposing panels of 18 kinds of boring trees or even from different softwood lumber on test fences at parts of the same tree. Consequently 11 exposure stations in different there is much overlapping in prop' parts of Jthe country, and painting crties between species; for instance, the surfaces of the panels with two dry western yellow pine is usually representative kinds of white, ex- heavier than redwood and lighter terior house paint. The panels were than Douglas fir, but the lightest inspected at intervals to observe the boards of pine weigh less than the course of disintegration of the heaviest ones of redwood and the coatings. heaviest boards of pine outweigh the The study shows that paint coat- lightest ones of fir. The painting ings last much longer on some wood characteristics depend largely upon surfaces than on others and reveals such properties as density and there- the properties of wood that exert fore vary widely within species, most influence on paint behavior. From the technical point of view it The study also indicates the direction is far more convenient in discussing in which improvement in paint serv- painting characteristics to classify ice on wood should be sought. The the woods according to their proper- : findings can be presented Here to best ties rather than, by species, hut the ? advantage by first describing certain classification by species must be con- v characteristics of wood and then dis- sidered also as long as wood is cussing their bearing on paint-service, bought and sold that way. Classification by Species Lumber is cut from trees of many different species and the groupings by species or closely related species is retained in merchandising because in general each species has more or less characteristic average properties ..- and finds uses accordingly. A sharp distinction is made in practice be tween hardwood lumber, which comes from deciduous trees, arid the soft wood lumber from evergreen trees-. Only softwoods need be considered here because the lumber used for the , exterior of buildings is almost en tirely of that kind. In choosing, lumber for a particu lar purpose, let us say house Siding, paintability is only one of a number of factors to be considered, and not necessarily the most important one. Ability to stay in place, ease of working and' of nailing, durability, cheapness; and availability in the de sired pattern must be given consid eration varying with circumstances. No wood excels in all respects and none in common use is deficient in all of them. Classification by Grade In commerce, lumber of each species is subdivided into grades on the basis of the number arid size of defects appearing on the surface of the boards. The highest grade ad mits only boards of clear lumber practically free from defects. Several of the higher grades are. known col lectively as the select grades; they Contain only "lumber of good ap pearance and finishing qualities" arid are the ones most likely to be used where' painting, is important. The common grades permit more defects and uspally go into concealed'parts of structures or are remanufactured, the defects being largely cut Out The defects that have most in fluence ori painting characteristics are knots, pitch pockets, pitch streaks, pitch, and loose grain. Classification by Grain Wood has an oriented fibrous Structure, that is, it has grain. Most of the fibers in a board are arranged parallel to the long axis of the tree or log from which the hoard is 'cut. 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To some extent selection of lumber in accordance with its painting characteristics can be practiced, but improvement in this direction is lim ited by the facts that in choosing wood for any purpose other factors must be considered besides paintability and that most of our avail able lumber supply is of the binds that contain much summerwood. Furthermore, second-growth woods are likely to be less desirable in respect to painting than the virgin stands because the trees will usually be grown more rapidly and will be cut younger. It is conceivable that some means of treating lumber to improve its painting characteristics may be invented, but there is no reason for regarding that point of attack on the problem as particularly hopeful. Improved paint or painting technique seems much more likely to furnish the solution. A coating that would endure in definitely is probably a vain ob jective and perhaps not an alto gether desirable bite, for most people would like to change their scheme of decoration from, time to time. The ideal coating for wood, however, ought to remain an adequate protec tive agent against wood Weathering until its appearance is so changed that repainting is dearly necessary, and it ought to wear down uniform ly over summerwood dud springwood alike, being firmly anchored to all parts of the wood when repaint ing is done. Flaking from summerwood should be uuknoWn. With snch a paint, all Wood surfaces would give equally satisfactory paint serv ice. The attainment of an ideal paint of this kind is an ambitious but by no means unpromising objective. As we see it, the problem is one of se curing firmer and 'more permanent adhesion between coatings and wood. Probably at present aged coatings cling to wood by mechanical embed ding in the rough surface, much as plaster grips lath. Summerwood, with its low void volume and very small voids, offers an uncertain sup port for adhesion of that kind, A true adhesion between wood sub stance and the matrix of the paint coating is called for. Glue sticks to summerwood; why can not paint be made to do so? The- Forest Prod ucts Laboratory proposes to. seek true adhesion between paint coat ings and Wood and invites the co operation of the technical men of the paint industry in that quest. I. i > 2^ : S' K FLB 000834 fl th&MAktdl OfijubStcw* rw(Je>'&'fi 0/ TESTING HOUSE PAINTS for DURABILITY F. L. BROWNE Forest Products Laboratory,* Forest Service, U. S. Dept, of Agriculture, Madison, Wisconsin Paint making is still an art rather than an applied science. The approach to a scientific knowledge of paints and paint durability must be made by the empirical route. The present article outlines some of the variables which must be taken into account in paint testing and describes a technic for the conducting and recording of durability tests. HOUSE paints have been developed empirically out of ancient craftsmanship; they are not yet to be regarded as products of science applied to industry. Many facts have been learned about paints through experience and practical testing but it has not yet been possible to establish general laws of paint be havior to correlate the facts. To be sure, the litera P1 0 q F1 0 X~ T F q _ < TQ0 K0 q Is N O< P Xq 10 q A TXX F q Eq _ X q Xq HX It is caused by moisture gaining access to the hack of the painted woodwork. The possibility of such developments makes paint tests on houses uncertain; it also makes it necessary to study the behavior of paints when subject to such conditions before their merits for general house painting can be fully understood. ture of the subject is replete with theories that are glibly accepted without verification by crucial experimentation and possess a remarkable ability to live on, long after they have been proved grossly inconsistent with the facts. Not only is there competition, between rival theories but the facts themselves must be sought among a mass of utterly contradictory assertions often unsup ported by citation of evidence. Moreover, there is as yet neither a generally accepted technic of measuring the durability of house paint nor agreement upon a definition of durability. The transformation of paint some minor aspect of the problem by methods that are more to his taste. A well-grounded fear that empiri cism in papers offered for publication in the chemical journals may be received with little enthusiasm by the evangels of the profession proves an additional dis couragement. The young chemist's early years in such Industries as paint making would be both happier and more fruitful if his college training taught him that empiricism must blaze the trail for science and that industry must solve its problems empirically when it cannot wait for the more adequate answer ultimately making from an art to a science is much to be desired but is not likely to be achieved for spme time to come even though progress in that direction is proceeding more rapidly than it has in the past. Meantime current problems must continue to be met through frankly empirical experimentation and observation. possible through the scientific method. Empirical experimentation to be effective must usu ally be conducted on a much larger scale than scientific experimentation. This is particularly true of paint testing. Failure to appreciate it has led to great waste of effort and the disappointing results have done much The young graduate in chemistry confronted with to throw durability tests into disrepute. The durabil the problem of paint evaluation often finds it difficult to ity of a paint depends on many factors besides its com adjust himself to the empirical method of procedure. position. Not all of the factors are known. It is, His college training usually has taught him very little about it and, still worse, may have led him to hold it in light regard. As a result he tends to shirk the direct attack upon the immediate objective in order to pursue therefore, essential that the testing procedure duplicate practical conditions of service as closely as possible and take account of the probable variations in conditions of service. Many exposure tests are required to ac * Maintained at Madison, `Wisconsin, in cooperation with The complish useful comparison of even a small number Of University ot Wisconsin. paints, and the tests must extend over a period of several 529 11 N41698.15 FLB 000835 530 JX q 1 C EX~ Q +0 _ 1 _ 1 0 Xq years before conclusions may be drawn. Great care must be taken to plan the tests adequately and to pro vide satisfactory methods of inspection, record, and evaluation. An adequate program of exposure testing is necessarily expensive, time-consuming, and exacting in its demands for trained technical supervision. In the writer's opinion durability tests of paint should never be attempted when these requirements cannot be met. ARTIFICIAL WEATHERING TESTS Strenuous efforts have been made to devise artificial weathering tests for house paints in which results may be obtained in much less time than is required in natural weathering (2). Such tests serve usefully as a subordinate part of the research program in large labo ratories. They are useful, for example, in rejecting from a large number of previously untried paint com positions those mixtures so seriously faulty that they merit no further consideration, so that the smaller number remaining can be tested adequately by natural weathering. Artificial weathering tests probably will increase in usefulness as the nature of the changes that take place when paints age becomes better understood and study of the disintegrating influences, one by one, becomes desirable. Artificial weathering tests are not at present accept able as the sole basis for determining the relative du rabilities"of practical house paints because accelerated deterioration is achieved by deliberate aggravation of some factors in weathering, a procedure that is out of harmony with the requirement that the tests be made leader conditions duplicating those of practical service as closely as possible. Results of accelerated tests are not always in satisfactory accord with results obtained by natural weathering. TEST FENCES The principal means of measuring the relative du rability of house paints is the test fence. For reasons that will be detailed later, houses are less practicable than test fences because complicating factors not yet fully understood sometimes affect the behavior of paint on houses to such an extent that there is often uncertainty whether the deterioration of paint on a house may be attributed purely to normal weathering of the paint. These complicating factors on houses must be studied separately by means of a special tech nic. The first paint test fence in the United States is said to have been erected by the U. S. Gutta Percha Paint Company some time prior to 1907 but its existence re mained practically unknown outside of the company until recently (2a). Many paint manufacturers and paint technologists now conduct such tests (3) but one of the most experienced paint chemists (4) said not long ago that he finds "too few paint companies who have comprehensive and adequate exposure programs. . , . Our future progress in paint development will continue to be based on the evaluations of our exposure tests and not on theoretical considerations.' ' Comparatively little of the data acquired from manufacturers' test fences becomes public through technical publications. The first fence tests to gain public interest were those started in 1907 by the late Senator Ladd while professor of chemistry at North Dakota Agricultural College (2b). They were an outgrowth of the famous North Dakota paint law that required all house paints sold in the state to bear a statement of composition unless they contained only white lead, zinc oxide, linseed oil, turpentine, and paint drier. Subsequent test fences to be made public are cited in the list of references (2c). The earlier test fences failed to provide the expected basis for decision between different types of paint. Some of the worst compositions were clearly demon strated but for the most part opinions about paint formulas remained as divergent after the tests as they were before. The difficulty lay in inadequate under standing of the essential conditions for conducting such tests properly and in the attempt to test too many paint formulas at one time with the means available. Mod em knowledge of testing technic, however, has thrown new light on many of the older tests as a result of which a re-examination of the old records often proves very fruitful (5). TQ0 R I 1 0 y q T q 0 F q _ 1 F q X , C ,1 0 ~X q 0 1 M1 0 q 1 0 q < Q W. P. F CX ., H1 B U q ~X T F< Q X P X _ t s L1 <X 1 X y S0 q _ 1924 No repairs have been required by the unpainted framework, which is made of heartwood Douglas fir and redwoodExposures are made on the south side of the fence only. Note that the panels were painted immediately after erection. The amount of paint applied to each panel was determined by weighing on the balance on the upturned box to the left of the fence. FLB 000836 S +< ,, 1933 TQ T F q _ X~ Q NX Q P V P q 1 0 q 1 q 1 q 0 Q X _ 0 Xq C < 1 Q S 1 F1 0 G X q , St . P1 , M0 q q X 1 , R O0 1 q q W0 G F 1 q_ PX X _ It ~ X+ MX 1 0 Xq Siding lumber is nailed directly to the open framework on both north and south sides.. The test areas were marked off by black stripes and numbered after the test paints had dried. 531 _ Xq _ 0 Xq X~ t ~ q _ protection for posts and paint is of no use whatever for As a rule test fences should be erected in suburban ^kat Ph5Posa' ^'^Le forest Products Laboratory fence or rural environments rather than in industrial centers. Macuson, Wisconsin, built with creosoted posts. Tests made near factories are subject to serious uncer- ^as stod fr nearly eleven years without a single re- tainties because of extreme accumulation of dirt and placement or any sign of rot. A fence at Seattle, soot and possible abnormal chemical reactions with Washington, built with untreated posts of Douglas fir, industrial gases. In such surroundings white paints *ias ^>een ia service for the same length of time, that ordinarily maintain reasonably good appearance The posts Should be connected with a simple frame- have been known to turn totally black and to last much work of 2 X 4-inch stringers and studs to which test longer than they can be expected to do on residences, panels can be attached and covered with a plate or Test fences in the country should not be located in rof projecting an inch or two beyond the face of the unusually damp ground or too close to rivers or lakes to test panels to keep rain water from seeping in behind permit the air around the fence to follow the extremes tee panels. It is advisable to build this superstructure of relative humidity characteristic of the climatic region, also with the heartwood of durable species, particularly Test fences consist of a simple framework for support- so if tee framework is to be painted, and to make all ing painted panels. The framework should be durable joints as tight as possible to keep out rain water, and strong enough to remain upright during the most Trouble has been experienced on some test fences with severe storms. A very satisfactory construction con- decay setting in at such joints when the lumber con sists of 4 X 4-inch posts or 6-inch round posts set at tained sapwood. If non-durable lumber is used it is least 2x/2 feet into the ground, projecting 7 feet above desirable to soak the ends of all pieces in creosote, ground, and set 6 feet apart from center to center. . A especially if they expose end-grain sapwood, to brush concrete collar at the ground line serves to prevent all surfaces, or at least concealed surfaces, with creosote, working under Wind pressure with consequent loosen- and to leave the framework of the fence unpainted, ing of the anchorage in the ground. The posts are although it may be stained if desired, subject to decay, at least below the ground line, and If desired tee framework may be enclosed with lum- must, therefore, be of durable wood. Heartwood of red- ber sheathing from the top down to the lowest stringer, wood of southern cypress is very durable and heartwood which should be not less than 18 inches above the of southern, pine or Douglas fir is satisfactory for ground. Sheathing presents a supporting surface like square posts; cedar or chestnut makes good round that on the sidewalls of most houses but it adds tna- posts. Sapwood of any species lacks durability and terially to the cost of the fence and is not really neces- decays relatively soon. If posts containing much sap- sary. ; wood or non-durable species must be used they should . The most satisfactory test fences are erected verti- be treated with creosote by impregnation under pres- ' cally because that is the position in which most house sure or treated by the hot-and-cold bath method to a paint is used. Most fences run east and west so that distance at least 18 inches above the ground. Failure test panels face -south, if but one side of the fence is to take proper precautions against decay has repeatedly utilized, and north and south if panels are attached to resulted in the blowing down of test fences or in the both sides. The fence should be far enough from build- necessity of replacing posts at frequent intervals. Sur- ings, trees, or other obstructions to expose all panels on face application of creosote does not afford adequate the south side uniformly to full sunshine. Faint wears , FLB 000837 532 JX q 1 C EX~ Q +0 _ 1 _ 1 0 Xq of paint in general but the comparative durability of different kinds of paint. There are two opposite ex tremes of unusually severe eEmate from the point of view of paint; most of the United States, especially the more populous parts, lies between the two extremes. One extreme is fqund along the southern Atlantic Seaboard and the coast of the Gulf of Mexico, condi tions in Florida being typical. Here, for example, paints containing high proportions of zinc oxide are distinctly more durable than pure white lead paint. The other extreme is found in the southwest, the region of the Great Plains, and the interior valleys of southern California. There white lead paint is distinctly more durable than paints containing even moderate propor 6 D ! "# % & $ Aq K _ 7<q T X T N1 L C .0 Xq 1 1 X1 F M q _ 1 0 q 1 0 q < S1 0 . N YX X The framework is covered with sheathing lumber before the test panels are attached. Both north and south sides of the fence are used for tests. The tests shown are a series by the Forest Products Laboratory in which each test panel consists of four boards, six feet long, marked off by stripes into three test areas of which the center is painted with a "control" paint against which the other two are compared. tions of zinc oxide. In both of these regions all paints fail more rapidly than they do in most other parts of the United States. Common characteristics of the two extreme conditions are relatively high amounts of sun shine and high maximum temperatures. The signifi cant difference between them is the high relative hu midity prevailing almost constantly in the one and the exceptionally low relative humidity characteristic of the other during at least a part of the year. out most rapidly on the south side and least rapidly on In recent years there has been a tendency to regard the north side. Tests repeated on north and south tests in Florida as a form of accelerated exposure testing sides reveal the range in durability normally to be ex free from the shortcomings of artificial exposure tests. pected in the region. On the southern exposure paints Florida exposure, however, cannot be accepted as a chalk and colors fade most rapidly, while on the northern satisfactory test of paint for use in other parts of the exposure dirt collects for a longer time, yellowing of country. Parallel exposures in Florida and in the paint oils may be more marked, and there is more southwest might be so accepted but it is wisest to test chance for mildew to develop. By considering both paints for national distribution in at least three charac northern and southern sides the relative appearance of teristically different climates. different portions of a house can be gaged more success- . fully than is possible with southern exposure only. CHOICE OF WOOD FOR TEST PANELS / Some workers prefer test fences on which the panels As a rule panels for testing house paints should be slope back at an angle of 45 degrees from the vertical made of wood because that is the principal kind of because the intensity of sunlight falling on the painted surface upon which they will be used. Paints that surface is thereby increased and failure of paint is ac endure well on metal often fail rapidly on wood. celerated (6). Like other forms of accelerated weather One of the principal difficulties in interpreting the ing tests, however, inclined exposure should be used only results of the earlier test fences arose with the discovery to supplement rather than to replace vertical exposure. that the nature of the wood had as much effect on the Inclined panels apparently undergo greater extremes of durability of the coating as the composition of the temperature and moisture content than vertical panels paint, unless the paint is a very poor one indeed. A and paint on inclined panels acts as it would on vertical prominent paint executive dubbed the earlier tests a panels in a drier and warmer climate. Observations of ` lumber lottery' ' (7). Although recognized since 1912, changes in the appearance of coatings on inclined panels the necessity for carefully considering the effect of the are not entirely representative of the behavior of the wood and practicable means of taking it into account paint on vertical panels- have not been properly appreciated until recent years. A good wire guard fence around the test fence is often Lumber for exteriors of houses is predominantly needed to protect it against vandalism. Many persons softwood lumber. The following factors affect the seem to have an uncontrollable impulse to write on durability of paint on softwood lumber (8): fences. Fences on farms need a guard fence to keep I. The proportion of summerwood, which is the dense, cattle from licking fresh paint with consequent disaster hard, dark-colored portion of each annual growth ring both to the paint and to the cattle. The guard fence - in the tree. When paint coatings begin to break up should be placed far enough from the test fence to leave and small pieces begin to fall off the wood, the disin plenty of room for photographing test panels, tegration sets in and progresses rapidly over the EFFECT OF CLIMATE summerwood. The more summerwood there is, the sooner such disintegration becomes serious. The The variations in climate in different parts of the density of a board at some standard moisture con United States materially affect not only the durability tent usually depends directly upon the proportion r > FLB 000838 S +< , 1933 > of summerwood. Other factors being equal, the u less a board weighs the longer paint lasts upon it. ' 2. The width of the annual growth rings. Slowly grown wood has narrow growth rings and may, there fore, have narrow bands of summerwood even though the wood is fairly heavy. Slowly grown wood holds paint longer than otherwise similar wood that grew rapidly. 3. The direction at which the surface to be painted cuts the annual growth rings. Edge-grain boards are cut with the principal surfaces approximately parallel to a radius of the log and at right angles to the growth rings. The bands of summerwood are of minimum width in such boards and paint is, therefore, held to best advantage. Flat-grain boards are cut with the principal surfaces approximately tangent to the growth rings so that the bands of summerwood are wider and paint fails more rapidly than on edgegrain boards. Of the two principal surfaces of a flatgrain board the one nearer the bark of the tree often holds paint longer than the one nearer the pith of the tree. 4. The grade of lumber. Lumber is graded for sale according to the size and number of defects, of which the principal ones are usually knots. The high grades hold paint better than the low grades, both because knots often cause early paint failure and be cause the low grades as a rule come from the central parts of the tree where the growth rings are usually wider. 5. Resin and other extractives. The resins and other extractives in wood have less effect on paint than is commonly supposed (9). The resin characteristic of the white pines and the yellow pines, which con/ tain rosin, exerts a slightly detrimental effect upon the durability of paints that contain zinc oxide. On the other hand the oily extractive in southern cypress and the aqueous extractive in redwood apparently tend to make most paints last longer. Since lumber is sold primarily by species the follow ing classification of softwoods for painting has been worked out, but it must be remembered that within each species there is wide variation in the above proper ties and consequent overlapping in painting character istics: Group I--Woods that are generally light in weight, of slow growth, hold paint well, and require little paint protection to prevent wood weathering: Alaska cedar Western red cedar Port Orford cedar Southern cypress Redwood Group II--Woods that are generally light in weight but not always of slow growth, that contain resin slightlydetrimental to paints containing zinc oxide, and that require more adequate paint protection than woods of Group I: Northern white pine Sugar pine Western white pine 633 Group III--Woods that are usually either more rapidly grown or heavier than those of Groups I and II and therefore hold paint less well and that require more adequate paint pro tection than woods of Group I: Commercial white fir Ponderosa pine Eastern hemlock Eastern spruce Western hemlock Sitka spruce Group IV--Characteristically heavy woods with wide bands of summerwood over which paint begins to fail comparatively early: Douglas fir Western larch Southern yellow pine By choosing lumber for test panels with careful con sideration for the properties that are known to affect paint behavior, the variability in results caused by the wood may he reduced materially. A relatively large supply of lumber may be sorted for boards of reasonably uniform properties. If such specially selected lumber for test purposes could be made available commercially there would undoubtedly be a demand for it in the paint industry even though it would necessarily be expensive. Variability due to the wood, however, cannot be entirely eliminated even by careful selection and other methods of allowing for it must be adopted. There are two methods of minimizing uncertainty due to variability in the wood. The first is multiplica tion of the number of boards in each test panel and of the number of panels painted with each paint, and the second is the procedure of "matching specimens," that is, comparing paints by applying them to neighboring areas of the same boards. The most practicable pro cedure combines the two. The style of test panel pre ferred at the Forest Products Laboratory consists of four boards of 6-inch siding, each board 6 feet long. Record is kept of the density, width of growth rings, and direction of the growth rings in each board. The face of the panel is then subdivided into three test " * ! #+ -.% & ' (TQ0 T F q _ W1 B 0 0 q 192 0 CXq 1 0 q ^) M _ Q S1 XX LQ +< )TQ1 Although decayed members were repeatedly replaced the fence collapsed early in 1933. The framework was kept painted. Durable lumber or lumber treated with wood pre servatives safeguards the investment made in conducting paint tests. it || ll I: M' w FLB 000839 534 /0 1 2JX q 1 C EX~ Q +0 _ 1 _ 1 0 Xq areas each 2 feet long, one of which is painted with some LAY-OUT OF TESTS paint chosen particularly as a suitable control against which experimental paints on the other two areas can be compared. The best wood for testing the relative ability of paints to remain intact over bands of summerwood is southern yellow pine. When a paint formula has been worked out that lasts well on southern pine it may be assumed safely that it will give good service on any other soft wood. Paint technologists working for paint manufac turers, however, are often expected to submit test panels to inspection by the sales department or by prospective customers and for that purpose they find southern yel low pine less desirable than a wood on which paint lasts longer and on which the ultimate areas of paint failure are not so conspicuous. For tests planned to disclose the range in behavior that will be exhibited by a paint offered for general use in house painting tests should be made on four kinds of wood, one from Group I, a second from Group II, and two from Group IV, of which one should be southern yellow pine. The writer recom mends the following: 1. Western red cedar bevel siding, ` `dear' ' grade, Vz X 6-inch size. This will be edge-grain lumber. 2. Northern white pine bevel siding, "B and better" grade, l/% X 6-inch size. This will be mostly flatgrain lumber. Ponderosa pine should not be ac cepted for this purpose in place of northern white pine, 3. Douglas fir drop siding, "B and better" grade, 1 X 6-inch size. This can be purchased entirely / vertical grain (edge-grain) if desired but the flat grain boards afford a more severe test of paints, 4. Southern yellow pine drop siding, "B and better" grade, 1 X 6-inch size. This will be chiefly flatgrain lumber. Exposure tests are made to best advantage when a fairly large number of related tests are started, at one time. By careful attention to the lay-out of such groups of tests it is often possible to weave together several problems in such a way that each one can be studied more adequately than would be possible if each problem were worked out separately at different times. An excellent illustration of well-planned lay-out is afforded by a test fence at St. Paul, Minnesota, erected by the Northwestern Paint & Varnish Production Club, the Minnesota chapter of the Master Painters' Associa tion, the Paint, Oil, & Varnish Club, and the Retail Lumbermen's. Club of the Twin-Cities (3d), The principal object was to study the optimum proportions of pigments, linseed oil, and turpentine in priming-coat paints. Panels consist of four boards of 6-inch bevel siding each 12 feet long. On unit 1 of the fence, for example, there are two such panels of redwood. Each panel is marked off into 6 test areas, each 2 feet long. The third test area of each panel is the "control" area, which is painted with three coats of white lead paint following proportions considered most representative of good practice among painters. On the first panel test areas 1, 2, 4, and 5 are painted with three coats of the same kind of paint except that the priming coat was mixed with four different ratios of linseed oil to turpen tine and on test area 6 the priming coat was an alumi num paint, the second and third coats being the white lead paint. On the second panel test areas 1, 2, and 4 were painted with two coats of paint only and the paint is, therefore, mixed with a relatively high pro portion of pigment, the ratio of linseed oil to turpentine in the priming coat being different for each area; areas 5 and 6 were primed with pigment-rich mixtures but were painted with three coats of paint. By comparing Lumber for test panels should not be stored in heated the results on each test area with those on the "control" rooms or kept very long in heated carpenter shops or area of the same panel, comparisons can be drawn fairly laboratories. It is best stored in unheated rooms or throughout the series. lumber sheds where the relative humidity never falls This group of tests, requiring 12 test areas, is re below that characteristic of outdoor air in the climate peated on north and south sides of the fence. It is in which the test fence is located. For most climates then repeated, again on both sides of the fence, on the moisture content of the wood should not be allowed panels of western red cedar, northern white pine, and to fall below 10 per cent, of the weight of wood when Norway pine. Finally the entire procedure is repeated oven-dry. ."with a white paint containing zinc oxide and white Test panels should be mounted on the fence with lead and repeated once more with a white paint con the boards running horizontally, as they do on most taining titanium pigment and zinc oxide. Thus there houses. At the Forest Products Laboratory the four are in all 288 test areas assigned to this study. The boards making up each panel are fastened together by large number of test areas, however, is abundantly cleats on the hack so that the panel can be handled as a justified by the assurance that definite conclusions unit before it is attached to the fence. It is fastened to about the primary objective will be reached at the end the fence by driving zinc-coated nails or screws through of the necessary exposure period. In addition, the ade the boards into the supporting framework. If panels quate scale on which the work has been done will yield are mounted against lumber sheathing or if both north additional conclusions about (1) the relative merits of and south sides of the fence are covered with test panels two-coat and three-coat painting, (2) the merits of it is not necessary to paint the backs of the panels but aluminum priming paint, (3) the paint-holding qualities if only the south side of an Open fence is utilized the of four species of wood, and (4) the relative merits of backs of the panels should be painted With two coats of three kinds of linseed oil paint. The three paints can exceptionally durable paint, such as aluminum paint. be compared even though they are not applied to FLB 000840 3MBER, 1935 535 ehed Specimens' ' of wood because each of them is If possible, the responsibility for all inspections for jlied to a sufficiently large number of test areas, they any one organization should rest in one man if the apph. il 0 . a0 variety of ways, and the lay-out is thor work must be shared all inspectors must first of all agree ny symmetrical, that is, for each test area of any upon a satisfactory system of judging to which they i paint there is an analogous area of each of the other must adhere conscientiously if their results are to agree. ijits. 33 4 5 67 8 98 : ;1 0 _ 1 0 XqX~ 10 q X 1 q It is further necessary that they periodically check their judgments against each other. To do so a fairly large J ** ft is best to paint test panels after they have been group of panels representing a wide range in paint r attached to the fence but it is often inconvenient to do ` deterioration should be inspected independently by m i Ian the fence is located at a distance from the each inspector. Their results should next be compared laboratory. If painted on the fence the priming coat and finally discrepancies should be reconsidered by should be applied within a day or so after the carpenter going over the questionable panels together. Groups of has attached the panels because even brief weathering inspectors should never set out upon a fence inspection ' of wood has been shown to impair the durability of pews. Exterior paints applied and allowed to dry indoors before the panels are attached to the fence often develop a coarse form of paint checking that is not representa tive of the paint when applied under more practical working conditions. In its new building the Forest ^Products Laboratory has a large, flat roof with southern exposure in front of the painting laboratory. Test panels will be fastened temporarily to racks on this roof for painting and drying and will later be moved to the test fences for permanent exposure. If painting is in terrupted by sudden rainstorms, trucks will be avail able for moving panels with wet paint into the labora tory until the storm passes. Test panels should be held in a vertical position while painting because mixtures that will cause trouble with running, sagging, and beads at the edges of boards will reveal their shortcomings in that position. Record should be kept of the amount of paint applied per area of surface and these spreading rates should fall within the range characteristic of practical painting. The tendency in many exposure tests has been to apply coatings much too thinly (10). <=> ? @ A BCTQ N1 X~ WQ XX Is 1 I+ X 1 q t D E FGHN1 Q 1 ? I J K L M NP D L P CX~ Q 1 0 q 0 q +0 q 0 q 3 Q 0 ~ X~ 1 10 q X1 0 q 3 OP Q O R R0 q _ 0 Xq 1 q _ X s Carefully planned inspections and records made in the light of a definite scheme for evaluating paint service are necessary if exposure tests are to be fruitful, yet all too frequently investigators have seriously neglected this aspect of the work. There are as yet no generally accepted standards of procedure although some prog ress in that direction is being made. Paints fail through a gradual development of numer ous defects, the mechanism and significance of which are not yet well understood (11a), (lid). Since none of them can be measured strictly objectively and quanti tatively the inspector must necessarily resort to per sonal judgments that are largely subjective in charac ter (lib). Such methods of observation are usually foreign to the training of the graduate in chemistry and yet, if his work lies in the development of house paints, they are essential for determining the value of the prod ucts of his labor. Paint inspection, therefore, is a highly specialized art that should be undertaken only after present knowledge of the subject has been mas tered and a definite plan of procedure has been adopted. This illustration stows a test area made up of three boards of the same species of wood painted with the same kind of paint. The bottom board is the heaviest and has the widest bands of summerwood; the middle board is the lightest. The illus tration shows also the very small photographs used by the Forest Products Laboratory for making records of inspections and the enlargement obtained from it. together, especially if they have not been schooled in a common system of judgment. The discussions that arise make it almost impossible for any one of them to adhere consistently to one plan throughout the inspec tion and the results of such group inspection are less useful than those made independently by any one of the group. The Forest Products Laboratory makes three detailed inspections a year of its test fence at Madison and makes other observations between times to watch for signifi cant developments that may call for additional record. More distant stations cannot be visited so frequently but are inspected at least once each year. The system of judging test panels and the plan for recording and evaluating data followed by that Laboratory have al ready been published in detail elsewhere (lie). 536 ST U VJX q 1 C EX~ Q +0 _ 1 _ 1 0 Xq necessary to use a tripod. An auxiliary lens that can be quickly slipped in place adjusts the camera for taking photographs at a distance of 96/s inches, which is easily measured off with a foot rule; the area photographed at this distance is about 24/3 by 4 inches; that is, it is about 3/g actual size in the contact print and may easily be enlarged to full size or to twice actual size. With this equipment, which can be carried in an overcoat pocket or in a corner of a brief case, the writer often takes less than half an hour to photograph a test fence requiring 100 exposures. The contact prints are about the size of two common postage stamps so. that a com plete photographic record for a test area can be mounted on one 8-by-lO inch sheet which, together with the standard form of inspection record (lie), provides the entire history of the area on two sheets of paper. Al though the contact prints are so small they show a sur prising amount of detail, especially when viewed through a good reading glass, and those exposures chosen for closer examination or publication can be en larged to at least 4 by 6 inches very satisfactorily. EVALUATION OF RESULTS W X Y Z [\ ] ^ _ `aA PQX X3 1 Q0 _ R T _ X X~ 1 A 1 SQX A 1 b c d e f g h ij kB V 3 0 q 0 Q1 0 X~ E AQ q0 1 < It Is O~ q l m n opp q b c r st uD S 0 1 < X + q It C0 Q X r V0 SQX v w xy z { | }D0 q 3 1 0 X~ T P0 _ 1 1 0 q D ~ _ s , S _ Q As TQ0 ~ Oq WQ0 S_ Q QX P1 0 q "CQ _ 70 q 3 " The area included in this view is about 22/3 by 2Vs inches. > A very generous use of photographic illustrations is ./a necessary part of the record of exposure tests. Good photographs of test panels are difficult to take and must always be regarded as supplements to written records rather than substitutes for them. A photograph that shows the entire area of a test panel or test area fails to reveal minute defects that are significant in the written record. On the other hand photographs or photomicro graphs of limited portions of a test area may give a very misleading impression of the area as a whole. An excel lent plan is to photograph the entire test area and to supplement this with photographs or photomicrographs of small portions of the area having typical defects. It is usually necessary to lake a very large number of photographs of which only a few will ultimately appear in final reports or publications. With a view to econ omy and compactness of records the Forest Products Laboratory has adopted a camera for photographic records in paint panel inspection that uses standard mo tion-picture film stored in cartridges for daylight load ing. Each exposure occupies the space of two frames of the usual motion picture, making a contact print about 1 by 11/i inches in size. From 35 to 40 exposures can be made with one loading of the camera. Test areas 16 by 24 inches in size fill the field when taken from a distance of about feet. The camera has an ac curate range finder for adjusting the focus rapidly with out using a measuring tape. The F 3,5 lens permits snapshots even on very cloudy days so that it is rarely An exposure test should lead to a decision about the durability or at least the relative durability of the paint tested. Few experimenters in the past have attempted to bring their work to such conclusion. As a rule they have been content to describe what happened and to leave it to others to draw their own conclusions. Evaluation of the results of exposure tests is admittedly a very difficult and complex problem but those most familiar with the facts should accept most responsibility for dealing with it. If durability is conceived as the period of time that will elapse before users of the paint will renew the coat ing it becomes evident that the behavior of the paint itself is only the beginning of the story. The patience of the paint user with paint defects or his ability to meet the cost of repainting is the center of interest. Perhaps the chemist needs help from the psychologist and the economist to complete his study, but with or without such aid he should reach, definite conclusions about the relative serviceableness of the products he tests. The writer's opinions about evaluating the service ableness of house paints have already been published (lie). For the present purpose it is sufficient to point out the following classes of paint users whose needs must be considered: (1) those who may become sufficiently dissatisfied with a paint because of changes fin appearance, such as soiling and fading, to renew the coating before it shows signs of failing to remain intact; (2) those who do not repaint until the coating begins to disintegrate but repaint before the disintegration goes very far; (3) those who may not repaint until the old coating has failed very badly anfi the house has needed repainting for several years;' and (4) those who never bother to repaint at all. For the first group a paint en dures only as long as its appearance satisfies them. For the second group it endures as long as the coating holds together. For the third group it is less important FLB 000842 i S +< , 1933 537 m ig iy ed is ily ith jat ten ace out qui tted the the Alsurrwed sures e en- that the coating endure than it is that the coating fail thoroughly, leaving a reasonably smooth surface free from patches of partly loosened old coating whose jag ged edges will show through the new coating. The fourth group probably is little concerned about paint durability. Paints considered durable by the first group are often unsatisfactory to the second and third; a few good paints are acceptable to the first two groups hut not to the third; no paint of the present day is entirely satisfactory to all groups. In considering the requirements of different users of paint nothing has been said about protection afforded the wood by the coating. Muchnonsense has been said atid written about the subject. In the first place paint is impracticable as a preservative of wood against decay by attack of wood-destroying fungi (12). Houses are protected against decay by building them so that none of the wood becomes wet unless it be temporarily. If paint-neglected houses were seriously subject to decay paint users of groups 3 and 4 would soon come to grief and would be far less numerous. There are the paint cracks and comes off in conspicuous scales whose size and shape bear no relation to the bands of summerwood beneath. Houseowners' complaints are usually made after this stage has been reached, when the surface not only presents a disreputable appearance but is very difficult to repaint properly. Abnormal paint failure of this kind is caused by moisture collect ing behind the painted boards during the season when the interior of the house is kept at a materially higher temperature than prevails out of doors. The source of the moisture may be leaking joints of one kind or another (15) or condensation from air within the hollow sidewalls when the air is chilled below its dew point. Although the extreme examples of abnormal paint failure caused by moisture are easily recognized the less well-defined cases are not. The writer has seen houses on which the type of paint failure was identical with that of similar paint on test fences but the comparatively early development of failure suggested that a few boards of siding be removed, whereupon the moisture in the sidewalls was revealed. Abnormal paint failures difficulties with decay in some houses but they occur as caused by moisture are so widely prevalent that the often where paint is well maintained as they do where it houseowners of the country are suffering a serious eco tt the paint upted i the S nil To isiotn ittedlv ; most sibility is neglected and the remedy lies either in improved con struction of the house or in the use of naturally du rable kinds of wood or of wood treated with toxic pre servatives. % Unpainted wood or paint-neglected wood is subject to a form of deterioration known as wood weathering, .fc against which paint affords adequate protection (12). "Hie degree of protection afforded by different paints ||: can be measured quantitatively and entirely objectively by technic that has been published and has been used in nomic loss through unsatisfactory paint service and unduly frequent and expensive repainting. Even when the cause of the trouble has been discovered, it is still impossible to tell many of these houseowners what they can do, within their economic means, to prevent recur rence of such difficulties, The uncertainties about abnormal moisture failure make paint testing on occupied houses difficult as well as inconvenient. Normal paint failure is best studied by means of test fences. On the other hand, paints le thul | ie coat- | e paint latience to meet |f Perhaps | and the without 1 oout the i ;s. I service- I mblished I dent to | several laboratories (13). The practical significance of paint protection is somewhat uncertain, however. On the one hand, it is true that changes in moisture content with consequent swelling and shrinking cause a great deal of trouble in using wood but, on the other hand, many houseowners, especially fanners and wageearners, do not seem to object very much to more or less weathered wood. Paint users of group 1 probably demand adequate paint protection but their painting habits insure adequacy of protection without worrying about it. For paint users of group 3, which is probably much more numerous if not so conspicuous, protection appears to be of minor importance. should also be studied under controlled abnormal con- rs whose I EXCEPTIONAL BEHAVIOR OF PAINT ON SOME HOUSES y become | f changes | Aaew the 3 tin intact; ; begins to 1 ition goes ; til the old las needed who never a paint ensfies them, die coating .'important " * ` * i | | | As a rule paint lasts somewhat longer on houses than it does on the south side of a test fence because few houses are as fully exposed to sunshine as a properly located test fence. Some houses will be found in nearly every community, however, on which paint not only fails more rapidly but fails in a very different manUer than it does on test fences (14). Such failure may become noticeable within a few months after painting and become pronounced within a year. In typical cases the first abnormal development is blistering but the houseowner rarely makes complaint at that stage and may never notice that it has occurred. Later on "B0 B0 q 3 X " For studying the failure of paint caused by the action of moisture behind painted woodwork the Forest Prod ucts Laboratory uses small "blistering boxes" placed out of doors in cold weather; the interior of the box is kept warm and moist. FLB 000843 ii 538 JX q 1 C EX~ Q +0 _ 1 _ 1 0 Xq ditions because some kinds of paint are more seriously damaged by moisture than others. The only really satisfactory remedy for such conditions lies in research that will make it possible to build houses with certainty that moisture will not collect in the sidewalls, but mean time houses subject to moisture conditions will hare to be painted for many years, A technic for studying moisture failures is gradually being developed. The writer builds test panels of 4-inch bevel siding 15 by 17 inches in area which are painted and exposed to the weather on a test rack for varying intervals of time, after which they are subjected to abnormal moisture conditions by attaching them in position as the side- walls of a "blistering box," within which the air is kept warm and humid by means of a pan of water heated electrically. The box is Operated out of doors during cold weather. When the paints have blistered thor oughly the supply of moisture within the box is cut off and the panels allowed to dry out again while the temperature gradient through them is maintains The panels are then returned to the exposure rack until the coatings fail by scaling. In the writer's opinion it is essential that the ultimate scaling of the coating be taken as the endpoint of the test rather than the pre liminary blistering while the panels are on the "blister ing box." LIST OF REFERENCES (1) Artificial `weathering tests: (a) M _ 7<q ~u s s , A. M., J. Ind. Eng. Chew,., S, 53S (1913). (&) N Xq , H. A., Proc. Am. Soc. Testing Materials, 22, (6) B X q , F. L., Am, Paint & Varnish Mfrs. Assoc., Scientific Sect. Circ. 219, 125 (1924). (c) G 3 X , D. V. 1 q I0 ~p, J. W., du Pont Paint Pt. II, 485 (1922). H. A.N Xq , 1 q S_ Q+ , F. C., ibid., 24, Pt. Mag. (May, 1930). (d) G Q1 q , J. C. 1 q O Q s , Am. Paint & Varnish II, 920 (1924); 26, Pt. II, 563 (1926). H. A.N Xq , S1 q _ Q+ , F. C., Ind. Eng, Chem., 18, 1222 (1926). N Xq , H. A, 1st Comm, New Internatl. Assoc. Test Mfcs. Assoc., Scientific Sect. Circ. 404, 596 (1932); (4) HX Paint, Oil & Chem. Rev. (Dee. 31, 1931), p. 8. , C. D., Federation of Print and Varnish Produc tion Clubs, Official Digest, 118, 957 (1932). ing Materials (Zurich), 1930, Group C, p. 117. (c) W1 7 r , P. H. 1 q H0 _ 7 Xq , E. F., Bureau of Stand (5) C1 < _ 7 , J. H., Ind. Eng. Chem., 18, 1220 (1926). (6) W1 7 , P. H., ibid., 16, 528 (1924). ards, j. Research, 1,1 (1928); Ind. Eng. Chew., 20, (7) H _ 7 , G. B., "The print industry," American Print 591 (1928). (d) G1 q r , H. A., "Physical and chemical examina tion of paints, varnishes, lacquers, and colors,1' Journal Co., St. Louis, 1931, p. 453. (8) B X q , F, L., Federation of Paint and Varnish Produc tion Clubs, Official Digest, 95, 106 (1930); Am. Paint J., Institute of Paint & Varnish Research, Washing 14, 22 (Apr. 7, 1930); Paint, Oil & Chem. Rev., 89, 9 ton, D. C-, 1930, Chap. 20. (Mar. 20, 1930); U. S. Dept, of Agric., Leaflet 62; (2) Older paint test fences: Am. Soc. Mech. Engineers, Trans. Wood Indus. Div., (a) H _ 7 , G. B,, "The paint industry," Am. Paint Journal Co-, St. Louis, 1931, Chap. 44. 53, 53 (Sept. 15, 1931). (9) B X q , F. L. 1 q H < 7y , C. E., Ind. Eng. Chem., (5) North Dakota Agricultural College, Paint Bulletins 1, 23,874(1931). 2, 3,4; and Bulletins 80 and 92. (10) B X q , F. L., Drugs, Oils & Paints, 42, 230 (Dec., 1926); ; N + 7 , L. P., Paint Manufacturers' Assoc, of the ibid., 42, 268 (Jan., 1927). ' U. S., Bulletin 39 (1912). (11) Recording and evaluating exposure tests: P<1 _ , W. T., Chem, & Met. Eng., 30, 463 (1924). (a) Sub-Committee XVI, Committee D-l, Am, Soc. Test K 1 0 q 3, K. J., Paint, Oil, Chem. Rev. (June 14, ing Materials Proc., 19, Pt. I, 384 (1919). 1928), p. 10. (&) W1 7 r , P. H. 1 q H0 _ 7 Xq , E. F., Ind. Eng. Chem., (c) G1 q r , Hi A., "Paint technology and tests," 20,997(1928). McGraw-Hill Booh Co., Inc., New York, 1911. (e) B X q , F. L., Am, Soc. Testing Materials Proc., G1 q , H. A., "Paint researches and their practical . 30, Pt. II, 852 (1930). applications," Inst, of Paint and Varnish Research, (d) Technical Committee, New York Paint and Varnish Washington, D. C., 1917. Production Club, Am. Paint and Varnish Mfrs. K0 q 3, B. H., Kansas State Board of Agriculture, 21st Biennial Report, 1917-18, p. 126. TQX q Xq , M. K., Jr ., Bulletin of the Agr. & Meek. Coll, of Texas, 12 (Oct. 1,1926). Assoc., Scientific Sect. Circ. 404, 563 (1931). (12) B X q , F. L-, Am. Paint J., 9, 56 (Aug. 24, 1925); Drugs, Oils, & Paints (Aug., 1925). (13) B X q , F. L., Ind. Eng. Chem., 19, 982 (1927); 25, (3) Test fences of the present time: 835-42 (1933). (a) G1 q , H. A., "Physical and chemical examination (14) B X q , F. L., Am. Paint & .Varnish Mfrs. Assoc., of prints, varnishes, lacquers, and colors," Insti tute of Paint and Varnish Research, Washington, Scientific Sect, Circ. 317, 480 (1927). (15) H1 I3 , O. R., Am. Paint & Varnish Mfrs. Assoc., D. C,, 1930, Chap. 21. ibid., 355, 742 (1930). ; Readers who desire to pursue the subject of paint testing farther will find an interesting study by the same author on "Effectiveness of Prints in Retarding Moisture Absorption by Wood," beginning on page 835 of the August Industrial and Engineering Chemistry. Do mill-priming and back-priming afford real protection against moisture? This question is answered for several typical priming formulas. Dr. W. T- Read, Dean of the School of Chemistry of Rutgers University, will direct the program of student courses at the Fourteenth Exposition of Chemical Industries to be held at the Grand Central Palace in New York, December 4th to 9th. More detailed information, which came to hand too late to be included in this issue, wiE be presented in the October number. FLB 000844 NATION : is kept heated during d thoi> i is cut hile the itained. ck until opinion coating the pre~ `blister- i. Assoc., nt Paint Varnish > (1932); p. 8. Produc- tn Paint Produo ?aint J., tf., 89, 9 ifiet 62; us. Div., . Chem., ,, 1926); he. Test- ?. Chem., Is Proc., Varnish >h Mfrs. Jl). 1925); 27); 25, Assoc., Assoc., :tiveness ring urfceenth iled U1 1 CIII1L Ull LiUllglCax Shortleaf Pine In general, the density and the Width of the annual growth rings are the principal properties of a softwood that governs its painting characteristics!1)*!. resin content, except when focalized in pitch pockets or pitch streaks, is not ordinarily a significant factof- in durability of paint coatings oh well seasoned wood(a). On the average, longlcaf pine tends to be denser than shortleaf pine; but, on the other hand, the longleaf pine also tends to slower growth, making the annual rings narrower. The two woods might therefore be expected to prove very similar in painting characteris tics on the average. Individual boards of either species, however, vary widely in density and ring Width, the ranges in these properties for the two species overlapping : greatly. For that reason the variations in paint durability between different boards of either species are undoubtedly more impor tant practically than any difference there may be between average values for the two species. In the earlier tests of the painting char acteristics of wood by the Forest products Laboratory!3, *) Southern pine was repre sented by a single shipment of commercial Southern pine, Which may have been a mix ture of species. The tests described in this article were therefore made to determine whether there is any observable difference in behavior of paint on longleaf as compared With commercial shortleaf Southern pine. .Lumber Used in the Tests The lumber for these tests was provided by the Southern. Pine Association. The boards were commercial 1 by 6 inch by 12 feet, surfaced on four sides, in the air-dry conditions. Before use they were stored in an open air lumber shed at Madison, Wis., and protected from the Weather. They Were taken indoors only long enough to cut and make the test panels and to paint them, but since this work was done during the winter the moisture content undoubtedly fell somewhat below that normal for Wood kept out of doors in Wisconsin. Six boards of each species were used for these tests. Measurements of the range in number of annual rings per inch radially and of the density were made at four points along each board; the results appear in Table 1. The boards of shortleaf pine on the whole were slightly lighter in weight and bad fewer rings per inch than the boards of longleaf pipe, although the light boards of longleaf pine were lighter than the heaviest boards of shortleaf pine. Of the six boards of each species three were definitely flat-grain and three were as nearly edge-grain as could be found amofig the boards supplied. None of them, how ever, could be considered truly-edge-grain; as a rule they ranged from Pearly flat-grain at one edge to approximately edge-grain , at the other edge. The Test Panels '. Matched test panels were made as fol, lows: The three flat-grain shortleaf boards, for example, were each cut into two pieces 3 feet long and four pieces 1% feet long. One 3-foot, piece from each of the three hoards made up one test panel for vertical exposure facing south and one lit-foot piece from each board made up one test panel for exposure in a potation inclined at 45, degrees from the vertical and facing south. Thus a set consisting of two matched panels for vertical exposure and four _ "The, numbers In parentheses indicate references given tat the end ot the article. By F. L. Browne Senior Chemist. Forest Products Laboratory. Forest Servtce matched panels for inclined exposure was made from the three flat-grain shortleaf pine boards. Similar sets of panels were made from the three edge-grain shortleaf boards and from the flat-grain and edge- grain longleaf boards, making four sets of matched panels or a total of 8 vertical and 16 inclined test panels. The Faints Tests were made with straight white lead p,junt and with a mixed-pigment paint the pigment of which consisted of 60 per cent basic carbonate white iead, 30 per cent zinc oxide, and 10 per cent asbestine. Each paint was applied in three coats, but two different priming coat mixtures were tried with each paint, one of which is a general priming-coat mixture widely recommended for juse on all kinds of wood and used in the earlier tests of the Forest Products Laboratory (', *) and the other a' pigmentrich primer that was tested in experiments previously reported!2,c). The white lead paint mixtures were as follows: .Priming Coat General Pigment- 2nd 3rd Ineredionts Mixture rich Coat Coat Heavy paste white lead (92 per cant pigment), pounds ... .. 1Q0 - 100 ISO jQO . Raw linseed oil, gallons.......... 4 l Ms 1% 3% Tnrpeotiao. enUonu .......... 2 2 1% . % Liquid paint drier, pints..... 1 1 11. The rtixed-pigment paint mixtures were as follows: Priming Coat General Pigment- 2nd 3rd Ingredients Mixture rich Coat Coat Paste paint (82 per cent pig ment), pounds .;............. 100- ' 180 100 180 Raw linseed oil, gallons ...... 3% 11-8 2% 2% Turpentine^ gallon* ..l........... 2 2 1% % liquid paint drier, pints.......... .2 2 22 , Painting and Exposing the Panels Each set of matched panels was painted as follows: One of the two panels for verti cal exposure was painted with white lead paint, using the general priming-coat mix ture on one-half its area and the pigmentrich mixture on the other half. The other vertical panel was similarly painted with the mixed-pigment paint. Two of the four panels for inclined exposure were painted with white lead paint one with each primer, and the other two panels were similarly painted with the mixed-pigment paint. The painting was done indoors in a heat ed laboratory. Two days were allowed for drying of the priming-coat paints before applying the second coat and three days for drying of the second coat before applying the third. One week after the painting Was completed the panels were placed on the test fence at Madison, Wis. This was- in February, 1928. How the Paint Wore The panels were inspected at intervals and the serviceableness of the coatings judged by the standard procedure of the Forest Products Laboratory c). During the first half of the useful life of the coatings no differences in behavior of the paints on longleaf and on shortleaf pine were observed. The coatings gradually be came soiled, the white lead paint somewhat more so than the mixed-pigment paint, the glpss faded and the coatings began to chalk. By the end of the first year the white lead paint coatings were checking in the manner characteristic of white lead paint. While checking of the mixed-pigment paint Was barely beginning. After 18 months in the vertical position the white lead coatings began to shed the accumulated dirt and to improve in appearance, but the mixedpigment paints continued to gather dirt un til they were two years old; No exudation of resin was observed on any of the boards, either of longleaf or of shortleaf pine. Failure of the coatings in integrity, that is by crumbling or flaking leaving patches of wood bare, began earlier and proceeded more rapidly on the inclined panels than on the vertical panels, as was expected. The inclined panels received materially more sunshine than the vertical panels and rain water probably drained less rapidly from the inclined panels, As soon as crumbling and flaking of the coatings began,, differ ences in behavior over different boards be came observable because such failures Figure 1.--Result of tests on shortleaf pine. Panels. 445 and 447 were made witli pieces from hoards 1, 2, and 3 of Table I (left to right), panels 440 and 448 with pieces from boards 4, 5, and 6, panels 445 and 446 were painted with white lead point and panels 447 and 44S with mixed pigment paint. Panels .A received the general priming coat mixtures and panels B the pigment-rich; mlxtnres. N41698.16 FLB 000845 r'> - --- HI1 1 " 1 ** >3 ;V! i\/t j i ^ f * TV) 1 rI a - - ->4>| Eiiliillll iI k"- 4 ;: V i > * !, '* uu.uiuui.iuK tne variations in. uuraomty on different boards. The beneficial effect of priming Southern pipe with aluminum paint before applying ordinary house paints has been pointed out in previous publications by the Forest Products Laboratory (7) and by others (*, *). Figure 8 shows some typical results of more recent tests by the Forest Products Laboratory; application of alum inum priming paint materially retarded flaking of ordinary paint, used for the top coats, from the bands of summerwood and not only prolonged the life of the coatings, but resulted in more uniform behavior op different boards. ' REFERENCES > 1 1) 4 Jt * *j) 1, Ptflpertifls of wood .that determine .the service given l,y exterior Feint coatings, by F. 1. Browne. Eederatiou of .Paint ftuct Varnish. Production Clubs, Official Digest No. 95, p. 106, Apr, 1930; Amer. Paint Journal, Nor- 28, 1932, p. 7, and Dec. S, 1932, p. 46. Figure Z--Result of tests ou Longleaf pine. Rauclu H9 and 451 were uliulft with pieces from boards 7, 8, and 9 ol table 1 (left to right), panels 450 and 453 with pieces from boards 10, 11, .and, 13.-.Fanola .44$ and 450 were pamted with ...white lead paint and panels 451 tn<i 463 with mixed pigment paint. Panels A received the general prbnlng eoat mixtures and panels II tka pigirient-ricli mixtures. ': 2. The effect of resin.' in longleaf pine on the durability p( bouse point, by F. L, Browne and C- E. Hrubesky. Industrial and Engineering Chemistry 23: 874, Ans-i, 1931. 3, The painting characteristics of wood, by. F. L; Browifec SflMtfcera Lumberman, 125: 219, Dec- 19, 1926. : -r 4. Summary of the fourth progress report: study appeared earlier and developed more rapid ly on some boards than on others. Crum bling or flaking- of the coatings was con fined almost entirely to the areas of summer-wood even when, failure had pro gressed to the point where most of the summerwood was laid bare. This, of course, is the customary behavior of coatings of paint of good quality on softwoods exposed to nornial conditions of weathering; . Results, .on. Longleaf and .Shortleaf Pine Southern Pine should contain more turpen tine than priming-coats for moat other soft woods. .Experiments have proved, however, that priming-coats rich in turpentine de crease rather than increase the durability of paint coatings on Southern pine (*), of the painting characteristics of wood--1924 series,, by F, L. Browne, Mimeographed report; For est Products Lhhdratory, 19259. . 5. Paint thianers l. Effect of different jpaint thinnere on the cturabiQty of house paints ia .out door exposure test, by F. L. Browne, industrial and Engineering Chemistry, 23: 868, Aug., 1931. 6..Procedure UAedbythe Forest Products Labora- TABLE L--Dwab/iitj), in Months, of Coatings of Paint an Shortleaf;and on Longleaf Fine. -/Durability of White Lead Paint : Durtplllty of lUxed Plgraont Pnlnts : InMonths . . In lloiths .- Growth - Density .Board. rings . pounds .Number. (Srairi . PSi Inch per cubie foot /. Vertical Exposure' Inclined Exposure Vertical Erppsuxo . Inclined Exposure General Piexnont- General Pi'emintprimer rirhDrtnjer primer rich primer primer - rich prlm^ primer ridi pi-hner Table 1 records the durability, in months, of the coatings on shortleaf and on longleaf pine. For this purpose the durability of the coating is defined as the age at which crumbling or flaking from, summerwoo j had progressed far enough to require repainting to restore satisfactory integrity of the coat ing. /Figure 1 is a photograph of the in clined panels of shortleaf pine at age of 28 months and Figure 2 is a photograph of the corresponding panels of longleaf pine at the same age. l Xl8& 7 to 11 % 3 JfJot Flat . 13 -to 8 to 24 11 4 - :Bd#e . 12 to 14 5 Bdt?c 14 to: 22 .8 .Av.eEradggee:.. 1 to 11 10. to 15 /' i' 98 . 1110 . 12: : ilat. Plat. : EdgeBdgo . .Edge Arerogo 17 to U 32 1C ..ttoo m 21 20 to SO , 32 10 .22 to, .35 -to 30 to .33 : S H O RILE A P p I'if'E 84 to 37 : 35 35 19 25 40 to 41 . 35 "-35- 19 25 95 80 92 1to0 87 39 : 33.:' 48:-, . ' 37 to 44 ' 30 to SI -': :'5'=- : 48 48 : '' :::,35-to:'38 :.42:>v.': -35 22 35 48 35 22 :35 : 35 . 22 .22222i:i. :/: 35 35 35 .:;32. ; ' . 48 . , .44b2-;' : iiONom v." :r AN 28 to 37 29 44 3482 to tttooo 5332. 5557 40 to 48 07 to 47 ? 45 . 45 .45 85 .- '3355 .' : .40 ..'-..85235555''"'' . 25 25:: - - . .;25. . . 25 ,'25 2211 21 ::,5. 30 33 . . 19 . lfi ' : 19 19 : 25 22B5-: .": - = . 35-: 40 . 35 35 . . 45 . .45 . 25 . 25 22 18 . 42 32 25 21- 19 p. ; On the average the coatings lasted a trifle longer on shortleaf than on longleaf pine. The differences between the two species on the average, however, are much too small to be of any practical significance, especially in view of the fact that much; larger differ ences in coating durability, were found on different boards of either shortleaf or of longleaf pine. The number of boards involved in these tests is too small to permit tracing a satis factory relation between durability of the Subsequent tests have indicated that the pigment-rich: primer would have proved superior if it had been mixed : with < about 2 1-2 gallons of linseed oil and 1 gallon of turpentine for 100 pounds of paste paint instead of the proportions that were actually used. -. Aluminum Primer-for Southern Pine Aluminum priming-coat paint offers the best means discovered: so far for increasing the life of paint coatings on Southern pine tory: for . evaluating paint tests on wood, by F. L. BroVm, Amer. Sac. Testing Materials, Proc. II, 30: 852, 1930. _ 7. Thc : effect of . priming coat'reduction and spe cial primers upon paint service on different woods, by F. L. Browne, Industrial and Engineering Chemistry, 22: 847, Aug., 1930. 8. Zinc and aluminum' powder paint tests; by H; A. Gardner,- Amer. Paint- and Varnish- Manufac turers* Association, Scientific Section, Girc. No.- 231, Apr., 1925. 9..-Protecting- wood- with- aluminum paint-, by; J. > D; Edwards, and XL I. Wray, Industrial and En- 19: 975, Sept., 1927. coating and density and rings per inch in the wood. The physical properties of many boards, can be expressed in simple figures only imperfectly at best because the.wood varies widely in different parts of the same hoard: The illustrations show clearly, how ever, that paint flaking developed met conspicuously over the parts of the. boards where the : bands of summerwODd were widest, : The boards classed as edge-grain likewise fail to demonstrate the superiority of edge over flat-grain very convincingly, but again an examination of the illustra tions shows that the edge-grain boards in reality had areas that were really flat-grain and that paint flaking was most marked over these fiat-grain portions. - The pigment-rich priming-coat mixture in general proved inferior to the general priming-coat mixture in these experiments. The pigment-rich priming-coat, however, (Contained a much higher ratio of turpentine to: linseed oil than the general primingcoat, which later experimentation indicates is the reason for the observed difference. At the time these tests were started the prevailing opinions of painters and paint technologists was that priming-coats for Figure S.-v-Kesnlts of priming- with aluminum paint. The boards of the upper row (A) vets painted with two coats white lead paint while those of the lower row (B) were primed with a priming coat of aluminum paint followed by one top coat of white load paint. The coatings, which were exposed in the inclined position; were 28 months old when photographed. FLB 000846 a durability ;ial effect of flinum paint paints has lications by r D and by >me typical the Forest )n of alumy retarded for the top ?rwood and le coatings, lehavior on e the service 1- Browne, action Clubs, 1930; Amer. and Dec. 5, pme on the Browne and Ensuierin$ wood, by F. i: 219, Dec. eport: stud}' wood--1924 report, ForFerent paint ints in out!, Industrial Au?., 1931. lets Labora~ Pine. tent Paints 1 JJmosurc Piirmontr.ieli primer 19 19 19 19 U IS 30 , by F. L. OC. II, 30: n iid speent woods, ngineering sts, by H. Manufacu No. 231, int, by J. and En ow (A) primed U The raphed. By ROBERT I. WRAY* Because of the growing importance of will show the maximum adherence to both mill griming in the lumber industry and spring and summer-wood. aluminum paint made with a long oil var nish, while the remaining two were primed with a typical white pigmented oil base primer. Two top coats of high grade white house paint were then applied to all panels. The panels were exposed at an angle of 45 degrees to the vertical facing south, an ex posure which is almost twice as severe as that normally encountered on the vertical side of a house. because of the effect this practice promises to have on the marketing of yellow pine lumber, great interest has been shown in the technical facts which underlie this de velopment. The store of both practical and technical knowledge concerning this practice is being augmented rapidly by ad ditional information gathered from re search and the experience of lumbermen in all parts of the country. Commercial use of mill primed lumber has confirmed the many merits of the product established by careful laboratory tests. This discus sion is concerned primarily with the techni cal aspects of aluminum paint as they per tain to the problem of lumber protection. The effectiveness of aluminum bronze powder in combination with a special var nish vehicle, as a primer for many species of wood, has been demonstrated in numer ous tests carried on in various parts of the country. Of particular interest is a com prehensive test involving a series of -long and shortleaf yellow pine panels which was undertaken for the purpose of compar ing the effectiveness of aluminum primers with white primers on this widely used wood. The panels were made in duplicate, one set being sent to New Orleans and the other placed on test at New Kensington, Pa, The sets consisted of panels of both long and shortleaf yellow pine. Selected boards were cut into four 2-foot length panels, two of each being primed with An inspection after 18 months' exposure disclosed the faet that the paint film on the aluminum painted panels was still in good condition and adhesion was excellent although there was top coat checking which stopped at the aluminum primer. In the case of the panels primed with the stand ard white primer it was found that the'top eoats had checked through to the wood, and the paint had flaked in most cases from the summer-wood bands. It was ob vious that the failure Was worse en the sections of the white primed panels which were flat grained in character, while the paint had adhered much better to the edge grain with its narrower bands of summerwood. Any differences in behavior of the paint on lbngleaf and shortleaf pine were Within the past ten years many of the fundamental ideas pertaining to wood painting have undergone radical changes. For example, it has been found that the use of a penetrating priming coat consid ered essential a decade ago is by no means as efficient as painters once believed. Also, the use of synthetic resins and varnish vehicles which yesterday were considered daring innovations are today rapidly gain ing favor with the modem painter. The introduction of varnish-base primers has been largely a result of the advent of alumi num paint as a priming coat for wood. The advantage of the varnish type of paint vehicle for wood priming purposes, as compared with a vehicle composed of drying oil and thinners is apparent when one considers -the structure oi wood and the actioh which moisture has on it. When moisture enters wood through a paint film it passes immediately to the ceil walls, caus ing marked expansion of the wood across the grain. However, drying oils on absorp tion by the wood do not saturate the wood fibers but pass into the cell cavities through the border pits. Obviously then, deep pene tration of an oil vehicle into wood can have little value in the prevention of moisture absorption by the cell walls. To be effec tive, it must prevent moisture from reach ing the wood surface by. forming an im pervious relatively thick continuous film. The result of deep oil penetration is to re move a considerable portion of the vehicle from the surface, leaving in many instances an insufficient amount to properly bind the pigment, Varnish vehicles, because of their more viscous nature, do not penetrate so deeply and consequently a heavier film re mains at the wood surface, resulting in bet ter resistance to moisture passage and im proved adherence and protection. Figure 1 Panels of shortleaf Southern yellow pine after IS months' 45 degrees' exposure facing south at New Kensington, Pa. Panels W32G, W322, W324, and W326 primed with alumi num paint; panels W321, WSSS, WS25, and W321 (from corresponding boards), primed with -white paint. Two top coats of white paint applied to all panels. The justification for using aluminum paint as a wood primer lies principally in its ability to retain its excellent moisture proofing efficiency over unusually long pe riods of exposure, thus protecting the un derlying surface and adding life to the top coats. Its uniform,adherence to both sum mer-wood and spring-wood makes it par ticularly suitable for priming flat-grained lumber. The first indication of paint fail ure on wood usually occurs over the hands of summer-wood. Here the cell walls are thicker and more dense whereas the cell cavities are smaller. Summer-wood can, therefore, Show much greater dimensional changes with varying moisture content and paint adherence becomes increasingly diffi cult. Wood, such as yellow pine, which is eut with a predominately flat-grained sur face shows wider bands of this hard horny summer-wood and it is therefore more im portant to use a paint as a primer which `Aluminum Company of America, New Ken sing-tan. Pa. Figure 2 Panels of longleaf Southern yellow pine after IS .months' 45 degrees' exposure facing south at New Kensington, Pa. Panels W328, W334, and WS32 primed with aluminum paint;, panels W329, W331, and W333 (from corresponding hoards) primed with white paint. Two top coats of white paint applied to all panels. FLB 000847 minor in character although in general the shortleaf panels appeared to be in slightly better condition. The panels exposed at New Kensington are shown in Pigs. 1 and 2. The panels in Pig. 1 are of shortleaf Southern yellow pine, while those in Pig, 2 are of longleaf. The panels are arranged in pairs, the even number panels on the left being primed with aluminum paint and the odd num- bered panels on the right being primed with white paint. : Each pair of panels was taken originally from the same board; thus, panels W32Q and W321 represent one pair, W32Z and W323 another pair, etc. The panels speak for themselves. In another test sections of siding simu- lating house construction were built and exposed in a manner to reproduce the ex- posure that would be experienced in actual service, < The sections were built with pat- tern No. 106 drop siding nailed to 2 by 4's spaced 16 inches on center. On one see- tion was applied yellow pine siding mill primed with aluminum paint and on the other, the unpainted siding, After erection the bare section of yellow pine was im- mediately primed on the face in the usual manner with a good grade of white paint properly reduced. Two coats of the same white paint were then applied to both sec- tions; ^ These sections have bean weathering for 18 months and already some differences are apparent. Slight paint Baking and paint cracking has occurred on the section primed with white paint particularly on the sharp edges of the drop siding pattern. Some shrinking of the White primed boards has also been observed across the . grain and bare wood is exposed at the joints--as much as 1-3 inch in some cases; The aluminum primed section, on the other hand, is still intact both with regard to the paint coating itself and the Joint between the hoards, The latter test brings out the evident advantages of mill priming of yellow pine lumber and the merits of aluminum paint as a mill priming material. Dimensional changes aim wood cheeking and warping during storage are greatly reduced by this procedure. Also because all sides of the lumber are coated, a maximum amount of protection against absorption of moisture after erection is effected, Furthermore, the mechanical application of aluminum primers of this type at the mill insures a better paint Job that will hold subsequent paint coatings longer without their failing prematurely by scaling and peeling from the summer-wood bands. This should help remove the growing prejudice against yellow pine that arises out of its painting eharaeteristics. Mill Priming and Trade Promotion By J; F, CARTER, Southern Pine Association More than eighteen months ago a co- Eight-inch boards were collected from operative study of the paintabiiity of long- longleaf and shortleaf producers. There leaf and shortleaf Southern pine was de- was a slight difference in density, though cided upon by the Aluminum Company of not noticeable if the boards were paired America and the Southern Pine Associa- rightly. The plan was to expose the boards tion. The tests were to ascertain some- at New Kensington, Pennsylvania, and at thing slightly different from what had been New Orleans at the same time, under like previously reported by the Forest Products conditions--with the panels placed forty- Laboratory. five degrees to horizontal, facing south, From Forest Products Laboratory re- that they might suffer the worst conditions porta it was evident that the best primer of, exposure. was one composed of aluminnm as the pig- These boards were painted in sets, so that ment, with a good oil vehicle. Proofs were duplicate sets of longleaf and shortleaf established (bat the primer's integrity could be exposed at these distant points, measured the integrity of the covering each showing flat and edge grain, paint coats. There is little point in discussing1 results However, from the data, we were not at New Orleans. The photographs are al- certain at that time whether longleaf or most exactly the same as those produced shortleaf would bear up better under teste, at New Kensington, Hence, o_ne set of il- Moreover, it was our desire: to make the lustrations tells the story for both tests, tests so that edge-grain of both species ' As we see it, from the standpoint of could be; compared with flat grain of the trade promotion-for Southern pine, there same two species. is every reason why manufacturers of sid ing, drop or bevel, should prime with aluminum at the mill. Southern pine loses markets because its siding is largely flat grain and the broad bands of suntmerwood cast off the paint, if the correct primer is not used. If Southern pine siding he primed with aluminum paint at the saw mill before shipment, that part of the painting is done at not as much cost as painting on the residence job, and the market will be regained so soon as the buying public, including the retailers, real ize-that the paintabiiity is good. Quite nat urally, the idea must not be kept a secret. The manufacturers will needs tell the world what are the values of null-priming. Some have suggested that retailers -he told to .paint ordinary Southern pine siding with aluminum primer.. This means that the story must be impressed upon every painter, contractor, builder, carpenter, real tor and architect. It would be an expensive proposition to get the story to all those who have to do with combusting a house; It seems a much simpler proposition to put on the insurance policy at the mill--- make the Siding paintiible before it goes to the retailer. It might be well to state that, harking back to tests, there is little difference in the paintabiiity of longleaf and shortleaf when properly viewed. It really does not matter which one failed the more--the fact that failure set in is sufficient. When the paint coat over ordinary lead or zinc primer is quickly flaked off the summerwood of either longleaf or shortleaf, that piece has poor paintabiiity. If either or both species are introduced to the consumer with a coat ing of aluminum as a primer, that siding will gain and hold its market. It does not require much use on the part of any painter, contractor or builder of a home to realize the difference, and also the saving which is effected. The selling points are all in favor of siding primed at the mill with aluminum. There may be other primers which work as well, but thus far they have not been put through the necessary paces to learn the value. Manufacturers have discussed the inade quacy of returns on such additional service. That is a subject controlled by the sagacity of the sales managers. They have added a definite cost for the service. Knowing the value of that service they will handle, it in a business-like manner. From what has been ascertained up to this moment by the activities of two Southern mills, the retailers will be only too glad to seize upon something which they can sell with more enthusiasm than ordinary lumber. FLB 000848 prime with irn pine loses i largely flat summerwood eot primer is le siding be at the saw* part of the trach cost as fob, and the soon as the staffers, real* d. Quite nat* :ept a secret, tell the world priming, retailers be a pine siding means that upon every rpenter, realan expensive to all those g a house, reposition to t the millfore it goes hat, harking difference in nd shortleaf lly does not ire--the fact . When the r zinc primer merwood of at piece has both spedes with a eoat- that siding It does not art of any f a home to > the saving in favor of i aluminum. Which work ve not been :es to learn i the iitademal service, the sagacity have added . Knowing Will handle From what his moment it mills, the 1 seize upon with more aer. Paintin Exterior "Woodwork,... By F. Senior Chemist, Forest Plo toducts Laboratory? Go o d paint is, o course, a necessary element in good paint maintenance, but it is far from being the whole story. For many years technical study and writings have dealt with paint composition almost to the exclusion of other factors in pa'.m service some of which are even more important. As a result there is a tendency to believe that satisfactory paint service can always be expected provided only that a sufficiently good paint is pur chased and that, when paint fails prematurely, there is necessarily something wrong with the paint purchased. A better understand ing on the part of purchasing agents and maintenance men of the other important elements upon which the servic'eableness of paint depends should help materially in securing more satisfactory painting and in avoiding unnecessary disputes. The Forest Products Laboratory has been studying the painting of exterior wood surfaces for more than to years. Two principal sources of information are utilized, namely, (i) observation of the behavior of paint on buildings in service that are brought to the attention of the Laboratory,- usually because of unsatisfactory experience with paint, and (2) practical exposure tests in which paints of known composition and methods of application are observed carefully throughout their life on different kinds of wood. Such exposure tests are made throughout the United States at stations representing various climatic conditions. The major objective of painting studies at the Forest Labora tory is to learn how to get the most satisfactory service from wood when painting is involved and how to do so with a maximum assurance of results and a minimum expense. This point of view is unique in paint testing and has led to significant improvements in methods of evaluating paint service and to a better under standing of the various factors upon which satisfactory paint-ser vice depend. The competitive claims made for different paint ingredients, for example, have not been allowed, to overshadow the importance of proper proportioning of ingredients, variation in behavior on different kinds of wood, application of paint in sufficient quantity, repainting before the old coating has worn too badly, and avoidance of certain abnormal conditions of service -that rapidly ruin the best of paints. ______ " ________ 'Maintained at Madison, Wisconsin, in cooperation with the University of Wisconsin. EARLY FAILURE CAUSED BY MOISTURE IN SIDEWALLS This house was painted twice in two years and failed in this way within a few months after each painting. Many other houses in this community failed in the same way. Experiments by the Forest Products Laboratory are Confined almost entirely to paints of known composition, usually manu factured at the Laboratory. Such paints can be described fully and can be formulated to bring out general principles of paint composition to best advantage. The Laboratory has nat been concerned directly with the special problems of paint purchasing, such as specifications for paint and the relative merits of pro prietary paints, but knowledge of the more general problems that it has been studying should prove helpful in the purchasing of paint as well as in the maintenance of painted buildings. Moisture Failures of Paint Probably the most frequent and costly cause of premature fail ure of paint on buildings is moisture getting behind painted woodwork, especially when the temperature behind the painted surface is higher than it is in front. Under such conditions good paint may fail within a few months after application and the fail ure may leave a surface that is unusually expensive to repaint properly. In pronounced cases failure begins with blistering and sometimes peeling; the blisters may subsequently disappear but in any case scaling or flaking of the coating sets in long before break down of the coating should be expected. In less characteristic cases the first form of failure observed is flaking of the coating from the harder parts of the wood surfaces, just as is ultimately to be expected, but the failure sets in much too soon. Failure of the latter type is especially likely to be attributed falsely to in ferior paint because the form in which failure takes place lacks the distinguishing characteristics of typical moisture failures. All linseed oil paints, good, bad, and indifferent, are subject to moisture failures if the causative conditions arise. To be sure pure white-lead paint escapes relatively unscathed under moderately severe conditions that prove disastrous to all other paints but if the conditions are bad enough white lead fails also. The only certain cure for moisture failures is to eliminate the moisture. In new buildings the moisture may get into the sidewalls when im proper methods are followed in drying the plaster. A second' source of moisture is open joints or inadequate flashing around windows, chimneys, dormers, eaves troughs, or other junctions in the construction. A third source of moisture, ofteu the most difficult to remedy, is sweating or condensation within the side walls during cold weather. Durability On Different Woods Paints last much longer on some kinds of wood than on others. The variation results from the fact that linseed oil paints become brittle after they have been exposed to the weather for some time and when brittle they no longer hold firmly to the dense, hard, horny bands of summerwood present in softwood lumber. For that reason aged coatings flake from the summerwood, leaving it bare. The larger the areas of summerwood the sooner flaking becomes serious. The heavier the wood and the wider its annual growth rings the larger are the bands of summerwood and the less desirable it is for durable painting. Of the western softwoods the best for painting are western red cedar, Port Orford cedar, Alaska cedar, and redwood followed closely by western white pine and sugar pine; somewhat less desirable for painting are ponderosa pine, Sitka spruce, and western hemlock; paint fails soonest on Douglas fir and western larch. There is, of course, much variation between boards of the same species. In genera! the lightest boards and those with narrowest growth rings are best for painting. Edge grain boards are always superior for painting to flat grain boards of similar wood. Priming Paints For Wood Two paints are outstandingly superior for priming new wood surfaces, namely, pure White-lead paint and aluminum paint. White-lead paint has the advantage of being white or easily tinted to a variety of colors so that it lends itself readily to two-coat o o o 18 Pacific Purchaser 1 Vol. XVI, No. 2 N41698.17 FLB 000849 tag Studies at Forest Products Laboratory B X q .We# Service, U. S. Department of Agriculture.. O painting. Priming-coat white-lead paint should be mixed with paints they buy should provide themselves with tables of the plenty of pigment; it should contain only slightly more liquid hulking values (volume per unit weight) of the important paint than a finishing-coat paint and the liquid should be mosdy linseed pigments and liquids and learn to compute the proportions of oil with only a ,small proportion of turpentine. So-called "rein paint ingredients by volume from formulas or analyses expressed forcing oils" and varnish should not be used in white-lead paint. in percentages by weight. Aluminum paint should be made by adding 2 pounds of Importance of Spreading Rate aluminum bronze powder or paste aluminum to i gallon of long- oil spar varnish made specifically for mixing exterior aluminum Next to the use of too much linseed oil the most common mis paint. Aluminum priming paint has the advantage of markedly take in painting is probably the stingy application of paint. Pur retarding the flaking of paint from the bands of summerwood. chasing agents will do well to regard with suspicion paints whose It is therefore the best priming paint for woods like ponderosa markers claim that they will cover more area per gallon than pine and Douglas fir. It has the disadvantage of requiring two other paints. On smooth wood surfaces priming coat paint should coats of white or of light colored finishing paint to hide its color not cover more than 575 square feet per gallon and second-coat adequately. or third-coat paint should not cover more than 600 square feet Finishing Paints For Wood per gallon. Rough surfaces, such as sawed surfaces or badly On buildings for which there is no systematic plan of paint weather-beaten surfaces consume still larger quantities of paint. maintenance and on which the paint may he neglected for con Stingy application of paint leads first to early loss of gloss and siderable periods pure white-lead paint often proves the most satisfactory finishing-coat paint. Such paint is not more durable particularly to uneven or spotty loss of gloss. If the paint is tinted loss of gloss is followed quickly by fading of the color. | than paints that contain proper mixtures of zinc oxide with other white pigments, but when it becomes brittle it changes from a The ultimate durability of coatings is often seriously impaired if they are applied too thin. sound coating into a loosely adherent mass of chalk that continues Publications to hide and color the surface fairly Well provided the wood is one More detailed discussions of the topics summarized in this containing only narrow bands of summerwood. Such a surface is paper are given in the following publications. Single copies of i easily repainted. Paints that contain zinc oxide, on the other these publications may be obtained free upon application to the | hand, flake in a more conspicuous fashion after they have be Forest Products Laboratory, Madison, Wisconsin: | | come britde and if repainting is put off the surface may prove difficult to repaint satisfactorily. List of Publications on Wood Finishing Subjects, mimeograph r 'I54- i For buildings that are repainted promptly when old coatings become brittle, paints that contain reasonable proportions of zinc Some Causes of Blistering and Peeling of Paint on House Siding, mimeograph R6. O oxide and white lead with or without some of the newer opaque vyhite pigments, such as the titanium and zinc-sulfide pigments, Testing House Paints for Durability, mimeograph Rioii. . 'are superior to pure white-lead paint in that they protect the Properties of Wood that Determine the Service Given by Ex wood adequately against moisture for a longer time and if tinted terior Paint Coatings, mimeograph R855. 'i they hold colors better. For white paint the presence of titanium Why Some Wood Surfaces Hold Paint Better than Others, or zinc-sulfide pigments is particularly desirable because such Leaflet No. 62. paints are less seriously discolored with dirt. Finishing coat paints should not be mixed with too much lin seed oil. After the volatile thinner has evaporated at least 28 per cent of the coating by volume should be pigment and of this pig ment at least 80 per cent by volume should be made up of opaque When and How to Paint Farm Buildings, mimeograph R962. Effect of Aluminum Priming Paint on the Durability of House Paints on Wood, mimeograph R1015. Weathering and Decay, Technical Note No. 221. white pigments (unless the paint is one of dark color in which there is little or no white pigment). Will we see you at the Joint Luncheon of the Paint Club and Purchasing agents who wish to know the real value of the the Purchasing Agents, Palace Hotel, Friday, February 2? \ 1 i i I i o VARIATION IN PAINT BEHAVIOR ON DIFFERENT WOODS The top board of each panel is redwood, the second board white pine, the third board southern yellow pine, the bottom board Douglas fir. The left-hand pane! is painted with pure white lead paint, the next one with, a paint containing zinc oxide and white lead, the next with a paint containing zinc oxide, white lead, and titanium pigment, and the right-hand panel with a paint containing zinc oxide, titanium pigment, and no white lead. Normal failure of this hind should not set in until the paint is at least three or four years old. Pacific Purchaser v February, 1934 19 ) ffteticoH Eq Registered, U. S- Patent Office a s S _ Xq -C1 M1 , D _ +< r 25, 1916, 1 Q St * LX 0 , MX ., PX X~~0 _ CX 0 3 Qt , 1934, < A P J+ 0 _ 1 q 10 q X q1 CX+ 1 q y . . lot. 19 ST. LOUIS, MONDAY, DECEMBER 10, 1934 No. 9 ^riroing-Coat Reductions for Painted New Wood Surfaces By F. L. Browne |For Test Fence Committee of Northwestern Paint and Varnish Production Chib j*HE5 principal object of this study is to discover the optimum priming |at reduction in applying common |>use paints to softwoods and to dermine whether the priming coat o.uld be reduced differently according the nature of the softwood painted, experiments have been described i detail in three previous progress rerts presented at the conventions in Bl, 1932 and 1533, and published in |culars of the Scientific Section (404 445 >. tne Official Digest (121), and | the trade press. Four woods and three paints were |ed in the experiments on primiiigat reduction. The woods were Nor|y pine, northern white pine, western cedar, and redwood. The paints e white linseed oil house paints that jfered only hi the nature of the pig|nts; in one the pigment was entirely fic carbonate white lead, in the see the pigment contained 60 per cent weight basic carbonate white lead, |&er cent lead-free zinc oxide, and 10 . cent magnesium silicate, and the dent of the third contained 60 per kt titauox B, 30 per cent lead-free ||c oxide, and 10 per cent magnesium ate. Ail three paints were made in (i: form of semi-pastes, one gallon of jich consisted of 0.435 gallon of pig|bt and 0.565 gallon of linseed oil. the various priming coats these |ie paints were thinned with linseed |turpentirie, and paint drier as in cited in Table No. 1. Some of the Kng was done in two-coat work ?er presented at the annual meet- >[ the Federation of Paint and Vartii Production. Clubs, in Washington, |:28-.30. The Test Fence commitillthe Northwestern Paint and Var|i introduction Club consists of W. J. ilipibar, chairman; L. P. Warren. T. f^p.Mahon, S. O, Sorenson, J. M. t-^jPeter Gydesen, M. H. Siine and Prowiie.--Editor.) and some in three-coat work. For the final coat in two-coat painting the paste paints were thinned with 0.655 gallon of linseed oil, 0.036 gallon of turpentine, and 0.066 gallon, of drier per gallon of paste paint, making paint of 26.4 per cent pigment volume. For three-coat work the second coat was made by mixing one gallon of paste paint, 0.218 gallon of linseed oil, 0.437 gallon of turpentine, and 0.036 gallon of drier, making paint of 35.9 per cent pigment volume; for the third coat the mixtures were one gallon of paste paint, 0.946 gallon of linseed oil, 0.036 gallon of turpentine, and 0.036 gallon of drier, making paint of 22.4 per cent pigment volume. Panels were attached to both sides of test fences, providing both northern and southern exposures. The panels were made of boards of bevel siding 12 feet long so that groups of six matched test areas each two feet long were provided on which six variations in priming coat reduction were tested on the same boards. In Table No. 1 the six priming procedures tested on subdivi sions of the same boards are grouped together. Priming reduction 1-3 was repeated on each set of hoards in order to reveal differences due to character istics of the boards in different panels of the same wood and to furnish a basis for comparing priming procedures tested on different panels.. Since the third progress report was written there have been two formal inspections of the fence, one .in June and the other in October, 1934. At the last inspection the coatings were 38 months old. The writer also inspected the fence in August, 1934. in .company with a group of visiting paint tech nologists but records were not made at that time. At 38 months the coat ings on the south side of the fence were failing in integrity sufficiently to reveal distinct differences caused by the variations in priming coat reduction. N41698.18 FLB 000851 8 A P J+ 0 _ 1 q 10 q X q 1 , 'St , LX 0 s. D _ +< 10,1934 Or the north side of the fence, however, the coatings remained intact except for certain local cases of moisture failure mentioned io the third progress re port. The present report is concerned chiefly with the trends in durability of the coatings on the south side of the fence. Effect of Priming Coat .Reduction Table No, 1 records the ratings of the coatings in integrity at age 38 months, the durability in months of those coatings that had become unserviceable and* were in the period of paint neglect, and. an arbitrary estimate of the durability of those coatings that still remained serviceable. The esti mated durabilities are based on the as sumption that coatings rated Poor plus at the last Inspection will remain serv iceable three months longer, those rated Fair minus six months longer, and those rated Fair nine months longer. The estimated durabilities calculated in this way greatly facilitate discussion of the results but they are far from accurate predictions of future behavior. Less than, one-third of the durabilities re corded in Table No. 1, however, are estimated in this Way and for that rea son the relative merits of the various priming procedures are as clearly re vealed as they will be when the tests have continued until all of the coatings are unserviceable. In Table No. 1 the priming coat re ductions numbered 1-1, 1-2. 1^3, 1-4. and 1-5 were mixtures in which .the concentration of pigment is suitable for three-poat painting, ranging from 17.2 to 23.2 per Cent by volume of the mix ture (including volatile). Reductions numbered 2-1, 2-2, and 2-3 had a higher concentration of pigment, 24.1 to 26.3 per cent, suitable for two-coat painting. Among the reductions of series one the best results were obtained with 1-1, in which no turpentine was used, and the tendency was for the durability to de crease as the turpentine was increased and. the. linseed oil decreased in the priming coat. The difference in results with primers 1-1, 1-2, and i-3, however. Was so small that they may well toe considered equally serviceable. Reduc tions 1-4 and 1-5 were on the whole dis tinctly inferior, although on redwood 1-4 was still proving nearly as good as 1-3. The reductions of series two when used in two-coat work revealed a defi nite superiority of the reduction 2-1, made 'with linseed oil and no turpentine, oyer those in which there was linseed o.ii and turpentine. Of the two reduc tions of series two used for three-coat work, the one containing more oil and less turpentine proved somewhat su perior. It should be noted that, in three-coat work, reduction 2-2 was slightly su perior to 1-3 in the cases of white laid and titanox and zinc paint and slightly inferior in the case of lead and zinc paint. In other words, reductions 2-2 and 1-3 on the whole proved about equally serviceable* The pigment vol ume in 1-3 Was 22.3 per cent (of the non-volatile) and the ratio of linsord oil to turpentine by volume was about 2.6> In 2-2 the pigment volume was 30.2 per cent and the ratio of oil to turpentine 3.4. Reduction 1-4, wlm fa was inferior to 1-3 With ail paints, had a pigment volume of 29.4 but a ratio of oil to turpentine of only 1.4, II seems, therefore, that the ratio of oil to turpentine is more significant, at least within the range of desirable 1 * auctions, than is the pigment -veinnns. Apparently a good primer should have at least ,2& times as much .liii <] pil as turpentine and it is questions bb whether there need be any turpentine in the primer at all. The pigment vol ume in a good primer for three-coat painting presumably may be anywhere in the range of 20 to 30 per cent but for two-coat painting practical consid erations require that the pigment v<l ume be in the upper portion of this range. Reductions for Different Woods The notion has long prevailed that lh. optimum priming coat reduction d iffors according to the kind of wood painted. There is no published evidence in im port of such a belief and its soundnos-, may well be doubted in view of tin* contradictory recommendations often made when Writers try to give spocjfn* : priming coat formulas * for different woods. The data: of Table No. 1 sug gest the same optimum priming coat reduction for all woods, namely, r< d i< tion with linseed, oil and little or no turpentine. The results are not at ail consistent With the view that th> re duction for red cedar or redwood should differ from the reduction for white pine of Norway pine* It should be recog nized, however, that the present ex periments were concerned principal iv with the proportions of linseed oil uni turpentine in the priming coat and did not cover possible Variations in pigment concentration as adequately as could I7 desired. Further research may show that for woods like redwood and i<l cedar, which absorb paint oils quwuiy, a slightly lower pigment ebneenti .ilion may be advisable in order to 4 \ aid unduly low spreading rates .and dilliculty with painters* laps than !> ap propriate for such woods- as No! way pine, southern yellow pine, and Dougin', fir. Nevertheless the present indicat ion* are that a single recommendation lor reducing priming coats for all kind*-* l woods is entirely practical and prob- IT D _ +< 10,1934 A P J+ 0 _ 1 q 10 q X q 1 , St . LX 0 . ably advisable. The "easily pain-table'* woods probably differ from the "diffi cultly pafntable" one chiefly in degree of sensitiveness to departure from the optimum reduction, that is, less damage to the serviceableness of the coating may be expected if the painter fails to (Continued ota page 4$) Table t.--Results Obtained With Different Priming Coat Reductions and With Aluminum Primer After 38 Months Exposure Facing South. Figures for durability enclosed, in parentheses are estimated on the assumption that the additional life of coatings still serviceable at the last inspection will be 9 months if last rated Fair, 6 months if last rated Fair minus, and 3 months if last rated Poor plus. i (AOOCOIO flOOO*ftOO chCACvoc+KN uWi (Ol*^(OlOO O CO <fl OCO 03 KN O4OiovOr\'ifCn--mlAO4l lnAiOoKmOwCOin-^i-o* (<MAl*MnUVrt KNu*i0 *ACOr<\ iilil iisil %o i } j I tiXtttiitU mo0p0a. op0 00o4 f0oit4u-H* o0uo, 00oL,o00t*4O40)0uo0,0ou0, tuifuuu rf <8 d 0O,0o, &e* 0_ 00io>440ou0uo atO0, <0tOu 00tO.00tO.0olo4l6. <. 0Uo0,0-Uo,00Uo4000Uo,0aSJ,.0Ouo, |t!vi ttti oo uoo oouoouootuoo tO tOtOtouO Hl uO0u0O u00.+40u0ou0o 0, 0.0,0)040, ltt<IQ4x il0rolmtO0:wo4tf0lJoilB0Soat4'l*bQ !,tuti EbbtAOiOtQt i; l 0*o04,00O4 000,044)404J.)00O, 0$a044 0o04 0ou04o0+41o-0n04o00* cocaa3-f oo5* OCOi CvVoIM'OO-J^O'OJC-Mt' muo0 tau0iiMou0ok0.Vn4fHc4i ^i nnnnno aos0*.0o0,00o,<m43X4j'd,)0ao. io .-a io*o io lo 00,04)004 04)00,00, Cm0<nOmC0i<nOK<0V4r* 0Uo0,00oU4 f0UOt, 00So4400O4t*40-41 ^ 4 0*4 o ^ 00,.04)004.04)0O.0O4 04)0441i 0-4O)0-t43)0AS)30Oo4 .0So40t 0uo0, 0uo0*0<44) 00uo,00uo> '<OyCoUf OcH)OfirO0)J*-Ti 0ia3oM)>wC:Jo^)oOi<OuJ i *- i i 00,.04104)04) 0C4))6t4S, 0S0,t 044*)04140)40O+)4cVa irxiot^KxKXKv Womw.Kxjfi JOtCVK%KV<Mf\ O)on\ouo<\ 4\K\K\rxiOK) 0r\O)K\K\ oHrv*--4MO<<-y*0o)jO-V4H-) <y cy iv <y <o -iO#A-rO4H-'OKOXOfOc--)OH8"I 'JoOD.'oOWXOgKioWVONJ*g') OrH OJf -4O0)H01M0O10>)|4-i OiWfO'OOJ'O iofilioowo/-.mnojatmn 'lPoO<QQo>JOKnXO<ftvlOOotJ<OO-l O I-IKV*--* 0d)0^1io0jo)0v)K4>- assgg 0)OtK)<OOJO yO>IKo^<OyIJuO*KSXoK1X <0<0S0rv6*\ ssssgg s_ 4 smat-cpoa(4 <O<My\<KirQ\.K<in0\<OoVsj<mK0> oino _ q_ X _ 4 en- a CoOVXimUPA<rl0eO<oCTUiVK<<v00 i m,.HO01vK-fr4V-.OM<v* int'~'oa\c-<r <O-*Ovl4>0) 4ft *4 o,t-o\ HOO-t 3 -SO< OvOJ-4-CM r4HH Art I ._-I4J Iccyy r7-0f <7Iy._<I4y y<Iyi H-4I rOII)HKIlH^ItHIn |I rOAIiOCIjJKHIvOyIiICO1yjc0AyI FLB 000853 Drei worn Ifl, 1 J1 S .tA P J+ 0 _ 1 q 10 q X q1 , LX 0 , 51 nl tin Iiit iiisimtion is recorded in lull* ''it ill >n `-iio'ial primers made with uiiilt pigments in Bakelite varnish the tit in 'd< with zinc oxide gave distinctly influm 10 ul(h. The ones made with nil hi n 0 1* id uid titanox were ironli so good as the better but aluminum primer reported in Table No, 1. The type of failure of the white lead paint, over these primers was not the same as that of white lead paint over white lead primer or over aluminum primer but took the form of flaking as dis tinguished from crumbling over the bands of summerwood. Table No A--Results After 18 Months' Exposure Facing South for Miscellaneous Tests on Units 7 and 8 of the Fence. Hating in Integrity on 1) scription of Coating' Norway White Red \ vi rOLl of white lead paint over priming Pine Pine Cedar Jtedwood * >ti >t \\ hil< <d in Bakelite varnish.......... Poor:-- Poor Poor 4- Poor /mr ovule m Bakelite varnish....1 .......... Bad Bad4- Poor-- Bad-- Titmox H in Bakelite varnish................. Poor Poor Poor-F Poor-- Inu * t of linseed oil- paints having the follow mu white pigments: White le id paint, as recommended by ' National. Lead Company..................... .. Poor * White lead paint, as recommended by : Eagle-Picher Lead Company.......... Poor Cryptone, leaded zinc oxide, inert, as recommended by New Jersey Zinc Company ......................................................... Poor 4- Titanox. white lead, zinc oxide, inert, as J recommended by Titanium Pigment * Company .1 ................................................... Pair-- Foor^jPoor-|- Poor 4 Poor 4 Poor-F Poor 4 Poor 4Fair-- Poor4" Poor 4 Fair-- Fair | -- , \ , in October - Wu;;]rii1idon, Dec. .3,--Vice Coinsul-- Frank Cftssans^-BonigSuxT renorts to the Chemical Division, Bureau of Foreign and Domestic Commerce, . that the must outstanding change which occurred, in the market during the month was\ the curtailment of exports to Germany, brought about by an announcement by the French Minister of Commerce to shippers that if naval stores exports to Ger many continue to Increase the Franco-German office in Paris would he unable to pay the exporters in full for the shipments made. The French naval stores inhrket.. was considered to be in a better pb tion as regards stock than it wiwf af , the end of October, 1933, due-'principally to the large quantifies ex ported to Germany duping recent months, and the estiiiufled decrease in this year's crop/from 15 to 20 per cent below last year's. Felton-SiEley "TVaffl- __ in Paint-BewBnarErague Philadelphia, Dec. 0.- -As a result of the games played last evening, the Felton-Sibley teix pin shatterers leaped into the sunberth of theJHrrtadelphia Save the Surfapje^fiowling League. By applying l-lm whitewash, brush to the AinpiOcan Can team, the Felton-Sibjey team earned 4 points and broke the deadlock for first plae^-fvith the George D. Weth- erill teafn, who lost 4 points to the E, Xr dn Point de Nemours & Co. tgdm. High average man in the league so far is Roman, of George D. Wetherill, whose average is 178; sec ond place honors are shared by Me- iley, of George D. Wetherill, and .JoeNMack, of Felton-Sibley, with an averse of 177. Thomas, of FeUonSibley, molds the high single game score of 27 J. B. Keisfdr, of the National Lead Co., recep-tfy returned to San FranciseoCaffer spending a month visiting in New York and other eastern cities following the Washington convention of the National Paint, Varnish and Lacquer Association. W, H. Loughlih, of Pitts & Lough- lin, San Francisco/sment the Thanks giving week-end in Death Valley and at the Boulder Pam, aVid stopped en route home the first of last week in Los Angeles at the southern branch, presided over by S, Y. Pitts 50 S .A P J+ 0 _ 1 q 10 q X q1 , t LX 0 . D _ +< r 10,1034 that, by reason of the higher pigment woods as red cedar, rbdwood, and white concentrations and lower spreading pine, yet the failures took place in less rates followed in the two-coat painting, than four years. The coatings of white roughly similar total quantities of paint lead paint and of lead and zinc paint were applied in the two-coat and three- applied with priming coat reduction 1-3 coat jobs. It is evident that two-coat as recorded in Table No. 1 may reason painting when done in the manner fol lowed in these experiments is thor ably be compared with certain tests by the Forest Products Laboratory in oughly practicable and gives coatings which the same paints were applied with that closely approach good three-coat very similar reductions and on some work in durability and prove distinctly of the same kinds of wood at Fargo, better than poor three-coat work. N. D,, and at Madison, Wis., in 1930. Aluminum Priming Paint Table No. 3 records data suitable for Table No. 1 indicates that the best comparing the results with those at St* results were obtained with aluminum Paul. priming paint followed by two coats of The reason for faster disintegration white paint. On all woods except white of the paints at St. Paul is unknown pine the coatings of all three paints but the fact that there is unmistakable over aluminum primer were still rated evidence of some moisture failure on Fair minus or better in intergrity at the the north side of the fence, as pointed last inspection .and in all cases except out in the third progress report, sug that of lead and zinc paint on white gests that moisture getting into the pine the coating over aluminum primer fence at some time may have hastened was rated as high or higher in integrity disintegration on the south side even than the best coating over a white though the moisture conditions were not primer on the same boards. On 10 out severe enough to result in typical blis of 12 panels the coating over aluminum tering or other developments clearly primer had the highest rating, on one recognizable as moisture failures. It panel its rating (Fair minus) was has been reported to the test fence equalled only by white priming coat re committee that at one time during the duction 1-1, and on one panel it was winter of 1932-33 snow drifted against distinctly superior to reductions 1-4 and ' the fence to the extent of practically 1-5 but inferior to reductions 1-1, 1-2, covering one side. This snow was not and 1-3. On the last panel, however, shoveled away and there is a possibility failure was confined to two of the four that entrance of moisture within the boards which developed loose grain to fence took place when it melted. ward the end bn which the aluminum Miscellaneous Tests on . Units 7 and 8 primer was applied but not on the end of the Fence that received reductions l^l, 1-2, and In addition to the main portion of 1-3. This panel, therefore, was not an the test fence there were two units exception, to the rule that the aluminum added for the purpose of trying the primer in these tests tended to hold the effect of special primers made with coatings intact longer than any of the white pigments in the Bakelite varnish priming coat reductions of the white used as a vehicle for the aluminum paint. .primer on units 1 to 6 and for trying Unusually Early Failure of the Paints the recommendations for thinning white Failure of the coatings in integrity; lead paint made br the National Lead took place unusually rapidly on the St. Co. and the HJagle-Picher Lead Co. and Paul test fence. Coatings of the white certain '.paints suggested by the New paints used should be expected to re Jersey Zinc Co. and the Titanium Pig main serviceable in the Lake States ment Co. The condition of these paints region for at least four years on such with respect to integrity of the coatings Table No. 3--Comparison in Durability Between White Lead Paint and Lead and Zinc Paint Applied with Priming Coat Reduction 1-3 at St.. Paul and the Same Paints Applied Very Similarly in Tests at Fargo and Madison, Figures in Parentheses Are Durabilities Estimated for Coatings Still Serviceable at 38 Months. Durability in Months with Respect to Integrity of Coating for White Lead Paint on Lead and Zinc Paint on Station Red White Norway Red White Norway Redwood Cedar Pine Pine Redwood Cedar Pine Pine & St. Paul. Minn.l...... (41) (4L) 36 38 (44). (41) 34 38 St. Paul, Minn.1... 38 38 38 26 (41) 38 32 (41) f Fargo, N. D.2-----Madison* Wis.2 52 .54 50 54 . 49 51 44 48 1.. | 1 At St. Paul there were two test areas on each wood painted with each paint using priming coat reduction 1-3; each of these areas is reported separately. 3 Data for Fargo and Madison are average durabilities for 10 test areas of each wood painted with each paint. on ?m life on ;ed igrne led j&n ;not listrly It =nce the insfc .ally not ility the i id 8 n of units the . with rnish inum eying white Lead . and New 1 Pigpaints atings 5; g : | i | .d and f he ing for .? ; on I Norway | Pine 38 I (41) ih paint | Jy. xeas of I;| AMERICAN WOOD-PRESERVERS' ASSOCIATION This is an advance copy of a report to be presented at the Thirtieth annual meeting of the American Wood-Preservers' Association to be held at the Hotel Rice, Houston, Tex., on January 23, 24 and 25, 1934. and is not for publication until after the meeting. Please bring this report with you to the meeting. This Association, as a body, is not responsible for any statement made or opinion expressed in its publications. DURABILITY OF PAINT ON WOOD TREATED WITH ZINC CHLORIDE By F, L. Browne, Senior Chemist, Forest Products Laboratory1, Forest Service, U. S. Department of Agriculture Summary The painting characteristics of wood treated with zinc chloride for preservation against decay were studied at the Forest Products Laboratory by observation of practical installations and by a care fully planned series of exposure tests in which matched specimens of wood were used with and without treatment. For interior sur faces the presence of as much as 1.5 lb. eu. ft. of zinc chloride in boards 1 in. thick does not affect the behavior of interior flat or gloss paint significantly. For exterior surfaces it is entirely practicable to maintain zinc-treated wood with ordinary linseed oil paints, but the paints do not last so long on wood containing zinc chloride as they do on untreated wood. When wood treated with zinc chloride is primed with aluminum paint before applying ordi nary white paint,' the durability of the coating is greatly improved. Wood treated with a mixture of 2 parts of Zinc chloride and 1 part of sodium dichromate by weight holds paint fully as well as similar but untreated wood. Since at least half of the zinc chloride in such a mixture must remain in the wood as such and whatever zinc dichromate is formed by the rest of the mixture is toxic in laboratory tests, the mixture offers promise as a wood preservative, although service tests to determine that point are lacking. The mixture of zinc chloride and sodium dichromate may be given serious consideration for uses in which preservation is necessary and maximum economy in paint maintenance is desired and where service records proving satisfactory effectiveness as a preservative are not considered essential. 'Maintained at Madison, VVis., in cooperation with the University o.f Wisconsin. i" N41698.19 DURABILITY OP PAINT ON WOOD TREATED WITH ZINK CHLORIDE ~ 'Paint is not a wood preservative, that is to say, it is not a prac ticable means of preserving wood against attack by wood-destroy ing fungi. Despite frequent assertions to the contrary in popular writing and advertising about paint; the common practice in the use of wood has been to rely for preservation against decay Upon (a) design and construction that prevent the wood from becoming wet for long periods, (b) choice of the heartwood only of naturally durable species or (c) impregnation with chemicals that are poison ous to wood-destroying fungi. Painting is usually confined to ex posed surfaces that are free to dry out promptly when temporarily wet by rain or other sources of water. On exterior surfaces the objects of painting are decoration and protection against the roughening, cupping, checking, and loosening of hoards that result when wood is left unpainted. On interior surfaces the chief rea sons for painting are decoration, improved illumination, and ease of keeping the surfaces clean. Paints and wood preservatives are, therefore, not competitors. For the most part woodwork that is commonly painted is not sub ject to conditions under which there is much hazard of decay while, on the other hand, the uses to which most of the wood treated with preservatives is put do not require painting. There are, however, some important applications in which both preservative treatment and painting are necessary or desirable. One example is offered by roof timbers and ceiling boards: in factories in which the opera tions release much moisture, such as paper mills, or in which humid ification is necessary, such as textile mills. In these structures the interior surfaces must often be painted for appearance gild; to improve illumination. Another example is offered by highway posts, guard rails, and bridge timbers that must be kept easily vis ible with white paint. :: /. At present there is no thoroughly reliable method of keeping creosoted wood painted with white paint. If the wood is so treated that the creosote does not bleed, creosoted wood can be painted suc cessfully with aluminum paint but it has not yet been established that white paint can be applied safely over the aluminum. The difficulty with creosote lies; of course, in the fact that it is missible with dryings oils and therefore discolors white paint... Water-soluble wood preservatives, on the other hand, are in capable of diffusion into drying oils and under ordinary circum stances do not discolor paint. Since zinc chloride is the most im portant non-proprietary water-soluble preservative at present, re liable information about its effect on the painting characteristics of wood is highly desirable. . 2 FLB 000857 Review of Earlier Tests .In 1914, panels of white pine were treated at the Forest Products Laboratory with (1) 1.5 to 1.75 lb. per cu. ft. of sane chloride, (2) 0.8 lb. per cu. ft. of sodium fluoride, and (3) 2.0 lb. per cu. ft. of a mixture of ammonium phosphate and ammonium chloride (S). t The panels were air-dried "for several weeks" and it was noted , that those treated with zinc chloride dried very slowly. It is now \ believed that they were not thoroughly dry when painted. There ; Were also untreated panels for comparison. The panels were ! painted with lead and zinc house paints by Dr. ;H. A. Gardner, and i sets of panels were exposed at Atlantic City, N. J., Washington, I D. C., and St. Louis, Mo. On the panels treated with zinc chlor ide, the paints lasted longer than they did on the panels treated | with ammonium salts, but not so long as they did on untreated | panels or panels treated with sodium fluoride. | In 1926, the Service Bureau of the American Wood Preservers' | Association arranged for a new series of tests (7, 8). A set of 60 | specimens of southern pine was prepared at the Forest Products | Laboratory; 20 specimens were untreated, 20 treated with 0.25 to j 0.68 lb. .per cu. ft. of zinc chloride, and 20 with 4 to 8.5 lb. per cu. ft. of creosote. The treated specimens were seasoned for about three weeks, but subsequent experience indicates that this was not enough time to dry the panels containing zinc chloride ade quately. The panels were painted by Dr. H. A, Gardner and ex posed at Washington, D. C. Two house paints were used, white lead paint and a lithopone, titanox, and zinc paint, each of which was applied with the white paint as the priming coat and over the following special priming paints, red lead, Zinc dust and zinc oxide, aluminum, and -a nitrocellulose paint. All of the specimens ; treated with creosote caused discoloration of the white paints. Qn the Specimens treated with zinc chloride, white lead paint lasted | nearly as long as it did on untreated specimens, but the treated I wood checked distinctly more seriously than the untreated wood. | The lithopone, titanox, and zinc paint failed more rapidly on the treated wood than it did on the untreated wood. | A third series of tests was started by Dr. H. A. Gardner in 1928 (8) : Southern pine specimens were impregnated with about 0.75 lb. and about 1-5' lb. per cu. ft. of zinc chloride and matched. specimens were left untreated. All treated specimens were sea soned until the moisture-content was below 17 per cent; most of I the specimens averaged about 12. per cent. A set of the specimens was then painted with a titanox and zinc paint and exposed to the | weather at Washington, D. C. After five months the coatings were still in good condition; no later reports-have been issued. | Another set was painted with white-lead paint, a lithopone interior flat paint, and a lithopone and zinc interior gloss paint. The S FLB 00085B second set was suspended from a ceiling indoors over a rat of steaming aqueous solution to simulate a roof in a factory of wet occupancy. Although a relative humidity of 90 per cent was at tained in the room, the test specimens lost in weight during the first 130 days exposure, indicating that there was a warm stratum of air of much lower humidity actually in contact with the speci mens. When the. specimens were later placed in a humidity cabinet they gained in weight significantly, those containing zinc Chloride gaining materially more than the untreated specimens. The test over the steaming vat was then continued for a month and a half but apparently under somewhat different conditions because the specimens gained in weight by enough to raise the moisture com tent above the fiber-saturation point after which the Coatings be came blistered. Specimens containing zinc chloride absorbed more moisture and apparently became blistered sooner than untreated specimens. In 1922, Dr. Hermann von Sehrenk exposed a set of test panels at St. Louis in which there were cypress and southern pine speci mens with and without zinc chloride, with planed and sawed sur faces, and eoated with two different white paints and a red paint. After two years exposure the paints were still in excellent con dition {11). Dr. H. A. Gardner later (S) published a photograph of the tests after six years exposure with the statement that the treated specimens held paint satisfactorily. In 1926 the Minnesota Highway Commission exposed a few speci mens of white pine and ponderosa pine treated with about 1.6 lb. per eu. ft. of zinc chloride and painted with two kinds of white paint, a chrome yellow paint and a black paint. The exposures were made in the inclined position facing south at St. Paul- The white paints failed completely in less than 16 months and the con clusion was drawn that the presence of zinc chloride accelerated the failure of the paint. There were no untreated control speci mens and there is reason to doubt whether the treated specimens were thoroughly dry when painted. The State of Illinois, Division of Highways, in 1927, began tests of paint on 10 southern pine fence posts treated at the Forest Products Laboratory. The posts, which were 6 in. by 8 in. by 8 ft., were treated with about 0.5 lb. per cu. ft. of zinc chloride. A lead and ziiic paint was applied in 1, 2, and 3 coat work, both with and with out special priming paints. After nearly two years of service the paints were all in reasonably good condition so that no conclusions were drawn,' except to point out indications that the aluminum primer appeared to be exerting a beneficial effect, while the other special primers were not. The California Termite Investigations Committee and the Calif ornia Paint Superintendents' Club in 1930 made an extensive study of the painting of woods treated with various preservatives in- 4 FLB 000859 ; i eluding zinc chloride (10). The woods were Douglas fir, redwood, and ponderosa pine. The specimens treated with zinc chloride con tained about 0.5 lb. of salt per cu. ft. Untreated specimens were included, but they were not matched with the treated specimens. The conclusion was drawn that it is entirely practicable to paint wood treated with zinc chloride, but that the paint does not last quite so long as it does on untreated wood. The durability of white paint was improved when it was applied ove,r aluminum priming coat paint. The first painting studies of treated wood at the Forest Prod ucts Laboratory were reported by M. E. Dunlap (5). The unpreg nants were sugar, 0.55 lb, per cu. ft.; borax, 1,26 lb.; zinc chloride, 0,64 lb.; sodium fluoride, Q.53 lb.; mercuric chloride, 0,13 lb.; and two proprietary preservatives. The boards were seasoned to con stant weight in a room at 60 per cent relative humidity before the panels were made and painted with white lead paint. On the panels treated with sodium fluoride and with mercuric chloride the paint lasted somewhat longer than it did on the untreated panel. On the panels treated with sugar and with zinc chloride the paint failed slightly more rapidly than it did on the untreated control and, in, addition, the boards containing zinc chloride developed more weather checks than the untreated boards. The paint failed most rapidly on the panel treated with borax. The writer has attempted to make a survey of practical ex perience in the painting of wood treated with zinc chloride. Through a producer of zinc chloride a list of installations was ob tained of wood treated with zinc chloride and known to have been painted. Most of the installations were roof timbers and ceilings in paper or textile mills or factories in which much moisture is evolved; a few were exterior woodwork of some kind. Some of these installations were visited by the writer, while, for others, in formation was obtained through correspondence only. As a rule, information so obtained is subject to the serious limitation that there is no means of comparing the behavior of the paint on treated wood with that of similar paint subject to exactly the same con ditions on untreated wood. In all but one of the installations with which contact was made, those in charge of maintenance were satisfied that Wood treated with zinc chloride can be kept properly painted as economically as untreated wood. The one exception was a state highway com mission that has used both treated and untreated wood on signs and guard rails that are painted white. For a year or so no differ ence in paint behavior was observed, but after two or three years the paint was found to be flaking more rapidly from the wood con taining zinc chloride. A fair statement of experience and prior experimentation seems to be as follows; Interior woodwork treated with zirle chloride 5 % FLB can be kept painted as easily and as economically as untreated wood. Exterior woodwork containing zinc chloride can be kept painted without unreasonable cost, even though the paint may not last quite so long as it does on similar but untreated wood. Tests Started in 1928 The Forest Produets Laboratory, in cooperation with the Grasselli Chemical Company, in 1928, started a series of tests of the painting characteristics of wood treated with zinc chloride, in which matched test specimens were used. The boards were thor oughly air-dry before painting, and the work was done on an ade quate scale to justify the drawing of conclusions. Lumber and Treatment The lumber used was 1-in. by 6-in. by 16-ft., southern yellow pine boards, surfaced on 4 sides, of select grade suitable for finish ing, Thirty-three hoards were selected that contained as much sapwood as possible and were reasonably uniform in density and width of growth rings throughout the length of the board. They were all flat-grain boards and were well seasoned. A "board number" was assigned to each board for purposes of identification. Each board was then cut into 10 pieces, each piece 18 in. long, and each piece as it was cut off was marked with its board number and a "piece number" (from 1 to 10) indicating the order in which it Was cut from the board. From the waste cuttings small specimens Were taken for determining the moisture content of the boards, which varied from 9 to 15 per cent and averaged approximately 11 per cent. Pieces numbered -1 from all boards were set aside as control specimens to remain untreated. They were stored in a room kept at 60 per cent relative humidity while the remaining pieces re-: ceived- treatments and were reseasoned subsequently. Pieces numbered --2 from all" boards were set aside as control specimens of another kind, They were treated to refusal with plain water under exactly the same conditions that were followed for the treatments with zinc chloride. The object of these con trols was to determine whether the increased susceptibility to weather cheeking observed in previous, tests of wood containing zinc chloride is caused by the conditions prevailing during impregna tion, or is a property imparted to the wood by the presence of the zinc chloride. Pieces numbered -3, -4, and -5 from all boards were treated with a 3.66 per cent solution of zinc chloride. Vacuum of 28 in. was drawn for 30 min., the solution was then admitted and. pressure of 140 to 150 lb. per sq. in. at 176 to 194 deg. F. was applied for 6 hr. Each piece was weighed before and after treat- 6 ... xwugiuy i -Pieces numbered -6, --7, and treated with a 1.74 per cent f retention of roughly 0.75 lb. p.e Pieces numbered -9 and --1 treated with a, solution contain! 1.2 per cent of sodium dichrom 1 lb. per cu. ft. of mixed salts, After treatment, all specimc grain surfaces with gloss oil a drying from the ends and were relative humidity to season. .1 bring the moisture content of th down to approximately 13 per < treated with water came to a ; cent m that time. Pieces numbered -4, -7, and to remove the layer of wood m there is some movement of wa toward the surface, making the ical higher near the surface ths was thought that the removal fore, tend to improve the pain Pieces numbered --3, -6, and --! all respects tb pieces i-4, --7, ante the sap side without planing off Pieees numbered -5 and -8 w side with a saturated solution fore painting. Borax reacts w compounds of zinc. It Was hop near the surface into insoluble tention of paint by the wood. Grouping of pi Each test panel consisted c taken from each of three boa: pieces among panels is indica for example, were assigned i lead paint. The three pieces 0 made up panel number 505, Wj for the group. The three piece made panel 506, the water-trea made panel 607, which contain chloride, and was neither plai painting. The --4, -5, -6, -7, ij FLB 000861 Ifllllflll in ill! luent to furnish data for calculating the amount of zinc chloride retained, -which was roughly 1.5 lb. per cu. ft. Pieces numbered -6, -7, and -8 from ail boards were similarly treated with a 1.74 per cent solution of zinc chloride, yielding a retention of roughly 0.75 lb. per cu. ft. of zinc chloride. Pieces numbered -9 and -10 from all boards were similarly treated with a solution containing 2.4 per cent of zinc chloride and 1.2 per cent of sodium dichromate, yielding a retention of roughly 1 lb. per cu. ft. of mined salts. After treatment, all specimens were coated thickly on the end grain surfaces with gloss oil and coating to prevent unduly rapid drying from the ends and were then piled in a Toom at 60 per cent relative humidity to season. About two months were required to bring the moisture content of the specimens containing zinc chloride down to approximately 13 per cent. The specimens that had been treated with water came to a moisture content of roughly 10 per cent in that time. Pieces numbered --1, -7, and -10 were planed on the sap side to remove the layer of wood nearest the surface. During drying there is some movement of water-soluble ingredients in the Wood toward the surface, making the concentration of impregnated chem ical higher near the surface than it is in the rest of the board. It was thought that the removal of this surface layer might, there fore, tend to improve the paint retention on the treated lumber. Pieces numbered --3, -6, and -9, which otherwise were similar in all respects to pieces -4, -7, and -10, respectively, were painted on the sap side without planing off the surface layer. Pieces numbered --5 and -8 were sponged thoroughly on the sap side with a saturated solution of borax in water and redried be fore painting. Borax reacts with zinc chloride to form insoluble compounds of zinc. It was hoped that changing the zinc chloride near the surface into insoluble compounds might improve the re tention of paint by the wood. Grouping of Pieces into Test Panels Each test panel consisted of three similarly treated pieces, one taken from each of three boards. The method of distributing the pieces among panels is indicated in Table 1. Boards 7, 8, and 9, for example, were assigned to panels to be painted with white lead paint. The three pieces numbered -1 from these three boards made up panei number 505, which was the untreated control panel for the group. The three pieces numbered -2 from the same boards made panel 506, the water-treated control. Similarly the -3 pieces' made panel 507, which contained roughly 1.5 lb. per cu. ft. of zinc chloride, and was neither planed nor sponged with borax before ; painting. The -4, -5, -6, -7, -8, -9, and --10 pieces from these !: 7 :! 5 FLB 000862 boards wade panels 608 to 514, respectively. Panels 505 to 514, inclusive, were all painted with two coats of white-lead paint. Boards 10, 11, and 12 Were assigned to panels for painting With lead and zinc paint and the arrangement of the pieces was exactly analogous to that described for the 10 panels painted with white lead paint. The remaining boards Were set aside in groups of 3 and the pieces distributed into sets of 10 panels each in the same lilt Fig. lr--Tyeated And Untreated Wood Painted with White~*L/ead Paint* The panels intheupper row w^re painted with two oats of whitelead paint* those in the lower row with one coat of aluminum paint and one coat of white-lead paint- In each row tile left-band panel was mode of untreated wood, jfhe middle panel of wood treated with 1*5 111. per cnu ft. of zinc chloride* and the right-band panel with a mix ture of i lb. of zinc chloride iunl 0.5 lb., of sodium diebroinate per cu. ft. The coatings were 26 months old when photographed., way. Thus, in all, there were 11 sets of 10 panels each, one set for each of 11 paints or painting procedures to be tested. Of the 11 paints or painting procedures, 9 were exterior coatings and 2 were interior coatings. : The ;exterior coatings only are tabulated in Table 1. Three common types-of house paint were tested, pure White lead paint,' a paint containing zinc oxide and white lead; and a paint containing titanium pigment: and zinc oxide without any white- lead; : Each of these -paints Wats applied in two-coat Wort, each Was applied as a finishing^ coat over aluminum priming paint, and each was applied | FLB 000863 in two-coat work using for the first coat a mixture of the paint with spar varnish. Both interior paints were lithopone paints made with a bodied limited oil vehicle; one of them was a gloss paint and the other a flat paint, 'the two sets of panels painted with these paints, numbers 485 to 494 and 495 to 594, respectively, are not listed in Table 1 bet nuse there are no acceptable methods of evaluating FJ?. 2.--Treated and Untreated Wood Painted ,viIf, Lead and Sine Faint. The panels in the upper row were painted with two coats of lead and rfnc paint, those in the lower row with one coat of aluminum paint and one coat of white-lead paint. In each row, the left-hand panel was made of untreated wood, the middle panel of wood treated with 1.5 lh. per cu. ft. of sine chloride, and the right-hand panel with a mixture of 1 lb. of sine chloride and OH lh. of sodium dichro mate per cu. (t The coatings were 20 months old when photographed. the serviceableness of interior paints and determining their durability. Composition of Paints The linseed oil used in the exterior paints was a raw linseed oil of "premium grade" intended for paint making; a typical shipment was found to have an acid number of 5,5 mg- KOH per g, and an iodine number (Wijs) of 178.0. The bodied linseed oil for interior paints was made by heating Varnish makers' linseed oil at 300 deg. C, for 3 hr. The spat varnish for aluminum .paint and for addition to some of the priming-coat paints was a commercial vehicle for aluminum paint of 80-gal. length in oil and presumably made chiefly of ester gum, tung oil, and thinners. It contained 52 per cent non-volatile by weight. . The liquid paint drier was a commercial brand of lead and man ganese linoleate paint drier. F1& 3*--Treated and Untreated Wood Pointed with Titanox and Zinc Paint. The panels in the upper row were painted with two cents of titanov and seine paint, those in the lower roxv with, one coat of aluminum paint and one coat of titan.ox and zinc paint. In each row, the left- hand panel was made of untreated wood* the middle pane! of wood treated with 1.5 lb. per cu. ft. of zinc chloride, ahd the right-hand panel with a mixture of 1 lb. of zinc chloride and 0.5 lb. of sodium dichromate per cu. ft. The coatings were 26 months old when photographed* - The paints and their various mixes are listed- below with a sys tem of symbols that will represent them in the subsequent discussion. Paints ............ White paints are designated by the letters L for pure white lead paints,: LZ for paints containing white lead and zinc oxide, TZ for paints containing titanium pigment and zinc oxide, and P for in terior paints made with lithopone; aluminum paint is desig nated by A: 10 FLB 000865 Li Paste paint Pounds Basie carbonate white lead-----*.--,--,------------ 92 Linseed oil------ ,----------------- ~------------------ ,--,-------- 8 Unit weight for mixing--,-------- ---------- ----------------,-------- 100 la Paste paint Basic carbonate White lead_____ ____________ ____ ,------ 85 Linseed oil____________ ^ - ,,,--,,--,-- 15 Unit weight for mixing-,_______ __________ -___ _100 LZ, Paste paint Basic .carbonate white lead_,____________,____ ,_________Zinc oxide, lead-free____,,,Magnesium silicate__,,_______ __-____ --__________ Linseed oil____________ ____ __________ ,_________________ 42.6 21.3 7.1 15.0 Unit weight for mixing___,____________ --_________,--_ 86.0 TZt Paste paint Titanox B __________ ________________-s._i 33.0 Zinc oxide, lead-free_____________________________,___16.5 Magnesium silicate__,___,_____________________________ 5.5 Linseed oil___________________ ______ __________________ - 15.0 Unit weight for mixing--------------- ----,--70.0 Pi Paste paint Lithopone ______________ --____________________,,____-- 53.6 Bodied linseed oiI__--,____ ______________ ,____________ 11.4 Mineral spirits _______ _____________________________ 9.9 Unit weight for mixing___________ ___,________________ 74.9 Per cent by LZ, Prepared paint weight Basic carbonate white lead_________ _____ ___________ 55 Zinc oxide, lead-free---------- _ _ __________ ______ 35 Magnesium silicate _ ------------ _ . -- ------------- - __ 10 Total pigments -- --------------- _________66 Linseed oil ______ __ ____________ - ____________ __ 90 Mineral spirits______ ___ Liquid paint drier ____ ______ __ Total Liquids---.---------------------------------- -------- 34 TZ2 Prepared paint Titanox B < -- ___________ ______ ,_________ ____ 55 Zinc oxide, lead-free_^_-_____________ _,,, 35 Magnesium silicate ________ -;________,__________,, TO Total pigments ---_________________ ,----------- 66 Linseed oil _______-,___ ,_____________________ - 90 Mineral spirits _-,___________________ _________ 5 . Liquid paint drier______ _________--______ __,,_______ 5 Total liquids-------- ______ ---,--------- ---,___ 34 A Mixed immediately before use Aluminum, powder standard varnish grade__ 1,5 lb. Spar varnish ---------------------------------------- --------- 1,0 gal. 11 FLB Mixes of white paints for application Mixes for priming coat are designated by letters a, ar (for re painting), and av (containing varnish), and mixes for final coat by c. In the mixing formulas below, the quantities of liquids in gallons are added to the unit weight of paste paint stated in the paint formulas or to one gallon of prepared paint: a, 2 linseed oil, 2 mineral spirits, 0.125 paint drier, a, 0-31 mineral spirits. a, Q.96 mineral spirits, 0.076 paint drier. av, 1.5 linseed oil, 0,5 spar varnish, 2 mineral spirits, 0.125 paint drier. av, 0.16 Spar varnish, 0.15 mineral spirits. ar 1,25 linseed oil, 2 turpentine, 0,125 paint drier. Ci 3 linseed Oil, 0.125 mineral spirits, 0.125 paint drier. c2 Prepared paint -without any addition. e 2.26 linseed oil, 0.125 turpentine, 0,125 paint drier, ci 0.96 mineral spirits, 0.076 paint drier. c5 1.12 bodied oil, 0.472 mineral spirits, 0.148 paint drier. Exposure, Inspection, and Evaluation AH panels painted with exterior paints were exposed on the For est Products Laboratory test fence at Madison, Wis., on October 29, 1928, They were placed on the fence facing south and sloping back at an angle <of 45 deg. In this position the painted surfaces receive Very nearly the maximum possible exposure to sunshine and paint coatings fail in two-thirds to three-fourths of the time required for failure when the panels are exposed in the vertical position facing south. Allowance should be made for this fact in considering the data in Table 1. In practice most exterior painted woodwork is in the vertical position. The 26 panels painted with interior paints were exposed alter nately in rooms kept respectively at 90 per cent and at 60 per cent relative humidity for periods of one month. The rooms were in terior rooms with artificial illumination only. The test panels were inspected at suitable intervals by members of the staff of the Forest Products Laboratory. The methods of inspection, records, and evaluation for exterior panels are described in detail elsewhere (2, 3). Coatings were judged for appearance, integrity, and protection. Appearance is affected by such developments as soiling, loss of gloss, and chalking when the dirt is thereby dislodged; during the early part of the life of a coating changes are usually confined to appearance, but toward the end of the life interest shifts to in tegrity and portection. In these tests the appearance of the coat ings was similar at all times on all 10 panels of any one group, in other words, the presence or absence of impregnated chemical had no effect upon the appearance of the coatings. There were, of course, differences in appearance between groups of panels painted 12 FLB 000867 a*o| 1 tin* 3SSg >, i|^ | 2 tfSi ill S c*s gs g C4 U+ 1 1 4oo cds o CU m Ai \fooc + a Ai m ffi + r*4- 0CO4 o> H04 4* C0O4 C0O4 <-o4 0r0l 4" C4 O + t2 'C'd.'t1j'O1TatjTS'o o*a comcQMCQinmffiCupq N Ill'S'S'Sii-a-a 3 Sd S,s pv5OO3otf*ca>f.caifedbfd*eO'Ogfficl'OgO'OOS NJH 0*tCj O04 rftirrlHr-ftt -t <0>H5rH^TH-4 C^NI 004 4- .j1S3jj e+cao'c,*o^4c*o*^'cft+oaei,c,*`s04o4-o4o4*cuoscc+o4 SS8gSSgS o 2 0.0*5 0*2 C C tflg42 Sft.0 C b <U 0 CD 0i-<O ai Q)Ho g gg gg gw to SC ijCCO CO fOlC.o so . 5*|fc1 1 *5 .*a6*8 ^<^du c -<-? 2*; ^ * <c S3 4*4* 0tO4 0(0400040094 r0-44O044<0C*0?t40 C94fiC0O4 S S&O OaSsSV^fijfaoacfi-s^-<Jfso2*o1*4*fa* .eg *-, e0g0 ga0c ga0e ga0.eg0g.s50cof^S'oSo* sS 5n *? 58SSS ca> J+HOB"S3 NHf0.<C'*1JXt* .Ia8$c. c^ds,,f` 4* 4- 4* 4-4-4-4- 8S8383S8S8 gee.! 2ge1a! s2 ea.a! gggijipgi gOO 4eoJ 0go eo go<J) QBo) aOS+'g,oM. e fc. e e a e e fio .1 g|S55$$gg >> ^wm-^ws^ot-coo> 3 U II1!1 1 1T *a4>-5rc3j fc .*s 18-5-M38.S8-8-^--88- *-04CO ISOt-000>.0 111 I 11 ! 1 M 3 ft "t3 3g>*^au-^3t.oaoia j'*^ioj U s "S rH + 0H B**f*a3d->>t (4 H N 'i*Ub <01-00o O 11 m 11 nt dcj0j0>050><7>05 0oo oo oo oo fl .ee oo co oo oo a 04 04 04 04 010404 0404 04 4t_{ HHHrtrtHrtrtHH HHi rtrt'irl H0 Q HHrtHHHHHWrt o o o oo ododo ri rH rH-r-t rtHHrlHri C lOusto letauaisvo io u> 44l_4 HriWrtHHHHiiri ^ * "tp co odoj co eo oo eo eo edco" H H H >(*M *< -ri U><e t- 00. r4NWio>b-oecjQ_ 4 _ rjt f1c.88 OujtOo uOs0OXvOouH>3r0trulsHuaWus tkH0tlH0u^SlW>t*H0W10U4 0430*40ClpO lOtOt-OOOjOtHOJO^ 04 0004CO 04 CO CO kO io U3 U) IO U3 U3 to to iO 13 FLB 000868 I J l?Btps3 8 - Qg H .S " ft ft ft ft 4- + ++ 'S ft ft ft .ft 4- ft 4- 3tT Q8~ Sw &*sl W O -5 i ft ^ a fc * .& . #!!" 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N gf oSo c % #SoSoSgabojSoSSo1o45-a'^4 s a c a c s-o fi?sS?*3sn C ^cJ W_* 4|||&P EP l.s -' <1 * aS ^ '5 * S+5 s p a s > o .S5-5, SS3$e$g S-SrH-*! ' * -- s Ad ^ S3 <f8t .35 'N^'i'OlOOr ZA e IICQ 03o ^ 10 uo.totr OC3t0p0Q01O00) g-S-irtrt ' 3tfPalt*rTQ0OSfjTcaOm33fSl'-83&5w-waa Bag*a4*aPa 5"s.8g| -a SS 3+'sl^.a'S, 1114-1 r* ,C4 CO it> 5 t- 00 Oi O II .rf WQlcO-^lOCOt-OOAO ft rf . -c0303-<|HtQ<0t-00-0JrO.5^Jf4S m 1111111 9 > az 1 i g>s>glg ! 111431 ct d w *5 .1 Ma o 0Sat +B<5j o,tiiO't-<.g rfSif13 e+.S^ Sv SB 4 C4<M03C4<M<N 0303? Mg r-sS-a 4 -FS*-"toS? gO-*(8eH {^0-/3t2i lifislt 11 U3 SO C- Ofi< O !-t 04 CO rf LO IQ U U9:iQ ID Q to w U5 VCQ-f.c<-0t.-t1*r>C0t0->0O0r0H000J3C0C0 0O0* <0 UJ IOIQ IO1QU3 LQ U3 IO O0O<0OO1O- 0O0O0O) OOOIHA.OOaIOOOlAO* o us to tmo 10 xa ua up ua omj sc0i)iZu0^>11 ?a? 16 FLB 000870 with different paints but since the present concern is not with com parisons of paints the data on appearance of the coatings are omit ted in the tabulation of results. Integrity of the coating is affected by such developments as checking, cracking, and particularly by flaking from the bands of summerwood, leaving patches of wood bare as shown in the illu strations. Batings of ``good", ``fair", "poor", and "bad" have beep defined in a reproducible manner. When the integrity first reaches the rating "poor" it is considered time to- repaint and the time elapsed is taken as the "durability of the coating considering in tegrity only." These are the figures reported in the seventh and tenth columns of Tabic 1. Note that a rating of "poor-(-" is a little short of the typical "poor" while "poor--" is a little be yond it. . It is customary to regard exterior paints as protective coatings intended to protect wood against wood weathering but it is de batable whether users of paint actually consider protection very seriously. Sometimes painted boards 'develop wood checks, cup, or pull loose from fastenings when the integrity of the coating must-still be rated "good" or "fair."' In such cases the; coating is rated lower in protection than it is in integrity; in the absence of such signs of wood Weathering the coating is assigned the Same rating in protection as in integrity. When the rating in protection first reaches "poor" the time elapsed is taken as the "durability of the coating: considering protection and integrity." These are the figures reported in the eighth and eleventh columns of Table 1. Satisfactory methods of evaluating interior finishes have not yet been worked out. The panels were weighed after each period of exposure in either the 90 per cent or the 60 per cent relative hu- midity room and; notes were made concerning any observable changes in the coatings. Repainting After the exterior panels had been exposed for 26 months the majority of the coatings had reached or passed the point at which repainting was in order, but some of the more durable ones were . still serviceable. It was also apparent that some of the variations tested, such as resurfacing boards after treatment and treat ing with water only, were without significant effect. It was decided, therefore, to repaint a representative portion of the panels, to continue the exposure of representative panels with the > more durable initial coatings, and to reject the remainder. The disposition of each panel at this time can be seen in Table 1. Thus : panel 505, on -which the coating was rated "bad" in integrity, was repainted, while panel 506 in similar condition was rejected at 26 months, as indicated by the fact that no further data are reported in columns 10 and 11 of the table. Panel 525, on which the in- 16 ^ ; j 1 | \ ; I ; j $ - "i FLB 000871 tegrity of the coating was still good at 26 months, was repainted, while panel 626 in similar condition was left on the fence to de termine the durability of the initial coating, which eventually was found to be 46 months. Panels that were either rejected or re painted at 26 months although the coating was still rated better than "poor", are rated 26-j- in durability in column 7 of the table; panels for which the durability recorded in column 7 is greater than 26 months were left on the fence without repainting, while panels rated 26 or less in column 7, and for which no subsequent data appear in columns 10 and 11, were rejected. RESULTS Exterior Painting With all of the paints or painting procedures tested, the eoatings proved measurably less durable on panels impregnated with zinc chloride (without addition of sodium dichromate) than on the con trol panels that had no treatment or treatment with water only. The impairment in durability of the coatings caused by presence of zinc chloride was greater when protection as well as integrity of the eoatings was considered than was true when judgment was based on integrity alone. The boards containing zinc chloride were evidently more sensitive to checking, cupping, and loosening of fastenings than matched, untreated boards; when the protection furnished by the coating became inadequate, the fact was revealed more promptly by the boards containing zinc chloride. Similar observations were made in the earlier test at the Forest Products Laboratory and in Dr. H. A- Gardner's studies (5, 8). The panels that had been treated with water held their coatings just about as long as the corresponding untreated panels and were not signifi cantly more prone to weathering. It is the zinc chloride, there fore, rather than the conditions under which impregnation is effected that makes zinc chloride treated Wood more sensitive to weathering. There was no consistent difference in the durability of coatings between the panels containing approximately 1.5 lb. and those containing approximately 0.75 lb. per cu. ft. of zinc chloride. Re surfacing the treated boards by planing off the surface layer of wood after drying failed to improve the durability of the coatings and sponging the treated boards with borax proved slightly harm ful on the whole. Earlier tests at the Forest Products Lab oratory indicated that borax alone impairs .the durability of Coatings (5). The impairment of the durability of coatings caused by the presence of zinc chloride was by no means great enough to render it impracticable to keep such wood painted. When it is remem- 17 % beyed that these panels were exposed in the inclined position, fac ing south, which materially hastens paint failure, and that; the standard of servieeableness adopted by the Forest Products Labora tory is higher than that of many property owners; the durability of paint on the panels containing zinc chloride must be considered reasonably satisfactory. The claim sometimes advanced by sellers Of proprietary, water-soluble preservatives to the effect that wood treated with zinc chloride is unpaintable should be dismissed as unjustified. On the panels treated with a mixture of zinc chloride and so dium dichromate, the coatings usually lasted fully as long as they did on the corresponding untreated panels and often longer. This statement applies whether durability is judged on the basis of integrity alone or on protection as well as integrity. The mix ture of zinc chloride and sodium diehromate is economical and prac ticable for use in wood preserving plants that now use zinc chloride. As far as laboratory tests can determine, the mixture should be effective in preserving wood from decay because chromates are toxic toward wood destroying, fungi and the proportions of zinc chloride and sodium dichromate suggested are such as to provide a large excess of zinc chloride after reaction with the dichromate. When injected in the proportions used in these tests the wood re tained fully, 0.5 lb. per cu. ft. of free zinc chloride, in addition to the zinc chromate presumably formed in the treating solution. It is reasonable, therefore, to expect that the treatment provided a satisfactory degree of preservation for applications in which zinc chloride alone would be suitable. There are, however, no records of performance ip actual service upon which a final evaluation of the effectiveness of the mixture of zinc chloride and sodium dichromate can be based. In view of the excellent retention of paint by the panels containing this mixture it may well be given serious con sideration for uses in which both preservation and paint main tenance arc necessary. Of the three white paints tested, the titanox and zinc paint proved decidedly more durable than white lead paint or lead and zinc paint. The titanox and zinc paint also proved distinctly su perior to the other two paints in appearance during most of the life of the coatings. The difference in durability, however, should nqt be attributed to pigment composition, either wholly or in major part. The pigment volume (ratio by volume of pigments to lin seed oil) in the final coat of titanox and zinc paint was 31 per, cent While that in the white lead and lead and zinc paints was 28 ' per cent,, Developments in paint technology since these tests were started emphasize the importance of pigment volume in the dura bility of paints and suggest that 29 or 30 per cent is a critical point below which durability falls off. In the writer's opinion the; white lead paint and lead and zinc paint would have proved more 18 FLB 000873 durable if they had been made with 31 per cent pigment volume. Few commercial white paints at the present time are made with as much as 28 per cent pigment volume (except cheap paints contain^ ing large amounts of inert pigments and volatile thinners) and painters mixing paste paints are accustomed to adding generous amounts of linseed oil. Addition of varnish in mixing the priming-coat paint proved distinctly harmful from the point of view of durability of the coat ings. i* also had a tendency to cause the coatings to flake in larger patches, so that a less satisfactory surface was presented for re painting. Application of the white lead paint and the lead and zinc paint over aluminum priming paint materially improved the durability and the improvement continued when the surfaces were later re painted with the white paints only- The titanox and zinc paint proved so durable when applied with the white paint itself as the primer that little room was left for improvement when aluminum paint replaced the white paint as the primer. In general, aluminum pruning paint has been found by far the best foundation thus far available for the painting of woods like southern pine, which have pronounced bands of hard summer-wood (f). When such wood has been treated with zinc chloride it is particularly advisable to prime it with aluminum paint. It should be pointed out, however, that two additional coats of white paint will usually be required Instead of one only as was done in these experiments, because it is very difficult for painters to hide aluminum paint satisfactorily with only one coat of white or light-colored paint. Interior Painting The alternate exposure to 90 and GO per cent relative humidity to which the interior panels were subjected was continued for about two years after which they were kept for about two years longer in GO per cent relative humidity. It was supported that each cycle of this test Would represent the extremes of moisture condi tions to which many interior surfaces would he subject in the course of a year and that completion of six cycles a year would greatly accelerate final failure of the coatings in integrity. There were, however, no failures in integrity on any of the panels when the tests were discontinued. These experiments, together with the Survey of practical experience in industrial buildings, lead to the conclusion that, in general, treatment of wood with zinc chloride does not materially affect its painting characteristics for interior exposures. In general, it is believed that interior coatings will usually he repainted primarily because the old coatings have be come soiled rather than because of failure of the coatings to re main intact. 19 FLB During the exposures in 90 per cent relative humidity, the in terior paints were attacked by a white mold that destroyed the gloss of the gloss paint and modified the sheen of the flat paint. On the untreated and water-treated panels, the growth of mold was uniform over all parts of the painted surfaces, but On the panels treated with zinc chloride or zinc chloride and sodium dichromate the mold grew less luxuriantly and some patches of the painted surfaces remained unaffected. Since these tests were started it has been learned that paints in which lithopone is the only pigment are very sensitive to attack by mold and that the in corporation of a substantial proportion of zinc oxide in place of part of the lithopone makes paint that is much more resistant to attack by mold. Paint Blistering These experiments were intended to study the behavior of paint under the normal conditions that lead to reasonably good paint service. Painted woodwork in buildings, whether the wood is treated with chemicals or not, is often subject to abnormal service conditions under which good paints often fail badly in a very short time (1). When the backs of painted boards become thoroughly wet while the temperature behind the painted surface is materially higher than, it is in front, paint coatings are prone to blistering. Once blistered, coatings usually scale badly within a few months. No attempt has been made to determine whether the presence of zinc chloride in the wood aggravates failure of this kind but it seems hardly necessary to do so in view of the fact that painting is an uncertain procedure at best under such circumstances. It should be pointed out, however, that wherever there is enough haz ard of decay-to justify the expense of treatment with a wood preser vative there is also likely to he enough moisture to expose the coating to the danger of failure by blistering. When early fail ures of paint are observed on treated woodwork care should be taken to make sure that they are not caused by blistering before attributing them to the chemical with which the wood has been treated. References 1. Browne, F. L.-- American Paint and Varnish Manufacturers Association, Scientific Section, Circ. 317, p. 480 (Oct. 1927). 2. Browne, F. L.-- American Society for Testing Materials, Proc. 30 (2) p. 852 (1930). 3. Browne, F. L.-- Journal of Chemical Education 10 p. 529 (1933); 20 FLB 4. Browne, F. L.-- "Effect of Aluminum Priming Paint on tie Durability of House Paints on Wood" to be published in Industrial and Engineering Chemistry early in 1934. 5. Dunlap, M. E--- Industrial and Engineering Chemistry 18 p. 1091 (1926).` 6. Gardner, H. A.-- Paint Manufacturers' Association of the U. S. Scientific Sec tion, Bulletins 44 (1914) and 61 (1916). 7. Gardner, H. A.-- Paint Manufacturers' Association of the U. S, Scientific Sec tion, Circ. 286, p. 140 (1926). 8. Gardner, H. A.-- American Paint and Varnish Manufacturers' Association, Scientific Section, Circ. 334, p. 688 (1928). 9. Gardner, H. A.-- American Paint and Varnish Manufacturers' Association, Scientific Section, Circ. 334, p. 588 (1928) : 342, p. 12 (1929) : 358, p. 11 (1930). 10. Harrison, W. P.-- Buchanan, D., Baird, R. M. and Doody, T. C.--American Paint and Varnish Manufacturers' Association, Scientific Section, Circ, 404, p. 407 (1931). 11, von Schrenk, Hermann-- Proceedings, American Wood Preservers' Association, p. 191 (1924). I 21 I FLB 000876 A Trouble- Shooter's View of the Gamble in House Paint By F. L. Browne Anyone who has had much experience , as a "trouble-shooter" in paint com plaints knows that a disturbingly large proportion of paint .jobs fails to give satisfactory service. There is as yet no reliable estimate o the unsatisfactory fraction of the total number of paint jobs because no systematic survey to determineit has ever been made. That it is alarm ingly large, however, is attested by the fact that at least one prominent paint manufacturer for some time gave .much valuable advertising space to an appeal to "end painting mistakes" by following directions closely. Still more significant, is the advertising of certain building ma terials that do not require paint in which the .principal sales argument is "end paint ing expense." A typical advertisement of the. latter kind is reproduced in Figure 2. That such advertising is effective with house owners who have experienced re peated paint failures was illustrated by a photograph on page 14- of the August 8 issue of R P , O C1 0 q 0 1 q Q +0 _ 1 0 . Paint Not Always to Blame .Poor paint is commonly held respon sible for early paint failures by nearly everyone except the experienced trouble shooter. That assumption comes natural ly because nearly everything written or said to the public about paint for many years has strongly emphasized the com position of the paint, particularly its pig^ ment composition, and has fostered the idea that there are great differences in durability between competitive brands of paint. The paint manufacturer for ob vious reasons likes to identify "poor paint" with "cheap paint," as illustrated by the advertisements reproduced in Fig ures 1 and 3. The experienced trouble shooter, however, knows that early paint failures are not particularly characteristic of cheap paints and that they are en countered by a considerable number of users of any one of the well known brands of high grade paint Trouble-shooting has formed an im portant part of the writer's work for more than ten years. The cases of early paint failure come to his attention from various sources including house owners, painters, paint dealers or manufacturers, and lumbermen; sometimes he takes the initiative himself by inquiring about inter esting paint behavior on houses that be happens to pass. The houses observed in clude residences of all price classes and farm and business buildings in many parts of the country. Most of the paints used have been high grade paints and among them can be found nearly all of the na tionally advertised brands as well as good paints made by smaller manufacturers. The writer's experience, however, inr dudes very few trouble jobs in which "CHEAP" PAINT DUTCH BOY . after 1 year after 5 years Dow! Gaml)I "cheap" paint ThisJob ime year offo coat tlijti TQdny if unlUost more . . for bwiina Y tl l f rr,mye Vtitrtit Tic*lU* i/ fl tintvioitI ' (L fun r' (\ TitPSflfeafyto&i*xmrisawua>ro0i/t . tC-Ul ` Jh. tlllftl' L, ir ti~j th h i L` \mfu / t n t / Jtit' twlj?, 1 ____________________ y.;..XtTvqTTtnO:*Ww<f^iftf.hkfrf.tctCcmveae.yWhRqdouiamere.S8qrtudeirmeImgflrpeIrnqosuvteeena!ttdApoeafpinwtcienoagvt,ehrweered- . #; attractive walls which trill never need any each - pwraoltle*cbtioynC- aArnedynothtKe wesxUtrateoihfctccktnhcenboaodsdeedcotoolerthiso summer oodwarVn in wmftr. : Modernizing n touw with Csrej-toc t* an lavcatiwt. notan expense--or inrestawottviiicft rcpaysitt - cost nwny times m purot savings. .pwntee and to. - proved appearance. Let as give you a. free estimate. NATIONAL LEAD COMPANY lOiasin IMUCM>, CL5eh9aedsPCttneaue-t,nSuDmOt,DA$Atvl.beLa.,onoyQiSan;ct,u2Bm2o4as0dta2j a48tiWf2e0:aSVttiocr8utd.SjLaPej^arutdiiac&rh.OcAitvlveC.ko.NCh. aliefiv.ve.lLanii-dii;,1J>1!'>*' ,jJi,jvW'^y'-J&1a,v *`* * T*.'** 4bA% .- ' 1v itb Are-. PlmbuigLi Ju&a T. LwriiA Bros. Co., Widetouer DBildigs.. Phi i -* i1 If ttill beat you every time! .: ygisDnrn,teMmiaorrti..tHlInirvuwf*'dri>psjto>Uora:fmoilH..vtptforodixitiBfkti--tnLo.'&U-Ufetfntefiaft,Slnute4ilpvirif-uwUfeliMwtthoat<ihi*&ierf '.dk'Htfntfai : iy(nIokfe.u-rsuOI.fcttt,lsi. miftrr'h<nAw/U4/7crte|tufH.lvlu>ImMrtetMc(Jniubtffes+csgtt<1!t"m,>ftik,r\t . piUouaf"cfiep"jCTt.: r<'>(iTnWi ibf.4kt..*a<dlsf ncif >pulfiart so.nvirmt iiIu.l'rl.N Voji jfl n( I tt I * m lilt L-t n am >.' 0.11.11,1. (( .1. .; .. .ri-irU/rnAri.ntt-n.r/s.j//i ltrtthitt*. <fc it. . cU-.v- ..f dwtji(> nwi>{<>ufWi</> : Udf v'-.nu.i % -+ Ktrutvoitar . la-lonrlilvscmWtittUeKieod. t>f. i brup" paint, ks >. tCmciwr-.s* IrtiAitina * fu tWlvl..tAwit'Artl,M..t,W..rWa<fr1..tov,AfllUrirt*fW|.irvn(iIi|l.i0sIb'.v.*I.vino)|\s>HsHiixtf-. . .: Hugo C. Krebs Decorating Co. 1407 CnWenlty Avena'PeA1KT HEAOQVAkTEX?' FnJrchttil.4776 ., Figure 1, left: Paint .manufacturers may attribute early failures like this ta "cheap" paint but trouble-shooters know that they are not related to the quality or grade of the paint and that the conditions under which they arise affect first grade paints as seriously as second grade paints. Figure 2, center: A newspaper advertise ment showing how manufacturers of building mqterials that take no paint play upon the disappointment of house owners who have experienced early paint failures. Figure 3, right: another illustration of the opinion that the gamble in paint lies in "cheap" paint. 28 N41698.2 FLB 30 PAINT, OIL AND CHEMICAL REVIEW October 17, 1935 Figure 4. A paint dealer's gamble with good paint on his own house. Five paint jobs were applied within ten years on this house which is owned by a retail dealer in lumber and paint. Three dif ferent brands of first grade paint were used, two of them unusually high priced paints. The last paint job was put on only three or four months before the photograph was taken. the paint .used was of a kind commonly classed as a `-cheap paint/' In line with this experience manufac turers with both a first grade and. a sec ond grade paint often report that most complaints come from users of their first grade paint It may also be significant that manufacturers who have changed the formula of their first grade paint fre quently in recent years are continuing to put out a second grade paint that they have been making for twenty years or more. The relative absence of cheap paints among the jobs about which com plaints are made does not prove, of course, that cheap ..paints give less trouble than good paints but it does show very clearly that cheap paint is not the dom inant cause of unsatisfactory paint serv ice at the present .time. Very cheap paints of the kind described as "Skins in Paint" in Scientific Section Circular 427, selling at $1.50 a gallon or less, are apparently made and sold to a ^pertain extent. That such paints may be inferior in quality as to fail badly within a year or two is easily understood but the sale and use of such paints on houses of any value must be far too small a factor in the paint market to lead firm ly established paint manufacturers to ex pensive advertising of the kind shown in Figures 1 and 3. It may be safely as sumed that the "cheap paints" against which the advertising is directed are of a much more respectable variety. The very cheap paints would have little chance of gaining a market if good paint could al ways be counted upon to give better serv ice. Three Reasons for Failure The conditions leading to early failure of good paints may be classified for con venience under three headings, moisture collecting behind painted woodwork, in compatible combinations of paints, and faulty technic of application and main tenance. The nature of the wood painted is not listed among the causes of early failure of paint By early failure is meant failure within one or two years after ap plication and of sufficient consequence to lead many house owners to complain. Dr. Gardner, quoting the writer's data, points out in Scientific Section Circular 489 that the life of good paint varies ma terially on different woods and in dif ferent climates. According to the data quoted, however, the average durability of good paints with respect to integrity of the coating exceeds two years except in the case 'of paints of hard type on woods of group IV exposed fully to the weather in regions characterized , by periods of extreme dryness. The expe rienced trouble-shooter knows that only a negligible number of paint complaints can honestly be attributed to peculiarities of the wood painted. As an alibi for un solved early.paint failures the alleged "re fractory" nature of wood lost its useful ness to the trouble-shooter when it was shown that common practice in house construction succeeded long.ago in select ing for exterior surfaces those woods that normally hold paint best. Moisture failures remain one of the most frequent causes of complaints about good paints. During the past ten years much has been learned about recognizing moisture failures after they have occurred but there is still no way of telling in ad vance whether the sidewalls of a house will sweat or how sweating can be stopped after it has been discovered. In spite of these serious limitations, how ever, much more is now known about moisture failures than about either of the other two classes of early paint failure. Failures from incompatible combina tions of paints have probably increased in number as proprietary mixed-pigment paints won a greater proportion of the market from white lead paint and as the different kinds of proprietary paints be came more numerous. Under present con ditions it may well be questioned whether the "progress" in production of new pig ments and new vehicles for paint, about which .so much has been said in recent years, should be considered an asset or a liability of the paint industry. Every new paint that differs significant ly from previous paints multiplies the pos sible number of incompatible combina tions with which the painter and the house owner must contend. As yet only a few of the many possible combinations of paints that prove antagonistic in one way or another have been recognized and even these few have not yet been estab lished to everyone's satisfaction. It seems fo be generally agreed that ochre priming paint is not compatible with any of the ordinary white or tinted paints but that is perhaps the only common incompatibility about which technologists are in sub stantial agreement. In P1 0 q , O0 1 q CQ +0 _ 1 R 0 , issue of August 8, 1935, the writer described several other incompatible combinations that seem to occur frequently. Figure 4 is an excellent illustration of incompatible white paints. The house, which is less than 10 years old, belongs to a retail dealer in lumber and paint who tries to maintain unusually good appearance. It has been painted five times at intervals of two or three years, but three different types of white paint have been used, all of them high grade paints and two of them unusually expen sive paints. Many early failures of paint arise from faulty technic of application or from lack of a properly planned program of main tenance. Paints are mixed with too much liquid, incorrect ratios of volatile to non volatile liquid are used, the coatings are applied too thin, loose old paint is not, properly removed before repainting, primers and body coats are allowed to weather too long before applying the finish coat, two coats are applied where only one is desirable or one where twp are needed, houses on which a good paim"' has failed too soon are repainted without attempting to discover the cause of the previous difficulty, paints are selected Figure 5. The first paint job on this house failed within a year or two although a high grade paint was used. The paint manufacturer made good by having the house repainted with the same paint but it failed again within two years. Who can tell the owner how he can get a satis factory coating of paint on this house? FLB 7, 1935 i of the d as the \ints besent conwhether new pigit, about n recent sset or a gnificantthe poscombinaand the yet only binations c in one lized and zn estabIt seems ` priming y of the lit that is ipatibility in subOn. 1 q .ugust 8, ral other seem to excellent te paints. 10 years 11 lumber unusually inted five ee years, lite paint gh grade ly expen- rise from Irom lack of maintoo much c to nonitings are tit is not epainting, lowed to tying the ed where here two pod paint d without se of the selected t r or two er made it failed t a satis- 32 PAINT, OIL AND CHEMICAL REVIEW October 17, 1935 without considering the nature of the paints used previously or the suitability of the paint for the painting habits of the house owner, and little or no effort is made to help the house owner to follow a rational program of paint maintenance, The Trouble-Shooter's Task The trouble-shooter's task as a rule is to determine the cause of early paint failure, fix responsibility for It, and recommend suitable procedures for avoid ing difficulty in future. He deals primarily with specific cases rather than with av erage performance. In the first part of his task, determination of cause, a mod erate degree of proficiency is gradually becoming possible. Many of the paint failures whose cause was mysterious or uncertain ten. years ago can now be diagnosed fairly easily although there is still need for much more progress along this line. In determining responsibility and future procedure^ however, little im provement has been made and the trouble shooter remains notably unsuccessful, Figure 5 is a good example of the dis couraging situation in which tire trouble shooter so frequently finds himself. This farm house was completed in the fall of 1928 and the white pine siding and trim primed with white lead paint put on with a spray gun. In the spring of 1929 two coats of high grade prepared paint were applied by brush. Peeling began in 1930 and in 1931 the paint manufacturer re painted the house with two coats of the same paint. Peeling began again in 1932 and the photographs were taken in 1935. A summer kitchen, not attached to the house, Was painted in 1929 with the same paint-and the coating gave good service, being in good condition for repainting in 1935. The primary cause of trouble on the house is probably sweating in the sidewalls, which does not happen in the summer kitchen; secondary causes maybe the lapse of six months between priming and finishing the original paint job and undue thinning of the priming-coat paint with volatile thinner for application by spray gun. Who is responsible for the paint failure? The house is thoroughly .con ventional in construction with no indica tion of violation of any accepted principle of good building and no reason apparent for more sweating in. its sidewalls than in those of other similar houses on which the same paint has been used with suc cess. The paint manufacturer has assumed the costs of one repainting although his paint proved satisfactory on the summer kitchen. Obviously the owner must pay for the next job but who can tell him how to get a reasonably satisfactory job for his money? No one knows how to prevent sweating .of the sidewalls, no one can wisely advise repainting without the heavy expense of complete removal of the old coating, no responsible painter wants to take the job, and no paint manufac turer can afford to offer his paint with any assurance tha| it will stand up. The farmer has the choice of letting the house go shabby or of taking another gamble with paint. The gamble with paint offer ing him the best odds is undoubtedly to burn off and repaint with pure white lead paint but who can blame liim if he de cides to reduce his ante as much as pos sible by gambling with cheap paint and cheap painters or if he prefers not to gamble with any paint by leaving the house unpainted Or by covering the siding with unpainted materials to "end painting expense"? The Problem of Responsibility Specific cases of early failure from in compatible paints or faulty technic com monly lead to a similar impasse in the at tempt to fix responsibility and to recom mend future procedure. Neither paint maker, painter, builder, or owner has con sciously violated any principle of sound practice generally understood and ac cepted in tile trade. The paint manufac turer feels that he has fulfilled his ob ligations by supplying paint capable of giving good service under many ordinary conditions of use. The painter rarely has enough technical training to understand the problems of incompatibility even if the paints he uses carry adequate formula labels; he assumes, however, that his own experience is the best guide for thinning and application and he assumes that any good house paint can be handled accord ing to his customary methods regardless of the directions supplied by the manu facturer. The builder and owner find no authoritative body of information to guide them in approving paint and painting methods and have to make shift with such information as they may obtain. Under such circumstances no party to the transaction can justly be held responsible for early paint failure; Unless one of them voluntarily assumes the burden of repair ing the damage the owner finds that he has gambled with good paint and lost. Many paint technologists regard the gamble in good paint as an inevitable consequence of the deterioration in crafts manship-:and the pressure to reduce costs of building and feel that nothing can be done about it even if the ultimate result is to destroy the market for painted ex terior woodwork. The writer does not share that pessimistic attitude. It is un doubtedly true that no single paint manu facturer cart solve the problems of early paint failures by his own efforts alone but that does not absolve the industry as a whole from responsibility in the matter. The intricate technical problems involved are of concern to the industry collectively and offer no great prospect of competitive .advantages to individual manufacturers within the industry. For that reason progress toward their solution is not to be expected from the technical research of laboratories dealing primarily with the competitive interests of individual con cerns. Broader attack from the point of view of the basic common interests of the industry in relation tp other industries such as the lumber industry and to the public is urgently needed The funda mental nature of the problems of early paint failures puts them logically in the field of research activity of the paint in dustry as a whole through its national as sociation. Taking the Gamble Out al Paint The following suggestions are offered by way of more specific illustration of types of study that are badly needed to remove the present gamble from good house paints: L There is need of a national survey of present experience with house paint that would reveal the relative proportions of successful and unsuccessful paint jobs and lead to a significant classification of the unsuccessful qnes in the order of their importance. At the present time our information comes top largely from cases of paint failure about which someone has complained. Much more attention should be paid to successful experience. Dem onstration of procedures that can be re lied upon is even more important than discovery of those that involve too much gamble. 2. Until the problem of sweating sidewalls has been solved it remains important to learn the relative sensitiveness of dif ferent paints and combinations of paints to moisture failures. Laboratory "blister ing boxes" as now used often give mis leading results. Our most reliable infor mation should come from analysis of the results of the survey suggested in (1). Elimination of the sweating itself is, of course, the proper final solution of prob lems of moisture failure but it goes beyond the field of the paint industry alone. 3. Vigorous study of paint compati bilities is urgently needed. If new prod ucts are to be placed on the market and proprietary brands of paint are to change in formula as frequently as they have in the past few years some means of guid ing paint users to successful use of such paints must be devised. If adequate , means of discrimination is not provided the paint user's only recourse to avoid gam bling with his paint jobs will be to return to the simple,, staple paint products of long established usage and to avoid pro prietary paints regardless of price or quality. 4. Facts should be developed about proper technic of application and main tenance of paint coatings. The impatience with painters and the public because of faulty technic frequently expressed by technologists is not justified because the technologists themselves are not in agree ment about such matters, as a survey of manufacturers' directions for application of paint will show. Claims made for the spreading rate and durability of paints for purposes of sale all too often fail to agree with the trouble-shooter's idea of proper application and maintenance after complaint has been made. Application and maintenance should be fully as important in paint technology as paint formulation but they are essentially problems of the industry as a whole rather than of in dividual manufacturers. Until tech nologists have established and accepted sound principles of application and main tenance they cannot justly feel aggrieved because painters and the h-ublic in their confusion so frequently make mistakes. FLB Sublimed White Lead has all thb characteristics of the Ideal paint pigment for exterior exposure, It is the finest white lead pigment. It assures proper plasticity and proper\ adhesion to the surface. Any Paint manufacturer making outside parnts should have ail the facts/about this superior lead pigment. It gives your customers more value per dollar than any other paint pigment. And remember, high-lead-content takes most of the trouble out of your paint business. EAGLE-PICHER LEAD COMM CINCINNATI, H I , White Lead, Carbonate -- Red Lead -- Sublimed Blue Lead--Sublimed White Lead--r Super Sublimed White Lead --Litharge-^--Sublimed Litharge--Orange Mineral--Zinc Oxide--lithopone^ FLB 000880 6 Canadian Paint and Varnish Magazine, September 15, 1955 Don't Let Faulty Painting Steal Public Confidence! What Paint Salesmen, Painters and Dealers Can Do to Prevent Paint Complaints By Dr . F. L. B X q Senior Chemist, Forest Products laboratory, Madison, fVis. EDITOR'S NOTE,---By special arrangement with Dr, Browne we are able to present to readers of Canadian Paint and Varnish Magazine important information regarding the success or failure attendant upon different painting practices. Pro viding customers with satisfactory enduring painting jobs is of vital importance to manufacturer, salesman, painter and retailer alike. Painting complaints mean loss of confidence, more difficult repeat business, loss of profits to the painting industry. In the accompanying article. Dr. Browne reseats the facts behind some paint failures and the means of avoiding them, NO SECRET is divulged in pointing out that some house paint jobs, even with the best of house "paints, fail to give satisfactory service. If the failure takes place within a year or two the houseowner often complains to the paint dealer or paint manufacturer. As a rule, the difficulty is not due to the quality of the paint but to some blunder in its use or unusual con. dition of service, but it is not always easy to convince the houseowner that the paint was not at fault after the difficulty has .arisen. Just settlement of such cases is of much more than passing importance because in the aggre gate these failures affect a Very large number of con sumers and the uncertainties because of them constitute a serious menace to the continued market for paint and wood for the exterior covering of buildings. Some of the conditions that give rise to short-lived paint jobs are now known and paint salesmen, working in co-operation with their dealers and painters, can pre vent many of the mistakes that would otherwise lead to complaints by seeing that customers are properly advised before the mistakes are made. A complaint prevented is far more profitable to everyone concerned than any pos sible adjustment that can be made after a paint job has gone bad. Moisture Failures One of the most common causes of premature paint failure is moisture collecting in the sidewalls of buildings during the time of year when buildings are heated. The latter part of winter and early spring are the times of year when the damage is most often done but the Scaling of paint and consequent complaint may not come to the dealer's attention until the following summer, when the walls have dried out again. Unfortunately there is much that is not yet known about moisture conditions in houses; for example, Why one house develops the trouble while neighboring houses do not and what steps can be taken to keep moisture out of the sidewalls of houses in which it collects. Salesmen, painters, and paint dealers can do much to prevent future complaints by asking about the behavior of the previous paint nsed on the houses of their cus tomers. If the last paint applied failed unreasonably soon it.is not wise to promise that the new one will give good service until the house has been examined for the cause Paint troubles lead to loss of market for paint. This house is being covered with composition material imitating brick because several paint Jobs on wood siding each failed within a year or two. The neigh boring houses were likewise covered over with composition material or with stained shingles for the same reason. N41698.21 FLB Canadian Paint and Varnish Magazine, September 15, 1935 7 of the previous difficulty. If the former coating shows evidence of moisture failure and nothing has been done to alter the conditions, the new paint will probably fail also. Under such circumstances a sale of paint without warning the customer about its probable failure amounts to an invitation for him to file a complaint a year or so later, A complaint represents loss even if no adjustment is made and it makes future sales more difficult. Soft and Hard Types of Paint No one paint is superior in all respects. Experience proves that soft types of paint, such as pure white lead paint, are less prone to rapid failure on houses whose sidewalls become wet than are harder paints, such as the majority of mixed-pigment paints. If a soft paint is applied over a hard paint, however, the coating re tains the characteristics of the hard paint so far as re sistance to abnormal moisture conditions is concerned. When a house is found on which hard types of paint have failed because of moisture, and no practicable means are discovered for making sure that the sidewalls will remain dry in the future, the safest procedure to recom mend for repainting is to remove all of the old coating and to repaint with a soft paint. Most house owners under these circumstances prefer to forego the advan tages of the harder paints for the greater assurance of having the coating remain intact for a reasonable length of time. The salesman's problem in advising a customer in such a predicament is to keep him from becoming dis couraged with the use of any paint On wood rather than to sell him the salesman's brand of paint for that particu lar job. Incompatible Paints Much has been said about the effect of different woods on the durability of paint but it is not always appreci ated that different kinds of old paint may exert even more effect on the durability of a new paint of different composition. This may be the case even though the old paint is still in very .good condition as far as integrity of the coating is concerned. Some of the incompatible com binations of paints are known, and painters and dealers can often warn their customers about them beforehand provided they make an effort to learn as much as pos sible about the customer's particular problem. The easiest incompatibility to recognize is a white or tinted paint applied over a full-color paint such as brown, green, or red. The incompatibility arises not merely from the difference in the nature of the pigments in white and A chronic case of moisture blistering. Not only has the last paint applied developed blisters, bat places where the previous paint job blistered and peeled are clearly evident. in full-color paints but from the difference in total amount of pigments. As a rule full-color paints contain much less pigment by volume than white or tinted paints. The well-known case of yellow ochre priming under white paints is perhaps the most clearly recognized case of incompatibility. Should Examine Coatings Where Cracking Shown Sometimes the harmful effects of an incompatible combination show up promptly the first time white paint is applied over a full-color paint; frequently, how ever, the white paint jobs merely prove slightly less dur able for a time, but after two or three repaintings, each less durable than the previous one, the surface develops such a bad case of deep cracking and curling that the whole coating must be removed before a satisfactory re paint job can be applied. For that reason painters should (Continued on page 14> NEXT-ISSUE What part does the incorrect use of thiuners in the priming coaj^ ^in premature failure of painting jobs? wiuch paint and too frequent application are sometimes causes of difScultyimmaintaining a satisfactory paint jolnjlorW'tliick should a coat be applied a&d-Jiow often renewed for_jpary1ng types of surface and paint used? Why does paint fail TkemjgntijCin protected portions of buildings? Why should quality Should suceessivejwrifit coats"be"spread" over a period of time before the entire job is^eoTirpleted? What effeehhas this spreading on the quality of the fimjl-'jbu? be given special care to see that they"frrenroperiy maintained? When should types of paint be Used in preference to "hard" types andscffaen not? In the CteWfier issue. Dr. prowue will conclude his interesting article on prevSn complgintsfby providing answers to these and other questions of importance to painters anT) salesmen. Don't miss this issue! FLB 000882 only has the last 'here the previous *rly evident : in total amount ;s contain much ited paints. The ng under white ognized case of eking Shown an incompatible irst time white frequently, howilightly less dur epaintings, each surface develops curling that the i satisfactory rei painters should lings? me before he quality aintained? rot? paint Canadian Paint and Varnish Magazine, September 15, 1935 DK-A-DOO PAINT, RUSH B. A popular line/that sells for 5c retail/--- Packed two dozen /n attractive carton -- Sell themselves when displayed. A harmlesV cleaner thaV will not injure or curl the bristles of the brush. Every customer a prospect. \ Carried py all jobbers. Manufactured/in Canada by ,e mappers of: DIC-A-D< /AINT CLEANER CANCO' tSTE POWDER CANCC WALL SIZE REX WALl >APER CLEANER Meredith, / Simmons & Co., LIMITED TORONTO / \ MONTREAL HXq . D1 C0 0 <X Minister J. F. M1 Q Deputy Minister DEPARTMENT O LABOUR includes among its functions ie provision of-- A COMPLETE INSPECT! for factories, shops an wprk: r SERVICE ; for steam boilers, air for caisson, .and tunnel A FREE EMPLOYMENT ^ with feces ia 26 centres in Ontario for tl and. ; ar all types of workers, whether semi-skilled or unskilled, and for tVICE use of all employers nofessional, clerical, rth men and women: THE EXAMINATION OF ENGINEERS and/the issuance of certificates to them for operating steam, pgeration, hoisting and traction plants:! TRAINING FACILITIES FOR APPRENTICES Wthe nine designated building trades under the supervision of ttye Apprenticeship Branch: PROTECTION IN THE MATTER WAGES i^or female workers with the exception of < iraestics and farm help under the Minimum Wage Act: PROMOTION OF THE ESTABLISHMENT OF STANDARD WAGES and hours of labour by agreements betweeh employers and employees. Under the Industrial Standards vAct such agree ments, when approved by Order-in-Council, ibecome binding upon all persons engaged or employed in the industry and in. the zone to which, the agreement applies. ` For further information apply DEPUTY MINISTER OF LJ Parliament Buildings, Torontd Don't Let Faulty Painting Jobs Steal Public Confidence (Continued from page 7) be advised to examine coatings on older bouses that show bad cracking and report the uncertainties that may arise if strikingly different colors are found underneath. There are likewise cases of incompatibility between different brands of white or tinted paints and sometimes between the tinted paints and the white paint of the same brand. In general it is not safe practice to apply paint of high pigment volume oyer paint of low pigment volume. A salesman whose company offers more than one type of house paint may well advise that customers who have started out with one type continue to use it rather than to apply another type over it Bad Painting Practices Paint salesmen and paint dealers can well afford to devote some time to getting acquainted with contracting painters who use their paints and helping them to avoid bad practices in paint application. Mistakes in thinning paint and in the amount of paint applied give rise to some of the common complaints about unsatisfactory service. Stingy application of paint and too much thinning of priming coats often cause difficulty in paint jobs on new wood surfaces, leading to inadequate hiding and spotted gloss, chalking, and fading. Three-coat jobs, of course, are less subject to such troubles than two-coat jobs but at the present time a large proportion of our painting of new wood is two-coat work. For good painting a sufficient quantity of paint must be applied whether it is done in two or in three coats. From experience it is known that the amount of paint should be enough to leave a coating about 1/200 inch thick ..even though a somewhat thinner coating of modern paints will hide the surface satisfactorily. Table 1 shows the thickness and some characteristics of the coating produced by two paint jobs of which Job No. 1 is a two-coat job with the paint applied generously and Job No. 2 is a three-coat job with typically stingy application. Both jobs are done with the same prepared paint. Job No. 2 is by no means an uncommon one in practice and does not depart much, if any, from recom mendations made by some paint manufacturers. Job No. 1, the two-coat job, gives a coating 0.0845 inch thick, which is close enough to 1/200 inch. The priming coat supplies enough linseed oil to "satisfy" the wood and leave plenty of oil to bind its pigments. On such a foun dation the finish coat retains all of its oil, dries with uniform gloss and color, and when it begins to chalk and fade it does so uniformly. Job No. 2, the three-eoat job, makes a coating only 0.0032 inch thick and the priming coat fails to supply enough oil to "satisfy" the wood and leave enough to bind the pigments. As a result the second coat is robbed of oil to make up for the deficiency of the primer. When (Continued on page 26) A Paint Salesman's Viewpoint to be coiigratulatejLufJon your August issue^CgnaJismftrffiT and Varnish Magazine. Wi4oaTa>Mm the articles in this issue are splgndicfTl dofflA|ee how any sales man wjurdushea to give the best-possible service mkis customers can afford to beWkJiout any -Issue of this magazine!" -- Joseph Seville, Kitchener, put. FLB 26 Canadian Paint and Varnish Magazine, September 15j 1935 An example of incompatible paints. On three sides of this house the paint has cracked and scaled badly as shown at the left. On the fourth side, which is more fully exposed to the weather than the others, the paint gives good service as shown at the right. On the bad sides the wood carries successive coatings of dark brown paint, deep yellow paint, dark grey paint and at Least three jobs of white paint. The good side was rebuilt after a fire some years ago and has only the last three jobs of white paint. Table I--Importance of Spreading Rate in Paint Application Step in. calculation: Thinning formula: Prepared paint ..................................................................................................gaL Linseed oil ........................... ............................................ ................... gal. Turpentine........................... ... .. .......................................... ... ... gal. Spreading rate...............................................................................sq. ft. per gal. Paint applied: gal. per 1,000 sq. ft. Pigments .................................................................................................................. Linseed oil....................................................................................................................... Volatile thinner,. .. ............................ .................................................... . . Oil taken from first coat by the wood...........................gal. per 1;000 sq. ft. Paint remaining on.surface: gal. per 1,000 sq. ft. Pigments ........................................................................................................................ Linseed oil...................................................................................................................... Total paint..................... ........................................................................................ Volume of pigment in coating...................................................................per cent Thickness of coating......................................................................................inch Prepared paint assumed to have the following composition by volui 10 per cent. First coat 1 0.25 0 475 --Job No. 1- Second coat 1 0 O 559 Total coating First coat 1 0.25 0.25 800 -------------rJbb.lq0.2-- Second Third coat .coat 11 0b 0.25 b 900 900 Total coating 0.421 1.520 0.168 0.7S0 0.455 1.180 0.182 O 0.208 0.750 0.292 0.750 0.222 0.578 0.311 0 0.278 0-.722 0;lll 0 . 0.421 0.455 0.376 0.208 0.222 0.278 0.708 0.770 1.180 1.950 0 0.578 0.722 1.300 1.191 1.635 2.826 .0.208 0.800 1.000 2.008 35 .28 31 .100 28 28 35 0.0019 0.0026 0.6045 0.0003 0.0013 0.0016 0.0032 Total pigments, 25 per cent; linseed, oil, 65 per cent; volatile and drier. Don't Let Faulty Painting Jobs (Continued from page 14) such a priming coat is used for a two-coat Job, spotted chalking and fading soon develop and another complaint is often made against the paint. To change Job No. 2 into a good paint job the painter need only reduce the spreading rates to 600, 700, and 700 square feet per gallon for the first, second and third coats, respectively. The thickness of coating is then 0.0046 inch and the percentage of pigment by voLume in successive coats is 53, 28, and 28. Such a coating is thick enough but the fact that second and third coats contain the same per centage of pigment is open to some objection. If a paste paint instead of a prepared paint were used according to accepted practice the percentage of pigment in successive coats would be more nearly 50, 37, and 28. The principal advantage of paste paint over prepared paint lies in the fact that the body coat can be made richer in pigment than the finish coat. The disadvantage of paste paint is that unskilled or unscrupulous painters can "dppe" it with inferior materials more easily. -. (To be concluded) Imjieriat Color 3ves Bonus to Ex Toronto, Ont.--pae-'Tmperial Varnisk Company, Ltd. has given-^to its employees tangible expressTofr-eL* its <ipprecmiKJifof their "loyal and faithful service.'1 The directors have distributed among 160 employees of the company a cash bonus equivalent approximately to a month's salary. Length of service was considered in the allocation of the bonus. Every member of the staff with over six months service participated, from the office boy up. A. _ Maybe! / ish Magazine makes unent -y*`Just the editojv'she bought a some touching up in teaching a brush to at the problems of sast of which is the the can.' itanust be borne in nay'riot be supplied open some cans and tccompanied by the r opening, the result cause of pointing, n of goods soicNmer bs and touching\(p ' publication of thh, .acquer Association, FLB 000884 15, 1935 s incompatible sides of this cracked and at the left, .vhich is more weather than gives good xe right. On rood carries dark brown paint, dark three jobs good side was some years he last three paint. Third 100coat 900 Total coating 0.278 0>722 00.111 0.278 01..702002 0.708 1.300 2.006 28 0.0016 35 0.0032 volatile and drier. ,yees of the > a month's llocation of six months _j makes Just the bought a ing up in brush to blems of Lch is the s borne in s supplied cans and by the result pointing, soia'qver uching-> ion of tho^ ssociation, 6 Canadian Paint and Varnish Magazine* October 15, 1935 Don't Let Faulty Painting Jobs Steal Public Confidence! PART 2 -- Conclusion What Paint Salesmen, Painters and Dealers Can Do to Prevent Paint Complaints By Dr . F. L. B X q Senior Chemise, Forest Products Laboratory, Madison, H is. Jnonmt>:itibility of some white paints. This house was origin ally painted with a lead and sine paint and subsequently repainted with a titanium, lead and zinc type of paint. The last paint was a very good one hut it is failing in an unsatis factory manner. TOO generous use of volatile thinners in priming coats is a common cause of unnecessarily early failure of paint. The mistaken potion that thinners are needed to increase the penetration and secure firmer anchorage of the paint fosters this blunder in paint. As a matter of fact linseed oil penetrates all woods more freely thah'is desir able and the object of good priming is to restrain, not to stimulate it. Special primers for wood now being offered by several manufacturers are designed with this object in view. In a good priming mixture with ordinary linseed oil paint there should be at least three times as much linseed oil as volatile thinner. It is entirely practicable to omit thinners entirely in the priming coat mixture. Resinous woods such as southern yellow pine offer no exception to this rule; in fact, too much volatile thinner is particu larly harmful in priming coats for such woods. Duration of Time Between Painting While too- little paint is a common blunder in painting new wood, too much paint and too frequent application of paint are likewise common causes of difficulty in main taining paint over a period of years. As far as practicable the coating on wood should be kept in the neighborhood of 1/200 inch in thickness. That can be done only if the old coating is given time enough to chalk and erode materially before new paint is put on. Hard types of paint Usually wear away less rapidly than soft types of paint and when repainted hard types of paint usually "hold out" the new paint better than soft types, that is, the hard paints absorb less oil from the new paint. As a rule, if repainting is done within three years only one coat of new paint should be put on. After four years, soft types of paint may wear away enough to take two repaint coats but hard paints may often be repainted to best advantage with one coat only, possibly with pre liminary spot coating of patches where loose paint has been scraped off. As already pointed out, the amount of paint applied rather than the number of coats is the im portant consideration. The failure of paint on protected parts of buildings, such as overhanging eaves, when the paint on the exposed parts is in good condition often comes from the fact that too thick a coating has been built up on the protected areas -where the Weather has little chance to wear away the paint. Such areas should receive less paint than the ex posed areas when repainted. Bad Practice to "Spread" Painting Jobs It is not good practice to apply two finishing coats in succession. Sometimes this occurs when a paint job is Completed and the owner decides that he does not like the color. Architects sometimes have it done deliberately in the belief that they can select colors to hest advan tage after the house has been erected and painted. Paint salesmen and dealers should try to get customers to select WmmKSM' N41698.22 FLB neglect <rf rpe. This tuiated re1 types of period of the owner >ld coating badly bepaint. The longer he or durably iting is re- letely- leaded for >w Pine to the weather fir. The right*inum paint, the top and bottom l paint, on the lat conforms to kadian Paint and Varnish Magazine, October 15. 1935 Examine Every New Product (Continued from page 18) and Plttetargh showed that the paint on the''former was ail gone white that in Pittsburgh was blackened by smoke but otherwise +0 good Shape. The failure on the Atlantic City fence was phebably hastened by the salt air." Says Zinc Adds to Appearance of Film C, Eoss Elliot, The Mwe Biyfthers Co.--"Do you place most importance on zinc orlefad for outside paint?" Mr. MacGregor--"I dp/not actvjjcate zinc for outside paint as far as wear i^fioncerned. r-have never seen an instance where the actual wearing qualities of a film were increased by the/tise of zinc. Zinc is valuable from the appearance pqim of view; it gives a nice film, when you add zinc to/a paint you face the danger that this will in turn cause the addition of too much oil and thinner at the result will be to produce a hard film with greater coljerion than adhesion to surface, which is an undesirable condition." Don't Let Faulty Painting Jobs Steal Public Confidence (Continued from page 7) under such conditions when aluminum paint has been used tend to undermine confidence in its recommendation for its proper purpose. Modern mixed-pigment paints are made to give im proved appearance during the useful life of the coating, to maintain their resistance to the passage of moisture longer, and to leave a surface that "holds out" new paint better than softer paint when repainting comes due. These improvements are gained by careful control of physical properties of the coating that may be called "hardness" for want of a better term. Quality paints of this kind, however, call for greater care-on the part of the house owner to see that they are properly maintained because the hardness on which the improvements are based makes a coating that cracks and curls badly if repainting is neglected long after it has come due. The surface should be repainted before it begins to disintegrate seriously. Once disintegration has been allowed to go on through a period of paint neglect it may become difficult to repaint the surface smoothly and the new job may not last as long as it should. Those property owners who are accustomed to leave their paint in a shabby condition of neglect for several years before they repaint should be advised to use only a soft type of paint until they are willing to raise their standards of paint maintenance to a point justifying the use of mixed-pigment paints of a harder type. Selling a hard type of paint to a man expecting to repaint every 10 years is merely adding one more name to the company's complaint file and possibly a red ink entry in its ledger. Ji be Value of Special Training Classes (Continued from page 12) . to such surfac&^JBlat paints, sealers, enamels, varjdsties. gloss paints, kalsomines aniLwater paints wiE all^peceiye attention during the progress of tlfeAessons. The art of the paperirangebsgair'not by any means be forgotten, as the hanging of wafijjapbriAs well as the ordinary fabrics, such as wall cloftg'grass clotE"sqnitas, etc., wiE ah have their place infhe'eourse of study. The care of brushes and instruction in the cratine of correct tools for eagh'purpose will be thoroughly explained^'SQthat it is verypyident that any young man attending the claSs^nd appMhg himself, cannot fail to be materiaUy benefitted: apd wilTwithaut question become a more capable journeyman. The success of those who attended- the classes under Mr. Gordon in former years and the fact that they, because of the instruction which they had received, were better men in their ... chafeen field of endeavor, is a practical demonstration of the / desirability, as well as the actual necessity for such.education.,/ "hese Classes were primarily organized for the benefit of the indentured apprentice, but for this year at least, thqy have Been thrown -open to the young journeyman, and. to the journeyman- who is not so young, who is sufficiently ambitious to acquire a knowledge of methods and materials that he would have little or no opportunity to acquire in his every day routine Of high pressure production, j Employer Can -Devote Little Time to Instruction / The employer of today, because of keen and sometimes nbne-too-honest competition, is compelled, to concentrate <on the j ob of getting the work, financing his business aiWgeneral supervising, so. that he cannot afford, to devote any time to the personal irfetructtem of either apprentice or journeyman; the man in charge of the job, because of the low prices obtainable by the employer on account of the competition mentioned, is interested almost exclusively in getting the job done and producing a profit for the employer sex that he .can not devote any time to individual instruction of the apprentice. Then, too, because of changing materials, ap-d this change has been particularly noticeable during thd past decade, neither master nor man is in, a position to give any authentic information relative tp the materials in daily use. Generally speaking, they are satisfied to accept the manufacturers say- so as to the composition, of materials, and tfye results obtained through their use. Therefore to Obtain reliable information .on the composi tion of materials and theirr, various uses, as-well as the theory Of the painting trade, tne Toronto apprentice, or young mechanic, depends entirely\upon such j. class as is available at the Central Technical School. Thef small sum of a $2.00 registration fee will undoubtedly pra-v'e to be a ..sound invest ment,ir. skill and knowledge from which wiE accrue daily the greatest dividend of all--security oi employment. Employers would be well aavir'ei to lend every encour agement to these classes by urgitW not only their apprentices, to attend, but also journeymen, who desire to attain further knowledge in the more advanced and- artistic branch of their trade, the better to .qualify th. be .reaUy designated as "Craftsmen." Reardon's Water Putty Claimed Shrink-proof Crack Filler \ The introduction of Reardon's Water Putty makes available another indispensable brpduct for filling cracks In floors, holes in concrete, flaws in/furniture, woodwork, 'and many other everyday uses. The ^manufacturers state thaft tests by actual performance have proved this water putty to be shrinkproof. It comes in dry powder form and has simply tope mixed with water to a paste of (he required thickness for use. Upon hard ening it can be footed or finished exactly like wood. Nails or screws may he drivgi into it without danger. it is maimed. EuE information from fthe Reardon Company, 23 Hammersmith Ave., Toronto. j \ THE MACLEAN PUBLISHING COMPANY, LEJIITED 481 UNIVERSITY AVE., TORONTO, CANADA \ JOHN BAYNE MACLEAN, Chairman of the Board H. T. HUNTER, President \ H. V. TYRRELL, Vice-President and. General Manage^ Publishers of Canadian Paint and Varnish Magazine, Sanitary 1 Hardware and Metal, Canadian Grocer, Drug Merchandising^Dr: and Stylewean Review, Bookseller and Stationer, Men's Wear Merchan dising, Hardware and Metal's Data Service. The General MerdJant of Canada, Canadian Meat and Provision. Buyer, Canadian. Hotel Review and Restaurant, The Sheet Metal and Warm Air Beating- Review, The finan cial Post, The Financial Post Survey of Corporate Securities, YThe Financial Post Survey of Mines, The Financial Post Business Year Book, The Financial Post Record of Prospectuses, The Financial Post Directory of Canadian-Directors and Officiate, The Financial Post Corporation Ser vice, Maclean's Magazine, Chatelaine, Mayfair, Canadian Homes and Gardens, Caziadian Machinery and Manufacturing News, Canadian Printer and Publisher, Canadian Advertising, Canadian Trade. Abroad, Modem Power and Engineering, Canadian Automotive Trade, Bus and Truck Transport in Canada. FLB 000886 Canadian Paint and Varnish Magazine October 15, 1935 Cermath Heads Hamilton Painters' Board Hamilton, Ont- Charles Kermath was elected cmiiimnm of the board of the newly-fornietOPninters' Beard for Ham ilton district under the Industrial Stand ards Act, and George Thomewell was elected secretary. Other members of the board ares George Henry, A. MacArthur and Charles Yorston, The members have been given power *to act as inspectors. The new Act provides thaKanyone hav ing entered into a contract prior to Sep tember 22 may, by application to the board, receive consideration on sUeh con tracts which may have been made at a lower rate, Mr. Thornewell saidt There is also a provision that persons physically incapacitated may recen consideration by the board if they maid application to be permitted to work at a lower rate. The Act went into effect officially on September 24. It prescribes an eighthour day and five days a week, The work hours are to he between the hours Of 8 o'clock in the morning and 5 o'clock in the afternoon. Quebec Province Moves to Prevent Lead Poisoning Canadian Paint & Varnish Magazine understands that members of the Can adian paint and varnish industry are being advised by inspectors of the Que bec Association for the Prevention of Industrial Accidents of a change in the law requiring the use of counter-poison agents in paint containing white lead as a preventive measure against lead poison ing The change was recently approved by the provincial government aiid re quires that a counteracting agent be used in all paints containing white lead, salts of lead, salts of copper, ceruse or mimium. Under the law, the Department of Labor may upon advice of a doctor in hygiene and a chemist accept the use of any product deemed efficient. E. A. McPhee Opens Branch in Peterborougly Lindsay, Out.--K. A, MdPbee, progres sive painter and decorator; of Lindsay, has established an office in Peterborough which will be located at 355 McDonnel Street. This, however, does not mean that Mr. McPhee wiil/be leaving Lindsay, as he has secured the services of Mr. Beg. L. Collins, who inexperienced in paint ing and artistic/work, who will be asso ciated with Mr. McPhee. VV. GEO. Of Sturgeons Ltd., elected vice-presidm: and Varnish Two Ha; iitpn Industries Under Code Hamilton, Ont.--Copies of orders-ineoancil confirming the setting up of coded under the Industrial Standards Act foiyihe plumbing and painting industries ere contained in a recent issue of the Ontario Gazette. In both instances, the ''order became effective on September 21. Ordinary hours of labor are eight hours a day, not including Saturdays and Sun days. For plumbers, the minimum rate of wages shall be 85 cents .an hour and for journeymen painters 60 cents per hour, work to be confined in each case between the hours of 8 a.m. and 5. pm. Time and a half applies to all overtime employment. In the case of the painters,, provision has been made for work that cannot be performed during regular working hours. The code arrangement applies to those in the paperhanging and glazing trades as well as painters. THE BUYERS' DIRECTORY These firms solicit yonr business through) ieir advertisements in Canadian Paint and Varnish Magazine, H what you want is not advertised or list here, write us and we will beVlad to give you the informatioa yon desire. ALCOBOLS Gaoderbam & Worts, Ltd., Toronto. ALUMINUM PASTE Aluminum Company of Canada Lid.. Toronto, Ont. ANILINE COLORS J. A,. Taylor Limited, Montreal, Que./ BONE DROP AND IVORY Reichard-Coulston, Inc., New York, N.Y. Sherwln-Williams Co. of Canada,/ ited, Montreal, Que. BRUSHES Hamilton & Co. (London),/Limited, London, England. / Simms & Co., Limited, T. S./Saint John, N.B. CANS AND CONTAINER American Can .Co., Hamilton, Vancou ver, Montreal. Macdonald Mfg. Co.,/Toronto, COLOR LAKES Sherwin-Williams/Co. of Canada, Lim ited, Montrealj/Que, CRACK FH Savogran Co./faf Canada, Toronto. DRY COLORS Imperial Varnish & Color Co., Limited, Toronto/ Ont. McNulty/Jos. New York, N.Y. Reicham-Coulston, Inc., New York, N.Y. Sherwin-Williams Co. of Canada, Lim- Montreai, Que. Tayl6r Limited, J. A., Montreal, Que. DRY/EARTH COLORS t NuKy, Jos. A., New York, N.Y. Reichard^Ccplston. Inc., New York, N.Y. Sherwin-Williams Co. of Canada, lim ited, Montreal, Que. Taylor Limited, J. A., Montreal, Que. DYESTUFFS Taylor Limited, J. A., Montreal, Que. ESTER, VARNISH & LACQUER . Roller & Company, Detroit, Mich. Boehm Limited, Fredk., London, Eng. paramet Chemical Corp., Long Island City, N.Y. LAMPBLACK Binney & Smith Co., New York, U.SA. Imperial Oil & Gas Products Co., Pitts burgh. Pa. L. Martin Co., The, New York, N.Y. Relchard'-Coulston, Inc., New York, N;Y. Tay[<or Limited, J. A., Montreal, Que. Wilckes, Martin, Wilckes Co., New York. LINSEED OIL Brandrara-Henderson Ltd.. Montreal. The Sherwin-Williams Co. of Canada, Montreal. OXIDES Harrisons 8c Crosfield Ltd., Montreal. McNulty, Joseph A., New York, N.Y. 'Northern Pigment Co. Ltd., New To ronto, Ontario. ReLchard'Coulston, Inc., New York, N.Y, Ross limited, Bruce, Toronto. Sherwin-Williams Co. of Canada, Lim ited, Montreal, Que. Taylor Limited, J. A., Montreal, Que. PAINTS, VARNISHES, ENAMELS, LAC QUERS, WALL FINISHES, ETC. Aulcraft Paints Ltd., Toronto, Ont. Brandram-Headerson, Limited, Mont real. Canada Paint Co., Limited, Montreal. Imperial Varnish & Color .Co., Limited. Toronto, Ont. Lowe Bros. Co. Ltd., The, Toronto. Mnare & Co.. Ltd., Beniamin, Toronto. Pilkington Bros. (Canada) Ltd., Toronto. Reardon Company, The, Chicago, HI. Sherwin-Williams Co. of Canada. Lim ited, Montreal, Que. Sinclair Co. Ltd., Malcolm, Oakville, Ont. PAINT '`MACHINERY AND EQUIPMENT Consolidated Products Inc., New York. Greey Ltd., Win & J. G., Toronto. Taylor Instrument Companies. Toronto, Ont. PAINT SPRAYING EQUIPMENT De Vilbiss Mfg^ Co., Ltd., Windsor, Ont. PASTE Meredith-Simrao'hs Co., Ltd., Toronto. Taylor Limited, J. A., Montreal, Que. SOLVENTS ft SOLUTIONS Apoo Petroleum Products Ltd., Toronto, Oht. Beck. Koller & Company, Detroit, Mich. STEEL BARRELS Smart-Turner Machine Up., Ltd., Ham ilton, Ont. SYNTHETIC RESIN Beck, Keller ft. Company, Detroit, Mich. Canadian General Electric Coy. Toronto. Paramet Chemical Corporation, Long Island City, New Yor& . Resinous Products & Chemical Cb., Inc., Philadelphia, Pa. ULTRAMARINE BLUES Reichard-Couiston, Inc., New York, 1 Taylor Limited1, J. A., Montreal, UMBERS AND SIENNAS McNulty, jos. A., New York, N.Y. 'Reichard-Couiston, Inc,, New York, N.Y.v WALLPAPER Boxer Co., Ltd-, The Reg. N., New To ronto, Ont, Stauntona Limited, Toronto, Ont. Watson, Foster Co., Ltd., The, Montreal. WAXES, FLOOR 'Sherwin-Williams Co. :of Canada, Lim ited, Montreal, Que. WRITE LEAP Canada Paint Co. Ltd., Montreal, Que. WHITING Taylor Limited, J. A.. Montreal, Que. * f : FLB 000887 Branch y ee, progresof .Lindsay, Btefborough \ McDonnel 5 not mean ng Lindsay, ot Mr. Reg. id in paints dll be asso- es Under orders-in;ing up of mdards Act g industries ssue of tlie stances, tlie ptember 21. eight hours 's and Sunlimum rate ti hour and cents per i each case and 5. p.m. 11 overtime >, provision t cannot be king hours, es to those zing trades zme. rraa- WENT York. , Ont; .ronto. ronto, [Mich. Ham- Mich. ronto. Long , lac.. aw}'(iv) Cktj-f /f'5S~ Paint Application Often A Danger By F. L. BROWNE Senior Chemist, Forest Products Laboratory, Forest Service, Department of Agriculture, maintained, at Madison, Wis., in cooperation with the University of Wisconsin. M[INTAKES la thinning paint and in the amount of paint applied give rise to some of the com mon complaints about unsatisfactory service. Stingy application of paint and too much thinning of priming coats often cause difficulty in paint jobs on new wood surfaces, leading to inadequate hiding and spotted gloss, chalking, arid fading. Three-coat jobs, of course, are less subject to such troubles than two-coat jobs, but at the present time a large propor tion of our painting of new wood is two-coat Work. For good painting a sufficient quantity of paint must be applied whether it is done in two or in three coats. Prom experience it is known that the amount of paint should be enough to leave a coating about 1/200inch thick even though a somewhat thinner coating of modern paints will hide the. Surface satisfactorily. Table 1 shows the thickness and some characteristics of the coating produced by two paint jobs of which Job No. 1 is a two-coat job with the paint applied generously and Job No. 2 is a three-coat job with typi cally stingy application. Both jobs ace done with the same prepared paint. Job No. 2 is by no means an uncommon one in practice and does not depart much, if any, from recommendations made by some paint manufacturers. Job No. 1, the two-coat job, gives a coating 0.0045 inch thick, which is close enough to 1/200 inch. The priming coat supplies enough linseed Oil to "satisfy" the wood and leave plenty of oil to bind its pigments. On such a foundation the finish coat retains all of its oil, dries with uniform gloss and color, and when it begins to chalk and fade, it does so uniformly. Job No. 2, the three-coat job, makes a coating only 0.0032 inch thick, and the priming coat fails to supply enough pa to "satisfy" the wood and leave enough to bind the pigments. As a result the second coat is robbed of oil to make up for the deficiency of the primer, When such a priming coat is used for a two-coat job, spotted 1 < ,--0 0 + X 1 q_ X~ s p r 1 0 q 3 1 0 q 1 0 qt 1 0 _ 1 0 Xq y ' Step in calculation Job No. 1 Job No. 2 First Second Total First Second Third Total coat coat coating coat coat coat coating Thinning formula: ^Prepared paint--------------------- gal 1 Linseed oil--------------- gal 0.2:5 Turpentine -------------- gal 0 1 0 O Spreading rate------- sq.ft, per gal 475 550 Paint applied-gal.per 1000 sq.ft Pigments 0.421 Linseed oil 1,520 ! Volatile thinner 0.168 0.455 1.180 0.182 Oil taken from first coat by the wood------------gal.per 1000 sq.ft 0.750 0 - Paint remaining on surface gal.per 1000 sq.ft Pigments 0.421 [ Linseed oil 0.770 ; Total paint 1.191 0.455 1.180 1,655 Volume of pigment in coating- 35 28 ;v percent . -- 1 0,25 0,25 800 1 0 0,25 900 ___ ------ 0,208 0.222 0.750 0.578 0.292 0.311 0,750 0 0.876 0.208 0.222 1,950 0 0.578 2,826 0.208- oisoo 31 100 28 1 0 0 900 -- 0.278 0.722 0.111 0 - 0.278 0.708 0,722 1.300 1.000 2,008 28 35 ?;Thioknesa of coating-------inch. 0.0019 0.0026 0,0045 0,0003 0.0013 0.0016 0.0032 Pre pared paint assumed to have the following composition by volume : 5 Total pigments, 25 percent; linseed oil, 65 percent; volatile and drier 10 percent.. lo National Painters Magazine 3S N41698.23 FLB 000888 LEFT:. Paint Troubles lead to loss of market for paint. This house is being covered with composition material imitating brick, because several paint jobs on wood siding faded within a year or two. Other neighborhood houses were similarly treated for the same reason. CENTER: Photograph taken in June, 1935, showing scaling and moisture blisters. Painted in 1931 with pure white lead paint which proved satisfactory, it was repainted in 1934 with a hard type of paint made with a quick-drying vehicle. RIGHT: Result of repeated neglect of paints of hard type. This building has been painted repeatedly with hard types of paint over a long period of years, but each time the owner waited until the old coating was disintegrating badly before putting on new paint. The surface can no longer be painted smoothly or durably unless the old coating is removed completely. chalking and lading soon develop, and another com plaint is often made against the paint. To Make a Good Job To change Job No. 2 into a good paint job the painter need only reduce the spreading rates to 600, 700, and 700 square feet per gallon for the first, second and third coat, respectively. The thickness of coating is then 0.0046 inch, and the percentage of pigment hy volume in successive coats is 53, 38, and 28. Such a coating is thick enough, but the fact that second and third coats contain the same percentage of pigment is open to some objection. If a paste paint instead of a prepared paint were used according to accepted prac tice, the percentage of pigment in successive coats would be more nearly 50, 37, and 28. The principal advantage of paste paint over prepared paint lies in the fact that the body coat can be made richer in pig ment than the finish coat. The disadvantage of paste paint is that unskilled or unscrupulous painters can "dope" it with inferior materials more easily. This material is extracted from a paper entitled "What Paint Salesmen Can Do to Prevent Paint Complaints," prepared at the request of a paint man ufacturer for distribution to his salesmen. It is avail able at the Forest Products Laboratory, Madison, Wis., in mimeograph form, with illustrations. While the supply lasts single copies may be had pee on request, and 20 or more copies of 5 cents each. . . . The first section of the paper deals with moisture failures, previous behavior of paints arid incompati bility of paints (which subjects were dealt with in detail in Dr. Browne's articles in National Painters Magazine in April, May and June) and there is addi tional material touching briefly on aluminum prim ing and the care needed in maintenance of quality paints. August 1935 Too generous use of volatile thinners in priming coats is a common cause of unnecessarily early failure of paint. The mistaken notion that thinners are needed to increase the penetration and secure firmer anchorage of the paint fosters this blunder in paint. As a matter of fact, linseed oil penetrates all woods more freely than Is desirable, and the object of good priming is to restrain, not to stimulate it. Special primers for wood now being offered by several manu facturers are designed with this object in view. In a good priming mixture with ordinary linseed oil paint there should be at least three times as much linseed oil as volatile thinner. It is entirely practicable to omit thinners entirely in the priming coat mixture. Resinous woods, such as southern yellow pine, offer no exception to this rule; in fact, too much volatile thinner is particularly harmful in priming coats for such woods. Too Much Paint While too little paint is a common blunder in paint ing new wood, too much paint and too frequent appli cation of paint are likewise common causes of diffi culty in maintaining paint over a period-of years. As far as practicable the coating on wood should be kept in the neighborhood of 1/290 inch In thickness. That can be done only if the old coating is given time enough to chalk and erode materially before new paint is put on. Hard types of paint usually wear away less rapidly than soft types of paint and, when repainted, hard types of paint usually "hold out" the new paint better than soft types; that is, the hard paints absorb less oil from the new paint. As a rule, if repainting is done within three years only one coat of new paint should be put on. After four years soft types of paint may wear away enough to take two repaint coats, but hard paints may often be repainted to best advantage with Continued on Page 40 If 1 I FLB 000889 zrial imitating were similarly sters. Painted int made with been painted he old coating durably unless ;rs in priming ly early failure thinners are 1 secure firmer inder in paint, ates all woods object of good ,te it. Special several manuin view. In a iseed oil paint ! much linseed practicable to coat mixture. 7 pine, offer no much volatile ning coats for aider in paint"requent applitauses, of diffld of years. As should be kept lickness. That sn time enough iw paint is put ray less rapidly epainted, hard :w paint better absorb less oil tinting is done v paint should of paint may mats, but hard .dvautage with Stingy Paint Jobs a Danger Continued from Page 11 one coat only, possibly with preliminary spot coating of patches where loose paint has been scraped off. As already pointed out, the amount of paint applied rather than the number of coats is the important considera tion. The failure of paint on protected parts of buildings, such as overhanging eaves, when the paint on the exposed parts is in good condition often comes from the fact that too thick a coating has been built up on the protected areas where the weather has little chance to wear away the paint. Such areas should receive less paint than the exposed areas when repainted. It is not good practice to apply two finishing coats in succession, Sometimes this occurs when a paint job is completed and the owner decides that he does not like the color. Architects some time have it done delib erately, in the belief that they can select colors to best advantage after the house has been erected and painted. Paint salsmen and dealers should try to get customers to select color schemes carefully before starting the paint job, so that the paint job can be properly designed to give good service. It is likewise bad practice to spread a painting job out over six months or a year. Only the finish coat is designed to stand weather exposure; primers and body coats are not. Many houses that have come back as complaints in recent years have been painted with intervals of several months between' coats. Houses Mr. Keys on Convention Tout spharles B. Keys, director of fbe "BettenPalnted riea" Campaign of the International Society and author of the brilliant series^of articles which Have been appearing in National Painters Magazine enbusiness problerrm-of painters, gave his address on "Building Bettm Business" before the annual contentions or the Michigan, New Jersey and New York Store Councils in July, and after attending the International Board meeting in Cleveland left fqr'Tfetois and Kansas to speak at association merittogs.xAfter a brief vacation Mr. Keys will resume his tour of conventions and specially arranged meetings. Hn his address, as in his articles, Mr. Keys cites thKenormous pos sibilitiesTor painters that lie in aNqo-operative movement toward one common objective--that of creating more profitable business. His'artieles willr be resumed in the September issufe^of National Painters Magazine. completed late In the winter, for example, are often primed perhaps in December, second coated in March, and finished during the summer. As a rale it probably would be better in such cases to take great precautions to drying the plaster to avoid forcing moisture into the sidewalls and to complete the paint job in December by taking advantage of the warmer days of the month and confining paint applications to the hours between 10 a. m. and 2 p. m. CL ptodut tJuxtmlt 'AoUfc ott ipnatPcwXk Yakutsk- ptoMemi _ Is a transparent. .ffH^typo liquid; neutral to all piemenlsrNLQd mixes perfectly .with all alls, paints siDd var nishes. It improves flow and spread--is water>resiat&nvsaqd idkaU-prooi---gives more durability end .better gloss and ad>~< heaion to practically all types of flntshlog- coatings. Can ' used for exterior and interior woodwork, Wall and plaster board, concrete snd cement, metal ..tanka. Aluminum paint, stucco, brick and plaster walls. Free Sample and Full Information--Write Nearest Factory 0M_ CX 7 VARNISH CO. PHILADELPHIA CHICAGO LOS ANGLES A GUARANTEE */WHITER WHITES and CLEANER TINT* Make FREE TEST yourself Send for FREE sample toddy ANACONDA WHITE LEAD is pure. EJej;ci'6]yric dry white lead JLl --the purest kind known--^thoroughly ground in the finest grade of pure linseed oiLgsSuring you of a reliable purity that carries on to the finished^aint. This whiter leadaiso btiugs cleaner tints. Prove Anaconda superiority--send forafreesimple sited compare it sidev fry side with th.e kind you're now using. ANACONDA t^AD PRODUCTS CO., EAST CHICAGO, IND. I CONDA WHITE LEAD U-S-K Washable Water Paint The Titanated Water Paint , UNITED STATES KALSOMINE COMPANY 50 Church Street New York, N.V, Paint Questions Answered 2 IS THE PRICE of tiixRrcmarkable book, known and used wkercVer painting and decorating are done. Written by experts. Book contains 800 pages, thoroughly indexed and any subject may\be readily found. Mailed to any part of United States, postage prepaid, for Two NATIONAL PAINTERS MAGAZINE 12 Gold Street New York, N. Y. 40 National Painters Magazine FLB State Council Conventions Continued from Page 23 itire and others. <See details of Internationa] Society iard action, page 17, this issue.) THE BETTER PAINTERS ARE USING favoring voluntary agreements for regulation of industry and endorsing in principle state registration acts for the building industry. (See page 17.) Also, designating Sche nectady for ah experimental "Better Painted City" campaign. Reports: By President Treasurer, on con building it. and Guy R. Hunter, Secretaryion of the Council and methods of HEW JERSEY CONVENTION Hew Officers: E. J. McCoy, Atlantic City.Nyicceediag A. B. Henderson; First Vice-President;, Thomas Drayton, Montclair; Second Vice-President, V. G. Aschenbaek^Morristown; SecretaryTreasurer, Eli W. Jelsma, Paterson\(re-elected); Interna tional Board Member, Ell W. Jelsma. Features: "Building Better Business," by Charles B, Keys, EaglePicher Bead Company. "Is There No Help fohthe Painting industry?" by George S. Stuart. "A Demonstration of Sim plified Bookkeeping," by H. TV. Fisher, National head Com pany (see New York program). "Cracks," by Geoige Whigelt. "Safety in the Painting Industry," by J. N. YJorsey, State Director of Safety, E. R. A.. "Co-operation," by Charles R. Welti, President of the Travellers Association. Resolutions: Endorsing Eli W. Jeisma for International presidency and"1 asking accounting from former National Code Authority. Reports: President Henderson gave in detail his year's hard effort to build "a greater, bigger, finer New Jersey Council."/Mr. Jelsma gave further details of the progress of the association in the year and of the financial condition. George SeWIenker, Chairman of the Legislative Committee, reported on efforts to obtain a license bill and a bill to reduce present excessive compensation insurance rates. New Officers: MICHIGAN President, L. S. Hazen, Saginaw (re-ejfected); Vice-Presi dents, George EHiott, Muskegon, and'James A. .Moynes, Detroit; Secretary-Treasurer, E. C./Betzing, Detroit ire- elected) ; International Board Member, W. C. Conrad, Ypsilanti. AN INDEX TO ADVERTISEMENTS Alabastine Co.................................................... .............. ........... 38 Anaconda Lead Products Co/........................................... 40 Bakelite Corp--___ ,___ /.................... ................... ............. 1 Cabot, Samuel, Inc........./....................................................... 33 Craftex Co............... .,./....................................... .................. 35 Devoe & Raynolds Co/........................... ............................... 21 Eagle-Picher Lead CX ............................... ................ ............ 3 Fox, M. Ewing, Co./................. ....... .................. .................... 36 Gillespie VarnishJoo....... .................. 37 Hammar Bros. White Lead Co............................................... 39 Larkin Co., Inc/......................................... ............... ............... 36 Lowe Bros.../........ .......... ....... ........................ ................ 2. McCloskey Varnish Co................................ ................ ............. 40 Moore, Benjamin, & Co..................................... .........Back Cover Muralo Cp., Lie.................................................. .......Third cover Nationaj/Lead Co........... ............. ............................................ 31 New Je&ey Zinc Co............ .................................................... 4 O'Brien Varnish Co.,............................ 39 Pittsburgh Plate Glass Co.,..................... .................... ........ 29 CO...-.................... 25,32 alk Chemical Co...........,...........................-Second Cover S. Kalsomitte Co......... ....................................................., 49 August 1935 V *T- IT'S no secret today-yhe better painters are using better paint They're using it beq&ise it produ ces better work -- better customers--it me&ns better money. You can't do/first grade work with second grade paint any more than you can drive a nail straight with a lug wrench. It just isn't in the card^To'Brien Therm- olyzed TungyOil paint is setting new standards of painting quality. Ask anyone^who has used it; then urge yonyaealer tostock this great new liijfe O'Brien Varnish Com- th Bend, Indiana, Writefor fflustratedbooVettelling the interesting story of Tung 03 O'lf^FlN THERMOLYZED TUNG OIL FINISHES * Sin re, I "in gelling riy share of I'llA business. There's never any (rouble gelling a paiiil loan approved when HAMMAR WHITE LEAD Is used.* White. LecuL laAt^f FLB 000891 booklet.telling of Tuner Ou. IISHES ainting By Eh*. F. L. Browne, Senior Chemist, Turpentine and drier............0.090 gallon Total ...............................1.000 gallon Forest Products Laboratory, Madison, Wis. (Presence of the drier in the paste paint is assumed to simplify the Eurther con siderations.) Details of the thinning, ap plication, and the thickness and compo sition of the resulting coating are re corded in Table l, from which it appears that the initial coating was 0.0051 inch Much o the painting that will be done this year will be on buildings that should have been painted a year or more ago and on which the old coating is chalk ing so freely that it wilt absorb much of the oil from the first coat of new paint. It is rarely safe to attempt repainting such paint-thirsty surfaces with one coat because the new coating may be too thin to prove durable and may be uneven in gloss and color or become so after a very short time. Even if two coats of new paint are applied there may still be dif ficulty with spotty chalking and fading if the first coat is not thinned properly and is not applied generously enough. For that reason some authorities recom mend that three coats of new paint be applied. Few property owners, however, will be willing to go to the expense of three coats and as a matter of fact too much paint may prove as disadvantageous as too little. Obviously the first coat of new paint should supply enough linseed oil to The nature of the relations involved can he set forth explicitly by making certain simple calculations. In order to provide a specific problem for considera tion we shall assume that a painter is. about to repaint a house that was erected and painted for the first time in 1930. The exterior surfaces are all of woods that hold paint very well, such as slowly grown redwood, red cedar, cypress, and white pine. The original painting was three coats of a paint that stands neglect well and after five years the coating where fully exposed to sunshine is now chalking very deeply and checking deeply in a fine reticulated pattern as shown in figure 1. Such a surface may well be de scribed as paint thirsty. For simplicity it is assumed that there is very little crumbling of the coating and no curling, flaking, or scaling. The initial painting was done with a soft paste paint of the following composition: Figments ...............................0.523 gallon Xdnseed oil ...........................0.387 gallon thick, contained on the average 35 per cent by volume of pigment and 64 percent of linseed oil, and its content of linseed oil was highest at the surface, diminish ing progressively toward the wood. During the five years since the house was painted some parts of the coating have been fully exposed to the weather and have become badly worn while other parts have been protected by the shading cornices and porch roofs and by position on the north side where there is little direct sunshine. On the fully exposed parts much of the initial coating has worn away and the remainder has developed deep checking and its content of oil has decreased from shrinkage of the linoxyn with age and probable loss of volatile products of photochemical decomposition. Assume, therefore, that on the fully ex posed surfaces the old coating remaining is 0.0025 inch thick, that is, erosion has taken off all of the initial third coat and 0.00035 inch of the second coat. Assume further that 20 percent of the volume "satisfy" the old thirsty surface and still leave enough oil to bind its own pig A typical paint-thirsty surface. The area show ments so that they will not in turn ;rob the finish coat of oil. Many paint tech 2 inches by 2 inches ,yai nologists advise thinning the first repaint coat generously with linseed oil in order to accomplish this objective. At first thought it seems reasonable that the more oil there is in the paint the more oil will be applied to the surface. In practice, however, the writer 'has repeatedly ob served that the extra oil added to the paint leads the painter to spread it out enough farther to actually reduce the amount of oil applied to unit area of the surface. Neither Too Thick Nor Too Thin The Forest Products Laboratory's painting exhibit at the Cypress Log Cabin at A Century of Progress in Chi cago last summer included paint-out tests showing the harmful effect of undue thin ning of priming-coat paint in two-coat painting of hew wood. When the prim ing-coat paint was mixed rich in pigment enough paint was applied to prime the woqd adequately and the second-coat paint dried, with uniform gloss and color but when the priming-coat paint was mixed either too rich in linseed oil or too rich in turpentine the second-coat paint dried with spotted gloss and color. Ex actly the same principle applies in the repainting of "paint thirsty" surfaces, II N41698.24 FLB 00089: MX 16, 1935 PAINT, OIL AND CHEMICAL REVIEW COMPLETE PIGMENTS ^ Horse Head XX-SO meets all the requirements of a good all around Zinc Oxide for exterior and interior finishes. It excels in color, brightness, and durability. Horse Head XX-50 Zinc Oxide was designed primarily to give improved durability in outsid house paints. It is one of the newer pigments with this durability/prop erty produced by controlling the particle characteristics, /QX Q 1 ZINC OXIDE THE NI W IIS E Y ZIN C C VI PAN Y 160 FHON7 ST, 11 0 NEW . X..O R K FLB PAINT-NEGLECTED HOVSE NO. 1 From across the street the paint merely looks rather shabby. A close view, shows that the coating is worn down to bare wood hi many places. Through a magnifying glass it is seen that the coating is dis integrating by checking and crumbling. Repainting Paint-Neglected Frame Houses By F. L. BROWNE Senior Chemist, Forest Products Laboratory, maintained at Madison, Wis., by the Forest Service, U. S. Department of Agriculture, in cooperation with the University of Wisconsin. PAINTING contractors during the next year Or two should find a greatly increased demand for their services in the exterior repainting of houses. Everywhere house owners during the years of depres sion have been putting off repainting until in many communities the majority of the buildings are badly in need of new paint. While this increase in his mar ket should be encouraging to the painting contractor, there are certain complicating circumstances that he must he prepared to deal with if the new business is to prove permanently profitable to him. On many of the houses that the painter will be asked to repaint, the old coating wore out three or four years ago, and since that time has been in a state of paint neglect. If the old paint was one that stands neglect weH, the surface ean be prepared for the new job fairly easily. Many paints, however, do not stand neglect well; if the old paint was one of them, the painter may have a difficult problem on his hands. He knows that the safe course is to remove the old coating entirely, but if he bids on that basis he may lose the joh to a less scrupulous competitor who plans merely to slap on some new paint and trust to luck that it will hang for a time. On the other hand, if he follows his competi- --2 | :|f | j / / / FLB 00089"/ blouses roice, J7. S. it three or four years a in a state of paint i that stands neglect Cor the new job fairly lo not stand neglect iem, the painter may mds. He knows that pld coating entirely, iay lose Hie job to a ins merely to slap on that it will hang for follows his competi- Painting contractors must carefully examine surfaces and apply knowl edge of paint behavior to determine their procedure in repainting . . . Long neglect makes problems difficult. . . Safe course in bad cases is complete removal. . . What to do when owners will not permit removal.. . Recent survey reveals variety of difficulties that will confront painters. tor's methods and the job goes bad, he may seriously damage a fine reputation that he has taken years to build up. The'painter who is going to get the business this year, and get it again tour or five years from now, must learn to distinguish between the surfaces that can be trusted to hold new paint properly and those that it wlU be good business to concede to his competitors when the owner cannot be convinced of the need for proper preparation before repainting. How to Know What to Do No previous business "depression has left painters with such a difficult problem in determining what to do with neglected surfaces, in former times most resi dential painting was done with a paint of a relatively soft type whose outstanding merit is the ability to stand neglect well. During the prosperous period fol lowing the World War there was a shift toward harder types that have certain important advantages during the useful life of the coating, but, unfortunately, do not stand neglect well. These paints were designed for an age in which better performance during four or five years of useful life could be demanded at the sac rifice of good behavior during a period of neglect, because it Was believed that nearly everyone would be able to repaint before the coatings disintegrated. Like other enthusiasms of easy times, this optimism has led us into serious difficulties When hard times arrived. Many of these paints have not been renewed at the proper time, and their badly neglected surfaces ieave the painter uncertain about the outcome if he merely scrapes off the loose edges and repaints without removing all of the old coating. A recent survey of one of the residential sections of a city in the Middle West provided the photographs with which this article Is Illustrated, and shows the variety of paint neglected surfaces with which the painters of that city must contend this year. The houses shown were selected at random in a community in which as a rule the occupant is the owner and the painting is done by local contractors. Past experience has taught the writer that under such conditions it is rarely possible to obtain accurate Information about the painting history of a house. Even the owner's or the painter's statement of the date and kind of paint used at the last painting often proves incorrect. That, however, is exactly the situation that the painter meets when he bids on a new Job. He must rely -primarily upon his own examination of the sur face and knowledge of paint behavior to determine those facts about the past painting necessary for guiding his procedure in repainting. We can, there fore, examine these photographs much as a painter should examine a house that he is going to repaint. House No. 1 House No. 1 always has been painted With the soft type of paint, but no new paint has been applied for seven or eight years, and the surface has become neg lected. The coating has thoroughly disintegrated. From a distance it merely looks shabby, but close inspection proves that it has crumbled badly and has left considerable areas of wood entirely bare, SHU closer observation with a magnifying glass demon strates that disintegration of the coating developed from checking, which is characteristic of the soft type paint. When the paint "checks" finally penetrated the coating to the wood, some of the little "islands" of coating thus cut off became dislodged one by one, leav ing the wood bare underneath. Many painters call this kind of disintegration "chalking," but, although the paint has been chalking for a long time, the failure really develops from checking and crumbling. The painter who gets the job of repainting House No. 1 is lucky, because he has very little to worry about. After any necessary carpenter's repairs have been attended to the painter need merely dust off loose chalk and dirt, perhaps clean a few places where soot or grease from oil-burning furnaces have collected on shaded parts of the building, and he is ready to brush on new paint. Two coats of new paint are necessary, of course, because part of the wood surface has been left bare, and what is left of the old coating Is little more than a mass of porous pigment that WUl absorb much oil from the first coat of new paint. As a rule the new paint should be of the same soft type previously used on House No. 1, because the chances are that the job will again pass through a long period of neglect before it is repainted. If, how ever, the owner feels that in future he will repaint before the coating disintegrates badly and wishes to employ harder types of paint, It is practicable to apply them over this surface. The first coat of new paint should be thinned with linseed oil and relatively little turpentine or other volatile thinner, using not more than 1% gallons of total liquid to I gallon of soft paste paint. At least a gallon of the mixture should be applied for each 600 Square feet of surface. For the finish coat a gallon of soft paste paint should be thinned with not more than One gallon of liquid, mostly linseed oil, and a gallon of the mixture applied for each 600 or 700 square feet of surface. House No. 2 House No. 2 has been painted and two or three times repainted with paints of a fairly hard type, but the owner waits just a little too long each tee before he calls in the painter. As a result, the painter each time has a difficult surface to deal with, and, as time passes, successive repaintings are proving less durable. The paint is In a more advanced stage of disintegration than that on Hbuse No. 1, yet the last painting of House No. 2 was two or three years more recent than that on No. 1. The break-up of the coating on House No. 2 is easily observable from the opposite side of the street. Closer inspection shows that it is disintegrating by --3 -- Of an sir th bu te th re . flS ^^s8^*X.- *r*-<l**-. ^ ~ ,,, **- - " _" pggwBBjStoy^ff^S^^i^SS-SfearMs^^t-j^B r?wr*p**pm*?^jv wifi1"<j#aw^vw^;?^ k> ' ] Kp '0 ;0 L4 TM..,,s 4,,,-^' ft J ~U d~-f ' j. s ' y" s fv ^' - "'> c^r-r _ x ' v <\ ,, - r ^j<^cr`>==z Pa IET-NEJuEuTED aOVaa AO. s Even from across the street it can be seen that the coating is distintegrating. A close view shows how the coating comes loose from the wood in rather large and conspicuous flakes. Through a magnifying glass it can be seen that the coating disintegrates by cracking, curling, and flaking, flaking and scaling rather than by crumbling. The view through a magnifying glass shows how such behavior differs from the crumbling on House No, l. Note that flaking does not develop from checking, but from an entirely different kind of fissure in the coat ing, cracking, which is a much larger and mote con spicuous sort of break-up. At the edges of the cracks the coating curls upward and eventually falls off, leaving a patch of bare wood, and the coating still clinging to the wood has jagged and insecurely adher ing edges. For a really first-class job the old paint on House No. 2 should be removed completely. However, if the owner will not agree to pay for it this year, all loos ened edges of old paint ^should be carefully removed with putty knife, wire brush, and sandpaper, and a fairly good job of repainting can be done with reason able assurance that it will stand up for about three years, but probably no longer. The owner should be warned, however, that the new paint will not form a perfectly smooth coating, because the places where the old coating has flaked off will show as hollows in the new one. He should also be warned that continu ance of his practice of allowing the coating to get into this condition before repainting will eventually make a complete removal necessary before repainting can be done at all satisfactorily, In repainting over this old coating the painter should use a hard type of paint, preferably the same paint that was used previously. If a soft type of paint is applied, there is danger of conspicuous alligatoring developing within a year or two. The paint should he a real oil paint; it should contain no heat-treated oils or varnishes that tend to give enamel-like consistency to a paint. A real oil paint properly mixed will show brush marks, but it will fill the flaked patches better and more nearly conceal them than a paint containing oils treated to give quick drying or freedom from brush marks. Two coats of new paint should be applied. The reduction of the first coat is necessarily a compromise between the needs of the patches of bare wood and those of the remnants of old coating, which are much less absorptive than the old coating on House No. 1. Without knowing the composition of the paint to be used, it is not possible to make specific suggestions for thinning, but in general the paint should be mixed so that it wifi contain more pigment and the liquid por tion a higher proportion of turpentine than was rec ommended for House No. 1, In applying the first coat I h f; 0 1 n P f d s c I I c t X t $ t s t i i t i r 1 i FLB 00089S of new paint a good plan is to lay oil a stretch of paint and then, after the oil has had Just time enough to sink into the wood of the bare patches, go back over the stretch without dipping the brush in the paint bucket. In that way much of the paint will be trans ferred from the poorly absorptive coated patches to the much more absorptive bare patches, and the final result will be a more nearly level coating, with the old flaked places showing less conspicuously. Part Two Anting can be painter should le same paint ?e of paint is :s alligatoring lint should be ifc-treated oils re consistency ,xed will show latches better int containing im from brush applied. The a compromise are wood and lich are much 2ouse No. 1, be paint to be uggestions for d be mixed so he liquid por;han Was recthe first coat Failures Caused by Moisture N examining houses before bidding for their repaint I ing the painter should look constantly for signs of failure of the old coating caused by moisture be hind the painted boards. On houses afflicted with this faulty condition the best of paints may fail conspicu ously in a very short time, often in less than a year. The wise painter will call the owner's attention to moisture failures before undertaking the Job of re painting. If he waits until his own repaint Job has failed, as it probably Will, he will usually find It very difficult to convince the owner that the failure came from conditions beyond the painter's control. The various ways in which moisture gets into the side walls of houses and ruins fine paint jobs are dis cussed in a mimeograph obtainable free from the Forest Products Laboratory, Madison, Wisconsin. Houses that are chronically subject to such conditions cahnot be repainted With assurance of success even if the old coating is removed entirely. The source of moisture must be discovered and means taken to keep the side wails dry before paint can be expected to give good service on such houses. For his own protection the painter before agreeing to repaint the house should warn the owner that moisture collects at times behind some of the painted woodwork and may cause difficulty with the new paint job if means are not found to keep the wood dry. Some of the forms of paint failure that should lead the painter to question whether the woodwork always remains dry can be described by considering specific examples from the writer's experience. House No. 3 The condition of blistering observable on House No. 3 is an unmistakable sign of moisture in the side walls. If a board of siding is removed while such blisters are Swollen the back of the board will be found thoroughly wet. A carpenter can easily remove a board of siding for such examination and replace it without damage if it is necessary to convince the owner that there is moisture behind the boards. As a rule that condition is found most often in late winter or early spring (House No. 3 was examined in March). Later in the season the side walls may dry out again and the blis tered parts of the coating become flabby or even sink PAINT-NEGLECTED HOUSE NO. 3 Blistering caused by moisture in the side walls during the winter months. It is obvious that the previous paint job had likewise 'blistered because the places where the loose paint had been scraped off show under the last paint coating. back almost to their original position so that the blisters may become hard to detect. While in the turgid state a pen-knife thrust into the blister may show it to be full of water, but that is not always the case. When the blister is peeled off it may reveal the bare wood beneath or it may reveal a prior coat of paint still clinging to the wood. Effect of Blisters Drying Blisters may break and peel soon after they are formed, but very often they merely dry out and shrink back until the Coating becomes more brittle as a result of weathering for- a few months longer, after which the blistered areas crack open and scale off. House No. 3 shows places where the previous paint job had blistered and subsequently scaled. The present coating was put on only a year or so ago and is still soft and flexible, yet it is already cracking and coming loose. The painter should recognize this house at once as a "chronic peeler" and should not undertake to re paint it even if he removes the old coating entirely unless the owner understands that the paint cannot be expected to give good service until proper steps have been taken to keep moisture from getting behind the painted boards. The Forest Products Laboratory has equipment for reproducing typical moisture failures of paint for the purpose of studying the effects of different woods and paints. The panel shown in the illustration was made of 4-inch red cedar siding of the kind used on houses. It was painted in October, 1934, with three coats of a --5-- | | f I I f | | J | = FLB 00Q90C PAINT-NEGLECTED HOUSE NO. 5 The paint on ail parts of the house was cracked as shown in upper righthand comer of the photograph. The boards shown contained 30 to 40 percent moisture when, the photograph was taken. representative house paint of the titanox, lead and , zinc type. On the left-hand half of the panel the paint liquid contained pure linseed oil, but an the right-hand half a mixture of linseed oil and heattreated tung oil was used. The panel was exposed to the weather facing south at 45 for 2% months, after which it was tested on the blistering apparatus. The apparatus consists of a wooden framework to which panels are attached as Below: House No. 4. Scaling caused by moisture in the side walls during the winter months. PAINT-NEGLECTED HOUSE NO. 4 though they were the side walls of a house. The miniature "house" has a roof and a floor, and inside there is a large pan of water that is heated elec trically to provide heat and humidification. The "house" is placed in a large cold-room kept at 40 F. The temperature within the house was approximately 80 F. Under such conditions moisture condensed on the backs of the boards of siding, making them thor oughly wet. Blisters began to appear on the top hoard of the panel shown after the "house" was in operation for one day. After two days blisters appeared on the sec ond and third boards also, and after three days they appeared on the fourth board. The photograph was taken after 11 days, when the panel was removed from the "house" and replaced on the test fence out of doors. At the present time, six months after painting, the smalier blisters have apparently disappeared, the larger ones have sunk back and left a few ridges near their lower margins, and the coating is beginning to crack and scale where the largest blisters were. House No. 4 The sort of scaling of the old coating to be seen on House No. 4 is commonly the result of wet side walls, but it must not be confused with some of the results of painting with incompatible paints that will be dis cussed subsequently. House No. 4 is one of nearly 200 houses in a single community that have been "chronic peelers" ever since development of the plat began some seven years ago. This house had been painted three times within two years When the photograph was taken, each job failing in much the same way. Some houses Were burned off and repainted and stall failed promptly in the same way, Examination of the houses showed that the backs of the boards of siding and the building paper behind them had become thor- --6-- FLB 000901 JT-NEGLECTED 'OOSE NO. S saint on all parts house teas cracked urn in upper right- comer of the graph. The hoards '. contained. 30 to io it moisture when photograph was if a house. The floor, and inside t is heated eleclidtflcatlon. The 3m kept at 40" F. ras approximately ure condensed on .aking them thor- top board of .the i in operation for >eared on the secir three days they p photograph was was removed from test fence out of tbs after painting, 7 disappeared, the a few ridges near ig is beginning to listers Were. ittng to be seen on ; of wet side walls, ne of the results of that will be diss one of nearly 200 have been "chronic >f the plat began had been painted m the photograph ich the same way, repainted and still Examination of the he boards of siding t had become thor oughly wet every winter. The writer knows of no way in which these houses can be kept properly painted at reasonable cost until construction practices in the community are altered in such a way as to keep the side walls dry at all times. House No. 5 House No. 5 is an old bouse to which additions have been made from time to time. There apparently had been no great trouble with the paint until the last alteration was made some eight or nine years agoSince then it has been necessary to repaint at yearly or bi-yearly Intervals, and a very thick coating has been built up except on patches here and there where scaling took place before the last repainting. In 1934 the side walls wore filled with insulation which, in this case, seems to have increased the condensation of moisture behind the siding. All over the house the thick paint is cracking badly as shown in the photo* graph, and under the porch on the south side the coating is now scaling very badly. At the time the photograph was taken the moisture content of the boards was 30 to 40 percent--that is, they were thor oughly wet. House No. 6 House No. 6 was erected In 1919 and painted with pure white lead paint, which gave entirely satisfactory service. In 1926 it was repainted with white lead paint. During the following winter the outlet to the sewer became clogged and caused water to rim back through the cellar floor drain, partly flooding the cellar floor. The difficulty was not properly repaired until the ground thawed in the spring, when it was less difficult to uncover the connection to the sewer. The photograph was taken in May, 1927, nine months after painting. Above: House No. 6. Discoloration of white lead paint with water soluble substances in redwood siding caused bp mois ture in the side walls during winter months. Proof of Wet Wood In this case there was comparatively little blistering because pure white lead paint is distinctly more re* sistant to blistering than most other kinds of paint. The siding, however, was redwood, a Wood that holds paint excellently, but one that contains colored sub* stances soluble in Water that turn dark reddish-brown in color when exposed to air. When the boards be came Wet the water carrying the soluble matter exuded through the paint, smeared over the surface, and developed the dark stains as shown. Under simi lar circumstances somewhat similar stains may ap pear over western red cedar, and on at least one house the writer has seen them on white pine. Such dis coloration of paint with water soluble material from the wood is unmistakable proof that the wood became thoroughly wet after the house was built. The fact that some woods discolor paint under such conditions should be no objection to their use in exterior con struction because no wood will hold paint properly unless the faulty moisture conditions are removed. The discoloration gives warning of the need of cor rective measures. House No. 6 was washed and repainted in 1927 after the plumbing had been repaired. No subsequent diffi culty with the paint has been reported. The panel illustrated below shows blistering reproduced in tests in the Forest Products Laboratory- See accom panying article for explanation. -- 7 -* FLB 000902 b. T : si e: PAINT-NEGLECTED HOUSE NO. 7 In spite of the dose resemblance to scaling caused by wet side walls, moisture seems to play only a minor role, if any, in this paint failure.. A coat of dark brown paint sand j 11 wiched between a preceding job of tinted white paint and a succeeding job of white paint made an incompatible coating. The white and brown paints are scaling from the tinted white paint. Part Three ............ ****''* P t; n i is | fi ' VS 1 to t- a w v !c Ib 1: fi vs lS Failures Through Incompatibility of Paints s: Ib PAINTERS today have more good paints from which to choose than they have ever had before. While Knowledge of incompatible paint combinations is es ; b sential for the painter who counts good will among a this variety of products helps the painter who un the assets of his business. derstands them all to suit the needs of clients with The remaining houses in our survey of a middle different service conditions, different habits of paint western city illustrate common cases of failure due maintenance, and different standards of satisfactory to incompatibility of paints. The first two of them, paint service, it likewise adds to his difficulties by in creasing the chances of premature failure of his re paint jobs because of incompatibility of the new paint houses Nos. 7. and 8, should be compared particularly with houses Nos. 4 and 5 of the second article in this series because there is such a close resemblance be 7 a 0 with the old one. There is no one kind of paint that tween failures from incompatibility and failures from can be applied over all other kinds of paint with as wet side walls that the two are frequently confused. surance that it will perform properly. Certain combi It is bad enough to have an honest job fail, but when nations of paints, all of which may be good paints, it does the painter gains nothing by attributing the result in early and conspicuous failures that can be failure to moisture only to have his client discover that set right only by burning off all of the paint and start the side walls were never wet. ing over again from the bare wood. The typical dwelling may be painted ten or fifteen times in the course of its life in service. Unfortunately, House No. 7 many property owners think that these ten or fifteen paint jobs can be considered quite independently of House No. 7 was painted when erected, in 1928, with each other, each one to be decided upon when it comes two coats of a dark gray paint, probably of a lead and due without regard for the others. Such a course zinc type, and a finish coat of a dark brown paint. often leads to a succession of unsatisfactory paint jobs The house was sold to a purchaser who disliked the ending with an expensive bum off and serious damage dark color, m 1932 there was some scaling of paint to the reputation of the last two or three painters. on parts of the house and a few typical moisture --8-- FLB 000901 Is estnong tiddle i due them, llarly 1 this e befrom fused, when g the r that With many fine paints to choose from, painters must study the compatibility of one product with another if they are to achieve successful results in repainting paint-neglected frame houses. . .Survey of houses in a mid dle west city illustrates common cases of failure due to this incompatibility of paints. blisters, such as those on house No. 3, were observed. The scaling was therefore attributed to moisture in the side walls, but the source of moisture and means of excluding it were not discovered. The house was re painted with white paint of the titanium, lead and zinc type. The photograph was taken in March, 1935. The moisture content of the boards from which the paint is scaling was found to be 11 percent, which is per fectly normal, and indicates that the boards were not wet during the past winter. On the opposite side of the house where blisters were observed before and after the application of the white paint a few boards were found with 20 percent of moisture, but there was very little scaling of paint on any of the moist boards. On those patches where the brown paint had scaled before the white paint was applied the coating Is now in excellent condition. Where the scaling occurs the white and brown paints come off together, but the gray paint of the initial paint job remains intact. Although some doubt may be admitted as to a pos sible part played by moisture in the paint failure on house No. 7 the sandwiching of a dark brown paint between a tinted white paint and a white paint makes an incompatible combination that is certainly the pri PAINT-NEGLECTED HOUSE HO. t Careful examination, including removal of boards of tid ing, shows that the side walls have always been dry. A quick-drying type of paint was used over ordinary linseed oil paint on the north side (left), but the painter had so much trouble picking up laps that he added white lead paint to the quick-drying paint for the other three sides. The south side (right) shows little scaling. mary cause of difficulty in this case. To repaint with out burning off all of the old paint is to invite further disappointment. House No. 8 The failure on house No. 8 bears a striking resem blance to moisture failure like that on house No. 3, but the house was examined carefully for moisture In March and the boards found to contain slightly less than 11 percent. Four boards were removed and ob served to detect signs of water on the backs of the boards, rust at the nail holes, or rumpling of the build ing paper behind them. Apparently the side walls have never been wet. House No. 8 was completed late in 1929 and a primer coat of paint applied. In June, 1930, the painting was completed with what the owner understood to be lead and oil, but on examination proved to be a mixed pig- PAINT-NEGLECTED HOUSE NO. 9 Three sides are in the condition shown at the left. Here there was successively a dark, reddish-brown paint, a yellow paint, a dark gray paint, and at least three jobs of white paint. On the east side, shown at the right, there were only the last two or three jobs of white paint, because that side had to be rebuilt after a fire some years ago. , with A and paint, d the paint isture aaaafc-^l meat paint, probably of the lead and zinc type. In July, 1933, the owner contracted to have the house re painted with one coat of lead and oil, but the painter purchased one of the quick-drying house paints in which the liquid contains a mixture of linseed oil and a re-inforcing oil and the pigment contains titanium, white lead, and zinc oxide, " The painter began on the north side, but had so much trouble picking up his laps that he reduced 100 pounds of soft paste white lead and mixed it with five gallons of the quick-drying paint to complete the job. Paint scaling began within a year. The photograph was taken in March, 1935, There is scaling on all sides of the house, but it is distinctly worse on the north side than elsewhere. The quick-drying paint is a well-made product put out by a responsible manu facturer and will give excellent service over a proper foundation, but It differs so markedly from the paint used previously that the combination failed very early. The failure should not be considered a fault of either the old or the new paint, but a mistake in using the one over the other. The painter, however, is badly compromised in any case because he used a paint other than the one specified in the contract. House No. 8 must be burned off before it can be repainted with reasonable assurance of a durable coating. House No. 9 House No. 9 is an old one that has been painted at least six times. On three sides the paint is failing very badly, but on the east side, which is as fully exposed to the weather as any of the others, the paint is in such excellent condition that one repaint coat should prove sufficient. About ten years ago a fire in the house made it necessary to rebuild; the east wall, but left the other three walls undamaged. Examination of the old coating shows that the house was painted initially with a dark reddish-brown paint, then successively with a paint of the color of yellow ochre, a dark gray paint, and at least three times with white paint. The east side has only the three jobs of white paint. The yellow paint may have been com patible with the brown paint, but the gray paint and the white paints were not. Painters have repeatedly struggled to repaint these three sides of the house smoothly with less success and less durable jobs each time. The east side, however, has never presented any difficulty. Now the three sides with the incompatible coatings must be burned off before they can be painted at all smoothly. House No. 10 House No. 10 was painted initially with a white paint of the lead and zinc type and then repainted some years later with white paint of the titanium, lead and zinc type. The second paint probably was mixed with a materially higher proportion of pigment than the first, as is commonly the case in manufacturing paints of these two types. The failure takes place by scaling of the second paint, leaving the first paint still firmly adhering to the wood. Successive coats of paint should, as a rule, contain decreasing proportions of pigment. Violation of this principle probably accounts for the unsatisfactory form of failure on house No. 10. House No. 11 House No. 11 is another example of white paint ap plied over paint of dark color with which it is incom patible, The incompatibility, however, is more pro nounced, appeared after fewer repaintings, and pre sents a more characteristic form of failure than house No. 9, where the yellow and gray paints perhaps ef fected a more gradual transition from the dark brown to the white paints. Paint failures of the kind seen on house No. 11 have been common in recent years on the freight stations and other wooden buildings of many railroads. They were formerly painted with red "freight-car" paint for economy in maintenance, but were repainted with a more cheerful color chosen to represent the railroad for advertising purposes. The brighter paint often proved incompatible with the red. House No. 12 House No. 12 was painted about seven years ago with a white paint of the lead and zinc type, and again three years ago with pure white lead paint. The conspieuous alligatoring that has now developed is very objectionable to the owner. The writer has repeatedly observed it on houses where white lead has been ap plied over other kinds of white paint and has repro duced it by painting panels in that way on test fences. j ; ; -- 10 -- FLB 00090 ever presented any i the incompatible bey can be painted with a white paint ;n repainted some titanium, lead and ily was mixed with pigment than the nufacturjng paints es place by scaling ;t paint still firmly its of paint should, rtions of pigment, r accounts for the louse No. 10. of white paint apwhich it is incom;ver, is more proaintings, and pre failure than house paints perhaps efjm the dark brown ; of the kind seen in recent years on joden buildings of iy painted with red . maintenance, but ,'ul color chosen to ing purposes. The liable with the red. PAINT-NEGLECTED HOUSE NO. 10 An incompatible combination, in which titanium, lead and zinc type of paint was applied oner an old coating of lead and zinc type of paint that probably contained less pigment than the new pigment. iven years ago with ic type, and again 4 paint. The con developed is very iter has repeatedly lead has been aptnt and has reproway on test fences. PAINT-NEGLECTED h o u s e NO. 12 - Coarse aMgatoring of pure white lead paint applied oner old paint of the lead and zinc type. FLB 000906 e h JE sl p o ; '3 p h c The articles included in this bro g u r< ""BEBSC: chure have beep referred to by paint authorities as the most impor tant contribution to the subject of painting wood exteriors yet pub g w Jrr ibi lished. Additional single copies will be furnished without charge. hi ot Copies in lots of 100, S00 and 1,000 may be obtained for a nominal sum. \ZT N7 NATIONAL PAINTERS MAGAZINE 12 Gold St. New York, N. Y. b< O as `in m pi as ap fo sic io CG to w R< joi Alv -- 12 -- FLB 00090' Vftw,^v^iYiivlu\rv^'M^^v.^i[vAVv;iVAuVi>>ao>AiX\'Xu.',v.'', The Preservative Treatment and Staining of Shingles Most of the wood shingles used at the present time for roofs and side walls of buildings are of Western redcedar. Redwood, baldcypress, and East ern white-cedar find use to a small extent. The heartwood of these species is resistant to decay. Experience proves that good quality, all-heartwood shingles of these woods give good service without preservative treatment under the ordinary methods of using Shingles in building construction. It is im portant, however, that the shingles be entirely of heartwood because sapwood is not resistant to de cay. Edge-grain shingles are much better than flat- grain shingles because they warp much less and withstand weathering better. Commercial Western redcedar, cypress, and redwood shingles of the No. i grade promulgated by the United States Depart- ! ment of Commerce are all heartwood and all edge- grain. For lasting service the shingles should be properly laid and nailed with corrosion-resistant nails. The thickest standardgrade shingles (4/z have butts r/2 inch thick and will last longer and give better service than those with butts 0.4 inch (5/2) or 0.45 inch (y/2-%) thick Roofs are more severely exposed to weathering and decay than are walls. Only the No. r grade shingles are ordinarily recommended for roofs of permanent buildings. Shingles of lower grade may be suitable for side walls if it is more important to minimize cost than to obtain the best appearance. :On side walls, however, shingles may be laid with as much as 714 inches instead of a maximum of 5 inches exposed to the weather and wider shingles may be Used on side walls than on roofs. These practices increase the tendency for shingles to curl as a result of weathering. Moreover, a moderate amount of curling that might be unobjectionable on a roof is unacceptable on side walls when the best appearance is desired. For best appearance, there fore, shingles of No. 1 grade should be used for side walls as well as for roofs. Shingles of lower grade may be used for temporary buildings, for the lower layers when shingles are laid in double courses, and for side walls when it is not necessary to maintain the best appearance. Roofs should have sufficient pitch to make rain water drain off rapidly and to prevent water from melting snow from backing up under the shingles. Roof sheathing may be laid tight or with open joints. Tight sheathing affords better insulation By F. L. BROWNE, Chemist, Forest Products Laboratory against heat and cold. Open sheathing provides better opportunity for the escape of air-borne mois ture entering through leaks. No actual evidence is available to show that the method of laying the sheathing has a noticable effect on the durability of the roof- Where desired, it is entirely practicable to let shingles of the species named weather naturally without any surface treatment. In a few months the original color of the wood changes to a pleasing gray that blends harmoniously with many color schemes. For shingled side walls as a rule, and very often for shingled roofs, surface treatment to pro vide color is desired. Good shingle stains generally offer die most satisfactory and economical means of providing color. Stains provide color without gloss and without entirely concealing the grain and tex ture of the wood, a combination, of conditions usually very appropriate for the rough, sawed sur faces of wood shingles. The most satisfactory shingle stains are highly colored, such as brown, green, red or yellow. It is not possible to make a white stain because stains do not entirely hide the color of the underlying surface. There are light gray stains but they are not so durable as paints. For that reason it is common practice, when white or a pale color is desired, to paint shingle ride walls. Ordinary house paint may be used for the purpose; two coats of it are required for the first painting, one coat for repainting unless the previous coating has very largely worn away. The finish coat should usually be so mixed as to dry with as little gloss as is possible. Highly glossy paint is inappropriate for rough surfaces. Paste white lead, for example, may be mixed with its own volume of a mixture consisting of one-third linseed oil and two-thirds mineral spirits or turpentine, or the paste may be thinned with its own volume of "lead mixing oil." When shingles are to be painted, the first coat of paint is best applied before the shingles are laid, so that the backs and butts as well as the faces are well coated. The paint may be applied by dipping the shingles to at least two-thirds of their length in the paint and then standing them vertically until the paint has dried. If the backs are not so painted. -AMERICAN FEDERATION OF LABOR Page Fifty-three % N41698.26 FLB 000908 WISCONSIN CARPENTERAND BUILDER rain water seeping under die shingles may cause more curling than would otherwise take place and die paint near the butts and edges of cedar or red* wood shingles may be discolored by water-soluble dyes extracted from the wood. The finish coat may be applied by brushing or spraying after the shingles have been laid, but care should be taken to see that the exposed butt ends are well coated with the finish paint. Good paint coatings on shingle walls usually should last about 5 years, after which the paint should be renewed, again seeing that butt ends of shingles are well painted. Painting is not recommended for shingle roofs. Because of the sloping position of shingles on a roof, more water penetrates beneath shingles and it stays there longer than is the case on side walls. Moreover, painting or repainting after the shingles have been erected tends to build little dams of paint across die bottom of the gaps between shingles, which on roofs adds to the amount of water backed up under the shingles while the paint coating on the exposed wood surfaces retards the rate of sub sequent drying out of the moisture. Painting shingle roofs, therefore, tends to increase cupping and the chances for decay to set in. Stains are not subject to these disadvantages and may properly be used on shingle roofs. Commercial wood shingles can be purchased al ready stained, or they can be bought unstained and stained on the job, The commercially stained shin gles have the advantage of convenience and may prove to be more uniformly and durably stained, but at times requirements of availability, grade of shingles, special color, or price may make it desir able to buy unstained shingles and slain them on the job. Staining on the job is done to best ad vantage by dipping the shingles one by one to at least two-thirds of their length in the shingle stain and standing them up nearly vertically to drain and dry. It is also practicable, as far as decorative effect is concerned, to apply stains by brush or spray gun after the shingles are laid. Stains, even though they contain preservatives, applied to a completed roof can have little .effect on decay resistance for they do not reach the hidden surfaces between the shin gles where decay is most likely to develop. Shingle stains can be purchased in ready-mixed form or they can be mixed on the job from the necessary ingredients. Some commercial shingle stains contain coal-tar creosote in addition to other ingredients, for the purpose of imparting protection against decay. If the shingles are entirely heartwood of cedar, cypress, or redwood there is little need of toxic chemicals in the stain. On the other hand, shingles containing sapwood or of species not resistant to decay require more effective treat ment than superficial application of creosote stains, if good durability is to be assured, at least when they are used for roofs. There is, however, no ob jection to the use of coal-tar creosote in stains for durable woods provided that it does not displace more necessary ingredients, such as linseed oil, and provided further that there is no thought of painting the shingles at some subsequent date with white or light-colored paint. Coal-tar creosote remaining in shingles may discolor paint even several years after die creosote stain was applied. The most important ingredients of shingle stains are linseed oil and pigments of suitable color. For stains to be mixed on the job the pigments should be bought in the form of colors ground in linseed oil, which are obtainable from nearly all retail paint dealers. Pure colors of highest quality only should be used. They should contain no "inert" or "ex tending" pigments, such as china clay, barium sul fate, silica, or magnesium silicate. The higher cost per pound of the pure colors is more than offset by the smaller amount that need be used and the greater durability of the stain. For good durability the liquid part of the stain should be at least onethird and may well be two-thirds linseed oil. The remainder of the liquid may be volatile thinner such as turpentine or mineral spirits, coal-tar creosote, or a mixture of volatile thinner and creosote. Ordinary coal-tar creosote as used for wood preserving has a brown color that makes it unsuitable for stains of bright colors. For that reason makers of "creosote shingle stains" often use a light-colored, relatively volatile fraction of creosote that makes stains of bright color; but it is doubtful whether such "creo sote" stains retain effectiveness against decay very long. Used automobile crank-case oil, sometimes suggested for use in home-mixed stains, has none of the toxic properties of creosote, but usually shares with creosote the disadvantage of dark color. Crank case oil can be used to replace some of the volatile thinner in shingle stains of dark color, but no ad vantage other than a trifling saving in cost can be obtained thereby. Crank-case oil must not be used as a substitute for any of the linseed oil. The amount of color-in-oil to be mixed with the liquid varies with the nature and quality of the colors and must be determined by trial. The fol lowing formulas for guidance, which are from the Handbook on Painting by the National Lead Com pany, give the amount of colors in oil required for each gallon of the liquid mixture to produce some of the more common colors: AMERICAN FEDERATION OF LABOR Page Fifty-five wood or of species more effective treatin of creosote stains, mred, at least when ; is, however, no obreosote in sains for it does not displace h as linseed oil, and thought of painting date with white or eosote remaining in t several years after its of shingle stains suitable color. For pigments should be und in linseed oil, Iy all retail paint uality only should 10 "inert" or "ex clay, barium sulThe higher cost more than offset be used and the r good durability 1 be at least onelinseed oil. The atile thinner such il-tar creosote, or sosote. Ordinary d preserving has ible for stains of :ers of "creosote lored, relatively makes stains of her such "creoinst decay very oil, sometimes ins, has none of t usually shares k color, Ciankof the volatile or, but no adin cost can be ist not be used oil. nixed with the juality of the ial. The fob are from the al Lead Comt required for iroduce some Page Fifty-five 4! "m WISCONSIN CARPENTER AND BUILDER mm Gray--12% pounds white lead and touch of and less curling the thicker and narrower the shin lampblack. Deep red brown -- t pint Indian red. gles and the shorter the length exposed to the weather. Curling is especially marked in dry cli s Bright red -- i pint Venetian red.. mates or in spells of very dry weather. Ordinary ? Permanent green -- % pint chromium exide. staining of shingles probably has little effect on f Fairly permanent green -- i !4 pints medium their curling, though the thorough treatment of | chrome green. sapwood shingles with creosote or with water- I Golden broom -- % pint raw Italian sienna and repellent preservative, discussed farther on in this | % pint burnt Turkey umber. report, probably reduces curling appreciably. On I Seal brown -- i pint raw Turkey umber. walls, painted shingles, if well primed on the backs I Deep brown -- i pint burnt Turkey umber, before laying and if the paint coating is well main Shingle stains are sometimes used on bevel siding. tained, curl less than similar unpainted shingles. | For the most attractive results it is best to attach In some parts of the United States it is believed | siding that is to be stained with the sawed side that superficial application of creosote, of linseed | rather than the planed side exposed to the weather. oil, or even of spent crank-case oil will keep shingles | Stains, particularly those of the deeper colors, last from curling. Thorough treatment of sapwood 1 even longer than good house paints, especially when shingles with any of the oils mentioned probably I applied on rough surfaces such as the split or sawed would delay curling for a long time, especially if | surfaces of shingles. Good stains should last at further applications of the oil were made every few I least 5 years on shingle roofs and at least 8 years On years for maintenance. At the Forest Products |: shingle walls or the sawed side of bevel siding. The Laboratory it is doubted, however, that superficial L stains, however, will eventually wear and and must application of any of these oils to heartwood shin then be renewed if the original color is to be re gles of cedar, cypress, or redwood materially re I stored. Fresh stain can be applied by brushing or spraying; it should again last at least as long as the first staining did. duces -curling. Once serious curling has taken place, no material is known that can be applied to straighten, the shin gles out again. Some improvement can be effected I - f f After stain has worn out on shingle wails it is of ten practicable to paint them if paint is desired in stead of fresh stain. If the original stain, however, contained creosote there may be question whether it will discolor white or light-colored paint. The tendency for creosote to discolor paint gradually diminishes during exposure to die weather, espe cially if the creosote was applied superficially by dipping, brushing, or spraying. After 4 or 5 years, such creosote-stained shingles can often be painted satisfactorily but there i$ a problem of determining whether that stage has been reached. The best way to tell is to cry painting a few shingles, preferably on an inconspicuous part of the house and on the area that receives least sunshine.. If the paint re mains free from discoloration for as much as two weeks, it is safe to paint all of the shingles. An additional test on a few shingles may be made by applying one coat of aluminum house paint followed by two coats of white or light-colored paint Some times aluminum paint will prevent discoloration where ordinary' house paint will be discolored. Exposure to the weather tends to make shingles curl, although with commercial shingles of best quality the amount of curling .should be unimpor tant. Cedar, cypress, and redwood usually curl less than most other woods. With any wood, there is by face nailing the badly curled shingles, allowing the shingles to split as the wider ones will, but the large nail heads will be left showing. Treatments for Shingles of Less Desirable Woods Where building materials are purchased from the customary retail channels, it is rarely advisable to consider anything but the heartwood of durabje species for shingles to be used on roofs. For walls, shingles of cheaper grade may be used because there is little chance of decay, though the cheaper shingles cannot be expected to lie so flat and maintain so good an appearance as die better ones will do. In rural communities, however, it sometimes proves desirable to build with locally grown woods, none of which may provide naturally durable shingles. Shingles of the less desirable woods may be expected to curl more and present somewhat less satisfactory appearance than shingles of die best woods; for that reason, shingles of the inferior woods probably should not be more than 6 inches wide and should not be made less than 'A inch thick at the butts. It is usually sufficient to dip such shingles for walls in suitable wood preservative or in stains that eontain coal-tar creosote, but for roofs more adequate preservative treatment is necessary. Impregnation of the shingles by pressure treatment is not pracr ticable unless there is a treating plant within reach. less curling of edge-grain than of flat-grain shinglesI Page Fifty-seven I AMERICAN FEDERATION OF LABOR ii yU, to 6 to National Painters Magazine FLB 00091( WISCONSIN CARPENTER AND BUILDER butmany woods can be given a reasonably thorough for submerging die shingles and separating them treatment by the hot-and-cold-bath method, with from each other so that the stain can gain uniform equipment that can be easily improvised. For such contact with the surfaces and color them evenly. treatment sapwood shingles are preferable to heart- The best way to accomplish this , is to open the wood because sapwood takes treatment more read bundles and put the shingles in screen-wire baskets ily. The shingles should be in an air-dry condition of suitable design. It is best to have the shingles before treatment, because green or wet shingles will stand on the butt ends in the treating baths, par not absorb enough preservative in the hot-and-cold- ticularly in baths containing pigments. Such baths bath method. * must also be stirred frequently to keep the pigments The effectiveness of coal-tar creosote as a pre in suspension. . servative for wood shingles has been well established In commercial shingLe-staining operations special by practical experience. Because of the difficulty staining machines are in use in which the shingles of making bright-colored stains with creosote of can be stained with suitable stains without opening dark color, the time may be ripe to consider pre the bundles. It is doubtful whether these machines servatives for shingles based on more recently de could be used with some of the stains to be de veloped fungicides that impose less limitation on scribed, but in any event they would hardly be the color of stains made with them. Although they available at places where the use of shingles that have had little use in the treatment of shingles, oil require preservative treatment can be recommended. solutions containing, for example, either 5 per cent Experiments at the Forest Products Laboratory by pentachlorophenol or copper naphthcnatc equivalent the procedures described in the following para to not less than 0.5 per cent copper metal are prom graphs resulted in reasonably satisfactory penetra ising preservatives and can probably be used effec tion and retention of coal-tar creosote and good tively for that purpose. The oil solvents or carriers staining of sapwood shingles of ponderosa pine. The used in these treating solutions must be carefully stained shingles were exposed to the weather on a selected to meet special requirements such as com test fence at Madison, Wis., from February 1935 to patibility wirh shingle-staining materials, freedom September 1938. The stained shingles retained their from bleeding, and suitability forbearing to the colors well during the test period, but die appear temperatures required in hot-and-cold-bath process. ance was somewhat marred by a certain amount For the present, however, the only procedures that of exudation of creosote during hot weather in July ban be recommended are those involving creosote; and August of 1935. Although the performance in preservative staining treatments using the newer that respect was inferior to that of commercially fungicides can be suggested only on an experimental stained cedar shingles, it was considered reasonably basis to be verified by practical experience. acceptable. The sapwood shingles did retain an The hot-and-cold-bath method of treatment re over-all bright appearance of the chosen color and quires two tanks for creosote or stain, one of which at the same time they contained enough preservative is equipped for heating the liquid do z t zF. The to. ensure reasonably long life. The mottled effect best method of heating is with steam coils, because caused by exuded creosote was not considered seri there is then little danger of setting the oil afire and ously unattractive for shingle roofs. When sapwood the temperature can be maintained more uniformly, shingles must be used, the procedure makes a variety Fairly light galvanized iron tanks with joints riveted of colors available without sacrificing durability to and soldered will do if the heating is done with gain color. steam coils. If the heating must be done by direct fire underneath, the tank for the hot bath must be In these treatments die hot bath consisted of coal- heavy enough to withstand the flame, say 3/16 inch tar creosote of the kind generally used for com black iron, with the joints welded or riveted and mercial impregnation treatments of railway cross- caulked. Unless the tank for the hot bath is to be ties and telegraph poles. The shingles were sub used for treatment of fence posts or other timbers merged in the hot bath at 212 F. for 54 hour, after also, it need be only large enough for the immersion which they were quickly submerged in stain at of a single bundle of shingles. If more than a few room temperature for z hours. They were then bundles of shingles are to be treated at one time, stood on the* butt ends to drain and to permit the the old bath should have capacity for at least four stain to dry. bundles, because they may have to remain in the cold bath as much as four times as long as they do in the hot bath. There must be some arrangement The stains were made from colors-in-oil, boiled linseed oil, and mineral spirits. The colors-in-oil had the following composition: Iron oxide re Iron oxide yt Ferrite yello'1 Vandyke br< Chrome gree The iron oxi rellow were al nents contain! >y weight. Tt SrOreen consist! [Prussian blue [Vandyke bro* | The five sfc ^following eon . Chrome Boiled 1 Mineral . Iron oxi Boiled 1 Mineral 3. Vandyl Boiled Miners 4. Ferrite Boiled Miner: 5. Iron o 'The trav a small gej saw a dog, ta board wi "You m. -"that your "Sure," "Why, . there?" a: vaudeville J smart as 1 AMERICAN FEDERATION OF LABOR Page Fifty-nine AMERIC/ FLB 000911 tingles and separating them t the stain can gain uniform :es and color them evenly, mplish this is to open the tigles in screen-wire baskets t best to have the shingles in the treating baths, par sing pigments. Such baths tently to keep the pigments staining operations special use in which the shingles lie stains without opening d whether these machines } of the stains to be det they would hardly be the use of shingles that ent can be recommended, t Products Laboratory by in the following parably satisfactory penetral-tar creosote and good s of ponderosa pine. The ed to the weather on a frpm February 1935 to d shingles retained their period, but the appear1 by a certain amount ing hot weather in July igh the performance in that of commercially considered reasonably hingles did retain art ' the chosen color and :d enough preservative The mottled effect is not considered serioofs. When sapwood edure makes a variety uificing durability to ath consisted of coalrally used for comts of railway cross shingles were subF. for !4 hour, after merged in stain at . They were then t and to permit the Boiled linseed oil ........... .................... 67 gallon linseed oil by Mineral spirits ............. .. .33 gallon Iron oxide red .............72.5% 37.55S> Iron oxide yellow...... 56.2% ,43.8% Ferrite yellow ___... .60.5% 39-556 1 Vandyke brown ........... 6<S.o% CThhreomiroengorexiedne..r.e..d..,..i.r.o.n. 8o0x.0id%e 33-456 yellow2,.0--a.n0d%ferrite These stains do not dry rapidly, but inasmuch as a stain is more or less absorbed by the wood, rather than a coating over the wood, rapid drying is not usually necessary. The shingles can be handled and laid without undue inconvenience before the linseed oil is thoroughly dry. Drying probably can be wellow were all pure, manufactured iron oxide pig- hastened somewhat by adding one-half pint of liquid merits containing more than 95 per cent iron oxide my weight. The chrome green was a so-called C. P. Igreen consisting entirely of chrome yellow and Prussian blue with no extending pigments. The paint drier to the above formulas. For dark brown stains it is practicable to substi tute creosote for the mineral spirits in the above formulas and thereby increase the amount of creo Vandyke brown was a natural earth pigment sote retained by the shingles. On che other hand, H The five stains used in the experiments had the if a browm color is desired it is possible to omit pfollowCinhgroCmoemgproeseintioinns:oil ...... ...........t.j pounds Boiled linseed -oil ............. ............. 67 gallon Mineral spirits........... .33 gallon Iron oxide red in oil................... ,1.5 pounds 2. Boiled linseed oil ........... 67 gallon pigments altogether, in which event the cold bath consists of exactly the same creosote used for the hot bath. Such treatment with creosote alone is safer than any of the stains suggested where maxi mum preservation against decay is more important Mineral spirits ................. ..................33 gallon Vandyke brown in oil......... 1,5 pounds Boiled linseed oil .....,....67 gallon Mineral" spirits ............................... 33 gailon . Ferrite yellow in" oil..... ......... 1.3 pounds Boiled linseed oil .......... . .67 gallon than bright colored shingles. Detailed description of hot and cold bath treat ment and other nonpressure treatments will be found in Farmers' Bulletin 744, "The Preservative Treatment of Farm Timbers," which may be ob tained from the Forest Products Laboratory, Mad Mineral spirits ............................ .33 gallon ison 5, Wis., on request ;. Iron oxide yellow in oil......... .. 1.0 pound "Oh, I don't know," sniffed the smrel^ep^"He '"'The traveling man's eyes bulged when he entered isn't so smart. I beat him thejagsrisftregames." a small general store in a distant community and saw a dog, seated-in a chair, pushing discs about on Scratiget>-^Tnoticed your advertisement in the i a b"oYaordu wmietahnhtios tferollrimFpea,"whse. lSquited incredulously, paperTms morning for a man to retail imported "that your dog is playing checkers?paper^this tnooimg .... _ "`SWurhey,", rmepalnie, ddtoheyopuropkrnieotwor, w"hIalet aymqepdiv^thri^nrVolf->^-c'c~aa^nnPaarroiieepsr.i'"e' tor of Bird Store: "Yes sir. Are you lookProprietor m .Un*u ------- tvhaeured?e"villaeskaendd thceleasnaleuspmaanf.or"tfYinoeu^ewoiuthlclagdoogintaos uxgS'tfrbar^gefotjTob~b?^?"4ju no; "I mere'ly- Uha~Ad a* 'c umriionsityv to know how the canSri^slose their tails." smart as that" colors-in-oil, boiled The colors-in-oil Page Fifty-nine I AMERICAN FEDERATION OF LABOR Page Sixty-one I page Sixty-two AB too ma reasonabl paint has failure takes p tion, as it oft] a complaint ar follows, in whi ufacture each the others or 1 her dealer, car cases a settlerr to some loss, ; paint fumishe tlement of sue) completely res the painter's c tant for the pa plaints from qi In addition I plaints are ms FLB 0009 ation treet ag 1606 SUCCESSFUL MAINTENANCE WITH WHITE T.EAn PAINT: Bouse 27 years old. Painted only four times, last time five years ago. Only a soft type of paint is suitable for swell long intervals between paintings. (House No. IS in Dr. Browne's experimental series.) How PcUntecs Co*. PeevcHt --- Nol m 1j 36 ay rci^> & Examining Condition of the Old Faint By F. L BROWNE First article in a new series by Dr. Browne, Senior Chemist of the Forest Products Laboratory, maintained at Madison, Wisconsin, by the Forest Service, If. S. Department of Agriculture, in cooperation with the University of Wisconsin. ONSIN RATION OF LABOR FARreatosoonmabalyny jobs of durable house painting fail to give service, even .though good paint has been applied by honest painters. When .failure takes place 'within a year or two after applica tion, as it often does, the house owner generally makes complaint and asks for redress. An argument usually 'follows, in which painter, paint dealer and paint man ufacture each try to pass the responsibility to one of the others or to some other interest, such as the lum ber dealer, carpenter or general contractor. In many cases a settlement is made, in which the painter is put to some loss, perhaps for the labor of applying new paint furnished by the manufacturer. While just set tlement of such complaints is important, no settlement completely restores the house owner's confidence in the painter's craftsmanship. It is much more impor tant for the painter to learn how to prevent such com plaints from occurring at all. In addition to these early failures about which com plaints are made, there are many jobs that last long 10 enough to keep the house owner from complaining, but not long enough to keep him from feeling dissat isfied. In the aggregate, the proportion of unsatisfac tory paint jobs is large enough to seriously undermine public confidence in paint and painters and to lead many house builders to use Unpainted materials merely to avoid the uncertainties of painting exterior wood work. Painters, therefore, are vitally concerned with the problem of reducing the number of unsatisfactory ^paint jobs in order to safeguard the future of the painting business. If the painter is to take any steps at all toward pro tecting himself and his customer against early paint failures he must take them before the new paint is applied. For that reason the preliminary examina tion of a house for estimating should consider much more than the matters of how much paint and labor Will be required for the job. The painter should use this opportunity to learn as much as he can about the previous history of the house with respect to paint and National Painters Magazine N41698.27 FLB 00091 Q'lahonal PAINTERS MAGAZINE PAINTING AND DECORATING 12 Gold Street * New York MARCH, 1936 What Painting Industry Wants: An End to federal Competition and Recognition of Responsible Contractors HAT the painting industry -wants, as htecated by action taken at the fifty-second annual convention of the International Society of MastersNpainters and Decorators, Inc.: An end to Federal competition with various unite of ,uie Construction Industry--of which painting 1: is one of the largest--because it is a menac/to private enterprise.. .and that steps be taken by the government to restore confidence by utilizationsnf fiorinal, private channels of construction. SUCCESS House 6II Paint B in 1927, e painting long peri up and i) An end to "the threat of pending legislation which would further undermine the Construction In 2: dustry. ,." / A continuation of Title I of the Federal Houffing Ac\for one year, because "it has been of such 3: benefit to the painting and decorating industry.' 4; A continuation of intensive publicity and advertising, so that home and property owners may be made aware of the dangers of paint neglect/.and of the economic wisdom of using competent and reliable contractors, skilled mechanics' and quality material/, .and so that they may be informed of the payment out of income plans/now available for painting and decorating jobs. 5: A restoration of "the painting business into the hands of the painting contractor and profit into the painting job".. .A stronger organization. . .A continuation of the Study of the License Law question for the benefit of those states/desiring such type of legislation./Cooperation with allied trade groups . . . Cooperation with /abor. Development of the League / Master Decorators "to provide for its spVsors the benefits of a well6: rounded decorative service:" / Gordon Marshall Na/iied President j CONVENING in the Palme/ House, Chicago, on Feb ruary 18, with President John B. Dewar, of Pitts burgh, in the chair, allphases of business, technical and artistic problems/were handled in the four-day convention, which ele/ted Gordon P. Marshall, of Bos ton, to succeed Mr. J0ewar. Mr. Marshall is head of the H. Newton Marshall Company, nationally known paint ing contractors, formerly was a member of the code authorities of both the painting and the construc tion Industrie/ and has been representative of the Internationa/m the Construction League of the United States. Hi/study and work in behalf of the industry have won/him recognition throughout the country. Threp/Vice-Presidents were chosen--Henry Atman of Continued on Page 36 March 1036 Mr. Marshall's Find Message TO ALL PAINTING CONTRACTORS: D O YOU know that every hour of the day a great organization is working to protecVyour individual interests and to advance the business of painting and decorating through which you earn your Do you know of its efforts to show the putoc, through advertising and publicity, that the maximum, economy and value in preserving and beautifying property comes by employing expert painting contract Do you know of its fight to end government c< tition with your business, of its battle to stop pa on public works by the day labor method, and of success in having millions of dollars of painting shifted to the contract method, with open bidding? Continued on Page 34 to searc unsatisf: choosing while fo tions bei painter develops It sho tice of p that lea factors paint m that ms mainter paint b; results cannot often is knows i of coats position The i questioi often si prepara an adec princip; prising pends i someth painter nate th s part of | of pain In hi Mar FLB 000915 Ml 0P&YJ6I ii - . ';! . j- ---A *I " > - \ v , ,; t * I* 'm Illlill mm Gordon p. m lr ' P *'.*.* i convention h painting ken by the n. notion In- n of such y be made etent and informed t into the 7 question led trade of a well- J .ay a great individual .luting and ing? ic, through , economy property ctoi nt col p paintHs and of ng shifted1 J* ,,V VCCESSFVL MAINTENANCE WITH HARD PAINTS: rome built in 1921. Painted with two coats of white lead aint. Repainted with one coat of titanium and zinc paint in 1927, again in 1921. Photos taken in 1935 just before re painting again. Hard paints can be maintained well for b ng periods if repainting is done before old coating breaks Up and if only necessary amount is applied. (House No. 19.J to search carefully for conditions that might lead to unsatisfactory, service of the new job or guide him in choosing the/proper type of paint. It is also well worth while for him to keep a written record of his observa tions, because a record made beforehand may place the painter in a very advantageous position if difficulty develops later. It should constantly be borne in mind that the prac tice of painting suffers from a division of responsibility Uiat leaves no one in a position to control all of the factors upon which successful results depend. The paint mauufactttrer cannot as yet make any one paint that may be used safely on all surfaces and for all maintenance programs. The painter can ruin any paint by faulty application and can often obtain good lesuits with poor paint by skillful application, but he cannot determine when the surface is to be repainted; often is not permitted to prepare the surface as he kuqws it should be or to apply the necessary number 'Of coats, and is often asked to apply paints whose com position and properties he does not know thoroughly. The customer usually decides the very important question of when the surface shall be repainted, and often sets cost limitations that determine how much preparatory work can be done. Since there is-rarely a a adequate meeting of minds on the part of the three principal interests in a specific paint job, it is not sur prising that the cooperation upon which success de pends is often lacking, and the outcome is therefore something of a gamble. Of the three interests, the Painter is in the best position to reduce or even elimi nate the gamble, but the most difficult and important part of his work to that end comes before a brushful o E paint is applied to the job. In his first survey of a paint job,the painter should ^1 V. oil '1 ' *. ` r, -1 gather as much information as possible about these three subjects; First, the past history of the house with respect to painting. Second, the owner's ideas of good paint service. Third, the present condition of the surfaces to be painted. Knowledge about these three subjects is essential for proper planning of the new job. Past History of the Job From the past history of the job the painter needs to learn the kinds of paint used previously, how long they lasted, and how they failed or wore out. This infor mation is needed to determine whether the house is one on which paint behaves normally or abnormally, how long the owner expects to wait between paint jobs, and what sort of paint may be used safely for the new job. If there are signs of abnormal paint behavior, the cause of it must he investigated before a conscien tious painter can afford to accept the job. Very often the owner does not know what kind of paint was used previously or, still worse, he may report it incorrectly either from mistaken memory or because the previous painter misinformed him. A very common cause of misunderstanding arises from the loose use of the term "white lead paint" or "lead and oil paint." These terms should mean only linseed oil paint. In which the pigment consists entirely of basic carbonate or basic sulfate white lead, except for such added tint ing colors as may be necessary to provide the desired color. They should not be used when there is zinc oxide, whether added by the paint manufacturer or by the painter. March 1936 11 ../l RESULTS OF REPEATED NEGLECT OF HARD PAINTS: OH farm bunding painted many times, always with paints of fairly litted type, "bet each, time the old coating woe al lowed to flake badly before new paint was applied. Good paints have always been used by good painters, but for this type of maintenance program Only a soft paint like white lead pi/iint is suitable. (House No. 15.) Unfortunately, some persons use the term "lead and oil" to describe any paste paint that is reduced for application by the painter, and others apply the term "white lead paint" to any paint that contains an ap preciable amount of white lead. For these reasons the painter should accept the owner's statement of the composition of the previous paints, only subject to confirmation by his own inspection of the job. Owner's Ideas of Paint Service Too often the painter forgets that it is the owner who mast be satisfied by the paint job, and the paint therefore should be the kind the .owner likes, rather than the kind the painter likes. What the owner really wants is best determined by what it was that led him to have the house repainted and what qualities of the old paint he recalls with favor or disfavor. Very often the owner thinks that there is somewhere a magic paint that has an the merits he wishes and none of the disadvantages to which he objects. The painter knows that no such paint exists. If paint is to be selected for the best possible appear ance during its early life, it must usually be a paint that requires repainting before It' begins to break up badly. If the owner wishes to be free to repaint when it is convenient, even though the surface may remain neglected for some time, he may have to be content with less satisfactory appearance during the early life of the job. The paints used previously may set limita tions on the kinds of paint suitable for the new Job. A clear understanding of the extent to which the owner must he responsible for. Important decisions should be reached before the job is undertaken. \ 12 It is not possible to analyse an old paint merely by looking at it, of course, but enough can usually be teamed by careful Inspection to tell the general class of paints to which it belongs, to check the owner's statement of its composition or brand and, if its age can be established approximately, to determine whether Paint behaves normally or abnormally on the house. To do so the pointer must team to recognize the characteristic normal behavior of the different types of paint on the market. Whenever a paint falls to follow its normal course of behavior or passes through it too quickly there are abnormal conditions to be discovered and rectified before new paint of any kind can be expected to give its customary service. The nature of the abnormal paint behavior often suggests the cause of the diffi culty. In some cases the necessary corrective measures can be taken. In others correction may be difficult or impracticable or the owner may be unwilling to make it, but in any case the painter who knows how to make the old paint tell its own story, and takes the owner fully into his confidence in the matter before he accepts the job, will rarely find his good name jeopardized by complaint about unsatisfactory service of his jobs. In a subsequent article the writer wifi dismiss more specifically the sort of Information the painter should collect during his preliminary* survey of a prospective job and how to use it in planning his work. The dis cussion will make use of the illustrations of houses involving paint difficulties that appear in this issue and to the issues of April, May and June, 1935. II If :j :|f Ill jI WHY HARD PAINTS MUST BE REPAINTED BEFORE THEY FLAKE BADLY: This house was repainted less than a pear ego bat the previous paint, of a hard type, had been allowed to flake badly before repainting. Surface was thor oughly wire-brushed, but new coating is not smooth and is already beginning to crack. It win flake again much too soon. (House No. li.) Ke National Painters Magazine aspects of the uses tl operation 1 1. It is . for repaint the surface it will be ' of that fact should be e first time a 2. The p; list from v which pros] manufactur paints to p afford to co 3. Evenjt ful may pro customer wl the work ci painter's ad point out tv the March, FLB 00091 1 paint merely by h can usually be the general class hech the owner's id and, if its age r, to determine .bnprmally on the earn to recognise of the different its normhl course quickly there are red and rectified < expected to give of the abnormal luse of the difflrrective measures lay be difficult or nwilling to make tows how to make takes the owner ratter before he good name jeopaetory service of wifi discuss more le painter should of a prospective s work. The disations of houses jar In this issue Tune, 1935. UNTED BEFORE epaimted less than vrd type, had been Surface toss thornot smooth and is e again much too How PcUntecf Cut Pcevmt Keeping A Written Record of All Painting Jobs By F. L. BROWNE Second article in d new series by Dr. Browne, Senior Chemist of the Forest Products Laboratory, maintained at Madison, Wisconsin, by the Forest Service, V. S. Department of Agriculture, in cooperation with the University of Wisconsin. AFILE containing an adequate written record of the painting history of all jobs on which he bids can be of great help to a painter in several aspects of his business. The following are some of the uses that can be made of it once it has been in operation long enough to serve its purposes: 1. It is an ideal prospect list for future contracts for repainting. The painter knows beforehand when the surfaces should be due for more paint and when it will be worth while for him to remind the owner of that fact. Those jobs that he won in the first place should be easy to win again and those that he lost the first time are still worth another attempt, 2. The painter's successful jobs make a convenient list from which to select examples of his work to which prospective customers can be referred. Paint manufacturers are using houses painted with their paints to promote their sales and painters can well afford to copy their example. 3. Even jobs on which the painters' hid is unsuccess ful may prove useful at times. When, for example, a customer whose house is due for repainting feels that the work can be put off a year or two longer the painter's advice will be far more effective if he can point out two or three houses, like Nos. 14 and 15 in the March, 1936, issue of National Painters Magazine, to on which paint of the kind in question has been neglected too long. Moreover the painter will soon find that the practice of studying the history of paint jobs wherever possible will greatly increase his own knowledge of paint and explain many things that previously seemed unaccountable. 4. If subsequent difficulty..arises with a paint ;job for which the painter made an adequate record the recofd may establish the sincerity of the painter's explanation by showing'that his opinion-is not a mere excuse invented after the difficulty arose. Very often the owner has forgotten that the previous paint blistered and scaled, for example, hut the painter's record made before he took the job may well Settle that part of the dispute; The items to be included in recording the painting history of a house can be explained to best advantage by considering some of the houses already illustrated in this series of articles. As a rule the record should be made while going over the job to prepare cost estimates but we are not concerned here with the problems of estimating. Let us suppose that the painter is preparing to bid for repainting House No. 19, on page 11 of the March, 1936, issue. This is an unusually simple example because the owner Is able to furnish all the necessary details accurately. Ficti- National Painters Magazine N41698.28 FLB 00091 spfc Q^aitonal PAINTERS MAGAZINE FAINTING AND DECORATING 12 Gold Stroet Now York APRIL, 1936 msm Typical paint exhibit in oner of the- FHA National Horn Shows which are being heldAhroughout the land and whlq ore developing much business under provisions of Title of the Housing Act. \,FHA Trtle Aid to Painting, Is Extended EXTENSION for another yeaX of the Federal Hous ing Administration's prograri\of financing paint ing, repairing and remodeling of homes and business properties was approved bysCongress in an eleventh-hour action. This program, Title I of the Federal housing Act, would have expired April 1, but a bill extending it for another full year was agreed upon by both Senate and House March 31 and rushed to President Roosevelt for his signature. The FHA immediately annou that its rules and regulations under this title will tinue in effect except for the necessary changes. Loans for Flood Victims Extension of Title I will be good news for home owners in the areas which were devastated by floods, and for painting contractors as well, inasmuo as loans under its terms will be available to victims of the flooded rivers. The houses were damaged/not destroyed, and therefore are eligible risks. Paint, new foundations, new roofs, replacements, practiaally all major destruction wrought by the floods can be re paired under the terms of Title I. (.Congress is now considering measures to permit banks and other lending agencies to make insured loans in the flooded areas on special terms, but final action has not yet been taken.) An interesting national broadcast on Title I as amended and extended was glverr on April 7 over the NBC network by L. R. Gignilliay deputy administrator of the FHA, and Ernest T. Trjgg, president of the Na tional Paint, Varnish and llacquer Association. The broadcast was in the lornt of questions and answers and among the highlights brought out by Mr. Trigg and Mr. Gignilliat, are the following: 1. FHA has insured almost a million different loans under title one, amounting to $327,000,000. 2. It has been estimated that the total value of con struction work stimulated by FHA, activated under title one, is about $1,500,000,000. 3. The/changes made in the law are based on the experiences of the FHA during the year and a half of operation. Basically the Same Law 4. The most important conditions of the law remain rthe same. Eligible borrowers can still borrow up to 10 to Improve homes and farms and other types iroperty and up to $50,000 for improvements to special types of property, such as manufacturing and industrial plants, stores and shops and so forth. Borrowers still have as long as five years to pay and the charges hsr these loans still cannot exceed a set maxi mum established by our regulations. 5. One new thing is that loans can be made only for improvements on property on which there is a completed structure. You cannot build a new home as you could under the original Title I. New construc tion is provided for in the Insured Single Mortgage System of the Federal Housing Administration, which is a long term program and which was not affected by the new legislation. 6. To be eligible for a niodernization credit loan, you must either own the property, or you must hold a lease on it running for at least sixunonths longer than does the loan itself. A person with a short term lease is not eligible for modernization credit.' Continued on Pam 52 /Join Fight on "Jerry Builders" and "Paint Pot Jobbers" Help the Federal Housing Administration, the construction industry--and yourself--by joining in the fight againJt "Jerry Builders," those racketeers who use poor materials and unscrupulous iqethods. Warnings/are being posted all through the country. The FHA, aroused by reports of the activities of "Jerry Builders" now that there is an upturn in residential building, urges all persons using the Mohqrnizatior/Credit Plan or the Mutual Mortgage Insurance Plan to "give careful scrutiny to all bids for wbpk subimtted to them by contractors and builders"----- To that official warning should be added a denunc tiofi of the "Paint Pot Jobber," the man who poses as a painting contractor and who uses the same chisel-> iilg tactics to defraud the American home owner and to cheat legitimate contractors out of their busi ness. Responsible painting and decorating contractors can be of great service to their country, their communities and themselves by helping in the fight against this type of racketeering. April 1936 0 tious n for obv Owner: Jai Addrea 123 City: M? House Fa Materi Cy pone stair Ap ON OPPOSITE PAGE: House No. 19 in Dr. Browne's series of tests, discussed in his articles in this and last month's issue. ON THIS PAGE: House No. 16--A Typical Moisture Failure. This house was erected and the painting completed in February, 1929. Repainted in the sum mer of 1930 following failure of the first job. Photo graph taken in the summer of 1931. tious names and addresses are used In the discussion for obvious reasons. A Typical Painting History Owner:' James R. Black. Address: 123 E. Belmont St. City: Mytown. INFORMATION SUPPLIED BY OWNER: House Erected: Fall of 1923 to spring of 1924. Materials Painted: Cypress siding, redwood and ponderosa pine trim, ponderosa pine doors and windows, southern pine stair treads and porch floor at kitchen entrance, April 1936 galvanized iron gutters and downspouts, sheet metal porch roofs and flashing, iron screen wire. Initial Painting: Two coats of lead and oil on siding, trim, doors and windows except screen door leading to roof over sun parlor, which had two coats of spar varnish. Stair treads and porch floor at kitchen entrance, two coats of lead and spar varnish tinted gray. Gut ters and downspouts, two coats lead and oil. Metal roofs and flashing, two coats of iron oxide paint with spar varnish, screen wire painted with black enamel by manufacturer. % Repainting: In September, 1927. Siding, trim, windows, doors, gutters and downspouts painted with one coat of Brand A semi-paste paint thinned with one quart of linseed oil and one quart of turpentine per gallon and applied at 550 square feet per gallon. Brand A contained 70 percent pigment, composed of 70 per cent titanium, 20 percent zinc' oxide, 10 percent asbestine, and the liquid consisted of 90 percent lin seed oil and 10 percent thinner and drier. Stair treads and porch floor at kitchen entrance painted 11 FLB 000920 with Brand B long-oil enamel with iron oxide red Preparation of Surfaces: pigment. Metal roofs and flashing painted with Remove; entire coating from screen door to porch Brand C iron oxide red linseed oil paint. Screen roof. Scrape off all loose paint from gutters and I wire painted with zinc dust and zinc oxide paint. downspouts, clear to metal wherever possible. Wire In June, 1931. Siding, trim, windows, doors, gutters brush loose paint from overhanging eaves on north and downspouts painted with one coat of Brand D and west sides and Wash these surfaces with water prepared paint applied at 600 square feet per gallon. containing trisodium phosphate to remove all dirt This paint contained 60.9 percent pigment, composed and reduce the gloss as much as possible. Scrape of 60 percent titanium, 30 percent zinc oxide, and 10 off ail loose .paint at junction of bailuster members percent asbestine and the liquid consisted of 81 per with lower stringers of porch rails. cent linseed oil and 19 percent turpentine and drier. Stair treads and porch floor at kitchen entrance, Repainting: metal roofs and flashing, and screen wire painted Give gutters and downspouts a priming coat of with the same paints used in 1927. red lead paint and two coats of white piant. Spot- prime the bare wood where loose paint has been OWNER'S OPINION OP PREVIOUS JOBS: The initial job became too gray with dirt and the change to titanium-type paint was made to get maximum whiteness. The 1927 Job was satisfactory everywhere except on the screen door leading to the porch roof, which was previously varnished. Here the paint crackled and scaled rather badly and is doing so again. He plans definitely to have one coat of paint applied every four years. removed on bailuster members of porch rails, using the white paint without thinning with either oil or turpentine. Prime the door leading to sun parlor roof with lead and oil priming paint applied at 600 square feet per gallon. Then give all white wood work one coat of white paint at 600 square feet per gallon except under overhanging eaves, where the least amount of paint that will hide properly should be applied- The white paint proposed is Brand E (the paint most similar to the previous paints that i 1 He is available from the painter's usual source of sup PAINTER'S INSPECTION: ply) . It is a prepared paint containing 65 percent I August 1, 1935. The appearance of the paint on the major sur faces is entirely consistent with the owner's report pigment, composed of 40 percent titanium, 30 per cent white lead, 22 percent zinc oxide, 8 percent asbestine, and the liquid consisting of 87 percent linseed oil and 13 percent thinner and drier. Give of the painting history. The white paint is chalking stair treads and porch floor at kitchen entrance one freely on ail surfaces except the under side of the coat of Brand B iron oxide red long-oil enamel, overhanging eaves, where it is still glossy on north, metal roofs and flashing one Coat of Brand C iron east and west sides. The chalk has the appearance oxide red linseed oil paint and screen wire, one characteristic of titanium pigments and when wiped coat of zinc dust and zinc oxide paint. off reveals a smooth, glossy film of paint. The paint on north, east and West sides is entirely free from .Checking or cracking except under overhanging eaves noted below. On the most exposed parts of \ Wallpaper Hides Ugly Switches the south side cracking is just beginning. Paint on galvanized iron gutters and downspouts cracking and scaling fairly badly, On all important surfaces the paint behaves normally for paint of this type, giving no indication of abnormal moisture condi tions, incompatible paints, or poor workmanshp. sSKLzsva BBfc-' Abnormal Paint Conditions: Screen door leading to porch roof shows results of incompatibility in painting, evidently due fo painting over spar varnish in 1927. Bailuster mem bers of rails around porch roofs show cracking and 'sealing, at the junctions 'With the lower stringers of the rails; this is due to moisture seeping into these joints. In a few cases the nails have corroded and left the member loose. One stringer of steps at kitchen entrance has decayed where it rests on the ground although the paint is still intact on it. There is some cracking and scaling of the last coat only on the under side of overhanging eaves on north and west sides, apparently due to the fact that the pre vious paint was still glossy when repainted in 1931. PAINTER'S RECOMMENDATIONS: Preliminary Carpenter Work: '; Have rotten stringer in back steps replaced and renail loose bailuster members of rails around porch roofs, using corrosion-resistant nails. .W. HP" We are indebted to Frank Crdss, of the E. J. Cross Company, Worcester, Mass., for this illustration show ing the manner in which his company overcomes the ugliness of the common Electric switch plate by the use of wallpaper. Even/after the plath\is papered it is removable and washable as the paper wylaeed. It is important in using thus method to make sate that all lacquer is remoped from the switch ple,t\befgre papering. Ther screw heads and switch butthn are stippled, in co/Cyrs to blend vfith the paper. Note that a masked/plate is slightly discernible in the wfme circle tojthe left of the ordinarily exposed switch. This! treatment made quite an impression in the exhibit at the Annual convention of the Massachusetts Society, of which Mr. Cross is president. ers had tim< are ofte his forn 1935 of fi judg 1935 don clea ally ThC and of t werj con 12 National Painters Magazine FLB 000921 3en door to porch from gutters and er possible. Wire tg eaves on north rfaces with water a remove all dirt possible. Scrape talluster members priming coat of rite plant. spoti paint has been porch rails, using with either oil or ag to sun parlor nt applied at SOO all white wood0 square feet per eaves, where the e properly should 'Osed is Brand E rious paints that U source of sup ining 65 percent itanium, 30 per oxide, 8 percent g of 87 percent and drier. Give ten entrance one long-oil enamel, of Brand C iron creen wire, one lint. witches Figure 1.--The cheeking characteristic of pure white lead paint under normal circumstances. The areas shown in 1A and IB are U, by % inch in size, the area shown in 1C is 3 inches by 3 inches in size. An early stage of checking is shown in 1A, a much later stage in IB and 1C. How Painter* Can Prevent No 3 Nature of Previous Paint Coats By Inspection By F. L. BROWNE Third article in a new series by Dr. Browne, Senior Chemist of the Foi-est Products Laboratory, maintained at Madison, Wisconsin, by the Forest Service, U. S. Department of Agriculture, in cooperation with the University of Wisconsin overcomes the plate by the \is papered it ihylazed. It is se sutethat all i plai&sbefore ch button are per. Note that in the whh id switch. Thit\ the exhibit at .usetts Society, 's Magazine IT was a simple matter for the painter to collect the record of the painting history of House Ho. 19, as discussed in last montbfs issue of National Paint ers Magazine, because the owner knew exactly what had been done and what paints were used from the time the house was built. Unfortunately, most owners are unable to supply such reliable information. Very often the owner makes erroneous statements, because his memory is inaccurate or because he was misin formed. Some of the houses discussed in the dune, 1935, issue of National Painters Magazine are typical of the need for critical consideration and independent judgment in recording painting histories. When the writer first inspected House No. 8 (June. 1935, issue) the owner insisted that both the original paint job in 1929-1930 and the repainting in 1933 were done with pure white lead paint, because the contracts clearly so specified. He also said that he had person ally seen the painter break down the paste White lead. The painter likewise maintained that he had used "lead and oil" The checking pattern of the 1933 paint and of the 1930 paint where it was revealed by scaling of the later paint showed at once that both paints were of harder types than white lead paint. When confronted with this evidence the painter told the 18 true story as it has already been described. He had violated his contract in the sincere belief that the quick-drying paint he attempted to use, which was more expensive than lead and oil, would give a better job; but, unfortunately, it did not, and he was left in a legally indefensible position. The owners of houses No. 10 and No. 12 (see June, 1935, issue) did not know the nature of the paints used when the writer made his first inspections. Prom the typical behavior of the paints, however, it was possible to determine the kinds of paint involved fairly closely. Subsequent inquiries through the painters and paint manufacturers fully confirmed the conclusions reached. Studying Paint Behavior In order to guard against misleading information and to supply information where it would otherwise be lacking, the painter must be able to tell as much as possible about paint composition from experience in watching paints of known composition as they pass through the various changes that take place during the useful life. The painter should remember, how ever, that experience is not measured by the number of years of Work at the craft, but by the number of National Painters Magazine N41698.29 FLB 00092: larmomzing ir Plans MANTEL.PIECE-WOOD nka BAY WINDOW Old Furniture One of our readers recently asked us\to furnish him with a complete color scheme far the lower floor and one bedroom in a house a year and a ludj old, with plastered walls and ceilings which had never been decorated. The owners wanted a modern scheme and something a little different. The reader supplied us with a diagram, which our artist has visualized in a sectional view, together with a statement of the colors of the furniture and wood work which could not be changed. Re wanted a' scheme to harmonize with the following: LIVING BOOM: woodwork B. C. fir, stained light oak, highly polished. Oak floor, natural finish with one-inch dark wood border two feet from, s wall. Furniture upholstered blue and faur y Hearth rug blue and faun. DINING ROOM: Woodwork and floor samf as dining room, without border. Furniture/dark oak. Hearth rug blue and foam. Carpet deep red and blue, / BEDROOM: Furniture dark oak. Ceiling has oneinch molding six inches from wall. AThis mold ing also in living room, dining room and hall.) This inquiry has been answered by/Carl H. Dabelstein, one of our Associate Editors and a well-known New York decorator. Mr. Dabelsteim's suggestions are given herewith: By CARL H/DABELSTEIN IN the living roorpi, as we understand It, the wood work is the e&lor of light oak, the floor is the same color,/and the* predominating color of the furniture is bMe. With natural finish wood contrast ing colors ape most suitable to set off the furniture and make/me most pleasing background. The blue of the carpet and the blue of the furniture make it difficuy/ to offer many suggestions, as the natural finish/woodwork will lend itself to but one color that wilj/not offend the blue, and that is an antique leather , or a tobacco brown plain or mottled. Green May 1936 would be ideaf with the woodwork, but out of the question withr the furniture and carpet. Blue of a dark shade/woutd also go with the woodwork, but would noyoffer sufficient contrast as a background for the furniture. You say your client desires some thing modern. If that is the case, why not paint over the woodwork and make the entire room oyster white, whicl* is very popular at present and makes an ele gant background for your furniture. ae dining room, we understand, is the same as the [iving room, only that the carpet Is of red and blue, probably an Oriental design, and the frames of the ftrniture, we believe, are dark oak. If you wish to paint this room, we can only suggest that you employ about the same effect as suggested for the living ropm, as theycolor effects of the furnishings are the same, with the exception of a little red in the carpet and the dark\furaiture frames. This wifi give you an additional opportunity to paint the walls red of deep color, like antique leather. You state there is a molding around the room, which we take'to mean a cornice between fee wall and ceiling. This cornice could be painted and grained like fee woodwork, and then a ceiling of an old yellow color willSgive a very stunning effect. If, however, you wish to\use One of the modern scenic papers for the walls, you can avail yourself of an en tirely different effect anav.have more latitude to carry out a scheme that will bevlighter in color and more desirable, and in line with modem type of dining room. You do not mention the kitcliksn, but we wish to call to your attention that color here\js just as necessary, and it should not be overlooked. HrpreviouB issues of National Painters Magazine the possibilities a kitchen offers have been discussed in detail. You give no details regarding fee haH except feat it has a cornice at the ceiling. As therAjs so much blue in the furnishing of fee first floor it mMit be well to do the hall in a light color, and We would, suggest a paper of a foliage type on fee wall in a gray or sepia color, and carry out fee woodwork light like the ground of the paper, excepting fee treads of the sufes and the handrail which should be natural wood, however, you wish to paint the hall, you can paint it in a yellow and white effect, which will go very well' Continued on Page 49 17 & off fell not gra mo: typ me; ani; pai FLB 000923 tit out of the | | it. Blue of a || ropdwork, but I | a background j I desires some- | | aot paint over | | i oyster white, I nakes an ele- e same as the red and blue, tames of the you wish to it you employ e living room, ire the same, .e carpet and give you an s red of deep ;g ! .s ;p is ;[ ps d the room, een the wall painted and p ceiling of an tg effect. If, | odern scenic \ elf of an en- < f,; ;ude to carry | \ or and more ] rpe of dining f useful things seen, understood, and effectively remem bered. More than once the writer has had to show a painter who has worked with it for years that pure white lead paint under normal conditions of exposure develops checking comparatively early |n its life. Few men enjoy such excellent opportunities for learning how paints behave as does the painter, but he cannot learn without definitely setting out to do so.. This article is not intended as a substitute for obser vations that the painter must make for himself:among the paint jobs for which he has or can obtain the his tories, but, rather, as a suggestion of the kinds of in formation that a paint gives about its own composition to those who learn by careful study how to interpret it. When freshly applied there are very few features to distinguish different kinds of paint. Color, of course, serves to identify most of the paints made from col ored pigments from the white or tinted white paints. From his experience In tinting paints and his knowl edge of the' colors in oil the painter should be able to recognize the paints made With little or no white pig ment and to tell a good deal about the principal pig ments from which they are made. , Most of the white and tinted white paints, however, look pretty much alike at this early age,- "Enamelized" paints--that is, paints made with much varnish or highly bodied oils-- usually reveal their nature in a complete freedom from brush marks, a tightly drawn skin effect, a tendency to "curtains" at thick spots or formation of beads at tbe lower edge of boards, inability to fill cracks and other blemishes in the surface, exaggeration of planer marks or. raised grain in the wood or checking or patches of flaked areas in the previous paint, and a brilliant gloss. House paints ; made with linseed or similar drying oils exhibit opposite properties. Appearances of Crime As time passes, all paints tend to collect a gray film of grime, but certain differences in the appearance of this grime, recognizable to the experienced eye but not readily described in words or shown by photo graphs, usually establish slight difference between the more Important softer types of paint and the harder types of paint. With further ageing the next develop ments are usually loss of gloss, beginning of chalking, and fading of tints. Soft paints like pure white.lead paint generally shed most of the gray grime rather promptly after chalking-sets in, but paints hardened with, zinc oxide or varnish are likely to retain the grime for a relatively long time, even after chalking starts. On the other hand, hard paints that chalk strongly on the surface, such as typical titanium pig ment paints, may shed their grime quickly, and nearly completely leaving a bright matte appearance that is quite characteristic to one who has learned to recog nize it. By tar the most significant developments for distin guishing the different types of paint are the fissures and subsequent break-up of the coating that come at later age and are usually , well developed before the owner is ready to consider repainting. With soft types of paint like pure white lead paint, checking begins rather early in life, usually Well within two years on surfaces exposed to sunshine. It rapidly assumes a reticulate or interwoven pattern, as shown in Figure 1. Figure 14 shows an early stage of checking, IB and "l,C a late, stage, when 'the surface,may be- considered by some owners to he ready-for repainting; 1A and IB are views as seen through a good magnifying glass, 1C as seen by the unaided eye. The meshes formed by the interweaving fissures are about as high as they are wide, and: the pattern suggests polygons with more than four sides rather than square or rectangles. At the stage represented by. Figure IB the fissures are very, deep, eventually extending through to the wood .beneath, and the coating is so soft that most of it is ' removed by a few strokes of a wire brush or" sand paper. The edges , of the fissures are rounded off and the fissures have a cross-section like a letter V with a wide spread at the top. identification of Fissures . When paints are hardened by. addition of zinc oxide the development of checking is profoundly modified. To begin with, the checking does not appear until a somewhat later age, and it takes much longer to pro gress from a few scattered fissures, mostly parallel to the last strokes of the paint brush, to a reticulate pat tern in which the fissures become interwoven. Figure 2 (2A as seen by the unaided eye, 2B with a magnifying glass) represents the checking of a moderately hard paint at the same age as the checking of soft paint shown in Figure IB and 1C. In Figure 2 the fissures roughly parallel to the brush strokes are Figure 2.--The cheeking characteristic of a somewhat harder type of paint than pure white lead. The paint shown was ntade with lithopone and leaded zinc oxide Uhseed OH. - The area shown in. U is 3 inches hy 3 inches in size; the area shown tri- 2B is tt-inch by inch ip. sine. 2A 2B t wish to eall ' as necessary, fc .Otis issues of * ies a kitchen ft except that so much it be well pule! suggest n a gray or ight lit of the stairs il wood, can paint go very well' H, Figure 3.--The checking characteristic of paint slightly harder than the one shown in Figure 2. This paint was made with basic carbonate white lead, zinc oxide, and linseed oil. The area shown in 3A is 3 inches by 3 inches in size; the area shown in 3B is U, inch by % inch in size. deeper and more conspicuous than the connecting fissures that form the interwoven pattern, which de veloped later. All the fissures have sharper edges and are less V-shaped in cross-section than those of Figure IB. The meshes formed by the interweaving fissures are usually wider than they are high, and suggest rec tangles rather than polygons of more than four sides. The harder paint also resists the action of a wire brush or sandpaper much more effectively than the softer one. A still greater degree of hardness attained by adding zinc oxide is represented by the paint shown in Figure 3, photographed at the same age as the paints of Figures IB, 1C, and 2. In Figure 3 the checking devel oped less rapidly and is still in the "parallel" stage, but later it will become reticulate. At the stage shown in Figure 3 the fissures run predominantly in a direc tion roughly parallel to the last strokes of the paint brush, but they do not follow the brush marks exactly or form exclusively in the hollows. Very hard types of paint, hardened either with zinc oxide or with varnish, may never develop checking, or, if they do, the checking is relatively unimportant and is greatly overshadowed by the appearance of an entirely different type of fissures; namely, cracking. In cracking, the fissures when first observed pass en tirely through the coating, while in checking, the fis sures are at first superficial and penetrate through the coating only after some further time has elapsed. Paints that do not develop checking at a fairly early age and are hard enough to have satisfactory dura bility eventually exhibit some form of cracking, al though by wise formulation and careful application the cracking can be deferred as far as the fifth year of full southern exposure. House No. 19, for example, showed neither checking nor cracking of the paint at the end of the fourth year. Sigmoid Cracking There is a type of cracking known as sigmoid crack ing, because the cracks, when first formed, generally have curving ends and suggest the letter S in shape. The longer cracks, which are the first ones formed, run parallel to the grain of the wood, but later they run at right angles to the grain of the wood. In the examples of reticulate checking, Figures 1 and 2, the dimensions of the meshes of interwoven 20 fissure remain fairly constant under all normal condi tions of exposure. There is greater variation in this respect in the parallel checking of Figure 3, but the range is perhaps of the order of three or four fold, and the pattern is nearly always small enough to require rather close inspection to see it clearly. In the sigmoid cracking, however, there is an enormous varia tion in the size of the cracks and the dimensions of the meshes with different paints and even with the same paint under different circumstances. The longest cracks in some cases extend one-eighth or one-quarter inch; in other cases, three or four inches, and in ex treme cases, three or four feet. For that reason in cracking the general shape and character of the fis sures are the significant points to observe, while in reticulate checking the dimensions of the meshes are significant, also. President Endorses Paint Up Campaign President Franklin D. Roosevelt, in a letter to R. W. Emerson, Executive Secretary of the National Clean Up and Paint Up Campaign Bureau, which annually inspires thousands of community Clean Up--Paint Up campaigns throughout the United States and in Canada and overseas, from its headquarters in Wash ington, has extended his personal appreciation of the service which is being rendered by the millions of vol unteer workers who at this season of the year are en gaged in an organized movement to make their home cities and communities cleaner, safer and more at tractive places to live in. The President wrote: "I am glad to express my personal appreciation to all those throughout the nation who are devoting their time and energy to a National Clean Up and Paint Up Campaign. "It is truly 'In the Public Service' when civicminded men and women in all parts of the country, in cooperation with interested national business groups, unite for the accomplishment of greater health and beauty in our homes and communities. It is a further expression of what we in America can do through united effort to improve living conditions and solidify our fundamental institutions. "After all, there is nothing that can replace that pride which comes from a clean and well-kept home and a well-developed and beautified community in which to live." National Painters Magazine H ir N the Such statec mixin that by cl pract amon cruml fissur They wood that more and cedai char abser edge tinue after In Figui painl it br tern but chei piece illust this this show flaki in F: pear Fi] mon The teris 3 ini mad ferer was in a FLB 0009! How PcJudm Can. Peeveat Pointing Comp&iuUs No-4 Judging Normal and Abnormal Conditions s paint was 3 inches in normal condiriation in this ure 3, but tide ! or four fold, all enough to dearly. In. the lormous variadimensions of even with the 4 '. The longest or one-quarter .es, and in ex>hat reason in ter of the fiserve, while in he meshes are campaign letter to R. W. fational Clean hieh annually Up--Paint Up tates and in :ters in Wasbsciation of the nillions of vole year are enfee their home and more at- wrote; ppreeiation to are devoting Clean TJp and ' when civicf the country, onal business it of greater communities, i America can ing conditions is. 0 replace that ell-kept home community in s Magazine By F. L. BROWNE Fourth and concluding article in a new series by Dr. Browne, Senior Chemist of the Forest Products Laboratory, maintained at Madison, Wisconsin, by the Forest Service, V. S. Department of Agriculture, in cooperation with the University of Wisconsin, THE checking of paints of the soft type illustrated in Figure 1 (published in last month's issue of National Painters Magazine) leads eventually to the crumbling shown in Figure 5 (published herewith). Such paints do not disintegrate by chalking, as is often stated, unless the painter made the serious blunder of mixing them with far too much linseed oil. It is true that paints can be made so soft that they disintegrate by chalking but such paints fail too quickly to be practicable house paints and are not represented among commercial house paints. In disintegration by crumbling the little "islands" cut off by the Interwoven fissures of the checking pattern fall off one by one. They fall off sooner over the hard bands of summerwood than over the soft bands of springwood and for that reason disintegration sets in sooner and develops more rapidly on heavy woods like southern yellow pine and Douglas fir than on light Woods like redwood, red cedar,, eypress, and white pine. The most significant characteristic of the crumbling of soft paints is the absence of cracking and the absence of curling at the edges of the cracks. For that reason soft paints con tinue to offer suitable foundations for repainting even after crumbling has continued for a long time. In harder paints disintegration proceeds by flaking. Figure 4, which differs from crumbling in that the paint curls upward at the edges of the fissures before it breaks off. Sometimes the flaking follows the pat tern of checking fairly closely as shown in Figure 4 but more often cracking develops independently of checking and leads to curling and flaking in larger pieces as illustrated in the photomicrograph in the illustration of House No. 2 in the April, 1935, issue of this magazine. The magnification is not so great in this photomicrograph of House No. 2 and the area shown is about Vs inch in diameter. Curling and flaking developing from sigmoid cracking are shown in Figure 6B. (A description of sigmoid cracking ap peared in last week's article.) Figures 1 to 6 (Figures 1, 2 and 3 published last month) illustrate initial paint jobs on new wood under FIGURE e The sigmoid cracking and later curling and flaking charac teristic of very hard types of paint. Each, area shown is 3 inches wide. The two paints shown in 6-A and S-B were made with titanium-barium pigment and zinc oxide in dif ferent proportions in linseed oil. The paint shown in 6-C was made with, titanium pigment, white lead and zinc oxide in a synthetic drying oil of the alkyd type. 16 N41698.3 FLB 000926 An outdoor spot 0/ rare charm. A white paint job on pillars and ceuing, the sari-colored chairs anthcushions and flow ers make thU porch a thing of beauty as\oell as comfort. Photograph byhjcorge B. Van Anda. sm- salemes For Out-Door Porches SUMMERTIME is porch time, and 'the American people have become distinctly coloX-minded in low it with a prirpmg coat thinned with turpentine. Where the old finish is glossy, wash with a solution of . the decorating and furnishing of their porches, one pound sal soSa to a gallon of water and rinse. Whether they be fully outdoor covered affairs/terraces, glass-enclosed porches or built-in sun parlors. The painting contractor should have a variety of \:olor As for color Schemes for an open outdoor porch, they should harmonize with the color scheme of the ex terior of the house and contrast can be obtained hot schemes available and be familiar with current fn ture styles and little decorative novelties if he is to do a .'pleasing job for his client, and accordingly we give herewith a few tips gleaned-from data prepared by' the Save the Surface Campaign. In the first place, the new note in outdoor furniture this year is movability, Tables, chairs and sunbarrows ardall on wheels. If your customer has furniture of an older type, suggest that you be allowed to puty Wheels on the chairs--and then paint them to mate! Various types of furniture, of course, call for various types of coatings. For furniture on covered parches, if it's of Wood, wicker or rattan, fiat paint or enamel will be suitable. If the old finish is in good emMition, a single coat of either will be sufficient. Mat paint, incidentally, has the better hiding quality, jrnt enamel makes the more durable and washable finu only in the furniture itself but in the cushions and pillows./ For the enclosed porch where you have walls to considen'the room can be painted more "on its own." The waffs can be in such soft coloring as putty, ivory, irehment, tan, nile green or hydrangea blue. We now of one enclosed porch where a delightful effect secured through the combination of ivory wood work and pale yellow walls. In another the woodwork is ofNnuet gray-green antiqued with sienna, aU. the painte<T\waUs are of light gray-green, stencilled all over witn\a small modernistic flower-and-bird design carried outsin pastel gold, pink and rust. In enclosed porches where you want to emphasize the outdoor atmosphere, ymi can use some well-designed lattice work, painting ffiin blue-green, in Italian blue or Terra Cotta. For metal porch furniture^--if It's being painted for the first time--use a special metal primer to prevent corrosion. Over the primer use flat mflnt or enamel. For the porch, natural wicker should be protected by a varnish such as is used for/fumiture or wood work. However, if the wicker is/to be in the garden, give it two coats of outside house paint so that it can successfully resist outdoor exposure. Wooden furniture for thg garden also requires two coats of house paint, while unpainted metal needs a coating of a special metal primer and then two coats of house paint. / Here is a glass-en For a natural wood finish, use spar varnish for its closed porch, which * highly protective qualities. Remember this especially for deck chairs ymich are apt to be left in the rain nevertheless has an outdoor effect. White walls and trim again unintentionally/ serve as a back Proper washing and rinsing, naturally, are neces ground for the color sary. If the/old finish is in bad condition, brush it with a wirp brush, scrape off the loose particles and then rub /own .with medium sandpaper. If the,4urface is suffering from a bad ease of crack ful furnishings and plants. Photograph by George H. Van Anda. ing or/Scaling, use a paint or varnish remover and fpl- June 1036 t- i- m111II1iiI1i FLB 000927 normal conditions of exposure, that is, on wood that remains dry at all times and with, paint of the same kind used for all three coats. Succeeding paint jobs with white lead paint applied over the surfaces shown in Figures IB, 1C, and 5 will behave almost exactly like the initial jobs. If the paints shown in Figures 2 and 3 are repainted properly with the same paints used the first time the behavior will again remain much the same except that the meshes of the checking patterns may become somewhat larger with each re painting, especially if two coats are applied each time instead of one. If the surface shown in Figure 4 is repainted with the same type of paint two coats are necessary, the subsequent checking and flaking patterns become larger, cracking of the kind shown in Figure 6C is likely to occur, and if the practice is repeated through several paintings a condition like that shown in House No. 15 in the March, 1936, issue may be expected. If the surfaces shown in Figure 6 are repainted with the same kinds of paint cracking in a larger and still more Conspicuous pattern wilt probably occur at each suc cessive repainting. These surfaces should be repainted with one coat of paint long before cracking reaches the stage illustrated. A painter who makes a practice of studying the behavior of paint jobs about which he knows the whole history Will soon learn to recognize developments of the kinds described in this article and from these de velopments he will soon be able to tell rather closely the kinds of paint previously used on most houses on which he is asked to bid. It must be remembered, how ever, that paints go through their normal stages of behavior only when used under normal conditions of service. The three common types of abnormal condi tions result in characteristic abnormalities in behavior that are usually either superimposed on the normal developments or proceed logically from them. For that reason an adequate understanding of the normal de velopments with different paints enables the painter not only to spot abnormal conditions promptly but often to determine the nature of the abnormalities. The abnormalities in paint behavior caused by col lection of moisture behind painted woodwork are illus trated by Houses Nos. 3 to 6 in the May, 1935, issue and House No. 16 in the April, 1936, issue. In these cases the forms of failure differ so strikingly from normal behavior of paints that the existence of abnor mality of some kind is immediately obvious. Caution, however, must be exercised in assuming too freely that moisture is the real cause of difficulty because a com parison of Houses Nos. 4 and 16 with Nos. 7 and 8 proves that incompatible combinations of paints often result in forms* of failure remarkably similar to those caused by moisture; As a matter of fact there is a continuous gradation in early paint failures between typical moisture con- FIGURE 4 The curling and flaking characteristic of moderately hard types of paint such as that shown in Figure 3 (last month). The area shown in 4-A is 3 inches in size; the area shown in 4-B is Vi-inch by % -inch in size. FIGURE 5 The crumbling characteristic of soft paints that develop checking early, such as pure white lead paint shown in Fig ure 1 (last month). The area shown In 5-A is 3 inches by 3 inches in size; the area shown in 5-B is Vs.-inch by Vi-inch in size. ditions severe enough to ruin compatible paint jobs and mild moisture conditions that cause difficulty only when the paint job has been made unusually sensitive by an incompatible combination of paints. The latter condition is illustrated by House No. IV* On the other hand there gre times when moisture causes early paint failure in a manner that looks like the perfectly normal developments illustrated by Figures 4 or 6 except that the failure occurs far sooner than it would do under normal conditions of service. The second common class of abnormal conditions, which is probably far more numerous than the first, is that caused by incompatible combinations of paints such as those illustrated by Houses Nos. 7 to 12. The following additional information about these houses will help explain the methods of identifying types of paint from a knowledge of their behavior under normal conditions: House No, 7 The original gray paint that shows where the subse quent brown and white paints are scaling exhibits the checking pattern of Figure 3, which probably indicates paints of lead and zinc types. The brown paint, before the white paint was applied, exhibited brush marks and a softness of texture showing that it Was made with linseed oil With little or no varnish. The white paint was a titanium, lead, and zinc paint and was chalking but neither checking nor cracking except Where the scaling took place at the- time the photo graph was taken. * House No. 8 * The scaling goes clear to the wo6d in most places but in some spots it leaves the 1930 paint exposed to view, which exhibits a cheeking pattern similar to Figure 3 and is therefore not pure white lead paint but probably lead and Zinc paint. The 1933 paint exhibits the surface appearance of titanium pigments but shows parallel checking rather representative of an earlier, stage of the checking in Figure 3. Such behavior is reasonable for a mixture of white lead with the quick-drying paint finally reported by the painter. House No. 9 The checking of the paint on the east side is similar to Figure 3 but somewhat coarser in pattern as would be expected after three paintings. By scraping off some of the coating with a penknife the absence of colored paints on the east side was easily established. On the other three sides the colored paints could be seen in the order of their application by removing a chip of paint and examining its edge under a good magnifying glass or pocket microscope. Note that the white paints over the colored paints developed sigmoid cracking like Figure 60 but on a much larger scale, which is com pletely absent under the normal conditions of the east side. House No. 10 The original paint coating remains intact and ex hibits the checking pattern of Figure 3, indicating probably a lead and zinc paint. The last paint job has the characteristic surface appearance and chalking of titanium pigment paints and shows the sigmoid crack ing, curling, and flaking of Figure 6B but on a much coarser scale. Subsequent discovery of the manufac turer of the two paints made it possible to confirm these deductions. House No. 11 The colored pigment paint first used on this house is readily seen through the wide open gashes in the white paint last applied. The failure of the white paint is a development of the sigmoid cracking of Figure 60 due to a shrinking and "slipping" of the white paint over the very much softer colored paint beneath. House No. 12 Ailigatoring of pure white lead paint when applied over a harder paint containing nine oxide is a modi fication of the normal checking shown in Figure 1 in which the meshes of the checking pattern are greatly enlarged and there is shrinking and slipping of the white iead paint over the underlying paint much like that exhibited on House No. 11. White lead paint may alligator in much the same way when applied over clear varnish or over colored pigment paints. The third common class of abnormal conditions arises from faulty procedures in applying paints. Some of these were discussed by Glenn H. Pickard in the April, 1936, issue. Errors of application as a rule have less disastrous consequences than abnormal moisture conditions and incompatible combinations of paints. The common practice of thinning priming coats for new wood With too much turpentine and the Continued on Page 33 House No. 17 in Dr. Browne's series of test Houses, men tioned in accompanying article. The house was built in 1931 and painted with white lead paint. In 1934 it was repainted with a quick drying paint. The photos were taken early in 1935. stingy api ciably but aware of cracking a pattern fo thinning < paints to i their norn flaking. The pai: with the r to be used ties in bel erally find accurately informatio otherwise find hims< may lead early faiiu also be ab) value thai property. The wri: makes invc considered past presic there have edge of th acknowledi father of advice abo was begini Since Hr. the paintej ficult by tl on the mar of faulty i about. Bn sale and us shoulder n paints are owner canr paint beha for him. The pain and labor records of i in the long who has no jng paint. .ree based With the c tage, a dee green shut tion. Witt goes well, ters wri} ' FLB 000929 IS If Judging Normal Paint Conditions Continued from Page 18 h na stingy application of paint impair durability appre ciably but not enough as a rule to make the owner aware of that fact. The development of checking, cracking and disintegration usually follow the normal se pattern for the paint in question. Unduly generous le thinning of paint with linseed oil may cause some be paints to fail by rapid chalking at an earlier age than Df their normal disintegration by cracking, curling and ie flakipg- it The painter who has become thoroughly familiar with the normal behavior of the various paints likely to be used in his community and with the abnormali ties ..Ifihavior to which they are subject will gen erally find himself able to record painting histories i- accufatqky enough for practical purposes even when in info%ttion about previous paints cannot be obtained iy otherwise or is reported incorrectly. He will likewise le find himself able to avoid dangerous mistakes that ie may lead to early failures, expense of restitution for ly early failures, and damage to his reputation. He will 2r also be able to give his customers service of far more value than the mere application of. paint to their property. PROVE IT AT OUR EXPENSE The writer is well aware that the suggestions he makes involve more technical study than is commonly considered within the painter's province. Among the past .presidents of the International Society, however, .there have been men who felt that technical knowl edge of this kind is essential. The writer is glad to acknowledge his own debt to the late John B. Dewar, father of the recent president, for much valuable advice about the technology of paint when the writer was begining his own investigations of the subject. Since Mr. Dewar's time the technical demands upon the painter's ability have been made increasingly dif ficult by the multiplication of different types of paint on the market with consequent increase in the number "pAINTERS everywhere are -* making mere money and do ing better jobs with Texolite. colors. Texolite Deep Colors-- made in nine deep colors^-can be added to white to get any de This new kina of paint saves on sired shade;br Deep Colors canbe time, saves an paint, gives re das deep, brilliant paint for sults that please the fussiest cus unusual am ilorful decorative tomers. effects. Test T< olite yourself for Texolite it the new casein 'quality, cover paint that is sold in paste form, j age, for econ A gallon of Texolite Becomes a / omy. Prove to gallon and one-half of ready-toy yourselfyon're use paint. Yod pay for a gallon', lasing money but it's a gallon and one-half if yon don't when it goes an the job. In ad use Texolite. dition Texolitekives you a oval ity, one-coat job possible only with this type jof paint. It does of faulty combinations that may easily be brought about Under the present conditions of manufacture, sale and use of paints the painter.is the man who must shoulder most of the responsibility for seeing that paints ire chosen and used successfully. The house owner cannot be expected to master the intricacies of paint behavior and expects to pay others to do that for him. The painter who is able to sell his customers paint and labor plus sound advice backed up by a file of records of satisfactory jobs is worth more money and not yellow with age. Does not peel or crack or become brittle. It covers in one coat, gops 2S% farther and dries in aij! hour, leaving no brash marks! Send for Free Sapiple Learn about this gemttnely new paint. Learn how it can get yon more business -j at an increased " profit per job I Send coupon now for free quart of Texolite and tube of Deep Color. Texolite comes in white ind/ten standard *e*OLlT fc 7-IN.r pJfA 22Goes 2isncev^er\ 7 SiOtply in the long run will get more money than the painter who has nothing to offer but the mechanics of spread ing paint. TEXOLITE Colors for Cottages A PRODUCT qjr THE UNITED STATES GYPSUM COMPANY 0*7 ^ r" *'* '* J UWWij AVUAJi ^wfirgo exceptionally weU with a dark limp 1M* FLB 000930 ditions sevi and mild n when the j by an taco; condition i hand ther paint failu. normal de except thal do under r The seed which is px that cause such as th< following i will help e paint Iron normal cor The origi quent brow checking p; paints of before the marks and made with white pain was chalkii where the; graph was The seal] but ta sorb view, whicj Figure 3 a: but probafc exhibits thi but shows an earlier. I behavior ii with the q painter, j The checj to Figure 3 be expeete<j of the coat paints on t other thre< the order ^ paint and glass or pot over the co. Figure 6C 1 pletely abs east side. The orig; hibits the; House No. \ turned in acj and paintedI with a quid in 1935. TO PAINTERS. - - a new idea VHYLITE CASEIN WASHABLE PAINT, our newest product, j entirely different from any other cold-water paint because it is aufactured from the same pigment that goes into high-grade fcaint. This pigment comes from our own mines. l dry powder to which you merely add .water, is posi tively jJ^rmaaent. Does not rub off. Caa.be washed. No brush marks; nh lap marks. Shows so "hot spots'* on green plaster. Forms a nAtaral bond to surface to which it is applied. Phis un usual one-coot covering properties. Odorless. Quick-drying. Costs consunu&r less than 75b per gallon, painters considerably less. HYLITE forms Synatural undercoat before oil paint on wood, plastcryetc., fur bow interior and exterior surfaces, saving cost of oil paint. Lacqaerwyamiab, enamel also can be painted over it. Solves old probietnofdecorating insulating board by covering completely with one coah Representatives^^e^ers and jobbers wanted. TRY IT BEFORE YOU BUY IT. Write ror sample. CARBOLA CHEMICALXIO., Natural Bridge, N.y. three ways. First, it gives a painter sometK canvass with. And there are three ways to usj payment plan in canvassing for jobs. A pah,,. use his time payment plan as his big sales pop direct mail campaign to a list of people he i either from examination of his own record, observation, to believe need some painting Next, he can use the plan as a good reason forp up both old customers and new prospers on ti phone to inform them how easy it now is to having the work done that they've probably wi long time. Or the painter can use the plan as af for calling personally on people/he thinks services. And in this connection, I know frqll sonai experience, that it will pay any resj|| painter to hire good speifialty salesmen, elJT young fellows skilled in selling d0or-to-door,, toll and canvass his whole territory at a ten mission on ail sales he is able to close from fly fi they give him. / ^uratt PERMANENT GREEN Known the country over LIQUID AND PASTE FORM Sample sent on request. Have your dealer write us.' COLONIAL WORKS Manufacturers of Adhesium Wallpaper Size 223 Norman' Avenue Brooklyn, N. Y, 323 West Polk Street Chicago, 111. Paint Jobs on Budget Plans Continued from Page 9 This makes it easy for the customer. The dainter gets the purchaser, the purchaser's wife, ap'd other members of his family, if their incomes arWmcluded, to sign the credit statement, agreement, aha note, "Under most of the plans, the dealer from whom the painter expects to buy the brand of materials specified in the agreement, orders a credit Export from a re sponsible credit bureau, which report must verify the information on the purchaser's (Credit statement, in cluding a re-check on the property owner's statement of mortgage holder and the Amount of annual pay ment. If there is no credij/bureau ta his town, the dealer writes the nearest branch of the finance com pany for detailed instructions as to how the credit investigation should bemandled. After the first time, he works out a simple routine for handling this credit problem. The credit bureau's usual dollar fee is paid by the painter. "Practically ady wholesaler handling reputable mer chandise has /ne of these finance plans available to the painierf/who deal With him. If he doesn't offer such a plgn and isn't willing to help the painters in closing installment deals with their customers, then his painters, if they're wise, will change to some other wholesaler Who is interested in pushing these install ment contracts. "For this idea of time payments by customers and cash payments for the painters, helps the painter ta So nothing to Talk About "But a time/payment plan, besides giving a something interesting to talk about when earn is also a hejp to him when he is trying to make mind jusywhat kind of a job to try to sell to ai tomer 01/whom be may happen to call. It hi ferlence of the painters I've interested time payment plan that customers are willing grade of job if they can pay for it in : So in cases where these painters formes hundred dollar jobs, they now sell four hf obs, and where they formerly would : a job to cost seven hundred dollars, they now s and closka job costing nine hundred dollars. "But probably a time payment plan is most to a painters, when, after convincing a custom^ his ideas about the job are right, he runs up the objection that his price is too high. "The time payment idea is the best way y| covered for overco!taing a price objection and the sale. I've helped my painter customers dozens of time payment contracts. Just yeste went out on a call witma painter who had a cu that was threatening toNget in a cheaper mar job for which my painter had quoted $460. Bui I pointed out to the customer that the contract fled a nationally advertised, irtandard brand of and that he himself was to bmdhe judge of the manship, not being obligated tk pay one cent satisfied the job was done right,'and that he 1 draw any money out of the banKVto pay for could pay the small monthly installment of $31| of his regular income, he agreed toilet us frill credit application for him and start woqk just a| as this application was approved. "For the first time in years, we've all gtot a both to give the public real value and make a| ourselves too. But the key man in the eye painting and decorating contractor. If he'll out and push whatever time payment plan tlx ticular manufacturer or jobber he deals with is soring, he can offer his customers a better gr work, land more jobs, make more money for h and be the main factor in building up the wh< dustry to a greater degree of prosperity than us has ever known before." FLB 000931 The principal reason for coating woodwork is usually improvement and maintenance of appearance. Immediate considerations in coat ing wood for appearance are: (1) Paint or enamel is opaque and therefore conceals the grain and color of the wood, substituting a color, sheen, and texture of its own. (2) Varnish, lacquer, oil, or wax is transparent, thus revealing the grain of a piece more fully by displacing the air at its surface with a medium of much higher refractive index. In conjunction with stain the color is also altered. The sheen and the texture of the coating are substituted for those of the wood. (3) Stain without varnish or lacquer changes the color of wood without greatly altering its sheen or texture* Ultimate considerations in coating wood for appearance are : (1) Unless protected by moisture-retardant coatings, wood ex posed to the weather becomes dull gray in color; smoothly planed surfaces become rough and cracked; boards tend to cup, twist, and pull loose from their fastenings; short boards may split in two; snug joints are loosened; and straightj parallel lines are disarranged. Durable coatings adequately maintained prevent such weathering (Browne, first and fourth references) .** (2) Uncoated interior wood surfaces are porous enough to absorb liquids quickly, to stain and spot readily, and to hold dirt tenaciously. Honporous coatings or coatings that tend to shed liquids protect wood from discoloration and present a surface easily cleaned. Those parts of buildings that are customarily kept painted are not, as a rule, subject to much hazard of decay by wood-destroying fungi] (Browne, first reference) because they are well drained and dry rapidly. Decay and its prevention are discussed on pages 249 to 253 and the painting of wood treated for the prevention of decay on page 232. Ordinary paints and varnishes are not effective as preservatives against fungous decay. Paint is chosen for exterior woodwork more often than any other coating; it is much more durable than varnish or other transparent coating and usually affords more effective protection, against weath ering of the wood (fig. 62), Exterior enamel may be used in place of paint where a smoother, harder, and more wear-resistant coating is needed, and the surface may be washed at intervals to keep it clean. It is best to use enamels only on surfaces that are accessible enough to be easily repainted somewhat more frequently than the major sur faces of the building. Porch railings, columns, and window sills, for example, can often be enameled to advantage. ) 1 0 q 0 q 3_ Q1 1 _ 0 0 _ sX~ XX The same painting procedure and kind of paint are suitable for painting all native softwoods (conifers) and the native hardwoods 34 For further information, the references at the end of this section should be consulted. 227 % N41698.31 FLB 000932 s 228 tj. S. DEPARTMENT Or AGRICULTURE that have relatively small vessels (pores) (Browne, seventh anc tenth references). Hardwoods with relatively large vessels requiri a wood filler before painting or varnishing. SPREADING RATES ON SOFTWOODS (CONIFERS) The spreading rate of paint is the area of surface covered by a unit volume of paint. On smoothly planed surfaces of softwoods the spreading rate varies with species only for the first or priming coat of paint applied on the new surface; the spreading rate of subsequent coats does not vary with species (Browne, third reference) ; Even for priming-coat paint the species of wood has less effect on spreading rate than the individuality of the painter or the kirn) and proportion of ingredients in the paint. Some painters brush paint out farther than others; the best painters apply paint in many years of service only the painted letters on this sign resisted erosion. fairly thick coats roughly 600 square feet per gallonj while unskilled painters very often apply coating too thin, covering as much as 1,000 or 1,200 square feet per gallon. A few of our native softwoods tend to take 10 or 12 percent more priming-coat paint than the average, and a few tend to take as much less. By the time second- coat and third-coat paints have been applied, however, the difference in paint consumed amounts to only 3 or 4 percent above or below the average, a value that is probably within the limits of uniformity with which a good workman will paint at different times. The woods that tend to take more than the average amount of paint are, in general, the lightweight ones and those that tend to take less paint are the heavy ones that have a high proportion of summer wood. Rough surfaces, such as shingles, the sawed side of bevel siding, weathered wood, or surfaces on which repainting has been neglected for a long time may consume twice the amount of priming- coat paint, required for smoothly planed surfaces. DRYING OF FAINT ON SOFTWOODS I i The time required for a coating of paint to dry--that is, to : harden--usually depends almost entirely on the composition of the j HHiip PHHR& WOOD HANDBOOK 229 iventb; and els require red by a softwoods r priming j rate of jference). .ess effect | the Mud ;rs brush paint in paint, the intensity of sunlight, and the temperature and relative humidity of the atmosphere. The drying is retarded, however, if the wood is wet when painted; its moisture content should not exceed 20 percent. On wet redwood or southern cypress, primingcoat paint may remain liquid for days, especially when the paintis one containing little or no white lead or zinc sulphide pigment (Schrautz and Palmer). On air-dry redwood paint hardens as rapidly as on any other wood. On air-dry cypress in the absence of sufficient sunlight paint may take longer than usual to harden. Cypress boards that contain much more than the average amount of the oily extractive material characteristic of cypress may retard the hardening of paints lacking white lead or zinc sulphide even when the' boards are reasonably dry unless the drying takes place in strong sunlight. FILLING POROUS HARDWOODS BEFORE! PAINTING For painting purposes the hardwoods may be classified as fol lows: After Q. drilled ich as svoods n the eondrence W the mity The }aint take uner level oeen fng- to the Hardwoods with large pores : AsU Butternut Chestnut Elm Backberry Hickory Khaya (African mahogany) Mahogany Oak Sugarberry Walnut Hardwoods with small pores: Alder, red Aspen Basswood Beech Cherry Cottonwood Gum Magnolia Maple Poplar Sycamore Birch has pores large enough to take wood filler effectively when desired but small enough, as a rule, to be painted satisfactorily without filling. _ Hardwoods having small pores may be painted with ordinary house paints in exactly the same manner as softwoods. For hard woods with large pores, however, the usual priming-coat paint should be replaced with a wood filler, which is a paste consisting of pigment, chiefly ground quartz, mixed , with linseed oil and a paint drier. Filler is necessary on woods having large pores because paint ap plied by brush or spray gun does not fill the pores properly. With out filler the pores not only appear as depressions after the painting has been finished but also act as centers from which disintegration of the coating sets in. EFFECT OF NATURE OF WOOD ON WEARING OF FAINT During the first year or two after an exterior wood surface has been painted or repainted properly the nature of the wood usually has very little effect on the behavior of the paint coating. Later on, when the coating has become embrittled with age, differences between woods become very important and very largely determine how rapidly the coating disintegrates. Under normal conditions of exposure-- that, is, when the moisture conditions discussed on page 240 do not pertain--paint coatings on wood (Browne., eighth, eleventh, and thirteenth references) deteriorate most rapidly where the greatest FLB 000934 i 23.0 XT. S, DEPARTMENT OF AGRICULTURE amount of sunshine falls and deterioration proceeds in success!' but overlapping stages as follows: (1) The soiling stage. The coating gradually becomes dirty. (2) The flatting stage. The coating loses its gloss. (3) The chalking stage. Dirt may he thrown off more or h completely, but colors appear to fade. (4) The fissure stage. Fissures are of two general types, depen ing upon the nature of the paint (pi. 4): ( ) Checking. The fissures are at first superficial hut later m penetrate entirely through the coating. ( ) Cracking. The fissures pass entir first observed. The coating at the edges of the cracks sooner or lat comes loose from the wood and cum outward. As a rule craekii comes at a more advanced stage of paint embritt] (5) The stage of disintegration. Behavior in the fissure stage c termmes the form in which disintegration takes place: (a) Crumbling, which develops from checking, consists in the fa ing away of tiny fragments of coating cut off when the fissures b interwoven and penetrate entirely through the coating. (S) Flaking, which develops from cracking and curling. T loosened edges of coating that curl outward finally fall off, after whi the newly formed edges curl outward and the process continu Flaking is usually a more rapid form of disintegration than crun ling. From the tame that cracking or disintegration begins the nature the wood painted dominates the further rate of progress of failu On softwoods cracking, crumbling, and flaking progress chiefly o1 the bands of summer wood. The wider the bands of summer wc intersected by the painted, surface the more rapidly disintegrate proceeds and the more conspicuous the areas laid bare. I4epain what larger and may not begin to come off quite so soon. The following wood properties or characteristics (Browne, si reference) largely determine how long softwood boards retain ps satisfactorily : (1) Wood of light weight (low density) holds pi longer than heavy wood because light wood contains less sunn wood; (2) narrow-ringed wood holds coatings longer than wi ringed wood because the bands of summer wood are narrower; edge-grain surfaces hold coatings longer than flat-grain surfa also because the bands of summer wood are narrower at the surf? (4) flat-grain boards may hold paint better on the bark side t on the pith side because on the pith side there is sometimes a h eney for the edges of the bands of summer wood to loosen and outward, thus dislodging the coating; and (5) high-grade lun holds coatings better than low-grade both because knots and o defects hold paint poorly and because the low grades usually c from the center of the tree where the wood is likely to be w ringed. Coatings begin to fail to protect wood against weathering v deep fissures develop. The consequences or inadequate protec depend Upon the characteristics of the wood. Edge-gram bo are less seriously affected than flat-grain boards of the same spe FLB 000935 Wood fbiuWol sive PLATE 4 loss end ing yhfill later ang. a de- falleome The yhich Jiues. umb- ire of |lure. over wood Nation tinted I new some- sixth : paint : paint limner | wide- B (> paces, irface; e than i tendid curl lumber | other j come I wider j when itection boards A, Disintegration of a paint coaling ing, were at first superficial but ia by crumbling. The interweaving the course of time they penetrated fissures, entirely known as.recitulate check through the coating. Now species. tinintyhferawgomoednbtseonfecaotha.tinTghceutaoreffabsyhtohwenfishseurereissamreabgengifiinendinxg t4o.4f.ell away from the bands ofsummer wood B, Disintegration of a paint coating by flaking. Checking was retarded in this paint by suitable choice of pigments and the checking is still superficial but cracking has started in the embrittled coating, the coating comes loose over the bands of summer wood in the wood beneath.and curls upward at the edges of the cracks.. Finally the curled edges of coating break off. The area shown here is only 1 by 1 inch in ssiiztieo.n Tofhtehecopaatiinngt.s shown in A and B are similar in age and in all respects except the pigment compo FLB 000936 WOOD HANDBOOK 231 Woods that hold their shape well and do not develop conspicuous cheeks or cracks on weathering are less seriously affected by inade quacy of paint protection than are other woods. CLASSIFICATION OF SOFTWOODS FOE PAINTING Table 45 classifies native Softwoods by species with respect to their painting characteristics for exterior use (Browne, sixth and ninth references). The classification is based upon the average behavior of commercial shipments of select grades of the different woods ; that is, upon material of a quality that may be used for house siding or millwork. Boards of any one species may vary widely in paint re tention so that, in general, boards selected for tne physical properties that favor paint durability will serve much more satisfactorily than the average run of the species rated in table 45. T1 < 45.--Glassification of softiooods for padntfoifj Group 11 Group 2 2 Group 3 3 Group 4 < Alaska cedar. [license cedar. Northern white cedar. Port Orford cedar. Southern white cedar. Western red cedar. Southern cypress. Redwood. Northern white pine. Western white pine. Sugar pine. Commercial white fir. Eastern hemlock. Western hemlock. Ponderosa pine. Lodgepole pine. Eastern spruce. Engdmanh spruce. Sitka spruce. Douglas fir. Western. Iarc.li. Norway pine. Southern yellow pine. Tamarack. 1 Woods that hold paint longest andsufferleast when protection against weathering becomes inadequate. a Woods that bold white-lead paint aslongas those ofgroup 1 but do not hold mixed-pigment paints quite so long and suffermorethan those ofgroup 1 if protection becomes inadequate. 3 Woods that do not bold either white-lead paint of mixed-pigment paints so long as woods of group i and suffer more than woods of group 1 if protection becomes inadequate. 4 Woods that do not hold paint coatings so long as woods of group 3. ? EFFECT OF EXTRACTIVES IK WOOD ON PAINT BEHAVIOR In general, the extractives in wood have much less effect on paint behavior than has been commonly supposed. They are far less im portant than the width of the bands of summer wood. Distinction must be made between, piny resins, which axe charac teristic of pines but occur also in other softwoods, and other extractives. Piny resins consist of a solid rosin and a volatile liquid such as turpentine. They affeet paint unfavorably by exuding through coatings, leaving unsightly encrustations. Exudation is minimized by thorough seasoning of the lumber to drive out the turpentine, rendering the resin less mobile. Much longer seasoning is necessary to remove turpentine than to remove moisture (Browne and Hrubesky). The piny resins may also be responsible for the fact that paints containing zinc oxide fail somewhat more rapidly on the pines than they do on other softwoods having bands of summer wood of similar width. Other extractives in wood may have a favorable effect on the durability of paint (Browne, sixth reference). There is evidence that such is the fact with extractives in redwood and southern cy press, although colored extractives in redwood and red cedar that FLB 232 tr. s, 1 + q X 1 3 7 _ are soluble in water may exude through coatings if the wood beneath the coatings becomes very wet ; under normally dry condi tions these discolorations do not occur. EFFECT OF IMPBEtfNATED PRESERVATIVES OK PAINTING Wood treated with the water-soluble and other somewhat color less preservatives in common use can be painted satisfactorily. The life of the coating may in some instances be slightly less than it would have been on untreated wood, but the loss in durability is not enough to offer any practical objection to the use of treated wood for purposes where preservation against decay is necessary and the appearance of painted wood and protection against weathering are desired (Browne, seventeenth reference). Coal-tar creosote or other dark oily preservatives tend to stain through paint and no entirely satisfactory method of painting over them is known (Dunlap), but fairly good results can be obtained with 1 or 2 coats of exterior aluminum paint. CHOICE OP PAINTS FOB EXTERIOR WOODWORK House paints of the best quality- are recommended for nearly all needs for exterior painting. Inferior paints made to sell at materially lower prices must be applied in greater amount to ac complish the same result, may not last so long, and are less reliable generally. Even when low initial cost of painting is the chief con sideration it usually proves cheaper to use high-grade paint in til minimum number of coats because the labor for a paint job usually costs several times as much as the paint. For both low initial cost and great durability, whenever the colors are acceptable, paints of good quality made with iron oxide pigments are more economical than most other good paints. Two coats of exterior aluminum paint make an exceedingly durable, highly protective coating when a metallic appearance is not considered undesirable. For very brief- service or where very frequent repainting is desired for some reason and protection against weathering is not necessary, old-fashioned white-wash or modern types of exterior Water or water-emulsion paints are safer to use than linseed oil paints of very inferior quality The water paints give their best service on rough rather than on smoothly planed wood. For residences or buildings of architectural pretensionwhite or light-colored paints are most popular for the major painted surfaces, supplemented if desired by deeply colored paints on minor surfaces. When deep colors are appropriately dominant it. is often better and more economical to use rough Wood surfaces such as shingles or the sawed side of siding and apply exterior stains rather than gloss paints;. PASTE AND PREPARED- PAINTS Paste paints contain a greater proportion of pigment than pre pared paints and must be thinned with more linseed oil and turpen tine to make them ready for application. As a rule paste paints manipulated by a skillful painter in accordance with the particular conditions prevailing on the job permit closer adherence to the tra ditional technique of the paint craft than is possible with prepared paints. For example, in table 46 the second-coat mixture for three- FLB 000938 WOOD HANDBOOK 233 the wood dry condi- hafc eolorrily, The 3S than it lity is not wood for and the tering are e or other p entirely dap), but ; exterior coat painting and in table 47 the first-coat mixture for repainting contain iess linseed oil in proportion to pigment than the manufac> turer of prepared paint has already incorporated. For that reason these mixtures practically can be made only from paste paints. In congested urban locations or in parts of the South where mildew is troublesome, it is advantageous to mix even the finish-coat paint with less linseed oil than is already present in prepared paint. On the other hand, unskilled or unscrupulous painters can make far more serious blunders in manipulating paste paint than they can make with prepared paint. The manufacturer of prepared paint can also make sure that a larger proportion of the unseed oil used in the paint is of the type most compatible with the particular kinds of pigments he has used. Further advantages of prepared paints lie in the fact that they are commonly sold in a much greater variety of colors than paste paints, so that tinting by the painter is often unnecessary and they are simpler for the ordinary home owner to use for general household painting purposes. COMPOSITION OF PAINT ir nearly o sell at at to ao- The quality of a house paint depends upon the quality of the liq uids, the quality of the pigments, and the proportions of pigments and liquids of which it is made (Browne, eleventh reference), 5 reliable hief con QtTAHTY OF OTCE LIQUIDS it in the Linseed oil is the most widely accepted liquid ingredient for ex ) usually terior paints for wood. It is available in many degrees of refiner itial cost ment for different purposes. Proper choice of the kind of linseed i, paints oil most suitable for the pigments used is essential for making high- momical grade paint, but as a rule the purchaser must rely upon the manu uminum facturer's judgment in selecting the kind of oil, Substitution of lg when other drying oils for part of the linseed oil is not necessarily detri ry brief e reason ishioned imulsion quality, mental to the quality of the paint. In most high-grade paste or prepared paints from 80 to 1Q0 percent by weight of the liquid con sists of linseed oil or linseed oil and other drying oils. For the painter's needs ini thinning paints for application, raw or boiled linseed oil of good quality should be used. The oil for thinning than on mixed-pigment paints should have an acid number not exceeding 4. rhite or urfaces, Varnish is rarely a desirable ingredient in the liquid of good house paint (except in aluminum paint, p. 239)., hut cheap varnish is often used in inferior paints because large proportions of volatile urfaces. thinners, whieh-.are inexpensive, can then be incorporated. On the ter and other hand, good exterior varnish or heat-treated linseed oil or tiing 3 or the oil is necessary to make exterior enamels or exterior floor paints, n gloss which must stand mechanical wear as well as weather. In such enamels or floor paints of good quality as much as 50 percent by Weight of the liquid may be volatile thinner. Synthetic drying oils in pre- are now manufactured for paint oils; they make paints that dry turpen- | faster than linseed-oil paints, but they have not been in use long paints ; enough for their merits to be well, established, ticular )j The volatile thinner in most paints is mineral spirits, a petroleum he tra- j| product, but turpentine is commonly recommended for painters to epared |\ use in thinning paint. There should be no more than 1 or 2 percent three-1| by weight of water in the liquid of any good paint. 234 TT> S. DEPARTMENT OP AGRIOULTUKE QaM.rrr or Q P0 3 + q Differences iu the behavior of liuseed-oil paints during the suc cessive stages in deterioration with age (p. 229) are determined largely by the nature of the pigments. No kind of paint now known is superior in all stages of deterioration; improvement in one stage is usually effected at some sacrifice in other stages. For that reason the user's judgment about the relative importance of the different stages, and particularly about the stage at which he expects to repaint, determines what kind of paint he can use to best advantage. For intelligent paint maintenance, therefore, the user should know the pigment composition of the paint and its bearing upon behavior during deterioration. The opaque white pigments predominate in the pigment of good white paints. Tinted paints, which include the majority of colored house paints, are essentially white paints containing minor propor tions of colored pigments. The good white paints and white base {lainis for tinting may be grouped for convenience into pure white- ead paint, lead and zinc mixed-pigment paints, and mixed-pigment paints containing modern, very opaque pigments. In pure white-lead paint the pigment is entirely basic carbonate white lead. During the soiling and flatting stages of its life whitelead paint may become dirtier than mixed-pigment paints, especially In congested urban locations or when applied in the late fall, winter, >. or early spring, or in deeply shaded places. Chalking of white-lead paint and apparent fading, if it is tinted, usually set m fairly early, after which the dirt is thrown off promptly and evenly, leaving a clean surface which may, however, contrast strongly with deeply shaded parts of the building that are still dirty and not yet faded. Checking -begins comparatively early, usually inconspicuously, and gradually,Works deeply into the coating, but probably for that rea son craching and flaking rarely occur (pi. 4), The outstanding merit of white-lead paint is the long interval between checking and begin ning of crumbling arid the slow progress of crumbling in the stage of disintegration, especially on woods of groups 1 and 2 in table 45. Even badly neglected white-lead-painted surfaces can usually be cov ered fairly smoothly and durably with new paint unless large weather checks have developed in the wood. Initial painting with white-lead paint provides a very satisfactory foundation for subsequent paint ing with mixed-pigment paints, but it is not advisable to apply pure white-lead paint over mixed-pigment paints because checking may then assume the conspicuous form known as " alligatoring." In good mixed-pigment- paints of the lead-and-zine type, part of the basic carbonate white lead is replaced by zinc oxide, and another a;nd smaller part may or may not be replaced by inexpensive trans parent pigments such as magnesium silicate, silica, barium sulphate, clay, or calcium carbonate. In such paints basic carbonate and basic sulphate white lead are commonly considered interchangeable, either one or any mixture of the two may be used for the white-lead content of the pigment Incorporation of the zinc oxide reduces the chances of excessive soiling of the coating and retards both chalking and checking. Appearance during the soiling, flatting, and chalking stages may therefore be somewhat better than that of pure white-- WOOD HANDBOOK 285 lead paint, especially if the paint is tinted, but on the other hand the coating may remain dirty longer. Ultimate disintegration of lead and zinc paints usually takes place by cracking, curling, and flaking (pL 4). Long neglect of repainting after flaking starts, especially if the content of zinc oxide is high, may leave a surface that cannot be smoothly and durably repainted without removing the old coat ing completely. Federal Government Specification TT-P-36 for lead-and-zinc paint requires that the content of white lead shall be not less than 60 percent by weight and the sum of the white lead and zinc oxide not less than 90 percent of the total pigment. Transparent and colored pigments together must therefore be limited to 10 per cent of the total pigment. Some authorities who regard this as a satisfactory specification for white paint think that in tinted paints the minimum content of white lead should be 50 percent and the minimum sum'of white lead and zinc oxide 85 percent of the total pigment. In parts of the South where the relative humidity is always high, chalking and fading of paint are stimulated while crack ing and flaking are retarded ana paints are subject to the growth of mddew. For such a climate it is advantageous to increase the con tent of zinc oxide to as much as 50 percent of the total pigment. Mixed-pigment paints containing very opaque white pigments may be considered conveniently as lead-and-zinc paints in which part or all of the white lead is replaced by one of the titanium pigments, by one of the zinc sulphide pigments, or their mixtures. Good paints of this type are characterized by unusual freedom from dirt in the soil ing stage and prompt shedding of dirt in the chalking stage. When white lead is replaced entirely by one of the titanium pigments de velopment of fissures may be greatly retarded and checking entirely prevented; but if repainting is postponed long enough, cracking and flaking,ultimately set in as they do in the mixed-pigment paints already discussed. The most popular titanium pigment for exterior paints is a mixture of 25 percent titanium dioxide and 75 percent barium sulphate by weight. Some paint manufacturers prefer to use pure titanium dioxide, in which case it is good practice to consider a mixture of 1 part by weight of titanium dioxide together with about 1% parts of magnesium silicate, silica, or calcium carbonate as the titanium pigment that can properly replace 2% parts of white lead in good lead-and-zinc paint. The most important zinc sulphide pigment is lithopone which contains about 30 percent zinc sulphide and 70 percent barium sulphate. Pure zinc sulphide is now used in a few brands of house paint. Dull red, brown, and yellow pigment paints are made most eco nomically with iron oxide pigments, either natural earths or manu factured pigments. For good retention of color and maximum dura bility the content of iron oxide in the pigment may well be 80 percent by weight or more and should certainly be not less than 30 percent Bright reds require organic lake pigments that are more expensive and less durable than iron oxide reds. Bright yellows and oranges are made with chrome yellows (lead chromate and basic lead chro mate) which are fully as expensive as white pigments but are more durable. Greens are mad with chrome green, which is a mixture of chrome yellow and Prussian or Chinese blue (iron ferro- FLB XT. S. DBPAB.TMENT OF AGMCTUI/CTJRE cyanide). Durable blacks are made with carbon pigments, such as lampblack; asphalt paints make cheaper but less durable blacks for exposure to the weather. When color permits, colored-pigment paints often retain color and protective power better if they contain some zine oxide or white lead. If they do not, it is advisable to apply them over priming coats of white-lead or aluminum paint. P<X X7 0 Xq X P0 +<Q 1 q L0 0 Durability as well as color and capacity are imparted to paint by pigments. For that reason there is an optimum proportion of pigments and linseed oil in good paint. Although the optimum pro portions have not been determined accurately to the satisfaction of all authorities, it is known to be good practice with the paints described herein to keep the pigment volume, which is the percentage by volume of total pigment to total nonvolatile ingredients, within the range of 25 to S2 percent in tho finish-coat paint. At the lower end of this range or below it, paints may become unnecessarily dirty; while at the upper end of the range or above it, they may lose gloss rapidly and begin to chalk and fade early. Prepared paints, and paste paints when thinned for application as finish coats, should contain enough total pigment to fall within this range, pref erably nearer the upper part of it. Inferior paints, unless they contain very large proportions of transparent pigments, are usually deficient in content of total pigment. The painter can readily ada more linseed oil if it should be desirable, but it is seldom practicable to remove excess oil from prepared paint. Once the correct ratio of pigment and linseed oil has been establishedj some volatile thinner is usually necessary to obtain good brushing consistency and convenient application at the proper spreading rate. Paints that require unusually large amounts of thinner;to establish good consistency have "false body" and may justly be regarded as of questionable quality. The pigment volume in paint is not customarily indicated in the manufacturer's statement of composition, which gives the proportions of ingredients by weight, but it can be easily calculated if the spe cific gravity of each of the ingredients is known. Tables of the spe cific gravities of the important ingredients of paint are available (Gardner).* EXTEKIOB STAINS Exterior wood stains are essentially paints greatly diluted with linseed oil, a volatile thinner, and sometimes creosote. Stains are cheaper than paints, but they do not protect wood against weather ing and are therefore most suitable for rough surfaces, such as shingles or siding placed with the sawed side out. Good stains should contain only pare, finely divided, opaque pigments, free from trans parent pigments. The pure iron oxide, chrome, and carbon pigments are very satisfactory; white pigments less so. The liquid part of the stain should be at least one-third linseed oil by volume, with twothirds recommended by some authorities. Particular merits are claimed for stains made with pigments ground in very highly bodied linseed oil because the pigments are more highly dispersed in such V'. vy.-7 I::.;:..;.'..;;.. * si WOOD HANDBOOK 237 liquids and become more deeply embedded in rough wood surfaces. Houses with shingles or siding with the sawed side out, stained with colored-pigment stains, and with smoothly planed and painted "wood trim often have the trim painted twice for every time that the side walls are stained, v ar n is h es Transparent finishes are rarely practicable on exterior surfaces fully exposed to the weather, except on small, easily accessible sur faces such as doors, because even the best varnishes are far less dur able than paints. When transparent finishes are used, prompt re newal of the varnish when needed is essential to prevent the wood from turning permanently gray. APPLICATION OF PAINT Wood should not be painted when it is wet. As long as there is .no free water present, however, the moisture content is of minor importance; wood painted at 16- to 20-percent moisture content holds paint slightly longer than wood painted at 10-percent moisture content. Paint dries very slowly at low temperatures; painting should therefore not be done at times when the temperature is likely to fall below 40 F. When there is danger of dew or frost at night application of paint should cease several hours before sunset. In clear, warm weather coatings of paint can be applied within 24 hours of each other if necessary, but it is better practice to allow at least 2 or 3 days. On the other hand, it generally is inadvisable to allow more than 1 or 2 weeks to elapse between successive coats. On new houses faulty methods of drying ike interior plastering that drive moisture into the sheathing and siding (Browne, fifth reference, and Hartwig) cause blistering and peeling of paint (p. 240). If there is doubt about the moisture content within the side wall, it is best to apply only the priming coat to the exterior wood work and defer the remaining coats until the walls are thoroughly dry. The priming coat will not blister; hut on the other hand it fur nishes only partial protection against weathering, so that the painri^-. ing should bo completed as soon as it its safe to do so. On new wood surfaces or on painted surfaces on which the old coating has not yet become deeply cracked, paint may be applied by brush or spray gun with equally serviceable results. Over old coatings that have passed well into the fissure or the flaking stage of paint deterioration, however, sprayed paint may not prove so dura ble as brushed paint. The conventional procedure in painting new wood surfaces calls for the application of three coats of paint, a priming coat, second coat, and finish coat. Usually the three coats are made of the same kind of paint except for. differences in proportions of pigments, lin seed oil, and turpentine, but the current trend is toward the use of special paints for priming coats. Much painting of new wood is now done with only two coats, but this practice frequently leads to un satisfactory results. When properly done 2-coat painting is prac ticable, but it requires much more skillful workmanship than 3-coat painting. FLB 000943 238 IT. S. MPATtTMSNl' Of AG&XGtJLTTrtlE BOXING OP PAINT In three-coat painting of new wood, surfaces ft is well-established practice for the priming-coat paint to have a pigment volume between 20 and 25 percent, the second-coat paint 35 to 40 percent, and the finish-coat paint 25 to 32 percent. The high pigment volume in the second coat requires the use of paste paint. With prepared paint it is generally necessary to have the same pigment volume in the second and finish coats, but the second coat should never have a lower pigment volume than the finish coat. In two-coat painting of new wood both coats may have 25 to 32 percent of pigment volume, and they should be applied thicker than is customary in three-coat painting. Table 46 presents suitable directions for thin ning paste paints in accordance with the foregoing practices, provided the approximate proporation of total pigment in the paste paint is known. When using prepared paint the painter has little control over the pigment volume. In general, not more than 1 quart of linseed oil and 1 pint of turpentine should be added to a gallon of prepared paint for the priming coat, and the second coat Should be thinned with 1 pint of turpentine and no linseed oil. As a rule, no addition is made to prepared paint for finish coat. T1 < 46.- -Approaemate amounts of linseed oil writ turpentine to lie added, to 1 gallon of pasie point for pMntmg <neu> wood surfaces Reduction and spreading rate For 3-eoafc initial For 2-coafc ini- painting ' . . tial painting . First Second 'Third First Second coat coat coat coat coat For soft paste1 white-lead paint and other paste paints con- tainihg mbrfr tfrah 50 percent pigment fry voluiue: Raw Unseed oil ....... ............... Turpentm^......... --do.,-. -1 .. Spreading rate3 ^----.square feet per gallon.. For paste* points CQateinihg 40 to 60 percent pigment fry- volume: Spreading rate,^,,,feet per gallon.. For paste A paints containing less tfraii 40 percent pigment fry volume: Raw iftoeed oil _______________________ ,.Qiiarta-- .;....... --..__do--.. Si^eading tate ______ ...^ciimre feet per gallon.- 6 2 4 57m5 i 600 % 0 600 '. 5 1 . m 1 Z 0 ,575 600 : 600 13M 1 i 550 575 2 yi 576. 4" I 460 3 1 450 4 0 60G 3 0 500 1 If'the paste paint contains no drier about H pint of liquid paint drier should be added in each of the above mixtures. 2 Boiled linseed oil should be used in place of raw linseed oil only If the manufacturer indicates that it is satisfactory to do so. 3 If additional thinning is necessary to giro good frrushmg consistency, thin farther with, turpentine, not with linseed oil. and apply the paint at coirespondinglylower spreading rate. For congested urban districts where paint becomes very d^y or wheremildew is troablesoine, the amoimt oflinseea oil added tc finish coate mayhe reduced fry about 1 pint and the .amoant of turpentme increased byabout % pint. Changes in priming-eoat reductions according to the nature of the wood painted are often recommended in the mistaken belief that the differences in painting characteristics of woods can be offset in that way. The priming-coat mixtures given in table 46 are suit able for all native softwoods. For resinous woods such as south ern yellow pine the common suggestion to mix priming coats with V\ WOOD HANDBOOK 239 more than, the usual proportion of turpentine is very definitely bad practice. The durability of paint on woods of groups 3 and 4 of table 45 can often be materially increased by using special priming paints. Pure white-lead paint when used as a priming paint over which mixed-pigment paints are applied, especially paint high in zinc oxide,* may he considered a special priming paint for this purpose. The experience of the Forest Products Laboratory so far indicates that the most effective special priming paint on woods of groups 3 and 4 is exterior aluminum paint (Browne, seventh, fourteenth, fif teenth and sixteenth references, and Edwards and Wray). Alumi num priming paint is made Usually with 2 pounds of dry aluminum powder, standard varnish grade, or 2 pounds of commercial paste aluminum in 1 gallon of long-oil spar varnish made specifically for that purpose. The right hind of varnish must be used. Neither ordinary spar varnish, which is both unsuitable and too expensive, nor cheap bronzing liquid for interior use is acceptable for ex terior aluminum paint. When properly applied the aluminum primer hides the surface of the wood completely. Aluminum prim ing paint, uncommon with other colored primers, makes checking in those paints in which it occurs somewhat more prominent; but if the aluminum primer is a suitable one, it does not hasten the development of checking or alter the pattern in which it occurs. REPAINTING The fundamental factor in good paint maintenance is to repaint at the right time. Neglect of repainting results in damage that cannot be satisfactorily repaired by mere application of paint. Warped and checked hoards are not restored by paint, and a badly broken old coating cannot be covered smoothly without first removing it entirely, which is an expensive operation (Browne, twelfth reference). It sometimes happens that a relatively small number of boards on a house lose their paint much sooner and more conspicuously than the rest of the boards. In such cases the average life of subsequent coatings can often be increased by replacing these boards with new ones chosen for good painting characteristics in accordance with the principles stated on page 230, Those who are willing to repaint often to maintain the best possible appearance may do their repainting at some time during the chalking stage of deterioration. They should either have two coats applied fairly thinly or else have_ the dirt washed off thoroughly and only one substantial coat of paint applied. Those who wish to repaint as infrequently as is consistent with good maintenance usually wait for the stage of fissures or the very early part of the stage of disintegration before repainting. Two coats are then advisable and are usually necessary if crumbling or flaking has begun. Amy loosened parts of the old coating should be removed with a putty knife, wire brush, or sandpaper. Conspicuous spots of bare wood should be touched up with priming-coat paint. Two full coats of paint should then be applied. Table 43 may be used as a guide for thinning paste paints for repainting according to the same principles on which table 46 for initial painting is based. FLB 240 IT. S. DKPAItTMKKT OP AGBIC OXiTTJ BE T1 < 47.~Approanmate amounts of linseed oil mid turpentine to be aided, to 1 gallon of paste paint for repainting daring the fissure stage or the verg early stage of disintegration of the old coating Redaction and spreadingrata First Second coat* coat For soft paste1 white-lead paint and paste paints containing more titan 50 percent pig ment by volume: Raw linseedoU3--___--__________,_____________* ..____--_quarts-- Tuipeutine.--,___; ----____--;___ --.; --------**_____--..do___ Spreading rate *----- ---,--,,------- ----------------;-- _______square feet per gallon-- For paste1 paints containing 4Qto 50 percent pigment byvohrmo: Raw linseed oil *------------ _______________--______ ----________________quarts.. Turpentine............ .--_________ --.------------..........^............... _......... do___ Spreading rate *------------------------------ ---................. square feet per gallon-- For paste * paints containing less than 40 percent pigment by volume: Raw linseed oil* ____________ ____ _____________* ___...____--...quarts-- Turpentine.-----_____--._______ __________________________ ______do,--- Spreading rate K............................. ........................-..............square feet per gallon-- m 2H 600 2m 600 1 2 575 '4 0 3 0 600 2 H 575 1 If the paste paint contains no drier about H pint of liquid paint drier should be added in each of the above mixtures. * Bdfled Unseed oilshould be used In place of raw linseed oil only if the manufacturer indicates that It is satisfactory to do so. * If additional thinning is necessary to give good brushing consistency, thin farther with turpentine, not with linseed oil, and apply the paint at correspondingly lower spreading rate. For congested urban districts where paint becomes very dirty or where mildew is troublosome, the amount of linseed oil added to finish coats may be reduced by about lpint and the amount of torpentineincreased by about % pint- If repainting is neglected until long after flaking sets in, the sur face may present a difficult and uncertain problem in repainting unless the old paint was one that stands neglect well. The safest procedure may be to born off the old coating completely and repaint with three coats as for X wood. 1 In the maintenance of a paint over a long period it is advantageous to adhere to one type of paint, at least for all paintings after the first one. Changing the type of paint at each time of painting builds up a coating of varying composition with the danger that unpredictable vagaries in behavior may be encountered. BLISTERING OF COATINGS Conditions sometimes arise under which paint coatings on wood buildings do not undergo (lie normal course of deterioration already doscribedbut fail in an unreasonably short time by blistering followed by peeling or by scaling of the coating, generally in large patches, or else become discolored by exudation of water-soluble dyes contained in the wood or by blue stain fungi growing in sapwood (Browne, fifth reference, and Hartwig). Practically speaking, moisture gaining access to "the backs of die painted boards is invariably the cause of such abnormal paint behavior (pi. 5) . The quality of the paint, the workmanship during application, and, the nature of the wood are got directly responsible for abnormal behavior because under such circum stances all paints fail and trouble may be expected on any kind of wood. " ; There is only one remedy for abnormal paint behavior of this type, namely, location of the source of the moisture and improvement of conditions to eliminate it. Moisture may gain entrance to the side walls of buildings in sev eral ways, among whuffi tile most important are (1) by seepage of 1 FLB \ i )$ 1 The side walls of this house become wet every, winter and by spring the boards of siding are thoroughly | wet and cause scaling of paint. The house was painted in March of one year? repainted in.July the next i year, and photographed the.following year. | I | j l i 1 |: ) FLB 000947 WOOD HANDBOOK 241 rain, water or melting snow through joints and (2) by condensation from warm, moisture-laden air that originates within the building, circulates through hollow side walls, and is chilled when it meets the cold surfaces of sheathing or siding during cold weather. The follow ing joints in frame buildings have frequently been found sources of seepage moisture: Junctions between the siding and corner hoards, window and door easing, and chimney masonry; junctions between side walls and porch roots; the junction between porch columns and plinth blocks; and leaking roofs, eave troughs, and down spouts. The following conditions have often caused condensation of moisture within painted side walls: Hastening the drying of plaster by heating without adequate ventilation; enclosing damp, stagnant air spaces under porches or parts of structures extending beyond the basement excavation; lack of ventilation in unused attics; failure to obtain a watertight basement; plumbing leaks; and artificial humidification of activities within the building that give off much moisture during cold weather. BACK PRIMING AND MILL PRIMING Concealed surfaces are sometimes painted to retard changes in the moisture content of the wood (Browne, fifteenth reference, and Edwards and Wray). More than one coat is rarely applied for such purposes, and using the same priming-coat paint that is applied to the exposed surfaces is often convenient. Siding, shingles, and millwork are the principal items of building lumber back primed in this way. _ The practice of priming lumber and woodwork at the mill is increasing. One object of mill priming is to give protection against moisture during shipment, storage, and erection before final finish ing is possible. Mill priming in general should include back prim ing where practicable because boards coated on one side are more likely to warp when the moisture content changes than uncoated boards or boards coated equally on all sides. No coating that completely prevents changes in the moisture con tent of wood has been found; the best that can he done is to retard the rate of change. (Hunt). Good coatings furnish adequate pro tection against rapidly changing atmospheric conditions or against alternate rain and sunshine, but they are relatively ineffective against prolonged exposure to extreme conditions and do not prevent sea sonal fluctuations in the moisture content of interior woodwork. Table 48 gives the comparative effectiveness of various Common coatings in protecting worn at 11-percent moisture content against absorption of moisture during 2 Weeks' exposure to nearly saturated air. Table 48 gives also the comparative effectiveness of 1, 2, and 3 coatings. These values are for the coatings when new. With age the effectiveness at first increases somewhat and then decreases as the coating deteriorates so that the coatings must be kept in good condition to maintain their effectiveness. A similar comparison of coatings for interior use only is given on page 246. The degree of protection attainable with a priming coat alone is usually limited; at least 2 coats and often .3 are necessary to bnild up an adequate barrier against moisture (Browne, fifteenth ref- 50193*- 242 TT. S. DEPARTMENT OP AKRTC OX/T UHE ereuco). Mill griming, therefore, affords only a very moderate de gree of protection against change in moisture content before in stallation, and after woodwork has been installed the benefit de rived from back priming is probably limited. ^ Oils, resins, or waxes absorbed by the wood or forced into jit by impregnation are much less effective against movement of moisture than good coatings that form a layer of substantial thickness over the wood. T1 <+ 48.--Moisture-excluding effectiveness of coatings, suitable for both, exterior and interior use, during 2 weeks' exposure of wood (initially at 11-pereent moisture content) to nearly saturated air [For ordinary exterior house paints in their customary uses moisture-excluding effectiveness greater than about 60 percent is not necessary. The data in tins table should not be construed as an index of the serviceabfeness of such paints in general] Coat ing no. Description Effectiveness1 found for-- lpoat 2 coats 3 coats Percent Percent Percent 1 98 2 Aluminum powder in no. 16 vehicle..----..............---------- ----- --------- 39 88 .95 3 Extra fine aluminum powder in no. 16 vehicle----______ :__________ 78 92 84 4 Ahiminum powder in " alkyd " type synthetic vehicle------- ------... 16 81 93 6 White lead in a vehicle similar to no. 16------- -- ,,-- 62 86 91 6 Onecoatofno. 2t >1u s 2 coats ofno, 17---------- ------- -------------- ---- 39 86 91 7 Whiteltfadinno. 19 vehicle--.......... -------------- --------- 24 ' 85 91 8 Aluminum powder in no. 23 vehicle.................. ---------- -- 9 61 90 a 90 IQ Aluminum powder in bodied llnseedioiJ vehicle^____ 26 84 89 ii One coat ofho. 8 plus 2 coats of no. 17-___ -------------------- --------------- 9 62 86 12 White lead in no. 23 vehicle.---------------------------- -------- --------- 7 62 83 13 ATnminnm powder in linseed oil--.------ 14 57 77 14 Ahiminum powder and red lead in linseed oil............. ......... ................- 7 66 76 16 Luxseed-oilnouse paint containing zinc oxide and other white pigments with dr without tinting colors.........*------ --.........----------------- 30 -69 73 16 5 49 73 17 Linseed-oil house paint containing no zinc oxide, such as common lead- 20 67 70 18' Red leadInlinseed oil-------^------- -------------------------- 4 58 64 19 pstergum resin,.33^aIloii spar Varnish *--------------- --------- ---------------- 6 37 65 20 /Graphite in linseed oil. ------------------ -- 4 58 X Realinseed-ofibarnpaint, pigment 98 percentpure ironoxide.________ Red lihseed-oil bam paint, pigment Venetian red containing 40 percent 25 53 64 56 y. . .1 25 45 23 Ester gum.resra,75^aIIon long-oil spar varnish-..----------------- --------- 3 14- 35 24 Linseed oil containingpaint drier. -------------------- ----------- 3 5 21 i Perfect protection would be represented by 100-pereent effectiveness; complete lack of protection, as with uncoated wood, by zero. s A "SO-gaHon" yarhish is made in the proportion of 60 gallons of drying oil to 100 pounds of resin; a " 33 gallon varnishis made with 33 gallons ofdrying oilto 100 pounds ofresin. UNCOATEI) EXTKKIOK WOODWORK Architectural design sometimes calls for the appearance of weather beaten wood, and the best way to attain such appearance is to let wood weather naturally, especially since uneoated exterior woodwork is not necessarily lacking in durability. For Weathered construction it is advisable to choose woods that weather with a minimum of cup ping, twisting, and conspicuous checking, such as those of group 1 in table 45. Edge-grain boards weather better than flat-grain boards, and thick boards better than thin ones. It is also best to exclude boards containing pith and to place flat-grain boards with the bark side (the side nearer the bark of the log) out. Fastenings for wea- WOOD HANDBOOK 243 rate defore in- lefit de- thered construction should be secured especially firmly with noncor rosive metals, and joints should be designed to prevent retention of moisture as far as that is possible. yo it by loisture iss over I f I exterior '-percent INTERIOR FINISHING Interior finishing differs from exterior chiefly in that interior wood work usually requires much less adequate protection against moisture and that more exacting standards of appearance and a greater vari ety of effects are expected (Browne, second reference). Good interior finishes should last much longer than extenor paint coatings, but no interior finish should ever be used out of doors. 2rester than dex of the OPAQUE FINISHES 16 found Percent 98 9945 93 91 91 91 SO 90 89 86 n83 75 73 73 70 64 65 64 56 45 35 21 toil, as tesin; a fchera let vork ition cup1 Hi a >ark vTea- Interior surfaces may, if desired, be painted with the materials and by following the procedures recommended for exterior surfaces. As a rule, however, smoother surfaces, better color, and a more lasting sheen are demanded for interior woodwork, and therefore enamels rather than paints are employed. These finishes differ from paints in that linseed oil is replaced partly or entirely by bodied oils or by var nishes in order to make a coating that does not show brush marks and presents a harder surface with a desired degree of gloss. They may also be made of nitrocellulose lacquers or synthetic resins and drying oils that dry much more rapidly than oleo-resinous enamels. Unless made with expensive pigments of extraordinary opacify, such as titanium dioxide or zinc sulphide, enamels are less opaque than paints of the same color because they cannot be made with so large a propor tion of pigment. Before enameling, the wood surface must be made extremely smooth. Imperfections, such as planer marts, hammer marks, and raised grain, are accentuated by enamel finish. Raised grain is espe cially troublesome on flat-grain surfaces of the heavier softwoods because the hard bands of summer wood are sometimes crushed into the soft spring wood in planing and later are pushed up again when the wood changes in moisture content (Koehler). It is helpfol to sponge softwoods with water, allow them to dry thoroughly, and then sandpaper them lightly with sharp sandpaper before enameling. In new buildings woodwork should be allowed adequate time to come to its equilibrium moisture content before finishing. Hardwoods having large pores must be filled with wood filler before the priming coat. For all woods the priming coat may be white- lead paint mixed according to directions for exterior priming-coat jpaint, or special priming paints made for that purpose may be used. Knots in the white pines, ponderosa pine, or southern yellow pine should be shellacked after the priming coat is. dry, A coat of shellac is sometimes necessary also over the white pines and ponderosa pine to prevent discoloration of light-colored enamels by colored matter apparently present in the resin of the heartwood of these species. One or two coats of enamel undercoat are next applied; this should completely hide the wood and should also present a surface that can easily be sandpapered smooth. For best results the surface should be sandpapered before applying the finishing enamel, but this operation is sometimes omitted. After the finishing enamel has been applied it may be left with its natural gloss or rubbed to a dull finish. . ad ma the cy& If he'll < nt plan eats with * a better icmey fot>| up the ierftv tV FLB 000950 244 U. S. DEPARTMENT OF AGRICULTURE TRANSPARENT FINISHES There are many good ways of applying transparent finishes to either hardwoods or softwoods. Most finishing consists in some combination of the following fundamental operations: Staining, fill ing, sealing, surface coating, rubbing, and polishing. Before finish ing, planer marks and other blemishes of the wood surface that would be accentuated by the finish must be removed. Both softwoods and hardwoods are often finished without staining, especially if the wood is one with a pleasing and characteristic color. When used? however, stain often provides much more than color alone because it is absorbed unequally by different parts of the wood and therefore accentuates the natural variations in grain. With hard woods such emphasis of the grain is usually desirable; the best stains for the purpose are dyes dissolved either in water or in oil. The water stains give the most pleasing results but raise the grain of the wood and require an extra sanding operation after the stain is dry. "Non-grain-raising" stains are now available that often approach the water stains in clearness and uniformity of color. With soft woods, stains color the spring wood more strongly than the summer wood, reversing the natural gradation in color in a manner that is often garish. Figment-oil stains, which are essentially thin paints, are less subject to this objection than are other stains and are there fore more suitable for softwoods. Hardwoods having large pores must be filled before a smooth varnish or lacquer coating can be applied. If a smooth coating is not de sired, however, filling is optional. The filler may be transparent and without effect on the color of the finish or it may be colored to con trast with the surrounding wood. Usually colored filler is darker than the rest of the wood. Sealer is used to prevent absorption of subsequent surface coatings and to prevent the bleeding of some stains and fillers into surface coatings, especially lacquer coatings. Shellac is the oldest type of sealer. Varnish can be used as a sealer but is not so effective as shellac. Surface coatings may be of wax, shellac, varnish, or nitrocellulose lacquer. Wax provides a characteristic sheen without forming a coat ing of sensible thickness and without greatly enhancing the natural luster of the wood. Coatings of a more resinous nature, especially shellac and varnish, accentuate the natural luster of some hardwoods and seem to permit the observer to look down into the wood to a cer tain extent. Shellac applied by the laborious process of French polishing probably achieves this impression of depth most fully, but the coating is easily marred by water and is expensive. Eubbing var nishes made with resins of high refractive index for light are nearly as effective as shellac. Lacquers have the advantage of drying rapidly and forming a hard surface but require more applications than varpish to build a lustrous coating. Varnish and lacquer usually dry with a highly glossy surface. To reduce the gloss the surfaces may be rubbed with pumice stone and water or polishing oil. Waterproof sandpaper and water may be used instead of pumice stone. The final sheen varies with the fineness of the powdered pumice stone, coarse powders making a dull surface and fine powders a bright sheen. For very smooth surfaces with high WOOD HANDBOOK 245 polish the final rubbing is done with rottenstone and oil. Varnish and lacquer can be made to dry dull in the first pLaee, but the result is not quite the same as that produced by rubbing. FINISHES FOR FLOORS Finishes for wood floors are subject to severe mechanical wear and consequently deteriorate more rapidly than finishes on most other classes of woodwork. Floor finishes must, therefore, be renewed fre quently. Discussions of floor finishes usually place undue emphasis upon the kind or quality of material used and pay far too little attention to the maintenance. Any of the common types of floor finishes will keep wood floors in excellent condition if properly maintained, but no finish will do so if it is neglected. The essential problem is to adapt a systematic program of maintenance to the requirements of the finishing material chosen and of the degree of wear to which the floor is subjected. The opaque and transparent interior finishes already described are applicable to floor finishing, provided that the floor paints, floor varnishes, or lacquers are made with the careful balance between toughness and hardness necessary to make them resistant to mechani cal wear. The essential point in maintaining any floor finish that includes a surface coating is to recoat before the old coating has actually worn down to the wood in conspicuous spots. Good floor paints or varnishes require less frequent renewal than wax finishes under similar conditions of wear, but each renewal is more expensive in material and labor and keeps the floor from being used for a longer time than finishes that do not include substantial surface coating. For floors subject to heavy wear, coatings of any kind often prove unduly expensive and inconvenient. Floors subject to heavy wear are often finished with floor oils that are absorbed by the wood and do not form substantial coatings. They furnish less adequate protection against moisture and dirt than coatings, but are cheaper and can be applied with less labor and inconvenience. Most floor oils darken wood appreciably and do not present so fine an appearance as well-maintained coatings. A new method is coming into use that keeps oiled floors bright and clean by buffing them with steel wool after oiling, and at suitable inter vals. Machines for buffing floors with steel wool are now available. Floor waxes applied either directly to wood or over a sealer do not form substantial coatings. They are usually superior to floor oils in appearance although they must be renewed even more fre quently. Floor waxes of the emulsion type are very quickly and easily applied and .are relatively inexpensive. ! " ## ~~ _ 0 q X~ $%&( ) *-+X0 _ 0 q 3 FOR INTERIOR USE + / ,- ._ X1 0 q 3 0 1 < The comparative effectiveness of various common coatings in pro tecting wood at 11-percent moisture content against absorption of moisture during 2 weeks' exposure to nearly saturated air is given in the following tabulation in which perfect protection would be represented by 100-percent effectiveness; complete lack of protection, as with uncoated wood, by zero. A similar comparison of coatings for exterior use is given on page 242. 246 U. S. DBPAETMEOT OF AGBICTJI/TTI&E ,Ferc*if Description: twetess 3 coats of spar varnish, coated with, vaseline (for storage purposes only)------ ----.---------------------------------- '----------- --------- 98 Aluminum-leaf process, ccllulose-lacguer base_______ _______ ---- 94 3 coats of aluminum powder in gloss oil (quick drying) - -_ _;------- - -- 92 3 coats of aluminum powder in shellac------------------------92 Heavy coating of paraffin-- ------------------ -------------------- ------ -------------- 91 3 coats of rubbing varnish------------ ----------- ------ ---------------------- ---------- 89 3 coats of shellac------------------------------------:----1--' 87 3 coats of enamel (cellulose lacquer vehicle)------------------............ .......... 76 3 coats of ceEulose lacquer-------------,------------ ------------ - 73 3 coats of gloss oil bronzing liquid---------------- ------- -------- -......... ... 12 3 coats of furniture wax---------------- - -- ------------- -- 8 REFERENCES B<Xw q , F. L. ' 1 2 3 4 5 6 71925. Q noun Op *1 0 q 1 q 1 q0 Q0 q XX 8 9: ;_ Xq .1 0 Xq Jour. 9:56, 58, 60, 62, 64, 66, 68, 70, 72,74, 75, illus. Amer. Paint < =1926. XX ~0 q 0 : .Q0 q 3 1 3 1 q _ 1 Q 1 Meeh. Eugin. 48:1286-1288. 1920. ras SPBF.ADING BATE OP OTJTSIDE WHITE HOUSE PAINT ON DIFFERENT > ?XX . Drugs, Oils, and Paints 42: 230-232, 268, 270, 272, illus. 1927. @QA BXX q C D E FG H H< 0 0 q 3 NEBS) 1 0 q t .X _ 0 Xq Factory 39:655-656, 658, 660, 706, illus. I JK L M N E OP Q1927. BOMB CAUSES X +1 0 q 3 1 q 0 q 3 X 1 0 q t Xq QX .0 0 q 3 Amer. Paint and Varnisli Manfrs. Assoc., Scir Sec. Circ. 317, pp. 480-486. 1930. p r o p e r t ie s o f w o o d t h a t d e t e r m f n e p a in t s e r v ic e o f e x t e r io r c o a t in g s ,. Paint, OU,-and.Chem. Rev. 89n9-13, iUns. RS T U V W XY Z[ [\ ]^ _ `1900. EFFECT OF -0 _ 0 q_3X1 _ 0 Xq 1 q _ 0 1 0 + Xq 1 0 q a bc 0 _ Xq d e0 ~~ q f gXX . Indus, and Engin. Chem. 22 : 847-854, illus. 1930. PROCEDURE USED BY THE FOREST' PRODUCTS LABORATORY FOB EVALUATING E h ij1 0 q t 0 _ Xq kXX . Amer. Sdc. Testing Materials Proc. 30, pt. II, pp. 852-870, illus. 1930. @QA lXX m n o p o q1 0 q 0 q 3 1 _ Q < _ X+ Jour. Forestry 28:1136-1145. rs1 X< + t u0 q ~X t r y . 1931. DEVELOPMENTS IN THE STABILIZATION OF PAINTING PRACTICE FOR WOOD. Amer. Soc. Mcch. Engin. Trans. Wood Indus. 53:53-67, illus. v w x y z {1932. Q q 1 q QX X 1 0 q ~1 + . .< 4 0 00 q 3 < President's Conference on Home Building and Homo Ownership, Final Repts. Com. 7:102-116. 1932. FARM BUILDINGS | }QX ~ < 1 0 q < ~X . 1 Q 0 q 3 < 3 0 q tJ. S. Dept. Agr. Yearbook 1932:196-197, illus. 1933. 0 q 3 QX 1 0 q ~X< . 1 <0 0 Jour. Chem. Ed. 10 : 529-538, illus. 1933. DUBABHITO OF PAINT ON LONGLEAF AND SHORYLEAF PINEt South. IjUmberman 146: 20-22, illus. 1933. EFFECTIVENESS OF PAINTS IN RETARDING MOISTURE ABSORPTION BY WOOD. Indus, and Engin. Chem. 25: 835-842, illus. I FLB 000953 WOOD HANDBOOK 247 Bk o w h e, F. L.--Continued. I 1834 a l u min u m p r imin g p a in t , mrmr o n t h e d u r a b il it f o f soasm p a in t s o n w o o d . Indus. and Engin. Chem. 26 : 369. 1934 DDEABttirr op 1 0 q t Xq XX 1 0 Q 0 q _ XQ0 X 0 Q Amer. Wood Preservers' Assoc. Proe. 30: ---------- and He t j b es k t , C. E. 1931. EFFECT OP RESIN IN LONGLEAF PINE ON THE DURABELITY OP HOUSE p a in t s . Indus, and Engin, Chem. 23 : 874-877. Du n l a p , M. E. 1926. t h e p a in t in g OP TREATED w o o d . Indus, and Engin. Chem. 18: 1091. Ed w a r d s , J. D., and Wr a y , K. I. 1927. p r o t e c t in g w o o b w it h a l u min u m p a in t . Indus. and Engin. Chem. 19:975-977. G1 q , H. A. 1984. p h y s ic a l a n d c h e mic a l e x a min a t io n o p pain t s , v ar n is h es , l ac q u e r s , a n d c o l o r s . Ed. 6, 1174 pp., illus. Washington, D. 0. Ha r t w ig , O, R. 1929. c a u s e s o p p a in t f a il u r e o n s id e w a l l s . Amer, Paint and Varnish Manfrs. Assoc., Sci. Sec, Cite. 355, pp. 742-807, illus. Hq , G. M. 1930. EFFEOnVEMESS OF MOISTURE-HtCLUDING COATINGS ON WOOD. D. S. Dept. Agr. Cire. 128, 28 pp., illus. KOEHXER, A1980. c a u s es a n d p r e v en t io n o f r a is ed g r a in . Timberaiaii 31: 162, 164, 166, illns. 1982. s o me o b s e r v a t io n s ON b a is e d g r a in . Amer. Soc. Meeh. Engin. Trans. Wood Indus. 54: 27-30, illus. SXQ+ , F.-.C., and P1 + F. C: 1980. d r y in g o f e x t e r io r p a in t s u n d e r v a r io u s w e a t h e r , c o n d it io n s a n d o v er d if f e r en t w o o d s . Indus. and Engin. Chem. 22: 84-87, Ulus. (Comment by P. L. Browne, pp. 4(X>-401.) | vt" FLB 000954 K SOME INTERESTING FACTS ABOU By F. L. BROWNE, Senior Chemist Forest Products Laboratory*, Forest Service, U. S. Department of Agriculture TCLTHOUGH thousands of owners of frame buildings master painters, and the lead miners to encourage better / \ succeed in keeping them painted to their satisfaction practices and to study home owners' complaints about house A- there is another large group that experiences repeated paint. The regional lumber manufacturers' associations are and disastrous early failures of their paint coatings. The latter group is numerous enough to give rise to a growing public feeling that exterior paint and painting are not so reliable now placing pamphlets containing painting instructions in bundles of siding lumber but find thmselves badly handi capped by the fact that pure white lead paint is the only kind of paint commonly sold in a sufficiently standardized form to as they should be. Lumbermen and lumber dealers suffer permit making specific recommendations for its use. The from such public resentment against paint for two reasons: National Retail Lumber Dealers' Association from time to ! First, it becomes a factor in turning builders against wood in time distributes circulars about paint prepared by the Na favor of competitive materials that may be used without paint, tional Paint, Varnish and Lacquer Manufacturers' Associa and second, the lumberman is sometimes drawn into specific complaints and asked to share in settlement for them. Realization of the handicap of paint difficulties in the sell ing of their products has led various lumber groups to take active measures against bad painting practices. Ten years ago one of the regional lumber manufacturers' associations de tailed Otto Hartwig to inspect houses on which complaint tion. The Secretaries' Conference of the lumber dealers has appointed a research committee to study the paint situation and the International Society of Master Painters has a com mittee considering a plan to examine and certify satisfactory paints to its members. These various activities speak eloquently of the widespread dissatisfaction with painted woodwork. All of the movements about paint had been called to the attention of the association. Within a few years Hartwig studied over 1500 houses. More recently the Lumber Products Better Paint campaign was-, organized under the sponsorship of lumber groups, the When point failures lead io expensive jobs of removal -with the blow torch the cost of paint maintenance be Maintained at Madison, Wisconsin, in co-operacion with the University of Wisconsin. comes excessive and house owners become dissatisfied with painted exterior woodwork. ! I N41698.32 !. FLB 00095i have the commendable objective of making paint maintenance more reliable and painted woodwork more attractive to house owners, and therefore should be given every encouragement. There is some danger, however, that the separate groups in thijir zeal to protect their Own interests map tread on one ' another's toys sufficiently to embfioil them all in minor bick ering to the detriment of their common purpose. Each group fully appreciates the virtues and achievements of its own members but is less familiar with those of the others and con sequently is prone to see the other fellow's faults but not its own. Perhaps the temptation to mutual recrimination can be illustrated to best advantage by the following quotation from one of numerous similar letters received from lumber dealers by the Forest Products Laboratory: We furnished some Clear (name of species) siding on a job..here abput five years ago and have been receiving complaints at various times since on discoloration of the siding. We Were convinced that this Was due to the presence of moisture which in some man ner got to the wood itself, bur were unable to prove this to the satisfaction of the customer. We received the assistance of the.....................Lumber Co. who shipped us the siding and the owner had an architect inspect the job. The consensus of opinion was strongly to the effect that the paint was inferior and did not protect the siding. However, the owner has always been loathe to believe this, preferring rather to strongly condemn the wood. Undoubtedly the owner had heard also from the paint dealer and paint manufacturer and one of them may have written the laboratory telling how his fine paint had failed because it was applied to this inferior wood and asking whether we knew of any way of painting such wood satis factorily. Nothing is gained by blaming either the wood or the paint for failures of this and most of the other kinds that so often discourage house owners with painted woodwork. Both lum ber and paint suffer from the resulting public dissatisfaction. Removal of paint with modern house point removers is less expensive and involves less hazard of fire than removal with the .blow torch, but from the number of men. working on this job it is evident that the cost still remains too high. In good paint maintenance removal of paint should be unnecessary. FLB Both industries, therefore, ate vitally concerned with the causes of paint complaints and with the working out of meth ods of ensuring satisfactory service of house paints on wood. Self interest demands that the two industries recognize a com mon problem in which one is as much concerned as the other. Table X records the relative occurrence of different species of wood in the paint complaints. The species are grouped according to their ability to retain paint coatings under normal conditions of service, group 1 holding coatings longest and group 4 requiring more frequent repainting. s : i fi The basic cause of difficulty with paint is well expressed As a rule only one species, that of the principal paint in the following quotation from a letter from a contracting supporting surface, was recorded for each house. For houses I* painter: with wood siding the species noted was the siding, unless the I have spent 30 years studying paint failures and successes, and the real truth is shocking and disgraceful. Not more than 20 per cent of all exterior painting done today can be regarded as above reproach and welt over half of it is positively rotten and dis honest. As I see it, the chief causes are: No one is accountable to any one and it is comparatively easy to pass, the buck when failure comes; the great number of substitutes and adulterants available; the ease with which anyone can engage in die painting business, the prime requirement being that one is a fair brush-hand which can be acquired by painting two or three small cottages. complaint was confined to exterior surfaces other than siding. | For houses covered with materials other than wood, of course, | the species recorded was that of the painted woodwork about | which complaint was made. j Table 1 indicates that the order of occurrence of paint com- f plaints on different spedes of wood is just the reverse of out ; expectation if the nature of the wood painted had very much | to do with the troubles. The reason for this reversal of the true order of desirability for painting is easily understood. s:1 Divided responsibility for maintenance arises from the fact that the paint manufacturer turns out only a semi-fabri cated product that must be further fabricated by another interest, the painter, before a useful coating is obtained and this coating in turn must be renewed at suitable intervals at the dictates of a third interest, the property owner, who usually has little technical knowledge and is untrained in the art of paint maintenance. Even there the division of re sponsibility does not cease because some woods hold paint longer than others and certain details of design, construction, and occupancy may admit water behind painted woodwork to the detriment of the paint. As a result nearly every interest connected with the design and construction of the house may share with the paint manufacturer, painter, and owner the responsibility for factors upon which the serviceableness of the paint coating depends. Is it any;wonder that, when failure arises, everyone passes the buck to someone else and the owner is left holding the sack ? The Forest Products Laboratory's studies revealed a differ ence in paint retention between woods of group 1 and woods: of group 4 at the ratio of roughly 4 : 3, that is, a coating j lasting four years on wood of group 1 reaches a similar con- f dition in three years on wood of group 4. Paint complaints, however, rarely arise unless the paint fails within half of its normal period of durability, say within two years. Early fail ures that cause complaints therefore arise from factors other than the nature of toe wood. Lumbermen will promptly rec ognize that the spedes occur in Table 1 roughly in the order of most frequent use for painted exterior surfaces on buildings of value in the northeastern and middle western parts of the country, where nearly all the data were obtained. Bevel siding, for example, is made predominantly of woods of groups 1 and 2. Drop siding, which is often made of woods of groups 3 and 4, is used chiefly for cheaper construction which toe owner is not so likely to expect to keep well painted. It appears, therefore, that most of out complaints about paint arise on structures on which the best woods from the point of Some Statistics on Paint Complaints view of painting have been selected, < There is a general tendency on the part of the public, lum bermen, architects, and painters to attribute paint failures hastily to cheap paint. The paint industry, on the other hand, equally hastily attributes them to bad lumber, wet lumber, or "defects in construction." These conclusions come largely from toe human inability to see the forest for the trees. For many years toe Forest Products Laboratory has been asked for advice by owners, architects, painters, lumbermen, or paint manufacturers about specific paint complaints and the writer has inspected the jobs whenever he could gain access to them or has had boards of siding or photographs submitted with the reports. During the past two years record of over 200 complaints has been made from which certain significant generalizations may be drawn. Most of the complaints deal only with a single house but in some cases one complaint involves several houses and in a few cases one complaint deals with several hundred houses in one group. TABLE 1 Distribution of Species by Painting Group in Approxi- mately 2D0 Paint Complaints Species and painting group-- Group 1--Cedar, cypress and redwood.................. ,,... Group 3--Ponderosa pine, spruces, and hemlocks........ Group 3--Basswood and poplar..................................., . Speciesnot identified in the reports................................. Per cent of total complaints 42.7 15.1 5.8 3.9 3.8 28.7 100-0 TABLE 2 Distribution of Paints by "Grades" in Approximately 200 Paint Complaints "Grade" of paint-- Per cent of total complaints 57.5 7.5 2.1 32.9 100.0 Table 2 reveals a very similar situation with respect to the quality of paint that most frequently figures in paint com plaints. The paint industry has no recognized grading system for house paints but it is common practice for a paint manu facturer to offer two or more brands of paint at different: price levels in which case the brand sold at the highest price is first-grade paint and is toe brand featured most promi nently in the manufacturer's advertising. That first grade paints differ widely in quality must be admitted but until there is some accepted system of grading paints we have no other course than to consider all first-grade paints on an equal footing. In Table 2 the paints are classified according to this usage of toe paint industry. The list of first-grade paints occurring among toe 200 complaints is practically a roll call of toe best known brands of paint in the United States together with a smaller number of paints made by local manufacturers. The second grade paints are not to be con sidered "cheap" paints because many of them compare favor- I I FLB ecies iped tmal and saint rases s the ling, arse, bout, i coni: Out nuch : the :ood. ifferoods iting con- ; lints, j )f its j fail- ; other ' rcc-; jrdei | lings i f the ding, ips 1 oups: i the d. It I paintl nt of ] itely j cent total >latnts 7,5 7,5 2.1 2.9 0.0 ct to I com'stem tanu- j erenti price :omi>rade until re no n an ding >rade lly a nited local conavor-' i ably In quality with some of the first-grade paints. Only paints of clearly very inferior quality and sold at very low prices can be publicly branded as "cheap" paints at the present time. Most of the houses about which complaint was made had been painted more than once and more than one brand of paint had been used. If all paints were first grade the case was scored under first grade. If any one of the paints was second grade or "cheap" paint the case was scored under the paint of lowest grade. Very often on older houses the nature of the earlier paints had long since been forgotten and the scoring had to be done on the basis of those paints that were still recalled. About one-third of the cases are recorded as indeterminant because the writer did not accept statements when he felt it possible that he was being misinformed or that the owner ot painter was merely guessing. Table 2 shows clearly that "cheap" paints are not as a class responsible for a major part of our difficulties with paint. As in the case of the woods the order of occurrence of the paints is chiefly the order of frequency of their use for painting buildings of value. The complaints about paint responsible for the public's discouragement with painted woodwork for exterior surfaces come predominantly from those who have used the best paints the paint industry has to offer on the best woods for painting the lumber industry has to offer. Clearly there is some factor other than the quality of wood and paint and more important than either that as yet is not generally understood; because the dominant factor is not understood resort to (he time-honored pastime of passing the buck when trouble arises is almost inevitable. The forgotten factor in serviceableness of paint is the owner's program of maintenance. When paint is worn out it cannot easily be thrown away; we expat to renew it by puffing new paint over what is left of the old. Some owners repaint at reasonable intervals, say every four years, some Wait six, eight, or even ten years regardless of what happens meantime, some want to paint every year or two, some try to follow' a definite plan of spacing paint jobs, while some have no'plan at all. Rarely is any one kind of paint good paint for all of these programs. To make matters worse owners fre quently try a different brand of paint every time they repaint. Unfortunately two paints, A and B, may each be good paint when used in consistent programs of maintenance, that is, when A is repainted with A and B with B, but it does not follow that A will give good service over B ot B over A. Tables 3 and 4 reveal significant facts about the mainte nance programs of owners complaining about paint service. Table 3 discloses that only 13 per Cent of the complaints were about houses painted for the first time. The 13 per cent may be subdivided into 10.2 per cent in which the trouble came from collection of moisture in sidewalls, 1.4 per cent in which the owner expected paint of a hard type to last more than four or five years, 0.7 per cent in which the painter failed to apply enough paint, and 0.7 pec cent for which the cause of difficulty was not determined. In 30.8 per cent of the com plaints the trouble arose after painting for at least the fifth TABLE 3 Distribution of Complaints According to the Number of Times the House Had Been Painted Number of times painted-- 1 (initial paint jobs)............ 2 (first repaint jobs)............. 3 or 4..................................... 5 or more........................... Number of jobs not reported Per cent of total complaints 13.0 24.0 22.6 30.8 9.6 100.0 time. Complaints about the second paint jobs were nearly twice as numerous as complaints about the first job in spite of the fact that owners are usually most concerned about their houses and most likely to complain about anything that goes wrong when the houses ate new. Table 4 dearly reveals the preponderance of inconsistent maintenance programs among paint complaints. Unfortunately the writer has no statistics to offer about the relative propor tions of consistent and inconsistent programs among jobs that remain successful over a long period of years. Undoubtedly there are many satisfied owners who have changed paints at times during their paint maintenance but Table 4 very strongly suggests that such practice is dangerous unless the particular combination of paints has been tested and proved satisfactory. TABLE 4 Distribution of Complaints According to Consistent or Inconsistent Programs of Maintenance Character of maintenance program-- Per cent of total complaints Consistent (same kind of paint each time)...................... Inconsistent (more than 1 type of paint used)................ Houses with only the initial paint job or for which insufficient information was obtained.............. .......... 9.0 51.7 39.i 100.0 That the experience of paint manufacturers may often bear out the findings of Table 4 although they have not realized it is indicated by the following quotation from a letter to the Forest Products Laboratory : Not very often, but every once in a while we hear of peeling complaints. In practically every instance it isn't the paint we sold that peels, but rather the first original coat that may have been applied five, 10 or 15 years ago. And sometimes we find it due to an original ochre primer, sometimes due to excessive mois ture, etc. There is a question in out minds and possibly you can help us out with some information on the same as a result of considerable experimentations which we understand you have initiated on paint problems with respect to paint applied oyer wood surfaces. The question is tins: How many coats of paint will an average house stand before a burn-off job is necessary? The answer to the correspondent's question is that the ne cessity of a bum-off at any time should be regarded as proof that the program of maintenance was faulty. Probably the most common fault leading to the necessity of paint removal is changing the kind of paint used. Owners faced with the expense of a burn-off often prefer to cover the old siding with composition material that need not be painted. Responsibility for Bad Maintenance Programs The owner, of course, must necessarily be responsible for his maintenance program because he dictates when the house shall be painted and who shall do the work. Under the present circumstances, however, he cannot be blamed for the numerous mistakes that are made. He is rarely a techni cally trained man and still less often a paint expert. He must be guided by information furnished him in simple language principally by the industries whose products he purchases. At present they tell him next to nothing about the practical details of his maintenance program and how it affects his choice of paint. Consequently he is entirely justified in feeling that someone owes him redress when his paint coating fails badly after he has bought good wood, good paint, and hired a good painter. The present difficulty in advising owners about paint main tenance lies largely in the fact that the 30 or 40 different I types of house paint now on the market are sold merely as I house paint They are differentiated only by manufacturer's 1 brand and roughly by price level. Many of them bear a I complicated statement of composition on the label, which | is required by law in some states, but interpretation of forI mulas baffles many technical men. About all the layman can | do with a formula is to use it later in selecting another paint I having the same principal ingredients in much the same pro1 portions. An effective approach to the problem of paint main| tenance cannot be expected until the paint industry adopts | some program of identifying paints by types, each type stand- I ardized within sufficient limits to ensure compatibility of all | paints within the type, and reveals the types to purchasers | in simple language. Along with type identification will logi1 cally go a system of grading paints within each type. Type I identification and .grading of paint are closely analogous to I species identification and grading of lumber and should serve | similar purposes. 1 | Paint Failures Caused by Moisture | Many early failures of paint are caused by collection of t moisture in the sidewalls of houses. A recent booklet cir culated by the New Jersey Zinc Co., over Otto Hartwig's signature, asserts that "at least 80 per cent if not more of all paint failure complaints could be laid at the door of con struction defects of various kinds." Since Hartwig made his Studies we have learned that defects in construction cause 1 collection of moisture in sidewalls much less often than con| densation In houses where there are no recognizable defects in construction. How to prevent condensation in modem, tightly built and well insulated buildings, especially if air conditioning and- winter humidification are to be introduced, is an as yet uasolved problem on which much work is now being done in many laboratories. Until it is solved and prob ably for a long time thereafter we shall have the problem of < keeping" jpaint' on houses whose Sidewalls at times condense moistdre. ' 'l j -' The Forest Products Laboratory's records of paint com- : plaints reveal moisture as the cause of failure in 78.5 per cent of the cases where only the initial paint job had as yet been applied. These, however, numbered only 13.0 per cent of the total number of complaints recorded. In the total number of complaints moistute played a part in 47 per cent of the cases but among these many were also due in large measure to in compatible combinations of paints or other mistakes in paint maintenance. On the whole, therefore, moisture, serious though it is, is not the predominant cause of paint complaints. Moreover, studies of the Forest Products Laboratory made to test inferences drawn from the records of paint complaints" have shown that some kinds of paint are much more sensitive to adverse moisture conditions than others and have shown particularly that incompatible combinations of paints are sometimes exceedingly sensitive to moisture. Paints A and B, j for example, may each be reasonably resistant to adverse moisture conditions but if B is applied over A an extremely! sensitive coating that fails quickly and badly in the presence' of only minor amounts of moisture may result, j Friendly Co-operation Is Needed { Difficulties with paint maintenance at the present time? cannot in general be attributed to deceitful practices on the! part of any of the interests involved. As long as cheap paint, bad lumber, and bad painting are made scapegoats we can expect only continuation of buck passing and mounting indig nation on the part of those who ultimately pay the bill and whose patronage is necessary if the various business interests: are to remain alive. Paint difficulties come basically from divided responsibility for, and inadequate technical knowl edge of, the most important factors in paint maintenance. Since a large share of responsibility must remain on the shoulders of die owner, those interests capable of employing competent technical men must for their own protection work! out practicable means of placing paint and wood in the hands I of the owner with adequate instructions'fa simple language ? for using them, together with reasonable assurance of suc-j cess. The element of gambling must be eliminated. j Obviously the lumber industry and the paint industry are charged With the responsibility for technical leadership in the! enterprise. Sympathetic understanding and friendly co-opera- j tion between them is certainly essential. There should b.e no) time for mutual recrimination and acrimonious debate. In; both industries time-honored policies that were good busi- j ness in the expansive and somewhat irresponsible earLy dec ades of the century may have to be abandoned in these times of competition between rather than within industries when good business comes more and more to mean sincere adher ence to the fundamental law of mutuality of contract.: Changes in traditional policy are not readily accomplished! by compulsion; they are most effectively achieved by earnest)] devotion to constructive solution of mutual difficulties. I | | | FLB 0009f :! Reprinted from PACIFIC RETAIL LUMBERMAN, Portland, Oregon, and San Francisco, California, ' Volume IV, Numbers I and 2 | | l I 3 FLB 0009 PAINT VALUABLE DATA FOR BUYERS Buy House Paint for a Planned Maintenance Program/ By F. L. B X q F* d--. Senior Chemist, Forest Products Laboratory* Madison, Wis. TrQawpaminatteinriadlussttrhyaitnhraevceenlet dyetaors has new developed many new and better kinds o exterior paints. The new paints, however, rarely displace older types of paint, but merely multiply the number of types in common use. The trade custom has always been to identify paints to purchasers only by manufacturer's brand, sometimes supplemented by a detailed formula too technical to be fully understood by anyone but a paint expert. Consequently the im provements in paint formulas have failed to effect an improve ment in the average service given bv paint, have remained gen erally unappreciated by paint users, and have added seriously to the bewilderment of purchasing agents who have to buy paint. There have always been paints made to sell at different price levels, of course, and it has been tacitly assumed that the purchas ing agent's problem is merely one of getting his money's worth in paint quality. Presumably the more expensive paints are better paints; any good paint, supposedly, is good paint for anyone to use, which involves the assumption that one good paint can be applied safely over any other good paint. These assumptions caused trouble enough in the days when there were only a limited number of types of paint on the market, but with the multiplicity of paints now available they reduce most of our painting tosheer gambling. If the user is lucky, good paint will give him good service, but if he is unlucky there is always some factor other than the paint to which the difficulty may be attributed. In buying paint, getting his money's worth is only one of the purchasing agent's problems; getting the right kind of good paint for the specific purpose is much more important and often more difficult. House paint should be purchased in accordance with the re quirements of a definitely planned program of maintenance for the buildings on which it is to be used. In so doing the purchasing agent stands between the maintenance engineers of his company and the salesmen of the paint manufacturers, both of whose co operation he needs. From the maintenance engineers he should have the assurance that there is a carefully considered plan of maintenance and that adequate records are kept of the painting histories of the buildings. With a plan and record of its execution it becomes possible to select paint intelligently and to guide the maintenance program along lines justified by past experience. The uncertainties of experimentation can be avoided. Classification of Maintenance Programs Maintenance programs for exterior woodwork may be classified according to the length of time between paintings. The approxi mate period of durability of gopd white or tinted white paints offers a convenient yardstick. In most parts of the country and on woods that hold paint reasonably well (see P1 _ 0 ~0 _P_ Q1 X for February, 1934, page 18) good white paints should not be expected to remain durable beyond 4 to 5 years. It is not always practicable to paint industrial buildings so often. For programs with more than the expectancy of white paints between paintings either unusually durable colored paints should be chosen or the white or tinted paints, which will break up seriously before the next painting, should be chosen for their ability to stand neglect well rather than for their durability, Soft paints, such as pure white lead paint and the very durable colored paints, can be relital FIG. I--the unsatisfactory result of using a paint of a bard typ' in a maintenance program with long intervals between paintings during which the paint passes through a period of neglect. FIG. 2--The disastrous result of a marked change in type of paint. This house was maintained with colored pigment paints for many years and was finally painted with a tinted white paint of fairly hard type. ^Maintained by the Forest Service, U, S. Department of Agriculture, at Madison, Wis., in co-operation with the University of Wisconsin. Pacific Purchasor -r February, 1937 15 N41698.33 FLB 00096 upon to stand neglect well so that they can be repainted easily and durably without removing the old coatings. Programs in which repainting can be assured at intervals that anticipate the breakup of white paints permit the choice of any one of the good paints on the market when the building is new or the old coating has been removed completely. Once the pro gram has been started with a given paint, however, paint of the same type should be used for all subsequent painting unless the specific change in type that may be considered has been proved safe by much previous experience. When radical changes in type of paint are made there is no assurance that the new paint, no matter how good it may be, will give its normal period of dura bility. Paints of medium hardness are probably the logical choice for programs that make use of most of the expectancy of white paints although soft paints are also satisfactory and Very hard paints may he used if sufficient care is taken to see that they do not begin to break up before repainting. Perhaps the most difficult programs are those in which, for business reasons, unusually fresh and clean,appearance must be maintained at all times. Painting is then done at short intervals. The old paint scarcely has rime enough to reach a suitable con dition for repainting and does not wear away much. Under such circumstances consistent use of exactly the same type of paint is very important. Just as little new paint as possible should be applied at each painting. Where practicable washing of the coat ing to remove dirt and restore gloss should be practiced in order to put off repainting as long as possible. If the washing is done with an alkaline solution strong enough to remove some of the old paint so much the better.'Ultimately the coating may be expected to become too thick and break up badly so that a com- > plete removal will be necessary. For programs of this kind very hard types of paint, often enamelized paints, have certain ad vantages such as long retention of gloss and ease of washing. They should be made with very ofiaque pigments and have un- ttsiially great hiding power. ; - , Need for Type identification and Grading From the foregoing the difficulty of using striedy proprietary paints intelligently in a planned program of maintenance is obvious. If the purchasing agent is not fully informed about the composition of the paint and the paint manufacturer has no knowledge of the maintenance program there is no means of bringing the two into harmony. The purchasing agent's position is very similar to that in which the physician wpuld find himself if there were no pharmacopoeia and the only drugs available were proprietary medicines whose composition the physician did not know. To meet this condition in painting some of the large paint manufacturers offer to make painting surveys of industrial plants so that they can specify what they believe to be appropriate paints of their own manufacture together with the maintenance programs that should be followed. This system, of course, takes the whole responsibility for maintenance out of the hands of those who pay for it. A reasonable system of type identification and grading of paints adopted and enforced by the paint industry through its trade association would open the way for a sound program of education of purchasing agents, maintenance engineers, painters, and property owners in proper methods of guiding maintenance along lines justified by past experience and avoiding the numer ous uncertainties that now ruin so many paint jobs. So far all efforts to furnish adequate instruction in the use of paint fall down on the stumbling-block of buying proprietary paints with reasonable knowledge of their characteristics. Although there are in fact many varieties of paint they appear on the market merely as house paint. Formula labeling solves the problem only for those able to make a thorough technical study of paint and to keep it up to date. What we need is a label that reads somewhat as shown in the next column. Such a label based on adequate standards properly enforced would isolate the technical problems of paint and its maintenance in technical laboratories capable of dealing with them effectively. Type and quality of paints would be identified in simple, non +1 q ~1 _ < 1 q +<X ------ Brand Exterior Paint C 1 + CXXr 's Type TLZ, Medium Con- tent of zinc oxide Grade A, N, P. V. & L. M. Assoc, standards Manufactured by _ . ... PAINT ASSOCIATION SEAL technical terms. Sound programs of maintenance could then be specified in language easily understood by everyone concerned. Clumsy formula labels and the Cumbersome method of purchas ing on formula specifications could both be dispensed with. Type Identification and Grading are Practicable The details of a practicable plan for type identification and grading cannot be discussed within the scope of this article. For several years the Forest Products Laboratory has been follow ing such a plan in classifying paints used in its studies and for advising correspondents about paint formulas. The conventional formulas in percentages by weight are recalculated to show the volume of each ingredient in 1 gallon of prepared paint. The calculations are similar to those followed in the paint industry in computing yields and costs. From these data the volume of opaque pigments, the volume of total pigments, and the volume of non-volatile material (pigments plus fixed oils) are computed and used as the basis for grading as follows; Minimum content, of-- GRADE A B C D E F OPAQUE PIGMENTS TOTAL PIGMENTS NON-VOLATILE in gallon per gallon of prepared paint 25 ,25 .89 21 .23 .82 .17 .21 .75 .13 .19 .67 .09 .17 .60 ____ -- ____ The opaque white pigments commonly used include the white leads, the zinc oxides and leaded zinc oxides, titanium-barium pigment, and regular lithopone, Titanium and zinc sulfide pig ments in which the titanium dioxide'or zinc sulfide exceeds the proportions by volume in titanium-barium pigment and regular lithopone are credited with a proportionately greater volume of transparent pigment in computing the content of total opaque p gments in the paint. The paints are divided into types according to the nature of the opaque pigments present, the percentages of zinc oxide by volume in the total pigment, and the nature of the fixed vehicle. The white or tinted paints now on the market make it necessary to recognize at least the following types exclusive of the colored pigment paints; True house paints (fixed vehicle wholly or chiefly unbodied drying oil).: Zinc-less.paints: 1. Type L, pure white lead paint 2. Type TL, white lead and titanium-barium .pigment `TOO per cent pure" paints made with lead and zinc pigments only 3. Type LZ with high content of zinc oxide d. Type LZ with medium content of zinc oxide 5. Type LZ with lose content of zinc oxide Lead and zinc paints in which transparent pigments are used: 6. Type LZ with high content of zinc oxide 7. Type .LZ with medium content of zinc oxide 8. Type LZ with low content of zinc oxide Titanium, lead and zinc paints: 9. Type TLZ with medium content of zinc oxide 10. Type TLZ with low content of zinc oxide Lithopone, lead and zinc paints: ] 1. Type PI.2 with medium content of zinc oxide 12. Type PLZ with low content of zinc oxide Lead-less paints: 13. Types TZ, PZ, and TPZ with medium content of zinc oxide H. Types.TZ, PZ, and TPZ with low content of zinc oxide Enamelized, quick-dry, and resin-fortified paints: AU of the foregoing pigment types possible but so far usually LZ, TLZ, PLZ, or XZ with high, medium, or low content of zinc oxide. Very cheap paints with no lead or zinc pigments and with varnish and water in the vehicle: Type P, T. or PT. (Continued on page 28) 16 Pacific Purchaser r VoL XIX* 'No. 2 aew'~standards adogfed in I92t> cover various nonmetallic materials, xn^^Bg^helo^p^ing: High'Early-Stxmgtn^Qrtlaad Ce- .. ment. Natural Building Stone. Load'Bearing Concrete Ma Units. Structural Clay Tile,, Clay Fug^iSridCtor Malleable Fur- naccsS^Mnealin^Ovens, and Sta tionary Boiler^Service. Refractories fpr Incinerators. Ground. Fira'Clay. Sodium Silicate fot Titamtim j he Sulfide. Mormal Amyl Acets IndustrialSO-j^rcent Benzine (Ben- Rubfe^r Belting. Rabbdrsi&>s<5. Asbestos Kb^mg for Electrical Pur poses. AsbestosYani Woolen and Worste Round-Hole Screens foresting I pries of the book in blue clothj :3:sri?vtf::^:lrat3:qjSSrESs^-^^S^S7-^roaH~StIi PEiIadelphia, P<ti, *at the following prices: Either part, $7.50; both parts, $14.00. Buy House Paint tot a Planned Maintenance Program (Continued from page 16) When it is remembered that most of the above types of paint may run .the gamut .of grades from A to E or F and that an industrial plant usually requires many kinds of paint besides house paint the complexity of the modern paint market can readily be appreciated. If the frequent misfits between type of paint-and maintenance program are to become less numerous some such simplified method of reaching an understanding be tween buyer and seller as that suggested is essential. be presidents tabic was presided over by Ralph N. Jacobs^ .called the meeting to order and handled It up to f it was turned over to Ralph W. Myers for the "Old l Uners " participation, A giiest at the head table was C. P- Visel, Gavdier of Los Angeles, and now operating Asilomar-by-the-Sfea, who enlarged Vpon the advantages of that wonderful resort and Urged the\members to attend the weekend party on January 30th and 31 Short repoks were made by Ed Thatcher and Clyde Yjerge of the Program Committee and Al Short presented/our new mem^ber, Russell Mn|s of the E. 0. Bullard Company. , very interesting talk was given by Frank X Doane, associate al engineers of the San Francisco-! land Bay Bridge, wtib^spdke on the topic, "Hectrification of, ie Bay Bridge." He showed a number offsides depicting the urn lighting fixtures and the electrical connections and featuri for lighting and eon- trolling fete 'horns, signal lights, etc., Doane afterwards touched briefly upon thfiplans for operation of the two railway systems overVile bridge oh which the' work is now progressing. He stated that these trains would operate in units up to ten cars each and with a minimum, headway of seventy seconds. The maximum speqdj will be 35 miles per hour; other speeds will be 25 miles, 18 mi es and 8 miles. Special safety arrangements will be installed to iiminate any possibility of collision or delay in case of accident beyond the coritrol of the operator. After Ralph Myers turned the meeting back to President Jacobson at the close, Charles Wail, president of the X. P. A, Association and "Old Timer," who used to play harmonica ducts with D/ve Gray, was called upon and rendered in a very delightful add appropriate manner 'on his portable organ, Old Timers' Night ' "Aloha,''put of speciaj' respect to Past President Hobart W, Mears pfehe Matson Line, who was unableto attend the meeting, (Continued from p'age 5) al attendance at this meeting waV 104, fn closi^tet-it-be-saidrfjat the "Old Timers" deeplya] atea'thc opportunity to prSaTTllieniselye3s.- too ttffrtegr-TrnemmStiecrs. Our interesrin Association affairs is as kr-'-' asjifthe days when we were, activfely cngageoSn^thc po itipfi of its progress. The^ "Old TimersNwc ready am at all times to be ' upon for advice and counsel' in JQtfe. opc-that thcic-amenence wall prove to be Let's have an "Old/Hrqcj/ Night" every few years! New In Industry \ A new control? valve for vacuum brakes on trailers allows the operator of passenger car or tractor to apply tlftf trailer brakes without removing his hands from the steering wheel, A line of new type soft-face hammers for working on fine finished surfaces has tips of a tough ambcr-colorctk plastic that will not shatter, chip or break. When the tips becomcWorn, new tips may hi easily installed. \ A different seanne^frangembtt than usual was utilized at. this "Old Timers' Elirmer," inasmuch as there was no head table. ;s were all seateuNjt one long oval table at which Ralph WyMyers presided. At ah. adjoining table were seated the paift Presidents who were not charter members and at the/.fieayfqf/his table was Arthur H. Silvefstone--"the oldest living gait president who Was not a charter mcmlxr." At a third tabicyft "Old Timers" was seated the past secretaries as well as th^presejjt secretary, Arthur R. Woodman. Hardwood floors of two-inch pieces in a basket-weave pattern are now made into grilled Sections two by six feet that imay be quickly and economically laid over old floors. The block; com posing the sections are 5/1.6 inch thick. Sections are laid with adhesive,, not brads. \ A recently developed metal finish is said to dry with a lustrous hard surface, yet have resiliency to orevent checking and mark ing. Insoluble in oils, it is resistant to alkalis, commercial acids, and atmospheric corrosion. COMPANY 325~Madce^St:reet ` San Francisco Phone^XbtQok 4212 Wholesale and Retail Distributors PJ-NTS^VARNISH - D U CO 28 SlPtlSlll I* We invite your inquiries for PARAFFINE WAXES EuHyKefined--all melting points --- --------"JSemi Refined " Crude Scale " ^LlBL4B#rCHEB CO. JVareftd'use<Slocks at: SAN FRANCISCO PORTLXNEL LOS ANGELES SALT LAKE CITY SEATTLE Pacific Purchaser r Vol. XIX, No. 2 FLB 000963 lime has been added, have been passed through filter presses at a temperature of 190 F. without affecting the Industracote'finish or changing the original flavor of the juice, Many other more common tests have proved the adaptability o; Industrifebte Finish as a protective coating against unusual corrosive agents, according -to the General Paint Corporation, Reflection Values Diffuse reflection values on gloss house paints- Crcam . fvory . Buff (Pale) . . Yellow (Lemon) Tan Brown Cafe-au-Lalt Brown (Cocoa) Blue (Rag) Gray (Medium) Gray (Light) . Gray (Dark) Gray (Pearl) Blue (Pale) Blue (Bright) . Mandarin Red . Apple Green preen (Pale) lUtter Green G^een (Dark) . Rea/Pompelaxi) Red vQrimsoa) . Brown bDark) . Orange (&eep) . Yellow (Bright) Diffuse reflection values on flat wall paints \ Ivory....................................... 59% Peach or Salmon^ Cream ...... 71% Brown Cafe-au-Lafa Apricot Beige .... 66% Green (Light) , Buff (Light) .... 56% Aluminum . Apple Green (Pale) . . 51% Blue Gray (Dark) Light Gray (P.earl) . . 53% Medium Gray . Pale Green {almost sky blue) 45% Yellow (Lemon) Pale Blue . . . . .43% Rose (Deep) Lightlvory................................ 71% Dark Green * Diffuse 35% or total of diffuse and specular 55%. 'A. S. T..M. Book of Standards The American Society for Testing Materials has recendy issjled its 1936 Book of A, S. T. M. Standards, This triennial publication contains all op the standard specifications, methods of test, Recom mended practices and definitions formally adopted by the/Society. The 1936 issue is in two parts--Part I giving in their ktest form all A.S.T.M. standards covering metallic materials;/Part II, all standards relating to non-metallic materials. Both parts aggregate 2,400 pages. In each Part, the specifications for a particular/lass of material are given first, followed directly by the test methods, definitions, etc. A complete subject index lists each standard under the princi pal subject covered, with the keywords in alphabetical sequence. This index, together with two tables of contents, one listing stand ards by the materials covered, the other Jn order of sequence of the serial designations, facilitates the upfe of the book. Of the 181 standards in Part 1, 109 cover the ferrous metals, steel, wrought iron, pig iron and iron castings and ferro-alloys, while 60 relate to non-ferrous metals, including aluminum and magnesium alloys, copper and copper alloys, lead, nickel, zinc, bearing metals, solder metal, deoxidizers, electrical-heating and electrical-resistance alloys. Tw/lve of the standards involve metal lography and general testing'methods. During 1936 many ney standards were adopted relating to widely used materials. In Part I, the following materials are covered by new specifications: Alloy-Steel Castings toy Structural Purposes. / Carbon-Steel and Alloy-Steel Cast ings for Railroads./ Welded and Seamlws Steel Pipe or Ordinary Uses./ Electrie-FusionAVelded Steel Pipe. Lap-Welded, Seamless and EJectric- Fusion-Welded Steel Pipefor High- Tetaperamre and High Pressure .Service. Alloy-Steel Pipe, Forgings and Cast ings for Service at Temperatures from 750 F. to 3100 F. (Jncoated Wrought-Iron Sheets. Zinc-Coated (Galvanized) Wroughc- Iron Sheets. Gray-Iron Castings. Copper-Base Alloys in Ingot Form for Sand Castings. Bronze Trolley Wire. Rockwell Hardness Testing. Incl/ded in the 335 standards in Part II--Non-Metallic Ma terials--are specifications and test mfethpds covering the general classes of materials. Pacific Purchasor v February, 1937 Mr. Purchasing Agerm When buying paints, lacqtiers, and synthetic enamels . - ./specify the GMG brand. It simifres quality. / Garrett M* Goldberg Paint Co. Manufacturers 1 Years 1019 Mission/Street San Francisco Pacific/Vegetable Oil Corporation Importers, Refiners, Manufacturers, Dealers Oil Handling and Storage Linseed oa inawood Oil Pepula Oil ittonseed Oil Sardine Oil Castor Ofl Rapeseed Oil Soya Bean Oil Refined Oils Turpentine Quicksilver Address Inquiries to 62 TOWNSEND STREET, SAN FRANCISCO Cable Address: PAVEO Plant .and Mill Located at RAN FRANCISCO Stock carried m SEATTLE, PORTLAND, LOS ANGELES and Principal Eastern Cities \pEBMITE ALUMINUM PAINT PERMITE ^nds all the bother and waste of mixing aluminum paint on the job. PERMITExALUMINUM PAINT Comes ready mixed, ratdy to open and use. It remains in suspension and iloes not harden in the can. NON-CORROSIVE PERMITE For inside or outside--orriwood, brick, steel, concrete. Will resist temperatures up to 450 F. HEAT RESISTING PERMITE For boilers, furnaces, engines. May be used safely on surface temperatures up to 1000 F. Both types are described in the interesting folder "BUY IT BY THE FOC" Sent on Request TOOLS - METALS 76 First Street SAN FRANCISCO DOuglas 4180 SHOP SUPPLIES 11th and Alice Street! OAKLAND TEtaplebac 3800 27 FLB id* Developments in paint composi tion in recent Years have tended to complicate problems involved in the painting of both old and new structures. Important among these problems is that presented by the "incompatibility" of dif ferent paints, which is dealt with at length in this discussion. Thick ness of paint coats, frequency of painting and new developments in paint formulation are other matters that are given attention. By F. L. BROWNE Senior Chemist. U. S. Forest Products Laboratory, Madison, Wis. / Outcome of an Unplanned Paint Maintenance Program First: painting with two coats of white paint, scrawl painting with dark brown paint, and third painting with two coats of white paint. Photographed 18 months after last painting. Definite result of incompatibility. CCLOC/ Gu/\ rUcsOS- JC) 3 7 W(f/fT A-R 'B- 1 THE past decade or two marks a period of accelerating changes in paint formulation, the end of which is not yet in sight. Many of the changes in paints have been in the direction of furnishing distinctly improved products from the user's point of view. The same period of time, however, has marked also an increasing feeling Of exasperation with the uncertainties of paint be havior and with the numerous cases of unreasonably early failures of paint jobs. The dominant factor that has been so generally overlooked in the past is the fact that a good paint, if it is to give the good service of which it is capable, must be used in a pro gram of paint maintenance for which it is suitable and for which it was designed. Most painting takes the form of renewing a coating applied some years previously; the composi tion of the new coating and the be havior to be expected of it depend upon the composition and age of the paint or paints used previously as well as upon the composition of the new paint. ' What Is Good Paint? If a building stands 50 years it receives one paint job when erected and, if well maintained, some 10 or 12 paint jobs at suitable intervals subsequently. Each repaint job is applied over what is left of the pre ceding jobs; if it becomes necessary at any time to remove the old coat ing the maintenance program has been, unsatisfactory at least for that building. To the paint purchaser, therefore, the important point is not whether a given paint is capable of good service, but whether it can be relied upon to give good service on the particular building for which it is purchased. A good paint for one building may he bad paint for the one next door. Failure.to recognize that, after the initial paint job, a coating is com- 'Abstract of a paper presented before the con vention of the American Railway Bridge and Building Association on October 22. N41698.34 FLB 0009i Fbru*ry, 1937 Railway EnglneeringirfMaintenance joints between the stones and the heads clinched over the reinforcing iars. To prepare the spikes for this purpose, they are heated to a forging te: erature and flattened somewhat to ilitate driving. To render them more malleable they are allowed to cool slot An interesting innovation, involv ing the use'pf clamps of a special design, is employed in the repair of stone niasonryNpiers in which the stones in the top course have shown a tendency to sprea<Kapart under the weight of the superstructure. The clamps used are formed, of 1-in. by 4in. sfeel bars about 28 na. long. A 5in. right-angle bend is nWe at each end of each bar and the bent portions or legs are given an inwardSpr con cave curve. When the two lege of a bar are driven into holes drill) adjacent stones in the top of the the springing action induced by the curvature tends to draw the stones together. The horizontal portions of the clamps are inserted in grooves cut in the masonry so that the upper edges are flush with the top surface of the pier. Since the concrete repair program described in this article was inaugur ated the patching of such structures on about 700 miles of line has been completed, and as the repair forces have gained experience and skill in the application of patches, the rail road has become even more fully con vinced of the soundness of the policy of repairing concrete before deteri oration has been allowed to progress beyond the initial stage. The concrete repair program on the Burlington is being carried out under the general supervision of G. A. Haggander, engineer of bridges. `Don't Let It Occur to i*>u FROM 22.9 to 27.4 per cent of all railway employees killed while on duty during the last IS years lost their lives as a result of being struck or run over by locomotives or cars. For this reason the Committee on Education of the Safety section of the Associa tion of American Railroads has issued at least three circulars in each of the last five years dealing with this seri ous menace to railway men. The ef fectiveness of these appeals is indi cated by the fact that deaths from this one cause were reduced from 1,578 in the five years ending with Decem ber 31, 1931, to 628 for the foliowinj five years, and by the fact that fatal?ties from this cause represented 22.9 per cent of the total fatalities for the last five years, compared with 27.9 per cent for the five year;/ ending with December 31, 1931. As a means of continuing its edu cation work on this subject the com mittee has issued circular, No. S-517, that drives home theiiazard of "walk ing, standing or sitting on the track" and is distributing the poster repro duced on this page. The bulletin reads as follows: DON'T LET IT OCCUR TO YOU Walking, standing or sitting on tracks except when necessary in the performance of duty is prohibited. Thi^is a good rule to follow in our efforts to prevent men from being 103 tion, warnings, reminders, etc. By whatever means the effort made it is a long step in the rightr direction, for this class of accidents accounts for nearly one-fourth oY all employee fatalities and at least JoO per cent of the cases of "Struck or Runover," result in death or pennanent disability. It is said that we must learn from the horrifying experiences of others, but it is better to learn that way than not at all, so, with the hope that many now living aria unhurt may remain so, a few caseyare here related in which the victim/forgot their own safety. A young track foreman was super vising work being performed by two laborer's. It was snowing hard and a movefnent of time freight was soon to be made. The foreman became dis satisfied with the manner in which re of the laborers was doing his work, and taking the tool from him he undertook the job himself, squat ting down between the rails. He was killed by a yard engine within five minutes. There is no quarrel with the foreman for demonstrating to a la borer the correct method of work. We might even overlook his having taken on a laborer's job temporarily, if the emergency warranted. We can not condone his act in making a laborer of himself without delegating to a member of his force that part of a foreman's duty requiring him to safeguard his men. A traveling inspector from the gen eral offices was walking between the (Continued on page 110) 105 10) etc. By 'made it lirection, account smploy roblems-- cent o .unover,' lisability am fron <{ others What way thai hat man emain so in whic safety. ras supei posed of the old paint plus the new ;d by tw paint is largely responsible for the ird and failure of recent developments in was sooj paint formulation to effect an im- icame di provement in the general service- in whic) ableness of paint. Each new paint doing hj formula brought out adds one more from his to the already super-abundant types elf, squat of paint on the market, for the new s. He wa products never succeed in displacing vithin fiv the old. With paint users generally el with th making little effort to follow con- g to a lasistent programs of maintenance of wort this means that with every new paint his havin the chances of incompatible com- :mporaril) binations of paint are increased and d. We cai the number of abnormally early making paint failures becomes greater. On delcgatinthe other hand some of the new t that pai paints offer distinct advantages for ring him t those who learn how to work them into their maintenance programs Dm the get safely. jetween tf Haphazard programs of paint 110) maintenance so often lead sooner or _______ _latr to disaster even though high [grade paints are always used because me or more of three principal ilunders are made: (1) Incompa- ible combinations of paints are used :ither in the same paint job Or in uccessive paint jobs ; (2) either too uch or too little paint is applied at time, (3) either too much or too ittle time is allowed to elapse be- Are They Today?* tween paintings. To these three basic causes of difficulty with good paints must be added a fourth with which it is often very difficult to deal, namely, access of water to the backs of painted boards, causing blistering and subsequent scaling of the coating at an early age. Incompatible Combinations For a long time much emphasis has been placed on the fact that paints last longer on some woods than on others but very little has been said about the even greater variation in behavior when paint of any one kind is applied over paints of other kinds. We know certain combinations of paints that com monly lead to difficulties but we do not know yet just how far two paints may differ and still work reasonably well together. For the present, therefore, the paint user should take the conservative position of con sidering any serious change in type of paint in the make-up of a coating too dangerous unless there is good evidence in past experience that the particular combination under con sideration can be expected to give good service. A very common incompatibility results from the application of a white or tinted white paint over a colored paint made with little or no lead or zinc pigments. For example, during a 2,000-mile journey over a certain railroad a few years ago the cracking and slipping of a bright yellow paint over red iron oxide paint could be observed from the Pullman car at nearly every station. Early failures of white paints over greens, browns, and blacks are like wise to be seen frequently. Incompatibilities likewise arise among white paints when they are made with very different combina tions of white pigments. It has long been held that white lead and zinc oxide, unlike the remaining white and transparent pigments, are chemically active and profoundly modify the linoxyn formed from lin seed oil. Zinc oxide particularly has a definite hardening action on paint, the effect being roughly proportional to the amount of zinc oxide in the total pigment. At any rate, varia tion in the zinc oxide content of paints causes very distinct changes in the physical properties of the paint. It seems to be advisable to keep the zinc oxide content of paints used successively as nearly constant as practicable. When pure white lead paint, for example, is applied over a previous coating of paint that An Excellent Example of Incompatibility Failure of a tinted white paint applied on a building that for years previously had been kept painted with paints of dark color in which there would be no lead or zinc pig ments. 106 contains zinc oxide, especially if the previous paint has not weathered for a long time, early failure of the white lead paint by conspicuous alligatoring is often observed. To what extent the proportions of white lead and of chemically inert pigments in successive paint coats affect the durability of paint jobs is not yet known. A number of cases' have been observed, however, in which paints of the newer pigmenta tions involving titanium or zinc sul fide pigments, when applied over older paints of the lead and zinc type, have failed to give the service such paints have demonstrated in consistent programs of paint main tenance. Until more is known about the compatibilities of paints pru dence suggests the practice of re painting always with much the same kind of paint used previously. The proportion of total pigment to non-volatile liquids in paint is sig nificant from the point of view of compatibility. In the formulation of the newer paints it is being gener ally recognized that in a finish coat of white paint the total pigments should amount to roughly 27 to 30 per cent by volume of the total non volatile matter instead of the 20 to 25 per cent and even lower that was characteristic of the older formula tions. The undercoat, however, should never have less pigment than the finish coat and best practice re quires that it have more. For that, reason a painter, by thinning the un dercoat with too much oil can pro duce an incompatibility, even when working with the same paint. Raltway Engireering^Maintenance viceableness. Where the coating is allowed to become very thick in the course of time objectionable forms of paint failure are observed that are never seen with thinner coatings of the same paints, and the surface be comes more and more difficult to re paint acceptably. Frequency and Quantity The more frequently a surface is painted the less paint should be put on at a time. For a given interval between paintings the harder the paint used the less should be put on February, 1937 pronounced in the maintenance of the property of large corporations where it is desired to impress the public favorably. Where good ap pearance in a necessarily sooty en vironment is desired it is often bet ter to use hard paints of high opac ity that wash satisfactorily, wash ing them once or twice between paintings, and washing and repaint ing them with one Coat at reasonable intervals rather than repainting them at short intervals with two thick coats at a time. With mod erately hard paints, one good coat of paint applied about every four years An Example of a Well Planned Paint Program First painting in 1924 with two coats of white lead paint. Repainted with one coat of a harder paint of the modern titanium pig ment type in 1927, 1931, and 1935. Photograph taken just before last painting shows a surface that is chalking freely but is free from checking, cracking, curling, flaking, or scaling. Thickness of Paint Coats There seems to be an optimum range of thickness of paint coatings for optimum service. An initial coating of white lead paint applied to new wood according to customary recommendations is about 0.005 inch in thickness while initial jobs of harder paints are often nearer 0.004 inch. Thinner coatings of each type of paint, whether they hide the sur face satisfactorily or not, are less durable and more liable to difficulty with spotted chalking and fading. On the other hand thicker coatings, especially with the harder paints, not only prove no more durable but are prone to more conspicuous cracking, curling and flaking. In a good program of mainte nance the amount of paint restored at each repainting does not greatly exceed the amount worn away since the previous painting so that the thickness of the coating can be kept within the region of optimum ser at a time. Fortunately the harder paints, after weathering, are less ab sorptive and "hold out" new paint more easily than softA paints. Since different parts of a building usually receive different degrees of exposure to sunshine some parts need more paint than others at each repainting. For these reasons it is impracticable to make general statements about the amount of paint that should be ap plied in repainting. It may be said, however, that there is a general tendency to use too much paint in repainting when paints of the harder types are used. This tendency is likely to be particularly is ordinarily sufficient on woodwork. Much trouble with paint comes from failure to observe any system atic plan of repainting. Except with paints that stand neglect well, repainting should anticipate rather than follow break-up of the coating. Where repainting is done before the coating cracks, curls, and flakes in patches there is no problem of scrap ing off all loosened paint and a smooth, sound foundation for the new layer of paint is assured. The renewed coating, therefore, may be expected to have normal durability. The economical course in the long run is to adopt a planned program 1 FLB 00096! Fabrtjdry, 1937 Railway Engineerin^a^Maintenance 107 of maintenance when the building is erected, select a type of paint suit able for the program, and then ad here firmly to the program. The old custom of using red iron oxide paints for the maintenance of buildings of strictly utilitarian pur pose still has much to commend it. Good paint of that type is exceedingly durable and stands neglect well. For those reasons colored pigment paints like iron oxide paints are particularly appropriate for maintenance programs with long in tervals between paintings or for buildings for which it proves im practicable to adopt a definite pro gram. In times of financial depres sion maintenance painting is usually curtailed and it may be wise to rec ognize that some buildings at times will be neglected. Aluminum Point Aluminum paint is beginning to find use as a complete coating for wood for programs with long inter vals between paintings. From the point of view of maintaining protec tion for an unusually long time it is superior to iron oxide paints and its appearance, although metallic, is brighter and more cheerful than the dull red of iron oxide. Among white paints and tinted paints based on white paints, only formulations that make very soft paints are capable of standing neg lect well. Pure white lead paint is the best known very soft paint. It disintegrates by deep chalking, fine checking, and fine crumbling and it wears away by erosion fairly rapid ly but, in consistent maintenance programs, it does not crack, curl, or flake. White not an outstandingly durable white paint it is one of the very few white paints hat can safely be allowed to pass through periods of neglect and still leave a surface that can be repainted easily and with assurance of normal durability. For maintenance of railroad property, however, soft paints have the serious disadvantage of collecting dirt bad ly and being somewhat difficult to wash satisfactorily. Harder types of white and tinted paints are there fore preferred, but in using them it should be remembered that they can not safely be neglected and should be maintained strictly in accordance with a conservatively planned pro gram. In the writer's opinion the out standing development in exterior paints in recent years is the increas ing diversity in types of paint on the market and the consequent necessity for greater technical knowledge of paint composition and its significance in paint maintenance programs on the part of the paint user. Inas much as it is rarely practicable to place the maintenance program com pletely in charge of a single paint manufacturer, the paint user must as sume far more technical responsibil ity than he is often prepared to han dle intelligently. Combinations of Pigments The dominant trend in the manu facture of first grade white paints in recent years has been in the direc tion of combinations of titanium pig ments, white lead, and zinc oxide. The trend is less marked in tinted white paints because the very opaque chalk characteristic of titanium di oxide gives rise to marked fading. The disadvantage of fading, how ever, should be weighed against the advantage of greater freedom from dirt which is likewise characteristic of titanium formulations. In many tints a fairly clean surface even though somewhat faded, is superior in appearance to a dirty surface. With white paint, fading does not en ter into the picture and greater clean liness is a clear advantage. Most of the titanium formulations are further characterized by a lower content of zinc oxide and a higher content of total pigment than was customary in lead and zinc formula tions of similar grade. As a result these paints, when used in consistent programs of maintenance and prop erly applied, remain free from checking or cracking for a long time. Ou the whole the writer feels that the typicals titanium formulations are somewhat less dangerous than the older lead and zinc formulations if for any reason repainting is de ferred a trifle too long, hut they can not safely be allowed to go through long periods of neglect. Good ti tanium pigment paints have much greater opacity than older paints and are therefore especially useful in maintenance programs with rel atively short intervals between re paintings, in which the least possible amount of paint should be applied at a time. Lead titanate is a very new paint pigment that may become important in the future. It is not quite white, having a trace of yellow color, and for that reason the amount that can be used in a white paint is limited but a large proportion can be used in many tinted paints. The informa tion available so far indicates that lead titanate has a remarkable tend ency to retard the embrittlement of paint with age. If it proves possible to take adequate advantage of that property, white and tinted paints may be made more durable in the future. Soy Bean Oil In recent years many efforts have been made to replace the linseed oil in house paint wholly or in large part with other drying oils or resins. Soy bean oil is much discussed at the present time. While not so good a drying oil as linseed, very sub stantial proportions of soy bean oil can be incorporated in good paint, especially if fortified with superior drying oils like perilla or with a small amount of properly treated timg oil. The use of soy bean oil, however, is chiefly a question of utilization of domestic farm crops; there is no immediate prospect of obtaining definitely improved paints in that way. Some consideration is being given to the possible use of moderate pro portions of resin in the vehicle of paints in which there is no zinc oxide in the pigment, the resin being used to impart the desired degree of hard ness instead of zinc oxide. Whether such a radical shift in traditional formulation offers any material ad vantage remains for the future to disclose. A typeial stretch of track on the Western Lines of the Atchison, Topeka & Santa Fc. FLB 000969 The Lake Pontchartrain Trestle / GREGORY Professor of Experimental* Engineering, Tulanc University o Louisiana, New Orleans', La. It ft Built in 1882 of/dreosoted yellow-pine timber, this structure' is still carrying all trains of the Southern and the Gulf. Mobile & North- m railways into New Orleans. Although strengthened at various times to accommo date heavier loading, much of the original timber is still in use after 53 years service. The history and present status of this his THE Lake Pontchartrain trestle, 5.82 miles lbng, carries the Southern into New Orleans. Construction was started in February, 1882, and fin toric sauLcture were presented at the thirtythird annual convention of the American Wood-Preservers Association at NewOrleans on January'27. ished in September of that year. It was built of creosoted yellow-pine timber. Piles from 50 to 68 ft. long, below cut-off, were driven. The total penetration varied from 40 to 48 ft., I n/1,114. other bents the original four more attention and caused more ex according to the length of the piles piles had been ent off just above the pense. The road is now probably fac and the depth of water, which is from f water line and four-post framed bents ing a, much more extensive renewal 8 to 10 ft. The piles were cut off t<y erected. AH of the original ties had of striggers. support caps 12 in. by 44 in., laTcl been renewed, almost entirely as a \ flat; above the caps are the stringfers on which the crossties and decking rest. When first built, the crossties were supported by six stringers, 6 result of mechanical damage by reason of creeping rail and the thin tie plates used originally. Of the original string ers, only 194 had been renewed on Decay of Cutoffs Decay at\he tops or cutoffs of piles has been tn\ largest factor limiting in. by 16 in. in cross-section by 30 this date. The renewal of piles above the life and strength of the Lake ft. long. Originally the bents were 15 the water line had been made neces Pontchartrain rrestle. The piles were ft. apart. / sary almost entirely as a result of of generous diameter, so that the area The deck of the tr^tle is protected by a covering of gt'avel, the use of which was commenced in 1885 after fire had seriougly damaged or de stroyed about 325 panels to the water line. In 1928/' after almost 45 years decay of heart timber, where they were cut off for the placing of the caps. In connection with the Southern's bridge renewal program, 320 inter mediate pile bents in this structure were replaced during 1927, requiring the driving of 1,920 piles, varying in of bearing between the cap and the ring of creosoted lumber of the pile was sufficient for theSload, even when the inner part of theNpile started to decay from lack of adequate treat ment prior to construction. This decay of the tops of the piles service, there remained' intact 574 of the original pile bents out of a total of 2,010, or approximately 28.5 per length from 65 to 75 ft. To provide for heavier loading in the future, all new bents have six piles. did not cause much concern until about 1920 (37 years life). Tnto piles here and there in various locations cent/ln 322 other bents, half the piles Since 1928 more work has been became so poor that strengthcningSvas had'been cut off just above the water done driving intermediate bents, while required. By 1932, (49 years lit liifc and half-framed bents erected. decay of the tops of piles has required there were only 1,038 out of an orig*. & c; k id IT 111 n: l'< St L'i tit W cc di jo th hi be pr m; sp th. sh; sel of pa gn vie pn kn pr< ph co i CO! SUt CO! pa th: of In lie' ter pa ser na an. tal af FLB 00097 ASSUMING that a frame house remains XYserviceabie for fifty years before obsoles cence leads to its replacement, a good pro gram of paint maintenance for the exterior consists of one initial paint job when the. house, is erected and ten or twelve subsequent repaint jobs at suitable intervals. If the pro gram is successful, the coating of. paint re mains substantially intact and of. good ap pearance throughout the life of the house. Between, paint jobs the coating wears appreriably thinner by chalking and erosion but . it does not break up and fall off in patches. Each new repaint job.' is. applied ove,r what. is. left of the previous jobs without at any time. the immediate advantage of a sound basts for budgeting the approximate costs among the expenses of upkeep and, of more importance, it makes it possible to guide the maintenance along lines established by past experience. Above alt, a wisely planned program should keep the owner from, unwilling experimenta tion with untried paints and dubious: painting procedures -with the unexpected expenses to which they may subject him if the job turns out to be a disappointing one. Planned programs of maintenance,may be classified according to the frequency at. which repainting will Be done; (11 programs , in which more than four or five years may elapse ave a !'- having the expense and trouble Of removing 5 ` all of the old coating, down to the bare wood. 3 ' Such a program of maintenance is thqrough- : ly reasonable and has. been achieved success- : ' fuily by many property owners. With enough { * good tuck it may be realized without any s ; careful planning on the owner's part but /' luck, like the weather, is notoriously fickle i 'and likely to prove adverse at embarrassing " \ ` moments. The property owner who. feels, that I*, he can dispense with a. well-planned, program merely by hiring a painter whenever he hap- ` pens to notice that the dear old place could: .stand another coat .runs a grave risk of an. ft expensive disappointment. Those careless s owners against whom lady luck has turned will testify that a badly maintained paint t coating soon, turns into a heartless gold $' ''digger who makes you pay and pay! : Since paint maintenance involves separate --jobs at intervals .over a long, period of years, small property , owner is rarely able to ||te anyone to take care of it for him. He can 8|l|'ay single, paint jobs but not a maintenance program. Unacquainted with paint though he |Hay be, the maintenance program is a re- Ipjnsibility that he cannot escape. As a rule, ||e owner determines when each painting shall be done; he selects the painter; he often r-d&lects the paint; and. he may set limitations. L -TfE cost that profoundly affect the technique of ^'-."'painting. The oWner should also be able to. ' give each painter an accurate history of pre- - vious paint jobs. Under these circumstances f. property owners need considerable technical knowledge about paint. v $ The property owner's responsibility for his program of maintenance is not properly em- -phasized in the literature on painting that is commonly brought to. his .attention.. Paint .composition is such a fascinatingly complex subject and there has. been so much bitter controversy about, the rival merits of different paint ingredients and different paint fonnulas . -that the importance of the owner's program '.'of maintenance has usually been forgotten. I In consequence, the layman commonly be- f ' lieves that the secret, of successful paint main-, |. tenance lies almost wholly in choosing good jpaint. Good paints are presumed to give good, flfpervice if properly applied, regardless of the i nature and age of the paints used previously, ||fand conversely unsatisfactory paint service is ; taken as proof that the paint last used was ffTa poor one. As a matter of fact, a paint can- hot properly be judged good or bad apart from the maintenance program, in which it is to be used It should never be-forgotten that, in repainting, the composition and properties of, the renewed coating are not determined solely by the composition of the new paint because the new paint is. merely added to what remains qf the paints used previously. In such a planned program the frequency of repainting^ the type of paint to' be used, and the number of coats to be put on at a time are de termined in advance, before the house is erected, if prac ticable. Such planning offers A successful maintenance program in which paint of soft type is used with long intervals between point ings. This, house, which is nevt door to the one shown above,, was erected in 1923, repainted in 1931, a ,d In, photograph eras ttthen in 193G and show. between painting, (2) programs in which re painting can be assured at four- or five-year intervals, and (3) programs in which repaint ing may be done at intervals, shorter than fqur years. The size of the, owner's. ..income and the. 'painting habits of his neighbors, of course, may have, much to. do with his de cision. about this part of his program. In making the decision, it is wise, to; remember that the lifetime of a frame house usually spans onC or two serious periods of financial depression during which paint continues to deteriorate with complete indifference to the state of the owner's bank account. Paint is no respecter of persons. . , The interval of four or five years is taken . as the line of division between .maintenance programs, because it marks approximately the .maximum period during which good coatings, of white or light-colored paints can be ex pected to remain'substantially intact on the fully exposed, parts of a house, assuming that a consistent program is followed and that no moisture collects behind the. painted wood- <v * > C'V , II llaJ Ulw fitter, f l N41698.35 work. Within this period, which may he called the period of durability, inconspicuous fissures, known technically as checking, may appear in the coating; chalking and erosion should wear away a substantial portion of the coating, but the coating should not crack conspicuously or break up and become de tached at places, revealing bare wood be neath. In such case, something is wrong. Strong sunshine is usually a major factor in. deterioration of paint, hence those parts of the house, frequently the south side, that re- or of high density lead to earlier break-up of paint, coatings. The strong, heavy softwoods such as Douglas fir and southern yellow pine ordinarily cannot be relied upon to hold white paints intact beyond three or four years, but by priming them with exterior aluminum priming paint before the first job of white paint- is applied, the durability of An unsuccessful maintenance program in which repainting was done often enough hut. radical changes were made in die type of paint, used. Daring the first 15 years after erection, this house was kept painted with iron oxide paints, containing neither lead nor rioc pigments. Then a small fere made it necessary to. rebuild the cast side with ttew siding, after which the whole house wras painted with white paint of fairly hard type, the house was subsequently repainted twice with white paint, A few. years, after the fast job, the coating an tke bortlij soutk, and west sides was in die condition skown in tke pkotograpk at tke left .and skoald k.c removed kefore any fortlver painting is done. On ike eas.t side, skotvn at right, tke wkite paint jo&s Have served li ..... T..T. I 'unffpffffw WJIJWT fiiJUTOwiB i ' HIS ............. an a ceive most, direct sunshine determine the durability of paint jobs. The durability of white paint may btf'spmcwhat longer than four to live years on heavily shaded -houses and somewhat shorter in climates that combine: much strong, sunshine with, prolonged periods of either extremely high or extremely low humidity. The na ture. of the wood painted likewise has a bearing, on durability. The cedars, red wood, cypress, and true white pines in the select grades practically free from . knots can be expected to. hold, good paint coatings intact for four to five years un der normal conditions. Edge-grain boards of slowly grown and fairly light weight in, ponderosa pine, the spruces, and the hemlocks hold paint intact nearly as long, but the flat-grain boards of rapid growth ,, - w * _>****.. * r t**1, an -11*TT_Sr*s*_ % - " - (^SSfS&gS. The two strips at the bottom represent an unsuccessful maintenance program in which paints of harif types were allowed to go too long between tepaintings. This facm budding of a Middle Western university is repainted with paints of fairly hard type, whenever the state legislature provides fairly generous appropriations far maintenance. Repeated, periods of long neglect have left a surface that cannot be repainted acceptably without complete removal of the old coating the boating: can be raised more nearljto that on the woods of lighter weight. For programs in which more than four or .five years may elapse between paint ings, colored paints of great durability are . particularly suitable, Of the very' durable paints the reds, browns, and yel lows made with 'iron oxide pigments are probably the most commonly used. In a good iron oxide paint the major part of the pigment should be iron oxide. Un fortunately many red barn , paints have degenerated Into cheap paints containing very little iron oxide. Other very durable paints are those in which a major part ol the pigment is chrome yellow, chrome green, chromium oxide, lampblack, or carbon black. Aluminum paint, applied in two or three coats, is very durable. The very durable paints are limited tn the deep, colors or are metallic in ap pearance and are therefore unsuitable for the major surfaces of many residences. When white or light colored paints are used in programs with long intervals between paintings, each paint- job goes [Please turn to page 102] FLB 000972 .rly ;ht. our int~ lity ery yelr are na t of Unlave ting able t of ome or died ibte. i to ap: for s. : are rvals goes up the time and money l have saved if he had taken up study of garden prog and hods as a leisure time hobby just one'year be- . fore he raovci to >5s country :; place. He never people what those figures tot; he is going to forget them. and re member only/fhe pleasure he had in trying opt his experiments and atfaining/m last his present, satis fying r (/ Have you a paint maintenance program? {Continued from page 421 beyond its period of durability and passes through a period of neglect during which the coating breaks up in a manner charajKer- istic of the type of paint. Sotne paints, even after long neglect, can be repainted with reasonable as-, surance that the new job will be_. just as durable as the last one.! Other paints leave an uncertain surface on which a new paint job may break up much too soon. Of course, the old paint in the latter case can be removed but paint removal is too expensive to have any place in a program of extreme economy-. For such pro grams white or light colored paint must he chosen rather for thejr ability to stand neglect well than for their qualities during their normal period of durability. Pure white lead paint, in which white lead is the only pigment other than necessary tinting colors, and linseed oil is. the only liquid except thinners and driers, has' long been used successfully in pro grams involving, periods, of ne glect. Since white lead paint was the only high grade white paint available until comparatively modern times, painting traditions in this country are largely based I upon its characteristics. ...Pure t white lead paint develops duck ; ing and checking fairly early in j its life and it wears down with j moderate, rapidity. It is therefore f called a soft paint in contrast to i hard paints with opposite qual i ities. Soft paints stand neglect i well because they disintegrate eventually by fine crumbling rath i er than by cracking, curling, and j coarse, flaking or scaling. When | repainted after a period of ne | glect, soft'paints are little more } than a porous mass of pigment - "chalks.;'1 oil from the new paint t thoroughly permeates the old . coating and incorporates it with the new.' The new job therefore behaves much as the previous one did and has about the same dur ability or wearing quality. Programs with four or five ; years between paintings are best adapted to. the needs of owners 1 who wish to keep their property well maintained at all times with out extravagance, For such pro grams any one of the many types of good house paints may be chosen at the outset but there after it is wise to repaint always with the same type pf paint. Changing types of paint at suc cessive repaintings opens the pro gram to unnecessary possibility of failure because paints of different types are not always compatible with one another. Too much va riation in composition between successive layers of paint appar ently increases internal stresses within the coating as it ages and hiding power be chosen so that They may be applied as thinly as possible. If exceptionally good" ap pearance is desired it is'.often' safer t<5 use paint of a hard type that can be washed easily once a year ratheg-than to, jepaint at. short integrals; " To follow a consistent,program of maintenance the owner must learn how to identify the type of paint he has decided to use. House paints other than white lead paint are sold by manufacturer's brand, not by type, and the manufac turer reserves the right to change causes it to break up abnormally early or in an objectionable or unsightly manner. In conservative programs of this kind the surface should be repainted before the coating be gins to break up. seriously. It is dangerous to wait until conspicu ous cracking, curling, and flaking prove that the durability of the paint has been stretched to its -limit. The temporary saving ef fected by postponing repainting for a few. months may shorten the life of all subsequent paint jobs and eventually require expensive removal of the entire coating. When paints that do not stand neglect are used, repainting should anticipate rather than follow' the breaking up of the coating. Repainting should restore to the -surfaceappsoximately the amount of paint worn away since the pre vious painting. If too much paint is put on at a time the coating eventually becomes, too thick and may break up so badly -that it must be removed. Hard paints wear away less between paintings than soft paints; the harder the paint the less of it should be ap plied at each repainting. The painter gauges the amount ap plied partly by the number of coats and partly by the. extent to which he brushes each coat out. With soft paints two coats at each repainting may be necessary, while with hard paints it may be safer to. apply only one coat. For much the same reason different parts of a house may require, varying amounts of paint because less paint wears away from those parts which are more shielded, from sunshine. Programs- in which repainting may be done at intervals of less than four years are sometimes necessary for commercial build ings but as a rule are inadvisable for residences. On the protected parts of the house particularly the paint does not get. time to weather sufficiently to be in best condition for repainting and it wears away so Tittle that the coating'neces sarily becomes thicker at each painting. Under these conditions it is especially important that the new paint be as nearly as possible, like die previous paint in com position and that paints with great the formula at will. In recent years such' changes in formula have been of frequent occurrence. In. many brands the white paint and the tinted paints differ mark edly in type; in any brand the deeply colored paints necessarily differ greatly from the white and tinted paints For these reasons the manufacturer's brand does not identify paints by type. Many manufacturers, however, print the formula of.the paint on die label.. Although adequate interpretation of the formula requires much technical knowledge of paint com position, it is a comparatively simple matter to use the formula for selecting paint as similar as. possible to that'used the last time, Each paint used successively should contain the same principal ingredients in approximately the same proportions. Attempts, tq improve'upon oldfashioned white lead paint for the most part, have aimed at retard ing chalking, checking, and erosiqn, and improving opacity and whiteness. All of these objectives have been achieved, but the newer ' paints are necessarily harder in-, type and cabn'o.t be relied upon to stand neglect Repeated neglect of hard paints ulthnateJy'Feadsfoa condition demanding complete re moval before new paint can be relied upon to give satisfactory durability. Such paints are not intended-'for use in `accordance with the old painting traditioris-1 based on white lead paint because their manufacturers designed them for more exacting programs of maintenance. Their ' superior apr , pearance. .during..their.: period: of- ; durability- can be utilized safely only if reasonable, care is exer cised to see that they are always-, repainted before they begin to' break up. White paints other than white 1 lead paint always contain a mix- I tore of pigments one of which ; nearly always is zinc oxide. Mix- j tures of white lead and zinc oxide j have long been popular. Zinc oxide is die hardening agent in linseed oil paints; the greater the proportion of zinc oxide in the pigment the harder the paint. Zinc, sulfide pigments, . such as : lithopone, and titanium pigments j are more opaque than white lead j or zinc oxide and make whiter j e Ame r ic a n Ho me , Ap r il , 1937 [ paints with greater hiding power. The present trend in the industry is to use zinc sulfide pigments in cheaper paints and titanium pig ments in high grade exterior paints. Such pigments as. silica, magnesium silicate, barium sul fate, calcium carbonate, and cal cium sulfate are transparent in linseed oil and are used primarily to reduce cost or to increase the total amount of pigment without increasing .the cost. Until recently nearly all high grade house paints were made with linseed oil but attempts are now being made to introduce various resins in the form of oil varnishes or synthetic drying Oils. Resins harden paint . much, like zinc oxide so that it is often necessary to reduce or elim inate the' zinc oxide as resin is added. The resins likewise tend strongly to make the product an enamel rather than a paint, which makes it less amenable to, the common technic of house, paint ing. Enamel characteristics can also be imparted without resins by heat treatment of .the linseed oil or a major part of it. Since tung. oil must be heat treated for use in paint, substitution of it for a major part of the linseed oil results in an enameiized paint. In enameiized paints free from res ins the content of zinc oxide in the pigment is Often very high. Substitution of soy bean oil for part of the linseed .oil in house ., paint tends to make a softer product whose use is favored primarily to gain a market for a relatively new domestic farm crop becoming more abundant. The best way for a property owner to select a type of paint for a new house is to observe houses in his neighborhood,that., were painted with it one, two, three, and four years previously. Such observations- are infinitely ; more revealing than any other source of information, ft should be remembered that the appcar. ance of a paint changes, at in tervals during its life so that coatings of various ages must be seen to learn the whole story. On the other hand the shaded parts of a house and the fully exposed parts show paint at different stages of deterioration at tlje same time. If some of the neigh bors have coatings that are break ing up badly, do not attribute it hastily to the quality of the paint last used. First, make sure that the past program of maintenance has been consistent and that the paint is giving its normal service. A survey of this kind will show very clearly that after all_the par ticular:-type of paint, chosen is usually much less important than insistence upon a program of paint maintenance to which: the paint is properly adapted. The maintenance programs dis. cussed in this article are based on the assumption that the side- FLB 0009 wails, of the house remain dry at all times .and that water never, gains access to the backs of the painted hoards. Unfortunately there are some houses for which the assumption is unsound. In some of them rain gets, behind; the painted woodwork through leaks resulting from faulty con struction such as omission of necessary , flashing around win;-, dows, doors, dormers, roof angles, and back - of gutters. The more common cause of such difficulty, however, is: condensation during times when the interior of the house is heated while it is cold outside Humidification of the interior at such times .aggravates, the difficulty, Water behind., painted woodwork causes blister ing and subsequent scaling of the paint. . Such developments may destroy the, integrity of the coat ing within a few months after it is applied. Soft paints resist ab normal moisture conditions more effectively than hard paints, while heterogeneous coatings: consisting of paints of different types are often exceedingly sensitive to them, the only reliable way of assuring Satisfactory paint service on houses subject to abnormal moisture,.conditions is to find means of keeping the backs of painted woodwork absolutely dry, at all times. _ ' The secret of successful paint. maintenance over a ion| period of years lies in strict adherence to a program that has been proved satisfactory by actual ex perience in the past. The scientific principles that govern, paint be havior still await discovery and until they are revealed our knowl edge of the subject must remain , essentially empirical. There is no magic paint formula that can be relied upon to behave satisfac torily over all other paints on. the market. The property owner him-. self should see to it that his: pro gram, both with respect to, the. paints used and the inteTyals be tween. painting, is. so planned that there is past experience to give him reasonable assurance of success, unless he is willing to trust to luck and pay the penalty if it. turns out badly. Hie Swallows build aii nest tChjttmued from page 281 . a picl gate, to brogfi, low steps, which ite one to enter through the simple' iy into the tradi tional tiny' n'/' from which, as in all Ni England houses of > type, doors'ppen to either side ads straight up- i the bedrooms on the sec- sut the door to right, in-: 1 of opening into1 he box-like best room'' the jiy homes. --that's what menfolk fall for . . . , you can get it only with real plantation molasses T'S the most important ingre I dient for good gingerbread-- full-flavored, old-time molasses. Neither spibe nor brown sugar, alone,; will give, it that luscious, full-bodied flavor. Pour in. the mellow richness of Brer Rabbit classes--and you/ have gingerbread that for downy right goodness has no equal. Brer Rabbit is, made from selected grades of freshly crushed Loirisiana sugar cane. Try Bier Rabbit Molasses in/your next, batch of gingerbread. Keiey its . old-time flavor. And notice tge fine texture of your gingerbread. A new kind of shortcake! Cut hot gingerbread la squares and split. Place cut-up. orwtges.(orwhp)p sections, ' idle from skin) be tween the layers, .-and sprinkle with . powdered sugar. , "Top with whipped cream. Better cookies too, with; Brer Rabbit Molasses It's just as important to use real plantation molasses incookies if you want.a deli cious, mellow flat /vor. You'U find if-grand 'cooky srecv ipea In Brer ftabblt's brand-new . book of molasses I recipes. Mail Cbu- BBIT Zleaf JmL PDeempct.kA- J&I3F0o7rNei,wLOt4rle-,auinBc;,LQ R" eciNpeewBeJTff\..f.-inPBrcaeoler,coe,aiakspriReetecsaak.a'btfoctbnardiktgbe.-ia.smttr^ogepkeiwetthbsiet/rl.ei:.afinnPxeTuOwsf-,.. TiT i*1', ' _ City- " : - ,-t State' - leads into a spacious living/oom extending across the widthybf the house and with windows m three sides--'the sort of room /where a number of people can ffiigage in varied interests without getting in one another's way,/and there fore ideal either for family life or the entertainment of/friends. The fireplace is tritely centered on one of the Ion walls and di rectly opposite is space for a long sofa, or perhaps a convertible daybed lounge tb provide addi tional sleeping accommodations in an emergency. M'ith comfortable chairs grouped/ on either side of the fireplace,/lamps and small tables for books and; smoking ap pointments, and a low coffee table placed before the sofa, the stage is set for ./the rallying ground which is the heart of the home. A baby grand piano might be lo tted at orife end of the long" room ir the muijo lovers, and a library atrangemew? with bookshelves at\d desk at the other. . t the 4ar, almost in line with theutoojr leading into the dining room,/is one opening upon a roonfcrize open porch, which be- caus/Vof its accessibility to the kitchen can be conveniently util- d for an outdoor dining room, fet is not so closely related to it fas to prevent its use also as a sum mer sitting room. Anotheft praiseworthy feature of this house is the little room to the left offwhe front hall, a room, which opens as well into the din ing room,, from which it is. but a step to thfc adjoining, kitchen, and so to thd^ garage and service entrance. in the old days- such a room would have served as. a downstairs bedroom and' might now be util ized for that puWise.should any member of, the fmr.ily he temporarity invalided \or find stair clirnbing, difficult. But it suggests also a nursery, whefe the children can be looked afterVwhile mother : is occupied with kchen duties, '-..and also makes a grand playroom where toys and thingstcan be scat tered about without! disturbing the serenity of the lest of the house. A closet in which to put the toys when "picklup" time comes around is an ({specially, : helpful features Because of its locationAit is also a grand study-room for older chil dren going to, school, for Here they film be-shut off from the! rest of /he'family -and be undistikbed. ,<-Tf there are no children to'-be "'considered in-the househoidb ar rangements, this room wiH pro vide an ideal retreat for a person engaged in literary pursuits,Vsince it is well lighted and has plenty of wall space for book$helve$\and cabinets, ft might' also be verted into a game room, a : ing room, or a comer which' : ' man of the house can call his. o All in all; it is a very usable room-; TQ A H+ 0 _ 1 q X+ mm, FLB 000974 room if the three ere a ge in etting thereife or 5* itered id dit long :rtibie ajldi- oris in rtable de of small >g ap- : table stage found home. be toroom ibrary helves ;, | '! || 11 *l i I; I I |: I I I I | | | | | | | f s with dining >on a ;h he ro the / utilroom, 1 to it isum- | / eature m to : room le din- is but itchen, service room ristairs e util- id any ;empo- stair jggests lildren .neither duties, yroom >e scaturbing of the to put ' time edally, * :is also er chilre they rest of rbed. 1 tbi'be M ar il properson sssince plenty vest and : >e eona sW.icfe Uneven fading of paint of brick color applied in one coat over pre vious paint in good condition and uniform in absorptiveness. The photograph was taken about one year after repainting. The faded areas ate the thinner portions of the last paint coating. By F. L. BROWNE t Painted Surfaces' IN MOST exterior paints for wood, the colored pigments are chemically stable inorganic substances that do not change materially in color -from weathering. The fading of paints containing such pigments is not caused by any change in the pig ments but by loss of organic vehicle, usually dried linseed oil, from the ex posed surface of the paint coating, thus leaving the outermost part of the coating with insufficient vehicle to fill in all of the spaces between the particles of pigment. Under such circumstances we might expect to find the outer layers of pigment bound together inadequately, and to the remainder of the coating. In fact, we find that the loose pigment can be rubbed off easily with the fingers or a piece of cloth of a color contrasting with that of the paint. In other words,,fading begins when the paint begins to chalk. Why chalking causes fading may This discussion was submitted for publication in What's the Answer department for the July issue, in answer to a question as to what causes parts of repainted wood surfaces to, fade. Because of its scope, however, it was withheld for pre sentation here as an independent article. For further discussion of the subject, see page 489 of the Tufy issue. fSenfor chemist. Forest Products Laboratory, Forest Service, Department of Agriculture, Madi son, Wis. be demonstrated by mixing thor oughly enough dry iron oxide red, or other colored pigment, with dry white lead or zinc oxide to make a mixture very light pink in color. Save part of this mixture for com parison and rub up the remainder with linseed oil to the consistency of paint. The paint will have a far deeper red color-than the mixture of dry pigments. Chalking and fading are the reverse of this experiment, in that oil is taken out of the exposed surface of the paint leaving the pig ments dry. It should also be remem bered that such pigments as silica, whiting and barium sulphate, which are transparent in linseed oil, are opaque and white in the form of dry powder and, therefore, help to cause fading when paint begins to chalk. Fading Expected Ordinarily, chalking is the pre ferred form of deterioration for ex terior paints on wood. Fading is, therefore, a result that must be ex pected. Before choosing a tint in the first place, the faded appearance as well as the initial appearance should be considered. Some tints look welt in both the initial and faded colors, while others that may be very attractive originally look shabby when faded. In any case, painting should be done so that ail parts of a building that can be viewed from any one position will always be as nearly uniform in color as prac ticable, except where different colors are chosen deliberately to begin with. There are several lands of lack of uniformity in fading, some prevent able and others not. Paint deterior ates most rapidly on those parts of a building most fully exposed to sun shine. As a rule, therefore, fading begins earlier on the south side than on the north, unless the south side happens to be in the shade of another building. Fortunately the south and north sides cannot be observed from anv one position. Even if the east and south sides, for example, are seen at one time a reasonable difference in color may merge in the viewer's impression with the difference in intensity of il lumination of the two sides. This kind of lack of uniformity in fading, which is unavoidable, causes little trouble unless the extent of the fad ing is excessive or the color is one that looks very shabby when faded. Some kinds of paint begin to N41698.36 FLB 00097: chalk and fade at an earlier age than If two repaint coats are applied, thinner, and application in a coating others. With any one kind of paint the first should be thinned generous of substantial thickness. Such a re and a given exposure, fading will ly with a volatile thinner and brushed paint coat will prime the surface begin earlier the greater the propor put to 800 or 900 sq. ft. to the gallon. adequately and hold out the finish tion of pigment and the smaller the In this cas, the object' d! the first coat so that fading will be uniform. proportion of organic vehicle in the coat is to saturate the old paint while It will also come far closer to level exposed layer of the dried paint coat adding as little as possible to the ing off the flaked patches with the ing. If this outer layer of paint does thickness of the coating. The finish rest of the coating. not have a uniform content of or coat may then be brushed out to the There are many badly neglected ganic vehicle, some parts of it will . point at which it just hides adequate surfaces that ought not to be repaint fade earlier than others. ly and makes.a satisfactory job. ed without first removing all of the Uneven fading of this kind is al If the surface is repainted with old paint from them. When old paint ways objectionable, even though both one coat only, very little volatile is scaling from the wood in places the original and the faded colors are thinner should be used. The paint but the portions remaining are thick, in themselves attractive. Except un should be mixed stiff enough--with curling at the edges, yet resist dis- der a few rather unusual circum high content of pigment---to be lodgement by the scraper, the be stances, uneven fading caused by un brushed out properly at no more havior of a repaint job is uncertain even composition of the last coat of than 600 sq, ft. per gal., and the coat at best. Again, on a surface an paint can be charged definitely to ing should be laid on with a thick which various types of paint have bad craftsmanship on the part of ness as uniform as possible. been used and part of the coating is the painters or to unreasonable lim slipping over or . curling away from itations of time and materials im Old Surfaces Misleading previous coalings, it is wise to take posed on the painters by their super off all of the old paint and start from visors. An old surface that is cracking the wood with a properly planned On a non-absorptive surface, a conspicuously, but has not yet begun program for future maintenance of coating of new paint dries with uni to flake or scale often proves to be the surface. form composition, determined en misleading. The paint itself is One other factor affecting the uni tirely by the proportions in which usually quite uniform in absorption, formity of finish coats may be men the paint was mixed. On an absorp but the cracks, if deep, may take tioned. Absorption of oil by the un tive surface, however, part of the lin much oil from the new paint. After derlying surface goes on for some seed oil is taken out of the coating to repainting there may be early fading hours after fresh paint has been ap saturate the surface beneath. As a over the old cracks. plied, but it can continue only so result, parts of the new coating dry This occurs most frequently with long as the oil in the new paint re .with less oil than others, and these paints of hard type, that should be mains liquid. Reasonably rapid dry parts will fade sooner. v repainted with the minimum amount ing of the new paint will, therefore, If the old paint is Uniformly ab of paint at a time, seldom more than assist in sealing the surface against sorptive and takes the same amount one coat. The paint should be mixed further absorption. of, oil from the new paint over all to a stiff consistency with much pig Many painters are unduly cautious parts of the surface, the composition ment, and should be brushed down about adding drier to paint. While of the new coating might still re- into the cracks as thoroughly as pos overloading paint with driers should , main uniform, if the coating were ap sible before it is finally leveled off be avoided, it is equally bad practice plied with the same thickness every by the last strokes of the brush. to restrict the drier to such an extent where, Few painters are capable of When the old coating has started that the paint remains wet abnormal such meticulous craftsmanship, how to break up by crumbling, flaking, ly long. In good weather paint ever. Almost always there are areas or scaling, exposing bare wood, the should dry to a firm film overnight. thicker and thinner than the average. absorption of the surface is quite Slow drying is particularly likely to If so, the thin areas lose propor variable and two coats of new paint occur with dark-colored paints con tionately more oil and fade sooner, are necessary. All loose paint should taining no lead or zinc pigments. while the thick areas fade later than first be scraped off and the jagged When repainting with two coats of the rest of the coating. Uneven fad edges tapered off by sandpapering. brown paint, for example, the first ing of this kind is not uncommon. Even with two coats of. new paint coat, even after it seems to be firm, The writer has even seen cases in there is danger of uneven fading, un sometimes has the property of ab which the hollows of the brush marks less the first coat is thinned and ap sorbing oil from the second coat. The faded, earlier than the crests. ,, plied properly. writer has seen this occur to. such an In general, an old paint is uttl- A very common blunder is to thin extent that the finish coat dried with formly absorptive up to the age at the first coat, with much linseed oil out gloss. which it begins to break up seriously on, the theory that the way, to satisfy To avoid such possibilities it is by cracking, crumbling, flaking or excessive suction is to put plenty of wise to repaint before it becomes scaling. A nice question of. painter's oil into the paint. This theory over necessary to use more than one coat judgment arises in determining looks the important matter of spread of new paint. When two coats are whether one or two coats of new ing rate. The more oil there is in the necessary, it is sometimes advised to paint are needed over a substantially paint the farther the painter brushes use for the first coat white-lead paint unbroken coating of old paint. From it out, and the less oil there is left tinted toward the color of the finish the viewpoint of assuring uniform per unit of area. Moreover, the thin coat and then to use the colored paint fading, obviously, two coats are much ner the coating the greater.the.change fo.r the finish coat.. The writer does safer. On the other hand, repeated in its-composition caused by with not endorse this procedure, because repainting with two coats before a drawal of a given- amount of oil per the application of white or tinted large part of the previous coating unit of area,- Consequently, the prob white paints over colored paints con has worn away, builds up a very lem of excessive absorptiveness taining no white pigments, has been thick coating that may break up should be met with paint mixed with known frequently to cause unsatis early and badly. plenty of pigment, no added volatile factory paint service. Reprinted from Septernbsr, 1937 issue of Railway Engineering .and Maintenance Behavior of House Faint By F. L* B X q Senior Chemist, Forest Products Laboratory* t Q1 - been recognized for many years that house paints behave Paint Industry" (American Paint Journal Company) tells die Idifferently in different climates. The subject is of particular story and reproduces the famous "climate map" of the United interest on the Pacific Coast because of the unusually wide States by means of which the purchaser was to learn which of the variation in climatic conditions within the borders of any one of four types of paint made was pre-acclimated for his locality. the three states. In California alone there are practically all the Hechet considered the plan a "dud," which is probably true for variations in climate to be found anywhere in the United States. the large manufacturer who wishes to advertise on a national Technologists necessarily have to give careful attention to climatic scale. Small manufacturers doing business in a limited territory, Variations in designing and testing paints because paints may be however, can and often do design their formulas with special made that behave well in some climates but badly in others. For regard for climatic characteristics. Larger manufacturers whose tunately it is possible to make paints that serve well in all cli advertising does not commit them to any precise formula some mates even though their behavior varies in. certain details. Paint times supply paint of somewhat different formula in different buyers may well give some attention to climatic peculiarities in parts of the country. One large Pacific Coast manufacturer makes selecting paints, particularly in considering advertising claims a number of brands of paint and apparently has his local dealers based on tests made under one extreme of climatic conditions, handle the qne best suited to. the dealer's locality. but in general the subject is of most interest to the paint user The dominant factors of climate affecting the behavior of house from the point of view of planning his program of paint mainte paints on wood are sunshine and relative humidity, For paints nance correctly for the type of paint selected and the locality in on metal extremes of temperature are also important. Salt in the which it is used. air near die sea coasts adversely affects paint,on iron and steel by As far back as 19IQ. the Lincoln Paint and Color Company stimulating corrosion of die metal hut, in the writer's opinion, it attempted to build a merchandising program on the idea of "pre- does not impair "the service of good house paints on wood. Con acclimated" paint. George B. Heckei in his "Reminiscences of the tamination of the air by industrial fumes, which is a local rather than a climatic influence, may seriously affect paint on both wood Maintained by the Forest Service, U. S. Department of Agriculture at Madison, Wrs., ia co-operation with the University oi Wuconsin, and metal. Soot discolors paint and, if there is enough of it, may The behavior of paints at Gainesville, Florida, where the climate is. damp and sunny. Panels 1, 2, 5,6, 9, .10,13 and; 14 painted with a. moderately soft type of paint, panels 3, 4, 7, ft, 1.1, 12, 15, and 16 with a moderately hard type of paint. Circular area shows details of behavior of the two paints. Panels 1, 2, 3, and 4 .are southern yellow- pine, 5, 6, 7, and 8 western white pine, 9, 10, 11, and 12 ponderosa pine, 13, 14, 15, and 16 northern white pine. Panels of odd. number have flat-grant boards, even numbers, edge-grain boards. Pacific Purchaser r February, 1938 13 N41698.37 FLB 000977 The behavior of paints., at Grand Junction, Colorado, where the c iitaate is sunny with very dry summers. Panels 1, 2, 5,. 6, 9, 10, 13, F+ and 14 painted with a moderately soft type of paint, panels 3, 4, 7, 8, 1.1, 12, 13, and 16 with a moderately hard type of paint. Circular areas show details of behavior of the. two paints. Panels 1, 2* 3, and 4 are southern yellow pine, 5, 6, 7, and 8 western >a white pine, 9, 10,11, and 12 pondernsa pine, 13, 14, 15, and 16 northern white pine. Panels of odd number have fiat-grain hoards, .e> even numbers edge-grain boards. et make the paint last longer by shielding it from sunlight. Hydro are. much less likely to crack, curl, and flake off if they are always TJ gen stilfide turns white lead pigments black while sulfur dioxide slightly moist, which is the case in climates in which, the relative ct may render zinc oxide pigments soluble in water so that they humidity is always reasonably high. are washed out of the coating by rain. For die -above reasons sunshine largely governs, the rate at Sunshine shortens paint life by hastening the aging and dis which coatings grow old and brittle while the minimum relative af integration of the drying oils that bind the pigments together in humidity to which they are exposed largely controls the form in the coatings. The chemistry of the process is not yet known but which failure sets in after embrittlement has. occurred. The desir ils it is known that the blue, violet and ultraviolet rays are more able form of failure is die slow erosion known as chalking which t potent than the rest of the sunlight. Sunlight is less deleterious to is characteristic of moderately soft paints such as pure white lead _ ; T`, paints indoors because the ultraviolet rays are largely filtered out by window glass. Regions that are characterized by a high pro portion of sunny weather and by high content of ultraviolet in paint. The undesirable form of failure is a breaking up of the coating by cracking and curling and the sloughing off of pieces of the coating by flaking or scaling. Incorporation of zinc oxide is. the sunshine are particularly severe on paint. As a rule the ultra in house paints makes them harder and retards erosion by chalk feu ; violet content of sunshine increases in southern latitudes and with ing-but increases the chances of ultimate failure by flaking or altitude above sea. level but is always low,during doudy weather. scaling. Climates characterized by much sunshine and absence The action of sunshine may be especially severe where clear skies of periods-of low relative humidity favor disintegratioa of paint frequently follow swiftly after showers of rain. by erosion and make paints of the harder types more practicable. Moisture is absorbed by paint coatings and makes them much Climates characterized by much sunshine and periods of low 3 more flexible than they are when dry. Young coatings of good relative humidity accentuate failure by flaking and scaling and paint have plenty of flexibility even when thoroughly dry but make it necessary to avoid paints of undue hardness, gradually become brittle' as, they age. When old -and brittle they (Continued on Page 28) ACIJDSEAL FAINT ^ ..Contains no oils or nitro-cellulose--A rubber "Isomer" witJ^haraSefistics rCablt^to paint. A firm yet flexible film protepcioa^agaiitst the corrosive action of adds, alkaliesj^ltsretc. For S Machinery, Tanks, eTaj2Si|lts, Drums, Etc. rite for Descripts^Manual and Samples es Eqnipmeitt^ lllibber Co. ^50 THIRD STREET - SAN FRANCISbQ^-T^Xbrook 2575 Zstributors: THE B. F. GOODRICH COMPANY MECHA^ldXfr^UBBER GOODS "Everything in Rubber" >AS' tkC,; astex ays, atiel Pacific Purchaser i W. ) A new fir plywood which "finishes like the high temperatprte; makes the sheet suitable as a rcJi hardwood" is waterproofed, sealed, primed terial in the place at resistor alloys now used. 1 treated to prevent moisture absorption, A lightmg'nxture permits the reflector to be adj usted through a ecay and grain raising. Nosy produced on vertical arc of 37 degrees: and can be rotated horizontally through th\ Pacific Coast. 360 degrees. The reflector finish produces a soft even distribution Ay newly developed doifie combination__-o'Hght:-- unit utilizes an arrangement of three 150- 200 watt lamps around k central mercury The Effect of Climatic Differences on the lamp of 400 watts to prodvvcc a light whieh is visually com fortable and which possesses the property of blending well with daylight, An iron body gjohe and an; rlc valves/designed to withstand exceptionally severe service are ting offered. The plug type disc is made of nickel alloy and the dy Mat. ring of Exellby, a spe- dally heat treated chromium iron, " s combination of metals for seating surface has been found by (nsive tests to offer excellent resistance to wear, temperature, g png and scoring. In addition, these metals are harder, stronger nd tougher than metals ordi- narily used in iron valves, A protective coating for concrete, steel, or wood may be sprayed on with a paint gun; protects against many acids, alkalis, oils and other corrosives; prevents electrolysis! by its non-conductance. Naturally colorless, it may be given practically any color. It has a smooth semi-glazed surface. \ A completely flexible system for storage in boxes is built from steel racks in which the boxes slide like drawers. The rack units lock together easily witljout tools and unlock as easily for quick rearrangement. / A specially treated/titanium dioxide pi; nent has both high tinting strength and resistance to chalking, i can be mixed with chemically reactive pigments such as zinc, oxide. A novel thermometer for hot liquids is floating, all-metal, non- breakable, Spherical in shape, the temperatureWale is engraved Behavior of House Paint (Continued from Page l4) The accompanying illustrations show the behavior of a mod erately soft paint, (pure white lead paint) and a moderately hard paint (lead and zinc, paint of medium content of zinc oxide) after four years of exposure facing south, at; two stations typical of the extremes of climatic effect on paint to be found in the United States. In the study there were 11 testing stations chosen for climatic variations., at each of which these two paints were simultaneously exposed on flat-grain and edge-grain panels of IS different woods, At ail of the other stations, the behavior of the paints, fell between the two extremes, shown. At Gainesville, Fla., where the chntato may be described as damp and sunny, both paints wore away gradually by chalking with a minimum of crumbling, flaking or scaling. The moderately hard paint out lasted the moderately soft paint by a small margin and differences in durability on different woods were small. At Grand Junction, Colorado, where the climate may be described as sunny with very dry summers, both paints failed more rapidly anil the fail ures took place by crumbling or by flaking rather than by chalk ing. The moderately soft paint outlasted the moderately hard paint by a rather wide margin, and durability on the different woods varied much more strikingly. The effects of climate on paint, while great enough to deserve on the outside. When dropped in the liquid it floats with the num ber indieating/the temperature uppermost. A new tim?recorder is said to save time by its. ohe-hand opera tion. It prints, on the face of the card. Tardy or irregular registra tions may be printed in red, Black and colored lead for mechanical pencils is how packed careful attention by paint users, are far less important in deter mining serviceableness than correct planning of programs of maintenance, correct choice of type of paint for the programs, selected, correct technic of application, and: the avoidance of coatings of heterogeneous composition whose behavior is un predictable and often disastrously unsatisfactory. in transparent containers so that the owner may check his stock at a glance. X.P.A.S Elect New Officers Alun/inum coated steel, the surface of which after drawn can TI7 -XP.A. Association of San Francisco, which be polished with a cotton cloth to a high mirror finish, wttich will last indefinitely in ordinary atmospheres. The surface \of the coated metal is free from pin-holes, fts resistance to oxidaoiori at of a few choice spirits who formerly belonged to the Agents' Association of Northern California, and a real entity of its own with constitution and. WiPacific Purchaser r / of. XX, No. 2 FLB 00097S O plication will give an excellent job and will absolutely not. crack, peeler blister. Thefce is a Tnemec coating for every application, such as struc tural steelyjyalvanized iron, tank cars, oil and water storage tanks, underground pipe lines, concrete, stucco, brick and wood sur faces. v. Petroleum Equipment Company have been distributors for Tnemec for many years, and are supplying it to some of the largest industrial planh^n CaHfornia.Tkey carry complete stocks in San Francisco and LoKAngd.es and welcome any inquiries re garding the application ob\Tnemec for rust and corrosion pre vention. Ask them for Bulletin No. 4-36 on Tnemec No. 6 Red Primer and catalog covering other industrial coatings. Turco Keeps Pace With Changing Industrial Requirement The consistent and progressive growth orTurco Products, Inc., front a modest beginning some fifteen year^ago to its position today as the largest manufacturer of industrial cleaning materials in the West, furnishes a fine example of the succesSfiil application of enterprise, service, ethical business practice and superior tech nical ability. At the start "Turco" stood for not more than a half doken prod ucts applicable to only a limited few of the countless cleaning operations in the industries. As time passed a constant succession of new, original and exclusive materials emerged from the Turco laboratory and were accorded rapid acceptance in the field. I virtue of their sheer merit. There are now some two hundred standard Turco products in use in every conceivable line of in dustry throughout the eleven Western States, Manufacturing and merchandising this vast line of Turco/ industrial cleaning materials is only a portion of the part playe by this organization in serving the industries. New industrial practices, processes and methods are being adopted almost daily. These give rise to an ever shifting demand for cleaning com pounds specifically, suited to. new requirements. New and often complex cleaning problems are hems' constantly referred to the Turco Laboratory for prompt solution. Most of them involve serious and complicated original chemical reseanm. This tech nical labor is cheerfully undertaken--regarded as a regular and essential part of the day's, work, and carried through to a success ful conclusion. In this way new, modern ancy highly specialized Turco materials are constandy in process pi evolution and the usefulness of "Turco" to the industries, is esfcrlastingly increasing. One of many concrete examples of Xurco's contributions to industry is seen in referring back to. the time when aluminum alloys first came into use in aircraft/manufacture. These alumi num parts required cleaning, both m the course of the manufac ture of the ship and as a maintenance measure after the ship entered service. Aluminum is / highly reactive metal and the general rim of cleaning material; available were of such a nature as to cause varying degreeapf'damage to this chemically sensitive substance. The Turco Ltioeratory immediately undertook to evolve cleaning compounds sufficiently potent to. remove the heaviest grime from aluminum surfaces without reacting in the slightest degree with tne metal itself. How well the Laboratory succeeded is demonstrated by the fact that it was not long before every major aircrafttinanufacturer and maintenance plant in this and many foreign/countries, as well .as the United States Army and Navy at home and. at distant posts, have adopted the use of these Turco.Cleaning Compounds. As an aggressive, rapidly growing and responsible southern California business enterprise, Turco Products, Inc., has won its place in the first rank, officered by M. f. (Jim) Dee, President; "Bill" 'lTfornbury, Vice-President; S. G, (Syd) Thornbury, Sec retary and Technical Director; Ray Sanders, General Manager, supported by its loyal and highly efficient plant and office staff together with its corps of fifty sales and service men covering the eleven Western States. II5HE5 CQUERB R.N. NASON &CO. Manufactu rers >AN FRANCISCO LOS ANGELES fo wash paint safely to remove paint easily Among the nearly fift; ferent materials prod) by the Oakite are products which was' painted surfaces quickly thoroughly . . without the slightest injury to die finish. The complete solubility of these materials prevents films or streakiness. The paint is left clean . . . fresh looking... Bo you want to strip paint from machinery, trucks, tractors or other equipment before refinishing? Then profit by the special Oakite materials developed for this work. The method is sim- le, inexpensive. Old paint entirely removed. The underlying surface takes a smooth, firmly adhering new'finish. On any cleaning operation, tak^t advantage of our 29 years' experience. No obligation. Write or telephone today. OAKITE PRODUCTS, Oakite Offices and Stocks are located at Los A\igeles, Oakland, Portland, San Francisco, Seattle and Denve^ Consult local telephone directory. CLEANING MATERIALS a METHODS FOR EVERy CLEANING REQUIREMENT * Pacific Purchasor i February, 1938 WOOl In an absto f Browne, the well f of wood which de | coatings, a . re< | temporary. Drug 1 comments of dire' I Dr. Browne i I the U.S. Forest P I painted panels o ! that the same pa: I of woods than on I properties of wo :| behaviour of the i .p I In dealing v t application of th< I "The first * largely consnnaei 1 non-absorptive a I can built a coat: 1 three-fourths of | paratively small | it, A plaster wa I as. wood, The ce | granular structu: I because iu wood } cells cut open in 1 through the ver; | " The liquk < wood than do the ; oil-soluble red c 1 it*.' examining ! peiirtiatc1" Jlif remumnii at the that tint with a -. dull ls t 0 w X0 7. fiU-red b,t penetratn n.io parai^g '\rrTT,f>nx'0 FLB 000980 1 OOD AMD l*V!\T i Experiments carried out in America have shown that the durability and behaviour of a paint coating o wood may vary to a considerable extent according to the species and grading of the wood. Some of the conclusions of a well-known technologist on this subject are given in this extract. I|< In an abstract of an official paper by Dr. F. L. their deterioration at which they no longer protect the prowne, the well-known technologist, on the properties wood adequately against weathering and when they begin f;wood -which determine the behaviour of exterior paint to disintegrate by crumbling, flaking, or scaling, leaving atings, a recent issue of our American con- parts of the wood surface bare. From this point on, under japorary. Drugs,- Oils and Paints:,, publishes some present painting practices, it may fairly be said that the .fisannents of direct interest to painters, kind of wood surface rather than the composition of the ' Dr. Browne states that exposure tests, conducted by paint dominates the behaviour of the coating and deter festLS. Forest Products Laboratory over many years, on mines when repainting is in order." Hinted panels of various kinds of soft woods, showed With regard to the nature of the wood and ultimate Jaf the same paint lasted much longer on certain species ' failure, Dr. Browne observes : if,\voods than on others ; these tests further indicated the " There is much variation within many species in perries of wood which exert most influence on the density and ring width and it follows that there is a Saviour of the paint. corresponding variation in painting characteristics. Penetration of First Coat ft In dealing with the properties of wood during the ' application of the priming coat, he observes: I " The first coat of paint applied to new wood is very jfttargely consumed in filling the voids, leaving a level, Inon-absorptive surface on which subsequent applications f can built a coating, However, even though one-half to I three-fourths of the volume of wood is void, a cqm, paralively small amount of paint is required for pruning it. A plaster wall takes two or three times as much paint as wood. The cellular structure of wood in contrast to the Density and ring width consequently are a far more - precise guide to paintability than species, but woods are bought and sold by species and not hy density and ring width, " The bark side of flat-grain boards is far superior to the pith side in many species because there is a tendency for the grain tshell out on the-pith. side. This is a form of wood weathering against which paint should, theoretically, afford protection. In practice, however, paint as we now use it proves inadequate. Flat-grain boards should, therefore, be turned bark side out." olar structure of plaster accounts for the difference, Composition <Sf the Paint Coating Muse in wood, penetration beyond the voids in those The composition of the coating also exerts a decided cells cut open in making the surface can take place only influence upon durability, through the very fine openings in the pit membranes. " The Forest Products Laboratory has tried various, " The liquids of paint penetrate more deeply into expedients in priming-coat procedure that have been L wood than do the pigments, as can be proved by adding an recommended for obtaining better results on wood Xg&jpGift&fe red dye to the paint before application and surfaces containing much summerwood. The proportions 1 ~r e camming the depth to which the red color of turpentine and linseed oil; in the priming coat have been ("penetrates. The ratio of solids to 'liquids in the paint altered greatly, thinners like benzol have been used in remaining at the surface is thereby upset, so that a paint place of turpentine, and special priming-coat paints have that dries with a glossy film on glass or metal, dries with a been used. All but one of these expedients have either ' duILfflm on wood. Judged by the effect on gloss, more oil failed to alter the behaviour of the coatings, or have led -thus filtered off in springwood than in summerwood, to earlier loss of coating integrity: Aluminium paint used at penetration is found to be deeper in summerwood. as a priming coat under white lead: or lead and zinc paint |^The paradox is not mysterious, for the void capacity of materially prolongs the life of the coating both in pro ^ summerwood is only half that of springwood.' ' tective power and in integrity, but the ultimate failure influence of Exposure The influence of exposure is summarised as follows : " Under normal conditions of-exposure the behaviour paint coatings during the early part of their service not materially influenced by the kind of wood surface which they are applied. The, rate of loss in gloss, ^collection of dirt, the development of chalking and leading, the time when paint checking begins, and the ndistinctive pattern of the checking depend upon the kind It.of paint, the- climate, the local conditions of exposure, vgf. -and perhaps to some extent upon the manner of applicaIH-tion, but they are not influenced to any important extent ," ? by the wood." *' f i Nature of Wood and Ultimate Paint Failure takes place by flaking from the summerwood just as it does when the paints are applied in the customary fashion." Conclusion In conclusion, Dr. Browne states : " The variability in behaviour of paint coatings on wood surfaces of different kinds is the wood-painting problem that must be solved before consumers of paint and of timber can be given better paint service. To some extent selection of timber in accordance with its painting characteristics can be practiced but improvement in this direction is limited by the fact that in choosing wo'od for any purpose other factors must be considered besides paintability and.that most of our available supply is of the kinds that contain much summerwood. Furthermore, i t the " Die nature of the wood surface behaviour of coatings when they begins to influence reach the point in second-growth woods are likely to he less desirable in respect to painting than the virgin stands because the Page 73 THE DECORATOR N41698.38 FLB 00098. illStil #n# iUlK Painting on Keene's Cement The present attitude of the Building Research! towards the particular problem of Keene's cement i HE views of the Information Bureau of the Build ing Research Station on the traditional practice of '' following the trowel " with a sharp coat of paint in the painting of Keene's cement, are given in the the practice of painting following the trowel is unobjection-.'? able, provided that the paint contains: only a minimurn^l" oil, and that no forth m coat- of air, kind .ire applied untie drying of the structure is well advanced. * February Notes issued by the Bureau in a reply to an enquiry on the subject. The reply states that although the question of paint ing on Keene's cement is one which has interested the Building Research Station for some time, it must be Wood and Paint {Confirmedfoopiprevious. Page) stated at once that no definite conclusion has yet been trees will usually be.grown more rapidly and will be cat reached. younger. It is conceivable that some means of treating " While it: might appear at first sight a comparatively timber to improve its painting characteristics may be simple matter to decide whether or not a coat of paint invented, but there is no reason for regarding that pomt should he applied to Keene's cement immediately follow of attack on the problem as particularly hopeful. Im ing the trowel, the problem is actually somewhat complex. proved paint or painting technique seems much more One of the chief difficulties lies in the fact that the material likely to furnish the solution. sold under the name of Keene's is not a standard product, " The attainment of an ideal paint is an ajnbitnu.s and probably the difference between various brands but by no means unpromising objective. As we see it, accounts in part for the conflicting views, based on prac the problem is one of. securing firmer and more permanent* tical experience, which are often put forward concerning adhesion between coatings and wood. Probably aft the best technique for decorating this type of material. present aged coatings cling to wood by mechanical The problem is being actively investigated at the embedding in .the rough surface, much as plash'' gripsf present time as part of a study of the problem of painting lath, Summerwood, with its low void volume, and very on calcium sulphate plasters as mentioned in the Report smalt voids, offers an uncertain support for adtoron n of the Building Research Board for 1936, pages 87-95. that kind. A true adhesion between wood substance and Special attention is being paid to the causes of failure of the matrix of the paint coating is called for. Glue sticks adhesion of paint, which is the type of defect most fre to summerwood, why cannot paint be made to do so ? quently experienced on plasters, of the Keene's type. The. Forest Products Laboratory proposes, to seek true It may be of interest to. mention briefly certain, obser adhesion between paint coatings and wood and invites vations which have already heeu made :-- the co-operation of the technical men of the paint industry Some plasters of the Keene's type, combine with water in that, quest." somewhat slowly, With these it is desirable, therefore, to avoid unduly rapid drying in the early stages, since other wise the plaster may be weakened and the. paint fail to adhere. A thin, coat of paint applied early is likely to. Painting Case in the Courts reduce the rate of drying to. some, extent and may he of some value for this reason. If, however, this procedure, is ' "In a case heard before. Judge Hildyard at the Nottingham--- adopted with a piaster suited to treatment in this way, two essential conditions must be observed: (a) Any paint applied must. . contain only a minimum of oil, for it has been shown that if an appre ciable. amount, of oil penetrates into the partially set County Court last month,, Henry Unwin and Co, paint and varnish merchants of Nottingham, sued Tyson Bros.. Ltd,, painters and decorators, of the same city, for J15 5s, 6d., in respect of paints supplied. The defendants made a counter claim for ^13 6s. sd, for alleged damage done by the pamt in the. decoration of seven houses. plaster it will interfere with the setting of the surface layer, (b) no further coats of any kind must he applied For the plaintiffs, Mr. T.. S. N. Roose said that the issue!' in the case was whether or not six drums of ground colour* supplied by the plaintiffs to the defendants were worthless as| until drying of the structure is. well advanced. Within these, limits, therefore, the traditional pro cedure of applying a " sharp. " coat of paint immediately following the trowel finds experimental justification, but this conclusion does not necessarily, apply to all. plasters of the latter alleged. On the ernd August, these, drums were t supplied to Messrs. Tyson Bros., Ltd,, for use on the decoration of houses dn the Becston Estate. About a fortnight, later, a complaint was made that the ground, colour used on doors ou the estate hadVept and was, unsatisfactory. In September, a sample of the. colour was accordingly returned to the plaintiffs the Keene's type. There are otto considerations to be who carried out ttsts by applying it to various wood, metal, taken into account besides the degree of hydration of the and glass surfaces, on which they found that it dried satis plaster, and with some, piasters better results have been factorily. Mr. Roose added that defendants had informed the. obtained by-delaying the. painting to. a later stage. plaintiffs, that, in mixing up the graining colour, a. turpentine \J| P Hi It is sometimes stated that paint fails to " take " on Keene's cement which has been allowed to. set and dry fully and it is suggested that the reason for this lies in the dense, polished nature of the surface. Experimental evidence substitute had been used and not pure turpentine.: Mr. Henry Unwin gave evidence of supplying the paint; he. denied, however, that he had agreed to take back the paint and make good the' damage done to the doors. Mr. H. S. Unwin, who mixed the pamt, denied that there was.too much does not support this view, for ordinary oil paint has been oil in the ground colour. found to adhere well to even the most highly polished Mr. W, ,W. Taylor, public analyst, said that he had plaster surfaces. examined a sample of. the paint and gave it. as his opinion : The. " suction " shown by wet and dry plasters, the that it was unsatisfactory from a drying point of view. ease with which they permit the. formation of efflorescence and their behaviour on different types of backing may be In his judgment. Judge- Hildyard said, that, on. the evidence, there seemed to, have, been something, wrong with j mentioned as other factors, affecting decoration which are the paint, but that the subsequent damage ought not to. lmve i, being investigated, ft is not expected that the final results accrued when the. results, of the. trouble first became evident. , of this wrk. wffl accrue for some little time, but as soon as Judgment on the claim would, therefore, he given for conclusions sure reached they will be made known generally. /io 13s. od., and on the counter-claim, for 4 and chats., i; Page 74 15th MARCH, 1938 I FLB 00098 92 DRUGS, OILS ANP PAINTS a pimply film, due to aggregations of parti cles which cari usually be detected with, the microscope. Grain Raising: The objectionable roughness of wood caused by the application and ab ^fcia Classif icatinucleins. As derived fy'om fish scales, the material is used in /the production of "pearlescent" lacquer^. The material in I Paiints As s the pure state appear^ as colorless needlies, I insoluble in water, ^6ut soluble in alco3hhool l,l SS' tudy of sorption of stains or other materials. The `.roughness is due to the short broken fibres of wood which more-or-less stand up, due tcf .the swelling or raising action of the liquid coating. There are non-raising stains and varnishes now on the market which eliminate this disturbing condition. Grapeseed Oil: The seeds of grapes (raisins) contain a desirable oil with an iodine num ber of 95 to 140, which makes the oil valu able for use in paints and enamels. How ever, only small quantities are available, since it is economical only to produce it as a by-product of the raisin and grape wine industries- The oil resembles soybean oil except that it is slightly faster drying, and is somewhat darker in color. Graphic Red: A scries of lithol red toners having a specific gravity ranging from 1.43 to 3.63, and oil adsorptions from 30 to 50. Made by Sherwin-Williams Co. ether and alkalies, j Guiacol: C-H..O-. A colorless liquid of peculilliaiar*r1 odor consisting essentially of a phenol ether. Used extensively /as an antiskinning agent in varnishes and/ cnumels. Also known as methylpyrocatecfim. Guignet Green: A green pigment composed principally of ^ydrated chromium oxide- By F. F'orcet Product# L/a U. S. Depart?. In a recent paper ing Chemistry, 29, proposed a systema paints according to pose of guiding pa sound procedures of ance of coatings. T' that make classifies repeated here becau to emphasize inst< classification should of formulation. Fc been more of an art it has remained aim generalizations and be sure individuals attempted to ration Graphite: A native or artificially made allo- of common procedr tropic carbon which occurs in metallic, soft, often have failed t amorphous masses or hexagonal lamellae. and to stimulate tl Sometimes called black le^d or plumbago. to develop theories It is occasionally used as a pigment. The A serious effort to specific gravity is 1.9 to 2.3. Guild Colorimeter rectly toward appl Gravimetry: The measurement of specific grav however, must oe< ity or density of any material. Green Method: A method of determining* the particle size of pigments by the use of photomicrographs at a known magnification. For details, see J. Franklin Inst. 192, 637f' <1921). Greenockite: A rare and natural mineral cadmium sulphide <CdS), occuring in yello.(v, translucent, hexagonal crystals, and as'yan earthy incrustation. , Green Oxide: A pigment consisting' mostly of chromic oxide, and having a specific grav ity of 5.1 to 5.2, and an oil absorption of 9 to 11. Made by George S. Mepham Co. Green Toner: A 100 per cent, precipitated or ganic pigment having a specific gravity of 2.77, and an oil absorption of 38. -Made by Krebs Pigment and Color Corp. /build Colorimeter: A color analyzer of tht trichromatic, type which was developed atf the National Physical Laboratory. It isj not extensively used due to its high cost Gulf Solvent: A petroleum thinner having a] distillation range of 154.4 to 192-202 C., and a flash point of 102-103 F. Made by-j the Gulf Oil Corp. Gum: A natural, resinous or balsamic ma terial derived from certain trees or fossil sources. In general, it may be stated that gums are natural products, whereas resins are synthetic materials. Gum Arabic: The dried gummy exudation of A coda Senegal^ and which consists essen tially of the salts of arabic acid. The white ' powdered resin is often used in cold water paints, and in show card colors. Gum Elastic: Same as India rubber or caout chouc. Gun Cotton: C.eHnO. (NOn). A form of high ly pitrated cellulose (cellulose hexanitrate) used- in explosives. It is eonti'asted with pyroxylin in that it is sparingly soluble in the usual lacquer solvents. Gurjum Balsam: A yellow, oily, viscous ma terial which has been considered as a sub stitute for linseed oil. It comes from British Malaya,', and has a specific gravity of 0.934, and a viscosity of A-2. For details, see philosophy of formi tiona made to estab supplant it with a to contribute substa of a technology of in this paper the ct deriving the write scribed in the hope him will find the ba revealed more clea the establishment o will he stimulated. Formulation divi< nature of paint int< position of the pi* the vehicle, and tht in the paint. It is tion of the pigment tion because it co erties as color and to more complex va the concentration < not be regarded a minant of the qual a paint even thougl paint technology gi paint requires not good vehicle, suital of the pigment, a Scientific' Sect. Circ. No. 224. pigment and vehicl< Guttametor: A device for measuring surface of correct ratio of j tension by counting the number of drops. * particularly neglect Gutta Percha: (C^HTM)?. A material of rub- *ing attention being beiy nature which constitutes a group of is an encouraging complex hydrocarbons. It consists of the is getting beyond t purified and1' thick, milky exudate of cer between competing Gregory Plastometer: A device for measur ing the consistency of paints by the hori zontal tube nlethod combined with a vacuum tain trees. Used in protective coatings The proposed sys where good Insulating properties are de house paints into i sired. Also dsed as a rubber substitute. ture of the pigmer In properties it, resembles caoutchouc or rub types are then su {ber. Also known as gummi plasticwm. Gypsum: A nature, hydrous, crystalline cal cium sulphate. \ Also known as selenite, cording to the proptotal pigments, an in the paint. In alabaster, satin ' spar, gypsite. It has a ti- divisions are define specific gravity of 2.32, and is used as an damental requti'em< inert extending pigment in some paints. writer understands in a plastorheter. The instrument is not used extensively due to its high cost. How ever, it is. fundamentally sound in its de sign and operation. See J. Rheology, 1, 30, (1929). , Grenoble (Srecn: A 100 per cent, organic green pifement having a specific gravity of 2.43 to /2.48, and an oil absorption of 55,0. Made tyy Ansbacher-Siegle Corp. Grinding/ Oil: A vegetable oil (usually lin seed oil) used in the grinding of lead, particularly pulp lead- It has a high acid number (9 to 15) so as to impart the desir able/ wetting characteristics. Grittivless: See "graininess." Ground Coat: The coat of material applied before the graining colors or glazing coat to; give the undercoat the desired back ground. Guanine: CsHr.O N-,. A leucomain found in jeales of fish, in the excrespider, in swine, in human, i decomposition pr-oduct of ( To \ cot irtued) In. specifically s< demarcation betwe l*ast Presidents of (he Paint and Oil CLub and between one of New England wero\ honored at a meeting broad general prim held on February 17th \ at the Parker House, be interpreted qua Boston, at which President E. E. Morton pre quantitative interi sided. Of the club's \forty-two presidents s, eriously attemptei twenty ai*e still living* ai(d active in business, ^ done by the exer< according to President Mpvton. Those at the based on an extenr meeting included Albert \E. Cole, 1909-1910; market and long JL). William Wade, 1912-1913; George A. Rich paints in service, ardson, 1913-1914; March 'G. Bennett, 1918- feel that the subd 1919; Fank H. Nutting. 1^1-1923; Harry H. divisions should fc Hill, 1923-1924; Chas. S. Rabbins, 1924-1925; * effort to establish tl William H. Kirkpatrick. 19^5-1926; William f acceptably will rec D. Rockwood, 1926-1<27; George J. Beake,* 1927-1928; A. Irving McLauthlin, 1928-1929; Evert W. Hincklev. 1929-1930; Frank Bownes, 1930-1932. ar ' C. K. .Stodder. 1932-1934. At the meeting ^^^fLes 1&- McLaughlin was ap pointed execi..ive secretary of the "Clean Up and Paint Up Campaign." paint formulation Pig me Besides its cost, nutrient min' lAn address to the Loi tion Club, October 21 aMaintaiTied at Madlsc University of Wiscon N41698.39 FLB 00098.' March, 1938 DRUGS, OILS AND PAINTS The Men Behind the Guns " . c . it's savior of 'is country when the guns begin to shoot*'--K0 .0 q 3 Dr. Joseph Mattiello, M.Sc., I'h.D. Dr.'Mattiello, who handles the Higher math ematics as skilfully as a juggler keeps six balls in the air at one time, tells us that he "was born of ItaJian parents, in the city of New York, on February 28th, 1900"; but he also gives us a glimpse at the quality of his Italian antecedents, when he tells us that father Celestino Mattiello was a sculptor-- the direct descendant of a long; line of sculp tor's--who died when Joseph was four years old, and that his mother was Elizabeth Botti- gleri, who was the descendant of a family which for several generations served the church and the state in Important positions. The family, in Italy, today is prominent in the sulphur industry. Joseph's mother died while her son was in his eleventh year. He then passed into the care of an. aunt who saw that he received a good primary educa tion, first in the public schools and later in a private school. During his sixteenth year <1916) he en listed as a private in Company I, of the Four teenth Infantry, New York National Guard, which, it may be recalled, was one of the units sent to the Mexican border, during that same year to settle that little matter of inva sion with Senor "Pancho" Villa, who had evidenced his contempt for the "Gringos" by sacking the town of Columbus, New Mexico, and killing a number of its peaceful inhabi tants. It will be recalled that Senor "Pancho" later settled that account, on his native soil, with Gen. "Jack" Pershing. . And, on the other hand, it proved good practice for our American boys, in view of what was to follow --perhaps the higher-ups knew what was coming! In any case it was only a few months after their return from the Mexican border that CJncle Sam decided to help "make the world safe for Democracy" and young Mattiello found himself a member' of the American Ex- peditionary Forces, as Sergeant of Company H, 165th U. S. Infantry (the old 69th New York National Guards)--the "Fighting Irish," 42nd "Rainbow" Division. During his sojourn in "la belle Fmnce," Mattiello saw service in the defense sectors of Luneville (which the "Heinies" took and lost) and Baccarat, and played his part in the bat tles of Champagne-Marne, Aisne-Marne (Cha- teau-Thierry Sector), St. Mihiel and Meuse- Argonnc, where, with the smashing of the Kriemhilda defense, victory was in sight. Un luckily for him it was here, on October 17, 1918, that he "got his" in both legs and in his right arm. It cost him his right leg, but earned for him a Regimental Citation and the Order of the Purple Heart. He is still a member of the Father Duffy Chapter of Rainbow (42nd) Division Veterans and of the Purple Heart Association, and is,- active in American Legion affairs. On his return he was sent to the Walter Reed Hospital, in Washington, whence,, incifne- diately after his discharge from the army, he returned to high school and after "cleaning up" there, in 1921, went on to the /Brooklyn Polytechnic Institute, where, in l$)2i5, he re ceived his B.Sc. degree. ^ While there he participated in student activ ities, as President of the .Student Council, President of the Athletic .Association (1924- 25), received the "Merit' Key" for extra curricular activities and was elected to the Honorary Delta K appear Pi Fraternity, which he served as Preshj^nt during 1930.. He is still a member ofAAlpha Phi Delta and was President of its/Delta Chapter during 1925; and, for good measure, he is a member of the Board of Directors of the Polytechnic Alumni Association. / Shortly after acquiring his B.Sc. degree, in 1925, he found employment, as chemist, with the Hilo Vjarnish Co., and while holding down this job, continued his work at Polytechnic, which, in 1931, earned for him his degree of M.Sc., and more recently, still unsatiated, he attended the Department of Engineering at Columbia (still holding his job!) which, in 1P9h36n, conferred on him his ultimate degree of ow Technical Director and a memie Board of Directors of the Hilo Corporation. Dr. Mattiello is a "joiner" of the first rank, but is highly selective, as is evidenced by the following- list: Phi Lambda Upsilon, National Honorary Chemical Society (President of its Alpha Zeta Chapter during 1931), Sigma Xi National Honorary Scientific Society, Ameri can Chemical Society, American Society for Testing Materials, American Society for Mili tary Engineers, American Institute of Chem ical Engineers, Chemists' Club of New York, and New York Paint and Varnish Production Club (formerly Secretary-Treasurer, now Vice-President). As an author, both solo and ensemble, he has produced many important research papers on linseed, fish, tung'and oiticica oil, chem istry, paint, varnish and lacquer. In 1936 he served as Chairman of the Committee of his Club which prepared the paper entitled "Prop erties of Linseed Oil, Heat-Bodied in Air and in Vacuum, and Its Behavior with Pigments, with and without Wetting Agents." It won the "American Paint Journal Award" all right, and if there had been a prize for Applied Higher Mathematics he would have gar nered that also. Dr. Einstein would have enjoyed the lecture and Leibnitz, if he had heard it, would agree with every statement, but the average young production man had to take it on faith as did this writer. Fur thermore, when better "high brow stuff" is produced Mattiello will be its producer. Dr. Joseph' Mattiello Seriously, however,- all this work is of fundamental importance and it is fortunate that we.have available a competent man who likes it! In 1922, Dr. Mattiello married Josephine Critelli and today the couple are the proud parents of the Misses Margaret, Elizabeth, Rosamond and Barbara-Mattiello. He lists h.is chief interest as his family, oil studies, stamp and book collecting, and friends who wish to learn the how and why of things. "Work," he maintains, "should be done for the sake of what the results obtained actually teach--only in this way can men serve man kind." And thei'c wc have an enth'e code of prac tice boiled down to twenty-one words. Postscript! He adds: "I volunteered to fight for `Democracy,' but, to my surprise, on my return, I found that we had won only prohibi tion." The Mandis -Society, which is composed of of manufacturers and distributors who are associate members of the Painting and Deco rating Contractors of America, at its annual meeting held at Boston on February 10th, elected the following, officers: President John M.. Sturges, John W. Maswry & Son; vice-president, Joseph Klempf, Wilson-Imperial Co.; secretary-treasurer, George S. Merwin, Devoe &. B avnnlH^ fh* Di rqefcnr* JElnr.fi- G. Ziercs, Clark Stek-O Corporation; A.' G. Schumann, Hilo Varnish Corporation, and Milton K. Pine, Muralo Company. The Official Glossa By J ~~ R. S 1 t * t Tecfmolflsjiafc {Continued from?- February Glyceryl: A group of- compound from glycerol and /aldehydes, s acetyls. Frequently used as plas lacquers. Glycerides: A group of ethers or rived from gljpeerol. Most fats are glycerides^ of fatty acids. Glycerinum: Same as glycerol or g Glycerol: A syrupy, oily liquid, usua white, having the formula (GH.O. It is used extensively as a basic ra* in the/manufacture of synthetic ] plasticizers. Occasionally used ticizer In artists' colors. Also glycerine, trihydroxypropane, trilv hoi, propenyl alcohol, glycyl al glycerinum. Glyceryl Derivatives: This is the b used to indicate the numerous < of glycerol which are often uset ticizers. Giycopon: A liquid and viscous resin having an acid number of soluble in toluol, mineral spirits acetate- Made by Glyco Products Glyptal: A series of synthetic resi alkyd type. The specific gravit; to 1.040, acid number 2 to 6. Thi available as solid resins, but ai solutions in. which the solvents xylene, toluene or mineral spirits the General Electric Co. Gnaedinger Sampler: A sampling signed to sample drying oils in For details, see Scientific Sect. 254. Gneiss: A metamorphic mineral or ilar to granite, but containing su< uents as mica, magnesium sili arranged in cleavable planes.. Gothite: Ruby mica. The hydratec iron having the formula FeO.OH,( ite: Hackh). Gog gin System: A method of elim controlling the fumes in a varnis stack. It is based on condensing the condensable fumes and burni remainder-. Gold Bond Silica: An amorphous, d quartz or 450 mesh size. Th gravity is 2.65 and the oil absor; Made by Tamms Silica Co. It c .99.0 per cent, silica, the bala alumina, -magnesium oxide and Goldsmith Test: A test used for th* and determination -of tung ..oil in ' oils. \The principle of the tes the formation of a gel, and the tion of\the amount of .petrol* soluble mhtter in the gel. Gombrea: 'A resinous exudation of tree which iss occasionally used stitute to replace gum arabic. Goose Flesh: The appearance 5f a has small pimple^like elevations surface. It is similar in appeara peculiar ro-ughness of-^the human is produced by exposure to cold, i citement. Gossypol: The poisonous substance in the seeds of cotton or in cotto Gottsch Cone; A cone-shaped i>\str signed to determine the constate value and mobility of paints. T is specified in the testing pro< traffic paints for the City of Nev Gouache: A method of painting wi colors that have been ground in mixed with a preparation of ; any picture painted by this met! pigment. Graham-Unton Testerr An instri measuring the hardness of a film vice is designed on the principle ing the load in grams necessary aT ttuiAt; bliT1 "Lu cut" LiTTlTtflfr' Grainitiess: The objectionab * Editor. National Paint B-ulletin / FLB 000984 r^n March, 1938 DRUGS, OILS AND PAINTS 93 ing it into a paint formula, namely, its color, opacity, chemical activity, and effect on con sistency. Some formuJators may be accus tomed to considering a longer list of proper ties, including such items as the effect on dirt collection, fading, chalking, checking, cracking, and ultimate durability. The latter properties, however, may be consequences of the former and arc more appropriately con sidered characteristic of the paint formula as a whole than of the individual pigments. Titanium dioxide, for example, is white, opaque, and chemically inactive regardless of the other pigments present, the vehicle, or the concentration of pigment but the chalking, checking, etc., depend upon the other pig ments, the vehicle, and the concentration of pigment. At any rate color, opacity, and chemical activity play important parts in the proposed classification of paints with respect to pigment composition while consistency im poses certain limitations on the selection of a particular variety of any one pigment, say a zinc oxide, that will he suitable for a given formula. When paints are classified in types and divisions it is believed that the paints within any one type and division, if properly manufactured, will prove very similar in such properties as fading, chalking, checking, and cracking so that these properties may be dis cussed as characteristics of the types and divisions. It is commonly accepted that the white leads and zinc oxides confer distinctly useful prop erties on paint by reason of their chemical activity. The chemical activity no doubt arises from their chemically basic nature but the nature of the chemical reactions to which the effects of these pigments are due is not fully understood. To be sure it is often as sumed that lead and zinc soaps formed by reaction with free fatty acids of the drying oils are responsible for the characteristic ef fects of these pigments but, while there is no doubt that soaps form under some conditions, it has not been proved that the soaps give paint the properties in question. Reactions at the double bonded carbon groups in the fatty acids of the drying oils are also pos sible. Moreover the basic compounds may exert their effect by neutralizing the various acids set free during the oxidation of oils, preventing them from exerting a peptizing effect in opposition to the desired gelation in the final stage of drying. Whatever may be the nature of their chemical reactions, how ever, there can be no doubt that the white leads and zinc oxides profoundly modify the linoxyn obtained when linseed oil paint dries. The effects produced by the activity of the white leads and of the zinc oxides are dis similar. The effects are well understood by paint technologists although we experience some difficulty in agreeing upon satisfactory language in which to describe them. The white leads seem to keep paint films tough and slightly flexible to an advanced age, though they do not restrain checking, and make com paratively soft films. The zinc oxides, on the other hand, harden paint to the point of brittleness, retard erosion and often delay checking. Many consider cracking a prop erty imparted by zinc oxide but cracking may be regarded merely as a consequence of brit tleness with delayed checking and erosion be cause cracking is not confined to paints that contain zinc oxide. Because of their profound effect on the chemistry of paint drying the white leads and zinc oxides should be ex pected to have much to do with the compatibil ity of successive paints and there is already substantial evidence that they Although basic carbonate white lead is somewhat more readily reactive than basic sulphate white lead, the two are used more or less interchangeably in paint formulation and are so regarded for purposes of classi fication. About the zinc oxides ther-e is less agreement. Some zinc oxides with high pro portions of very fine particles are considered unfit for use in exterior house paints at all while among others there is said to be a wide variation in quality. From the evidence pub lished so far the differences between the zinc oxides do not lie in the extent to which they harden paint but rather in the extent to which chocking. There seems to be no reason at present for believing that the par ticular kind of zinc oxide chosen affects the properties of the paint that govern application and maintenance except insofar as it governs consistency, which can be measured directly by physical methods. For purposes of classi fication, therefore, all of the zinc oxides are considered interchangeable and the leaded zinc oxides are treated as though they were mechanical mixtures of basic sulphate white lead and zinc oxide. The titanium pigments and the zinc sulphide pigments are considered chemically inactive. Lead titanate, though said to be chemically inactive, is also said to keep paint films tough and flexible for a long time even more effec tively than white lead. For the present it is grouped together with the white leads for purposes of classification but this procedure may have to be revised when more informa tion becomes available. The transparent pig ments with the possible exceptions of calcium and magnesium carbonates are chemically in active. Calcium carbonate seems to have fallen into disrepute in recent years, presum ably because it fails to restrain checking as the other transparent pigments do. The writer believes that checking is not an un mixed evil and that there were good reasons for the favor that calcium carbonate for merly enjoyed for use in paints in which a high content of transparent pigment was de sired for one reason or another. Among the colored pigments the iron oxide pigments, the iron blues, ultramarine, aiul the carbon pig ments are chemically inactive. Red lead and the basic lead chromates are chemically active and possibly should be counted among the active lead pigments in paint. From the point of view of the effect of the pigment on the fundamental nature of the resulting paint film we can divide the pigment into three parts, the white lead, the zinc oxide, and the chemically inactive parts of the pigment. It is therefore convenient to chart the fields of pigment composition with the aid of triangular diagrams. Figure I is a diagram of that kind showing the variations in pigment composition of white and tinted paints in 68 paints belonging to 30 current brands of commercial prepared paints of the lead and zinc groups, LZ and (LZ)n. Each circle represents a paint of a brand indicated by the enclosed number. If there are two numbers two brands have a paint of the same pigment composition. The enclosed letters refer to the divisions into which the paints fall in the proposed system, of classification. Pigment composition is expressed, of course, in terms of percentage by volume in. the total pigment. At one time the left-hand edge of Figure 1 represented the entire market for house paints. The pigment in white paint consisted en tirely of white lead at one end of the line, addition of tinting colors or adulteration with transparent pigments moved the paint up ward along the line, while the full color paints were at the top of the line, which is the apex of the triangle. When zinc oxide came into the industry the straight line was spread out into the triangle and the paint market became very much more complex. Both zinc oxide and transparent pigments were adopted pri marily to reduce manufacturing costs, the zinc oxide doing so largely because its con sistency made it possible to decrease the total pigment in the paint. Technical rationaliza tion of these practices was not seriously at tempted until the North Dakota paint law made it necessary to discuss composition with the industry's customers. Since zinc oxide is an opaque pigment its presence in paint was more easily justified than that of the transparent pigments and some manufacturers saw a merchandizing advantage in excluding transparent pigments in order to advertise their paints as "100 per cent, pure" in the sense defined by the North Dakota law. White paints of that kind fall along the bottom edge of the triangle of Figure 1. When tinted, however, they move upward toward the apex, especially if the natural earths, which contain large propor tions of transparent ingredients, are used as tinting colors. Brands 1 and 2, for example, are "100 per cent, pure" paints that can be tt-aced through the triangle from the whites in the bottom edge through various tints clear to the apex. When tjhi* iiiX.j--are included, therefore, the LZ paints cover much the same range in composition as the (LZ)n paints. White paints in the interior of the triangle, of course, contain transparent pigments. A large number of them are strung along the level of approximately 20 per cent, inactive pigments. There were formerly many white paints in the upper third of the triangle but they have been largely replaced in recent years by formulas based on zinc sulphide pig ments so that the upper portion of the triangle now represents pvedominantly deeply tinted paints with full color paints at the apex. The region of very high zinc oxide at the right- hand corner is dotted because no paints seem to be made in the region at the present time although there were such paints in times past. The heavy lines drawn through the triangle mark the borders of the various types of lead and zinc paints set up in the proposed classi fication. Pure white lead makes an excellent paint that is still thoroughly satisfactory to large groups of paint users. Replacement of part of the lead with zinc oxide leaves the opacity unimpaired except insofar as advantage is taken of the higher consistency of zinc oxide to reduce the proportion of total pigment in the paint. Increasing proportion of zinc oxide hardens the paint, retards erosion and check ing, and improves the retention of some tints but these otherwise desirable improvements are offset against the disadvantages of crack ing and curling and ultimate disintegration by flaking instead of crumbling so that the paint becomes unreliable for maintenance pro grams involving the periods of neglect to which many paint users are accustomed. By diluting the chemically active pigments with Inactive pigments and keeping the content of total pigment high, cracking, curling, and flaking can be retarded but if the inactive pigments are transparent there is serious loss of opacity unless the paint is deeply tinted. For whites and the lighter tints, dilution with inactive pigments is limited to roughly 20 per cent, if the paint is to compare at all favorably with the "100 per cent, pure" paints in. both opacity and spreading rate. This still leaves us in a region in which checking is prominent during much of the life of the paint, and disintegration ultimately takes place by curling and flaking. Higher dilution with transparent pigments impairs opacity so seriously that the total pigment must be made high enough to force the application of a thicker coating with consequent reduction in spreading rate. At the same time the trans parent pigments stimulate erosion more than the remaining limited amount of zinc retards it. In spite of these shortcomings, however, these low-grade lead and zinc paints often proved less disappointing than the high-grade lead and zinc paints in the hands of those fol lowing the old traditions of paint maintenance involving periods of neglect before repainting. The zinc sulphide pigments were the first to offer a means of obtaining high dilution of the chemically active pigments without sacri fice of opacity in white and light tinted paints. Figure 2 shows the pigment composition of 36 brands of zinc sulphide pigment paints now on the market. Except for one brand they range over only a small part of the area of the triangle near the apex. Most of these paints, of course, are manufacturers* secondgrade paints. Zinc sulphide pigments were originally proposed for the purpose of dis placing white lead entirely. Unlike most of the inactive pigments, however, zinc sulphide has little tendency to restrain checking, and once the checking penetrates through the coating, zinc sulphide, in contrast to white lead, seems to stimulate rapid crumbling of the coating even over the soft bands of springwood in the lightest woods. If checking is restrained too much by the addition of zinc oxide, cracking is rapidly followed by curling and flaking. The leadless formulations with zinc sulphide therefore require a restricted content of zinc oxide and of zinc sulphide and leave no choice but the inclusion of much transparent pigment. Most manufacturers finally found it advisable to add some white lead, commonly in the form of leaded zinc oxide. A large proportion of white lead, how ever, usually defeats the business purposes of resorting to zinc sulphide in the first place. Undoubtedly, good paints can be made in the Lower left-hand portion of the triangle but there would be little point in making them because of their close resemblance in. cost and properties to the ordinary lead and zinc paints. A 94 DRUGS, OILS AND PAINTS March, 193 The titanium pigments offered another way of diluting the chemically active pigments without loss in opacity and without some of the disadvantages of zinc sulphide. Figure 3 shows the range in pigment composition of 64 paints belonging to 41 brands made with titanium pigments at the present time. Brands 63 and 64 are enamelized paints that cannot be considered representative of formulation for true house paints. With these exceptions it is evident that the industry holds the content of zinc oxide to lower limits in the titanium pigment paints than in lead and zinc paints but that the content of white lead varies nearly as widely as it does in lead and zinc paints. The TLZ paints fall predominantly in that area of the triangle representing greater proportions of inactive pigments than can be used in high grade (LZ)n paints but less than are commonly used in SLZ paints. In this area it becomes possible to retard erosion, practically eliminate checking, and greatly postpone cracking. Cracking occurs eventually and is usually of a rather conspicu ous sigmoid type but its seriousness is miti gated by the fact that, under favorable cir cumstances, there is relatively little curling and flaking may tag behind cracking for a long time. Vehicle Composition Fortunately the vehicle in house paints, in contrast to the pigment, has been kept rela tively simple and contributes very little to the problem of classification. For the most part the vehicle of white and tinted house paints remains essentially unbodied drying oil and thinner. There is, of course, much variation in the quality of linseed oil and there are developments in the way of substitution of other oils, such as soybean oil, for part of OfTOfTBN Of THE PIGJtNT funj&r001- a G!UP5'" T'TIZ. t z mu LEAP Fig. the linseed oil. As far as present evidence goes, however, such variations in the vehicle do not affect the nature of the paint with respect to its application, maintenance, and compatibility with other paints, although they may affect the quality of the paint and make trouble for the manufacturer in controlling such properties as drying time and proper drying in cold weather. Questions that affect the quality of the individual paint but do not govern the characteristics of the class of paints to which it belongs are questions of specification and not of classification. In trade-branded paints the manufacturer's brand certifies to the quality of the individual prod uct and he is responsible for seeing that it is capable of delivering the service to be ex pected from the class of paints to which it belongs. It is becoming increasingly customary to incorporate a small proportion of moderately bodied drying oil in the vehicle of house paints for various purposes such , as improve ment in consistency or in drying qualities. As long* as the amount and degree of body of the addition are too slight to compel reduction in total pigment or to change paint-like con sistency to enamel-like consistency there seems to be no reason for altering the classification of the paint. When the amount and degree of body of the addition are enough to impart properties of enamel, however, the paint must be assigned to a new type to differentiate it from a true house paint of similar pigment composition because its methods of applica tion, suitability for specific purposes, and probably its compatibility with other paints have been altered. As a matter of fact an enamelized paint is likely to differ seriously from, true house paints in its pigment com position. The enamelized paints among the com mercial brands charted in Figures 1 to 3 are Nos. 63, 64, and 74. which fall in regions of the triangles not occupied by other paints. The enamelized paints likewise differ from true paints in that the content of total pigment is necessarily lower and the content of volatile thinner higher. It is therefore difficult to make enamelized paints without using* the very high opac ity pigments, such as titanium dioxide and zinc sulphide. Until recently the use of resins, other than the small amount in driers, was confined to cheap hqtise paints, where a very hijgh content of volatile Ingredients without sacri- fice of gloss was desired to;. meet a price level. and to moderate proportions in the vehicle c unduly soft, slow drying, full-color paint! During the last few' years resins have bee introduced into some high-grade white an tinted paints for a variety of purposes. Resin may be used to produce enamel-like propet ties, to make quick-drying paints, or to harde zincless paints. Resin fortification does no appear to be particularly successful as ye and may not develop into a serious adde complexity in the paint market but if it doe w'e shall have to learn a great deal more tha we now know about the effects of resins o. the behavior of paints. Since resins as . rule roust be added in the form of vai'nishe it is not possible to introduce very large pro portions without giving the paint the con sistency of enamel and without diminishinj the content of nonvolatile well below th< level commonly expected in high grade houspaints. For the present it seems sufficien for the purpose of classification to make dis tinction between the resin-fortified paints, thenamelized paints containing resins, the enam elized but resin-free paints, arid the unbodie< drying oil paints. Pigment Concentration Some technologists who recognize the im portance of correctly adjusting the concen tration of pigment in the nonvolatile part paint seem to consider the concentration o: pigment in the total paint unimportant. The' add enough drying oil to make the concen tration of total pigment 29 per cent., let u: say, of the total nonvolatile and then ad whatever proportion of volatile thinner tha may be required to produce paint of suitabli consistency. That view, however, overlook! two vital considerations, raw materials cos per gallon and thickness of permanent coating obtainable at customary spreading rates. Foi high-grade prepared paints of the unbodiet drying oil types there is an informal conven tion that not much less than 90 per cent, oi the vehicle by weight, which is usually roughlj 90 per cent, of the paint by volume, shoulc be nonvolatile matter and the consistencj should be such that application to smooth primed surfaces in the vertical position ai 600 square feet per gallon is practicable though the industry likes to claim at least 70C or 800 square feet per gallon "coverage." For these reasons the amount of volatile thinner incorporated in a formula is not a matter of indifference and it is necessary to pay strict attention both to the concentration of the pigment in the nonvolatile part of the paint and to the concentration in the total paint. The writer feels that, in formulating a paint, the concentration of pigment in the paint should be decided first with due con sideration for the degree of opacity of the pigment and the spreading rate at which the paint is intended to be applied, and then the ratio of nonvolatile to volatile ingredients in the vehicle should be adjusted to give the correct proportion of pigment id 1 ilm ""RQftL volatile. Consistency, however, cannot be over looked, though it seems to be in many of our FLB 000986 March, 1938 DRUGS, OILS AND PAINTS 95 discussions of formulation. Observation of the tremendous variation in consistency of high-grade prepared paints on the market, without much observable relation to thinning' directions or recommended spreading rates, confirms the feeling that the significance of consistency is not generally appreciated even though production men need scarcely be re minded that their painter customers are quick to detect any very material change in the consistency of a brand of paint they have been using for some time. Obviously con sistency, thinning instructions, and spreading rates are necessarily interdependent and must be taken into account systematically in any sound technology of paint formulation. With the composition of the pigment and vehicle and the proportions of pigment in the nonvolatile fixed within rather narrow limits by other considerations it might seem at first glance that the formulator could exercise very little control over consistency and would have to accept it pretty much as it happens to fall. Years ago that was probably the case and set very definite practical limits on formulation. At the present time, however, there are a number of ways of varying con sistency with the formulation of the paint as recognized by the proposed system of classi fication already determined. Most of the im portant opaque white pigments are available in a range of consistencies from which the formulator may make his choice. This is par ticularly true of the zinc oxides, especially when it is remembered that, as far as classi fication is concerned, the leaded zinc oxides may be used interchangeably with mechanical mixtures of lead-free zinc oxides and white lead. That ingredient commonly described in label analyses as "silica and silicates" is like wise subject to wide range in consistency. The various types of unbodied linseed oils likewise afi'ord means of controlling consistency which can be further extended through the use of small proportions of bodied or oxidized oils. The choice of volatile thinner permits a minor variation in consistency. Finally, though not without apology, it may be confessed that certain soaps embraced within the somewhat elastic term "driers" and even a slight touch of water that need not be admitted on the label have long been used as methods of con trolling consistency. The suggestion that choice may be made between the various zinc oxides and leaded zinc oxides and between the composite and mechanically mixed titanium and zinc sulphide pigments largely on the basis of consistency of the finished product will not be acceptable to all technologists. Some hold that pigments of certain particle size distribution or particle shape are so superior to other pigments of chemically-like kind that they profoundly mod ify the serviceableness of the paint and should therefore enter into the system of identifying paints by types. At present the subject is decidedly controversial and the evidence in decisive. There has not yet been enough experimentation on the part of those with no axe to grind and it is notable that similar controversies that have raged in the past have largely died out without attainment of a decision as soon as some change in business conditions eliminated the element of compe tition between producers of raw materials. The writer's present opinion, subject to change when the evidence justifies it, is that the phys ical differences between varieties of chem ically similar pigments affect the behavior of paint with respect to application and service ableness only to a slight extent except as they do so through their effect on consistency. Examination of the high-grade paints on the market shows that the industry at present has no very definite idea of proper consistency for good house paint (H. A. Gardner, Scien tific Sect., National Paint, Varnish and Lac quer Association, Circular 507) because con sistencies vary exceedingly widely without (recognizable relation on the one hand to the concentration of pigment in the paint or on [the other to the instructions for thinning and jrecommended spreading rates. Apparently /many manufacturers defer to painters' prejuI dices instead of attempting to educate them correct practices. Paints may be made over too much surface or unduly thick so that he can add oil or thinner and then spread them too far. In formulation studies at the Forest Products Laboratory certain tentative standards of consistency are being used at the present time. Unbodied drying- oil paints of division L are made with consistency of 250 grams for 2 centimeters per second rate of fall of the Gardner mobilomctcr, using the 51-hole disc at 20CC. LZ paints of the "100 per cent, pure" variety, in which the content of total pigment necessarily decreases on going down in division, are made with con sistency 250 regardless of division through suitable choice of pigments, oils, and, in the lowest divisions, addition of small amounts of soaps or water. Paints in which transparent pigments arc used are usually made as far as practicable with higher content of total pigment and higher consistency the lower the division so that they facilitate application in thicker coatings to compensate for the diminished opacity. For such paints the con sistencies are tentatively set at 250, 275, 325, 375, and 450 for divisions L, M, N, O, and P, respectively. The above trend toward higher content of total pigment in paints of lower division is representative of much commercial practice in formulation of paint, especially in the region from division N down to division Q, but it cannot be followed in the LZ paints that contain no transparent pigment and is not always followed in the (LZ)n and other paints containing transparent pigments. It is for that reason that the minima for total pigments in the proposed definitions of paint divisions decrease in passing downward from division L to division Q. If we start with a given paint so formu lated that it falls in division L there are in general three ways in which it may be altered progressively to pass step by step through the various lower divisions. The first method is to reduce the content of total pigment in the pa,int without altering the composition of the pigment. By this method it is often possible to make paint through a range of four or five of the six proposed divisions with out altering the composition of the pigment and without letting the consistency fall below 250. The second method is to decrease the content of opaque pigment by substitution of transparent pigment. In this procedure the total pigment may be held constant, may be increased, or may be decreased less rapidly than the opaque pigment as the formulator prefers. By this method, however, it is rarely possible to shift a white paint of (LZ)n class through more than two or three of the six divisions without likewise passing over a bor der line into a different-type of paint because a material increase in the content of trans parent pigment must be effected at the ex pense of white load or zinc oxide or both. With paints of the classes containing much titanium dioxide or zinc sulphide pigments nearly any division can be realized within any type of paint because transparent pig ment may be increased at the expense of chemically inert opaque pigment. The third method of shifting the division of a type of paint is by control of the content of total nonvolatile but with paints made with un bodied drying oils this method is severely limited by the difficulty of maintaining satis factory consistency and by impracticably high content of total pigment in the nonvolatile part of the paint when the paint, contains too much volatile thinner. Discussion of Dr. Browne's Paper By Dr . J. S. LXq 3 I have been asked to discuss briefly the paper that Dr. Browne has just presented. The first question is whether we need a classi fication to replace the present label analysis. In my judgment, or as far as our experience goes, the average consumer does not get much from the label analysis. Its biggest value is directed to state chemists and others in offi cial capacity who use it to see if the material sold is misbranded. > .Jllpr sales department has run into many Tunny stories arising f*om attempts of cus tomers to judge paint, from the analysis. Some time ago I stopped in {a restaurant in South Carolina and noticed on tho wall an official state placard which said, "This is an A grade restaurant," and was signed by a state in spector. My immediate reaction was that the food in that restaurant, was safe to eat and represented the highest quality reasonably obtainable in commercial establishments. If it is decided by the paint people that Browne's proposal of classification is logical, then the next question that presents itself is the matter of nomenclature and system of classification. Browne has presented a logical system using the symbols L, Z, S, etc., with, subscripts. This can be considered by the paint industry and if anyone has a better or alternate system it can be presented for dis cussion, but Browne's suggestion has many things to commend it. Paint technologists will probably agree on the importance of percentage by volume rather than percentage by weight as the basis for classification. It is of course true that it will take some time before various state chemists and officials would agree to such a classification or the symbolizing of the paint composition and until such I'eplacemenfc of the analysis by the latter classification had been accomplished, Browne's proposal would not have its full value. I suspect that even the approval of the Paint and Varnish Manufac turers Association would not of necessity move the various states to rescind their label laws and substitute new ones. In connection with the final type and divis ion of paint, the letters L, M, N, O, P, would not seem as logical as either A, B, G, D, E, or 1, 2, 3, 4, 5. In general there is some significance in the popular mind to the sym bol A--in other words, an A grade paint would mean the highest quality. Browne had orig inally contemplated this but for the purposes of the paper changed it to the other letters while the system was in the tentative stage. Coming now to the detail as to what is to be regarded as an A grade paint, there will naturally be considerable opposition on the part of some manufacturers who have been marketing a certain quality of paint and who do not want to change but who would find themselves in the classification of B or lower on even their top quality product if the present system was accepted, as is. T do not feel that I can speak for the in dustry on this. What little conversation I have had has indicated some lack of agree ment on the part of various paint companies as to what constitutes an A grade paint, but I am inclined to think that these differences could be ironed out and a minimum standard of quality set up for each grade which would be acceptable to all of the sound technologists of the industry and on this basis the others would have to agree in common interest. There is one point which Browne has care fully circumscribed which, however, deserves further consideration; that is the matter of the composition of the vehicle and also the relationships of pigment to vehicle in the resultant dry film. Browne is considering essentially raw linseed oil as the vehicle with modest additions of bodied oil or the like. First of all, we all realize that the iodine number of the linseed oil is of considerable importance and affects the toughness of the film and the durability of the paint. At sev eral times in recent years actual paint ex posures involving series of oils having iodine number of broad range and in each case with which l am familiar, the oils of higher iodine number showed greater durability. This isjust an obvious starting point. The admixture of various oils such as China wood, perilla, fish, and others with the linseed affects the results seriously and the amount of heat bodied or blown, sulphur chloride treated, or otherwise processed oil present together with the extent of blowing, sulphur chloride treating, etc., have some influence. It therefore seems that considerable more atten tion must be given to the matter of the ve hicle which, after all, is the life of the film. The matter is not simple and the information is rather carefully guarded. In certain types of paints involving say 30 per cent- of zinc oxide or more, the simple addition of perilla oil has been found in at least one series c.1 experiments to throw definitely the paint over from a chalking type failure to a cracking type despite the fact that the average iodine \ i 96 DRUGS, OILS AND PAINTS March, 19, number of the mixture is not. as high as the of his experience has observed, that had: results now happen to him. So, in this respect, iodine number of linseed oil that has been are inherent in certain succession of types of think that Browne's thesis is valuable to thf successfully used in the same formula. paint. paint industry and merits our serious con-,, In addition to this, it must be remembered There are unquestionably some bad com sideration. that the final film architecture is not just the binations. I thiiik his most unfavorable ex sum of the non-volatile constituents but that chemical reactions occur which are a prelude to final collodial processes involving all the features of each. perience has been obtained when a very soft paint, such as straight white lead, is put over a hard paint according to practice normally followed and thinning directions normally sug A Simplified Chemistry ot Paint Technology 1y F 1 q _ 0 W0 0 1 +B X q . PQ .D. Whafl One obvious way to call attention to the differences that can result would be te refer to the influence 'of the percentage of driers and the ratios of these driers to one another. gested. Many cases of failure have also been noticed when repainting has been done with hard types of paint over surfaces which con tained somewhere down underneath a coat of \ Industrial Consultant, PhSa, Pa. iNote:\ in litis series of articles. Dr. Brawn, will cover tir, entire field, of. inorganic paint chemistry in. language the.,, Pain In certain cases very modest changes in com position v?ill change the film from a smooth drying one to one that will wrinkle badly. yellow ochre in oil, or over a surface where there is an old coat or coats containing a lot of iron oxide. Our knowledge today is such any paitmman with- an ordinary high school education ca understand! T*te editor is confident that this will constitut. a real service to every member of the tedustry, with th possible, exception of the professional chemists thereof.} , Slice This is of course well known to all of us but as to lead us to expect such a result. Continued from February) % % f is only mentioned as a simple illustration to put emphasis on the fact that two paints which would pass anybody's A rating might give vastly different results in practice. It is quite conceivable therefore that a paint with a coveted A rating might consistently fail to give good results in performance; whereas another with a B rating but of very smart design might give wholly acceptable results' to the consumer. Finally, the tremendously important vari ables!--the painter and the surface--must be considered. It is not just a matter of educa tion of the painter. Even in these days of regimentation, it is unlikely that painters as a class can he taught to follow the instructions on the can. Someone has aptly said that the painter does not think he is exercising his craftsmanship unless he adds something to the paint. This is undoubtedly a factor. How ever, there are others. Thus, different brands of paint, even with the same classification, will undoubtedly feel different under the painter's hand and if he is in general accus tomed to using a certain brand and is asked to use a different one on a certain job, he will encounter a difference. Whether the difference is favorable or unfavorable doesn't matter, there is a difference and it at least tempts him to do something to get what he is accustomed to. Furthermore, the surface varies and the conditions of painting vary--which again are factors. Two years ago, in November I went out to watch a painter painting on Cape Cod, right at the edge of the water. He was using our material. He was wearing a heavy jacket on the ladder and, although the sun was shining, the temperature was quite cold, even during the day. By actual test, instead of getting 700 to 800 square feet to the gallon, he was getting 400. It might be argued that he should not paint in such cold weather. Nevertheless, that is beyond our control. As a matter of fact I was called onto the job to make an adjustment, hue to the fact that one side of the house painted, three days be fore had wrinkled terribly due to a cold night following the application of the paint. Ip Chicago, last December, we had several other wrinkle jobs and the contractor involved finally became bitter and decided to switch back to white lead. The lead jobs wrinkled equally badly, so he thinned the paint tre mendously beyond the Lead Company's thin ning limits and then got to the point where the paint didn't cover in three coats of white. To overcome this, he tinted the paint buff and, although the house was supposed to be a white house, and all the other ones in the subdivision were white houses, this one is a buff house and the fellow that bought it on a Government loan could take it or leave it as he. saw fit. These various tales could be multiplied indefinitely when paint, men get together. Each one has had annoying and interesting experiences. My only thought, in raising the point is that what the painter does is beyond our control and probably will continue to be so. In some ways this is an argument in favor of a definite class label--A, B, C, etc. If the paint used is a certified A grade paint, no complaint or adjustment is thereafter pos sible. The painter takes the blame. You can imagine how he is going to love this. I can foresee some conflict, but in the broad general outlook I think it is a good thing. *TMJ3naIly, the., matter of paint compatibility will require a great deal of attention. Browne However, other factors are of at least equal importance. The excessive and uncontrolled and irregular penetration of a priming coat into an old surface has unquestionably led to bad results in many cases and is a factor of major magnitude. It is apparent from the way many companies are now proceeding that this is regarded as of prime importance and efforts being made to control this factor by the use of special primers containing thick ened oils. The finish coat applied over these primers after they are dry is of substantially different composition, so that this would warrant the general statement that it is undesirable ever to paint the same land of paint over itself. There are restrictions to this in the case of people who paint one coat frequently to maintain a gloss, but this is undesirable prac tice and leads to the building up of an exces sive quantity of paint on the surface. I mention this point; namely--that a system. of painting is needed rather than always using the same type of paint over itself--because I think it is an important point, not yet in corporated in Browne's classification and com patibility ideas, and I feel that discussion of it and experience along these lines is needed before the story will he complete enough for final adoption. I know', however, that Browne is doing this and with proper co-operation all around we can finally arrive at a rational sys tem or basis on which to advise the painter or home-owner what to. do. Daring the past few years, we have painted several hundred thousand houses with our own particular Two Coat System, Inspection, of a reasonable percentage of those houses by our field men has disclosed rather striking, examples of failures and has pointed out the things that happen to paint after it leaves the factory--and I refer to paint that would receive an A grade label under any classifica tion. Nevertheless, the percentage of complaints has been ridiculously small. It is unquestionably fair to assume that this one type of system has been put over practically every kind of paint ever devised, including recently one of the highly enamelized paints. Despite this, as I previously mentioned, the percentage of failures is extremely small, so tiiat we would have a very strong case against the necessity of considering compatibility, since sufficient time has elapsed to bring out any serious failures. It is our feeling, however, that the. results we hare obtained have indicated at least cer tain extreme eases where the idea of com patibility is useful; namely, painting with hard system over ochre in oil, or painting with what might be classified as an extremely soft paint over a very hard one. Proceeding from these specific cases it should be possible to anticipate the results on the. basis of coefficient of expansion and contraction and other general principles and so gradually evolve a minimum of practical warning signals to the customer. I say "minimum'' since. I think that the instructions to the customer or the painter must be kept at a minimum and he must not be necessarily alarmed. We are all familiar with the constant bar rage of advertising dealing with "pink tooth brush," "B, O." and the like, and I think it would be advisable to avoid this kind of ad vertising in the paint industry; but it seems likely that we can proceed to some rational basis which will minimize the, troubles en SALTS (Continued) Density The. heaviOy the metal present, in a salt, thq; greater its density. The greater the percent age of the. metal present, the greater /the; density. Conjpaunds that occur in natures usually have a higher density than the/sanw' ones artificially made, although the Aattci;; approximate thfe natural form if calcined. As"' a general rule the soluble salts of a metal art/ less dense than the insoluble ones. The active: Senic metal salts usually are more dense man the' metal, the less'eh active ones being less dense than the metal. \ Water Solubility All the salts off sodium, potassiuni and am monium (NH*) are soluble in water. Alls: nitrates, acetates \and chlorates are water soluble. The following salts are water insolu ble: \ / Ad Chlorides--Silver AgCl, Mercury? HgCl, Leads PbCh, V / Sulphates--Lead PbSO,, Barium BaSCh, Strontium SrSO, \ Carbonates--All except sodiuih, potassium ammonium, \ j Sulphides--All except sodiurfi, potassium ammonium, barium;, calciufn, strontium; magnesium, V/ Phosphates--All except sodium, potassium; ammonium. \I Natural compounds are nsuafiy more insolu-s ble than the artificial ones unless the latter are calcined. \/ Electrical Conductivity Dry salts are non-conduqtors, but in water solution are excellent, conductors. Molten; salts are fair conductors, mbile mixtures of molten salts are often better conductor s than the separate components, / I * Freezing and Boiling Points The presence of dissolved salts in waters lowers the freezing point and. raises, the boil-r ing point. The higher/the Concentration off the dissolved salt, the/ greater the change* The greater the number of component atoms in a salt, the greater the effects i. e., aluminum chloride, AlCls, which /contains (four atoms, is more effective than/sodium chloride, Nad, having but two atoms to the molecule, * Chemical Pfoperties of \Salts . ... Thermal Stability \ fee they uo not The naturally deeurring compounds are,, r usually very stable to moderate meat. As general rule, the unstable compounds area|iicr-beaten su more complex th^n the stable. Bor instance,^ m noc chlorides, carbides, sulphides, sefenides, andip . * nitrides are very/stable, Whereas the chlorates,ft paints, carbonates, and/nitrates are decomposed. byj|a new coat i; moderate heat./ Sulphates, phosphates and^r silicates, however, are very stable to high|^TrAvf purjERA' heat, although/they are comparatively com-is* plex. j \~ It is evident/ that high temperatures favor- the simpler compounds and low valei\ce. Heat? rarely liberates the free metal unless the^-1 1 ..... metal present/ is very inactive, such silver,^ ~mr gold, platinum, etc. j Metals A metal will react with a salt active metal, displacing the latter, acts with ijron sulphate to form zinc suli and free iron, zinc being more chemfcall; active than iron. A meter will, react with a salt solution\ if||L the latter has an acid nature. Ammonii chloride, a salt of the weak ammoni hydroxide^ (NH<OH> and the strong hydr<& chloric acuMHCl), in water solution gives a acid reaction due to hydrolysis. An active]' metal, such as zinc,, dissolves in anundhiuml has had considerable experience in observing countered and protect the position of the chloride solution just as it would in. any acid! paint faults and complaints and on the basis naint rn.mrffvhii'ra' sosmet Fha Ht-af cnlivf5. FLB 000988 Paint Maintenance More Successful . ... . . By Dr . F. L. B X q Senior Chemist, Forest Products Laboratory Madison, Wisconsin Address at the Recent Annual Convention of the Southwestern Lumbermen's Association at Kansas City Reprinted from American Paint Journal March 7 and March If, 1938 \ ! | k t N41698.4 FLB 00098S et, I I the ,eon- What Can Be Done to Make Paint Maintenance More Successful same atter s As 1 are jctive I the lense i am} All rater isolu- Lead aSOs, sium, sium, tium, sium, soluatter vater olten is of than vater boilh of ange. items inum is, is SaCl, : are As a are anee, and rates, d by ? and high com- favor TT + t By Dr . F. L. JB X q Senior Chemist, Forest Products laboratory Madison, Wisconsin Address at the Recent Annual Convention of the Southwestern Lumbermen's Association" at Kansas City Reprinted from American Paint Journal March 7 and Match 14, 1938 tion, tout conform to no standards by does not lend support to any one means of which the various hinds and school of thought about house paints grades can be recognized by the users, at the expense of contrary opinions. The Forest Products Laboratory has Each may choose whatever type of recently shown that it is perfectly paint he prefers and reject those he practicable to define good paints of dislikes. all kinds in such a way that they can The proposed classification assumes be set apart from inferior paints. In that the system would be administered fact, it is technically feasible to elaa- by the appropriate trade association, sify paints in a logical manner. The just as lumber grading is administered proposed "grading" rules, though tech- by the regional lumber manufacturer's nical in nature, are much simpler than associations. A commercial paint would the various grading rules for lumber, then be identified for sale Doth by the While some technologists of the paint manufacturer's trade brand, which industry recognize the desirability of would remain his seal of responsibility classifying paints the paint industry for quality of the product, and by the as a whole is opposed to it. Since the association's symbols of type and di idea is a new one originating out- vision. These Symbols would be sim- side of the industry, it is by no means pl6 enough to be explained to laymen, surprising that it should be regarded ^ contrast to the complicated for- with suspicion, especially since its pri- muia label that now appears on many mary purpose is to provide a clearer paints in conformity With the laws of basis of mutual understanding of the some states. A typical symbol of type composition of' the product between. and division might read: "This paint manufacturer and user in so far as is 0f TLZ (titanium, lead, sane) type composition affects the correct use of vrttb medium content of white lead tiie product in practice. If there is a and medium content of zinc oxide, di better way of accomplishing the lat- vision M, as classified by the.............. ,, ter. objective it is to be hoped that Association." With paints so classi- someone will soon propose it. fied there would be no great difficulty The Forest Products Laboratory's. tgiimg the public the difference be- proposed system of classifying house tween good paints and inferior paints, paints was published in detail in the The problem of cheap paint, therefore, American Paint Journal, issues of Oc- can* be dealt with effectively just as tober 1.1 and- October 18, 1937. Briefly, soon as we really wish to do so. paints are `separated into types ae- - '. ' cording to the nature of their opaque "Moisture* Failures and Their Cure white pigments and the proportions of Access of moisture behind painted the two kinds of chemically active woodwork is the cause of one large white pigments, namely, white lead class of early paint failures. The and zinc oxide. Each type is then moisture may get in through care- marked off intp divisions according to lessly designed or erected joints in the content of total pigments, opaque the construction, or by condensation pigments, and nonvolatile matter (pig- of moisture laden air from inside of ments plus drying oils). Where paints the house when it comes in contact contain vehicles other than the cus- with the, cold back surfaces of the ex tomary unbodied drying oils, such as terior woodwork. Trouble from con- linseed oil, additional classification is densation has probably increased ma- provided. In the writer's opinion the terially in recent years because of the proposed system of classification evalu- greater Use of thermal insulation, ates paints in essentially the same way which makes the back surfaces of ex- that any well informed paint technolo- terior woodwork colder by letting less gist, would evaluate them but, inas- heat escape from inside, and because much as the various types are merely of provision for air washing and hu- recognized as differing from one an- rnidifieation in modern healing plants, other without inferring that any one Condensation of this kind is more is inherently better than another, it troublesome in the northern parts of 4 I FLB 000991 the country, hut in more southern areas where studs are sometimes covered with drop siding- without sheath ing and heating is accomplished with inadequately vented open gas burners, condensation on or in the sidewalls or under the roof sometimes occurs as a result of the large amount of mois ture formed in the combustion of gas. Condensation in sidewalls and attics can be prevented by keeping moisture from passing through the walls. This can be accomplished by the correct in stallation of vapor barriers on the inside of tlie studs. and underside of attic floor joists. In houses already erected two coats of aluminum paint oh the interior surfaces of sidewalls and ceilings under the attic makes an effec tive vapor barrier over which other wall decoration may be applied. Where moisture arises from open gas burners it should be carried off by means of adequate flues. Much moisture is evaporated in houses during normal living opera tions such as cooking, bathing, laun dry work, and the breathing of per sons and plants. Families undoubtedly vary in their living habits that af fect the amount of moisture evapor- , Paint capable of giving good soxvico sometimes gives bad service in actual practice. The house shown at tho left was painted with a high-priced paint about one year before the photo graphs were taken. The bad cracking that developed has been observed on other houses on -which this paint was applied over previous coats of paints of other typos. The views at (he right show the excellent service given by tho brand of paint in question in an exposure test by the: Forest Products laboratory. The test panel consists of one beard each of redwood, white. pine. Douglas fir. and southern yellow pine, painted with three coats of the paint in question, rend exposed at 45 facing south (a very severe condition) for 2%. years. The square showing fine checking of the paint is an area only 1 inch by 1 inch in actual size. 5 V FLB Market. Manufacturers* Directions the Paints When So Thinned. of Semipaste Paints on the Coat, and Characteristics of $ <w Vd SB* *1 3S On, iu.ocfdlnuooSaf.coiroaws^o.c'iadoOioadQw'^OtqQocoooioonaiccoontoo^stdoO..ouW.iOr^U)JetooocM0d0 m 0o f.0tt, iW> Ifltt t> o U) O O 0 H ^ O) O O .CD 00 .c^ rc4o iCd3 rrt r-*J# cHi oHs" H cHo 0H3 r<di crrti ca ri oN oH> iHd _s 3is1 ^E rt . ffipinWHO. 0flOOH.l>MiniOMIq !\eMq edq rt3r0t0N6NoH05NNHoiHN r0s5 W' coto co 3 cq t> g cl O rrt oo. O O O O O O O .0 O O O *-? *rt o Pt * ' * * ` t? 'B Is 5* mg 8flgo .0 o o .. o cq .eq *Q i H ri ri r*T H H ri H rt" ri t> c ms sS o irtrirtHririrtri =>. s 2d3t&r* Oi t> t CaS 03* .< j; to+rdrat << 1b?fi " ` *^3 00n 00 10 cq wj r10t.uO> 2p5 ritfj tt *^g W <* rN ^Mr*rt.<r *tml< 50 B.BO* " O aD?. fc-g 5d 2 1o.Trtfl^ooo03t-cococo^fico'iit;cqcr>' eq co co cq w cq r< cq rrw ri w omposition for Finish l feo r1--TVhianrinaitinognTihnemC ab T tI: FLB 000993 *dT3l 'O+j ''g o sg ,|o opopoooooooo o-o .U) 8 SS o I o.o O 3 o 3 iA to w 5Og i^Ouatcoa0CX'cIOOCTM-_t_O___O___O__CTNJ^_OOrSJ og J * &M3 J1-4t o p2 i v * 2 *k'lO?lO- UjlNO t)IOlON03WlANlf5(MlO OO O t <0 $$ W p CM t -J f"< r-J rn v- w 5 53 73 *0 <1 ci *3 o>nt O.tspj So O_(,*;. o cIqO. Q HN CO <0_rN3 . CwMi 5 gf +aao a .a g. ga *S. aw tl .1 *,s *5 ffl O, 1 P I- $o. %ciO4ctIOo>IoQc-CI*OOttO>dNiOW'OrtONiaWi!3HqUWScU<5tiOiIsA 53 IS*1* m4>_os0 C3 go SS 53 :', to to to IO lO US to to 88i83333p3g3 8;833 >iCft>oOtCHr4j .OOlOOHOtOOCWMJtANtWo uCMs CO | i ! U3 3 lb 3 <D UCMS o cSa Ot -o3 <33 (O.IOWCIOS tSVtf*g oas M ft ufbljf.iAStf r- ft A Sste* n* I ow -+ >^ a . o w S3 "3 T3rt "V**t ated and the amount that can subse quently escape when the house is ven tilated by opening windows. House owners should be taught that conden sation on windows is an indication that the relative humidity indoors is higher than the house can carry safely with the prevailing temperature out of doors and that reduction of relative humidity by opening windows and ad justment of the heating plant is de sirable until the condensation is re- evaporated. In northern climates storm windows are necessary, whether or not the windows are weatherstripped, both to save heating expense and to prevent condensation without lim iting the house to unreasonably low relative humidity during cold weather. Fortunately the problems of mois ture leakage and condensation are be coming generally appreciated and at least for new houses and some of those already erected, we now have ef fective means of keeping the wood work dry. To be sure there remains the serious undertaking of educating those concerned with the erection of houses and the house owners them selves, but there are reasonable grounds for believing that in time moisture as a large cause of unsuc cessful paint maintenance can be elimi nated. The Cure for Mistakes in Applying Paint Much unsuccessful painting comes from faulty technic in applying paint. The most common blunders arise from the painter's very human desire to do the work with the smallest amount of expensive material possible just as the paint manufacturer tries to make his paints with the smallest practicable proportions of the more expensive in gredients. In most cases in which the bounds of safety are overstepped the painter was not intentionally dis honest, he was merely mistaken in his judgment or unfamiliar with the limitations of the material with which he was working. It should be remem bered that the painter's judgment is necessarily based on insufficient infor mation because, except in the case of lead and oil, he does not have prae- 7 FLB 000994 tical knowledge of the compoaitioii of the paint he is using and there are no generally accepted standards of cor rect application. Commercial paints differ in composition far too widely to conform to any general standards of application" and since they are not rec ognized by classes each paint presents a separate problem In application. Of ten the painter is asked to apply a paint that' came on the market long after he learned his craft and differs seriously as respects application from anything he has been trained to use correctly. To be sure directions for applica tion are usually printed on the label on paint Containers. The painter is often chided for paying little atten tion to such directions, but when manufacturers' directions are studied carefully in relation to the composi tion of their products it becomes clear at once that manufacturers' ideas of The behavior of a .finish coat depends upon what hind of .paint is underneath. The four squares show areas each 1 inch by 1 inch representative of the behavior of the coating en four test areas on the Forest Products laboratory fast fence after two years of exposure at 15 lacing south. Area A shows three coats of a commercial brand of titanium-lead-zinc paint. Area B shows two coats of that paint over a commercial sbtcless primer made by another manu cfacturer. Area shows three coats of a high-priced gulch drying paint made by the first manufacturer. Area D shows two Coats of the paint used oh A with a finish coat of the paint used on C. correct application are Just as diver gent and illogical as painters' prac tices. Since directions usually are most explicit about the extent to which, the paint should be thinned the conflicting state of opinion about ap plication can be illustrated by consid ering manufacturers' directions for thinning. Table 1, which is condensed from a much larger table of data, shows the composition of 18 semipaste paints on the market in relation to the makers' instructions for thinning to make fin ish-coat paint and the composition of the paints when so thinned. The paints are arranged in the table in order of their content of total pigment by vol ume, which decreases from 0.58 to 0.30 gallon in 1 gallon of semipaste. The content of opaque pigments, calculated by the methods described In the For est Products Laboratory's system of classification, ranges from 0.52 to 0,18 gallon per gallon of semipaste. Yet with negligible exceptions the thinning directions call for the addition of a gallon or more of liquid to a gallon of semipaste. This proportion is obvi ously determined less from considera tion of the best way to mix these paints than from the fact that the accepted proportions for mixing lead and oil, namely 3 gallons of oil and % to 1 pint of drier per 100 pounds of paste lead, is very closely gallon for gallon. That the thinning directions are not guided by any logical relation to the composition of the semipastes is shown by the very wide variations in the composition of the resulting paints after thinning. Table 2 shows that for prepared paints also there is a lack of logical relation between composition of the paint and directions for thinning. In Table 2 after the composition of the paint there are given the directions for thinning the first, second, and third coats in painting new exterior woodwork of the kinds of wood ike paint manufacturer considers best for painting. Sometimes the directions , call for variations in thinning the first, coat for different Woods, in Which case it is seldom possible to recognize any reasonable, connection between the properties of the woods and the varia tions in thinning specified. As a mat ter of fact the names by which the woods are designated often are not the names under which they are sold in commerce. An old rule of painting held that the undercoat (the second coat in threecoat work) should always be mixed with more pigment in proportion to oil than the finish coat. This rule is still recognized in directions for thinning lead and oil and many semipaste paints. It does not fit in, however, with the conception of prepared paint as ready for application without fur ther thinning. Consequently it was formerly customary to direct that the paint be thinned only with turpentine for second coat so that the undercoat would contain at least no less pig ment when dry than the finish coat. Sight of the twenty paints of Tabic 2 break With this custom and depart stili farther from the old rule of crafts manship by directing that oil be added to the paint for second coat. Of these eight only' three call for addition of oil to the finish coat also so that five of them definitely instruct the painter ' ta- violate a rule of craftsmanship to which the older painters were trained. It is curious that the instructions for eight of the twenty paints of Table 2 direct that the paint be thinned for all three coats, one of them calling for addition of .as much as half a gallon of oil per gallon of paint for finish coat. Such a paint ought not to be called a prepared paint, but rather a semiprepared paint. As put up in the can the paint in question is of very respectable quality, but when thinned as directed fer finish coat its content of total pigment drops to 16.7 per cent, and its content of opaque pig ment to 14.0 per cent, figures not at all in accord With modern conceptions of high quality in house paints. Bad technic of- application can be cured only by education in correct technic. We cannot teach painters to read and follow directions," however, until the directions are reasonable and are agreed upon by those to whom painters must look for instruction. Where the teachers contradict one an- FLB 00D996 other the pupils, being human, hold the. teachers' opinions lightly and follow their own Judgment, inevitably making many mistakes in so doing. It is the Writer's opinion that the present irra tionality in directions for applying paint arises less from lack of technical knowledge than from commercial con siderations of price competition. Manu facturers'-directions are written too much with a view to convincing the painter that the paint will "go far ther" than competitive paints and too little with the idea in mind of making sure that the paint will give the best possible performance. Tf paints were properly classified ac cording to composition, paint technolo gists probably would find no great dif ficulty in agreeing upon sound instruc tions for applying each of the classes of paint provided that they were per mitted to do so solely from the point of view of performance. With such agreement on standards of correct ap plication a campaign of education for painters becomes practicable, but un til there are such standards there is no way of giving painters adequate in struction. The cure for bad technic of appli cation, therefore, lies in classification of paints by some such method as that proposed by, the Forest Products -Lab oratory, followed by agreement upon reasonable instructions for applying each class of paint, and then by united and vigorous insistence that painters learn and follow the accepted stan dards of application. The Cure for Mistakes in Paint Maintenance In the writer's experience more com plaints about paint jobs are caused by incorrect programs of maintenance than by poor lumber, poor paint, bad application, or moisture. Neither the paint manufacturer nor the painter as a rule has much control over main tenance because the house owner gen erally derides when painting shall be done, how much work he is willing to pay for, and often what brand of paint shall be used. Efforts to attain more successful paint maintenance, there fore, must take into account the neces sity of teaching house owners how to space jobs correctly and how to choose the right kinds of paints for their purposes. Many house owners have no definite plan for spacing paint jobs and merely Wait until the old coating goes to pieces before trying to renew it. In this group many have no intention of painting more often than every eight or ten years. Since we have no white paints that can be relied Upon to re main durable for Such long- periods, those who follow such programs are more interested in the ability of the paint to stand neglect well than they are in its durability. They want a soft type of paint that breaks up slowly by crumbling So that it does not look too unkempt during the period of neglect and after neglect can be safely repainted without expensive removal of the old coating. Pure white lead paint, if used exclusively, will behave in this way, and is largely responsible for the fact that so many owner are accus tomed to maintenance programs in volving long periods of neglect. Most of the newer paints, however, are made to provide greater durabil ity and superior appearance, which can be provided only by making harder paints that break up finally by crack ing, curling, and flaking, and there fore cannot be neglected' safely. Of course, practically all paints are ad vertised as wearing away slowly by chalking, leaving a fine surface for repainting, and avoiding the defects of cracking and scaling, but such claims are made on the assumption that re painting will be done before the end of the period of durability and before neglect begins; they do not mean that the paint- is suitable for those who ex pect to let their coatings go through periods of neglect There are two ways of successfully Unking together the maintenance pro gram arid the kind of paint for those with unduly long intervals between painting. One way is to convince the house owner that it will be worth Ms while to change his program to per mit him to use paints of harder type satisfactorily. The other way is to sell him the kind of paint that will serve satisfactorily in the program to which he is accustomed. To persuade A great deal of research will be neces him to buy a paint unsuited to the sary to establish all of the ramifica program he intends to follow, however, tions of the principle of compatibility, is simply to add one more to the num but when it has been done many of ber of those who are dissatisfied with the present mysteries of house paint painted woodwork. maintenance will be cleared up, A A large proportion of paint com large proportion of the Forest Prod plaints that come to the writer's at ucts Laboratory's research on painting tention occur on houses that have been is now directed toward this problem. painted at reasonable intervals with Until future technical study discloses good paints well applied on woodwork the extent to which paints may differ that remains dry and yet the paint in composition and still remain com fails far too soon and often in a man patible, the Conservative practice in ner not characteristic of the normal maintenance is to start out with a behavior of the paint last used. In good paint when the woodwork is all these eases, however, two or more new and thereafter maintain it at paints of distinctly different compo proper intervals with paint of essen sition have been used for successive tially the same composition. Switch paint jobs or successive coats in the ing from one kind of paint to another same paint job. Some of the eombina- - is doubtful practice unless the par tions show up repeatedly in different ticular combination so produced has Complaints. Some well known combi been tested or found satisfactory by nations frequently occurring in com previous experience. Certainly those plaints are white paints over yellow combinations of paints that have fre ochre primer or paint, almost any quently led to difficulty should be house paint over clear varnish, and avoided. At the present time the only white paints over full color paints like white paint that is used consistently deep red, brown, green, or black. Un by large numbers of house owners is fortunately technical exposure tests pure white lead because it is the only in the past have been confined chiefly paint recognized by type as well as to initial paint jobs or repainting with by manufacturer's brand. In the writ the same kind of paint, but some past er's opinion the high regard in which records of tests involving combina white lead paint is held by so many tions of paints differing in type have good painters and paint users is due been discovered, the outcome of Which largely to this consistency in its use. reveals the same abnormalities of be When white lead is applied over paints havior found when these Combinations of other kinds it often fails prema of paints are seen on houses. turely and in an abnormal manner, in The evidence that good paints are dicating that it is just as subject to not all compatible with one another the requirement of compatibility with is now conclusive, but there is much previous paints as are paints of other difference of opinion about the serious kinds. ness of the problem. Some hold that The cure for bad programs of paint incompatibility occurs only in a few maintenance, therefore, lies in a Classi extreme cases such as those named in fication of paints that Will make it pos the preceding paragraph. The.writer' sible to teach house owners how to believes, on the basis both of observa-' buy the right kinds of good paint for tions of houses and of technical expos their purposes and how to get out of ure tests, that the principle of incom the paints they buy the good service patibility is very much more far reach of which they are capable! ing. Combinations of white paints, differing materially in content of zinc The Need for Classification of Paints oxide for example, have been observed Consideration of the causes of un to deteriorate more rapidly and in a successful paint maintenance and con less satisfactory manner than corre sequent loss of public confidence in sponding coatings made up entirely painted exterior woodwork shows that of either one of the paints separately. our most serious troubles have come % FLB 000998 $ ] I not so much from jerry building and group action because there is obviously I inferior paint as from efforts to im little or nothing that an individual prove building methods and paint3 that manufacturer can do about it by him have made the situation more compli self, Meantime those who deal in ; cated and unduly technical for crafts paint must continue to sell paint pretty ; men and laymen. Thermal insula much as they have been doing unless tion and modem heating plants are they can give the time and effort to ; distinct improvements over past prac closer technical study of the situation tices but, unless appropriate precau and individual contact with their tions are taken to control condensa painter and owner customers to help tion on cold parts of the structure, them avoid the more serious mistakes they tend to increase the number of about which there is now general houses in which moisture leads to early agreement. There is, however, one paint failures and other difficulties. In suggestion that the writer would like a similar way modem developments in to leave with paint dealers. That paint have given us better paints than suggestion is to make a regular prac we ever had before but there are now tice of keeping track of a fair sample so many kinds of good paint on the of paint sales and observing the serv market and they vary so much in ice obtained by the customers over a composition, manner of correct appli period of years. In the smaller cities cation, and compatibility with one an at least this should not be a very other that painters and house owners heavy burden and it has the highly 1 do not know how to use them all important advantage of letting the 1 correctly. Merely offering the public dealer know what sort of service his good paints that are capable of giving customers actually receive with the successful service is not enough to re material he sells them. As a rule the establish confidence in painted wood dealer learns only about jobs that turn work unless we likewise make it pos out badly and lead to complaints. No sible for each good paint to be so matter how good his paint there will applied and maintained that it will give be some complaints, the real causes of j the good service of which it is capable. which could be determined to every To accomplish that purpose the tech one's satisfaction much more success nical complexity of application and fully if the dealer could point spe maintenance must be simplified suffi cifically to other houses painted ciently to bring them within the com perhaps from the same shipment of prehension of craftsinen and house paint on which satisfactory service was owners. Such simplification can be ef being obtained, Such comparisons, if fected by some such classification as made conscientiously, will almost in the one proposed by the Forest Prod variably show that the paint was ea- 1 ucts Laboratory just as it was accom pable of giving good service but failed 1 plished years ago for lumber through to do so for some one or more of the 1 species identification and grading. reasons discussed in this article. . It I The working out of a classification of paints together with reliable in structions for application and mainte nance is a strictly technical problem that must be handled by paint tech nologists, that is to say by the paint will also restore the dealer's confidence in the paint he Is selling' and make him less inclined to experiment with some new brand that offers no greater prospect of avoiding com plaints and may even increase them by bringing about more heterogeneous | 1 manufacurers. Moreover it is a prob combinations of different kinds of paint lem of the industry as a whole through on the houses of his customers. FLB 000999 | When and How to Paint Homes and Farm Building ^ W? KEEPING A BUILDING satisfactorily painted de pends on three things -- good paint, good painting, and good maintenance. Before the paint is selected, however, and before any painting is done, the first f thing to do is to decide what appearance is desired and how much trouble and expense the owner is willing to undergo to maintain that appearance. Maintaining Buildings Without Paint The least expensive procedure is to leave the , building unpainted, and merely keep up the repairs as the building deteriorates with age and use. Paint does not prevent decay, and if decay is allowed to enter the structure, a painted building will rot just as quickly as an unpainted one. Decay is prevented by proper design and construction and the pse of decay-resistant or treated wood where necessary, and not by painting. When the weathered appear ance of old unpainted "wood is not objectionable, therefore, painting may be omitted altogether. If so, the plan should call for patterns of exterior lumber of substantial thickness and of woods that weather well, in order to minimize checking, warp ing, and splitting of the Wood and loosening of the fastenings. Except for shingle roofs and timbering, however, weather-beaten Wood is adaptable only to a limited number of architectural designs and to spaceous rustic settings. It is rarely appropriate for urban dwellings. Once it has become weather beaten, wood can seldom be painted satisfactorily, though it can be stained. On the other hand, properly main tained paint coatings protect wood against weather ing and retain the original architectural effect in definitely. . Using Stains Instead of Paint When color is desired but painting is, for one reason or another, not considered practicable, a common procedure is to use an exterior stain. Ex terior stains consist, in general, of linseed oil, tur pentine, and only sufficient mineral pigment to give the desired Color. They penetrate the wood sur face without forming a .substantial coating over it. Since they do not protect wood against weathering, they should be used where the appearance of a weather-beaten surface is not objectionable. Good stains are not expensive and they last lunger than most paints. One coat only is the usual application, and a new coat is easy to apply. AMERICAN FEDERATION OF LABOR . By F. L. BROWNE, Senior Chemist Forest Products Laboratory, Madison EDITOR'S NOTE: Volume I o the Proeei dingt <>l the Forest Products Research Society. This volume ot 3-tO panes, lOVi by 7Vz inches, which is substantially bound in green ifcirli with gold lettering, incorporates the papers (with discussion) pnstnud at ills First National meeting of the Society held in Chicago on October .31 and November 1, 1947. It also includes: record of mmdince at that meeting; monthly bulletins of the Society, May, 1917, to October, 1947, indosive; Articles of Association and Bylaws; style standards; alphabetical and geographical directories ot membership; and other features. The volume is for sale at $6.40 per copy. Orders should be addressed to Thomas R. C. Wilson, SecretaryTreasurer, Forest Products Research Society, P. O. Box 2010, Uni versity Station, Madison 5, Wisconsin. Linseed oil is the essential constituent of the ve hicle for wood stains; just as it is for paints. More volatile liquid and very much less pigment are used in stains than in paints, however, because a stain should be absorbed rapidly by the porous wood. At least one-third, some authorities say two-thirds, of the vehicle of a stain should be linseed oil. The remainder may be turpentine or mineral spirits and may also-contain some creosote. Creosote is not necessary and must not be considered a satisfactory substitute for the linseed oil. If the creosote is of a land that does not evaporate, it protects the sur faces with which it comes in contact from decay by fungus attack, but it does not penetrate deeply, hence the interior of the wood and the hidden sur faces are not protected. Exterior woodwork that is likely to be stained usually does not need pro tection against decay. Compositions of some typical exterior stains that may be recommended are the following: Vehicle, two parts linseed oil, one part turpentine. To one gallon of this mixture add -- For gray Stain, iz l/2 pounds white lead, a touch of lampblack. For deep red-brown, i pint indian red. For bright red, i pint Venetian red. For permanent green, % pint chromium oxide. Fbr fairly permanent i green, i J4 pints medium chrome green. For golden brown, % pint raw Italian sienna, % pint burnt turkey umber. For seat brown, i pint raw turkey umber. For deep brown, i pint burnt turkey umber. Pa,i*e Fifty-three N41698.41 FLB 001000 WISCONSIN CARPENTER AND BUILDER The colors named should be pure colored pig ments ground in linseed oil, which can be purchased at any paint score. The dry pigments should never be used for mixing stains. There are, of course, many other formulas that may be used. Using Paints The great majority' of people consider that build ings usually look best when kept well painted and, if they can afford it, are willing to spend money' for rhe purpose. Good paint maintenance not only keeps buildings looking well, keeps surfaces smooth, and retards warping and checking of rhe lumber, but it also gives the property' a look of prosperity', encourages general tidiness of the premises, and gives the owner a well-deserved 'feeling of pride in his property. When to Paint Exterior woodwork should receive rhe first or priming coat of paint as soon after erection as prac ticable. Succeeding coats should be applied at intervals not greater than two weeks; in warm, dry weather the intervals may be as short as two day's. It is very poor practice to let exterior woodwork stand for weeks with only a priming coat, or to postpone the application of the third coat of paint for six months or more. Metal surfaces that arc to be painted are often primed at the mill. Succeeding coats should be ap plied promptly after erection. If galvanized iron is to he painted, however, it is helpful to let it first weather for several weeks. Interior surfaces other than unreal should not be painted until moisture from the plastoring, concrete work, or other operations of building have entirely disappeared. Wood work should then be painted or varnished, because further delay is likely to entail more labor in sandpapering and properly cleaning the surfaces. Plaster and concrete, on the contrary, become more receptive to paint on aging and paint ing may therefore be deferred as long as desired. Exterior painting may be done in any' season of the year during which the painter can work with reasonable comfort. Obviously, paint should not be applied when it is raining or foggy and the sur face should be allowed to dry after rain, fog, or dew before continuing to paint. During cold, damp weather paints harden more slowly' than they do in warm, dry weather. A sudden drop in temperature while die coating is hardening may make it wrinkle or it mav cause dew to form on the fresh paint and damage it. Coatings applied during late fall or winter arc likely to become more seriously soiled as time passes than coatings applied in the spring or summer. On the other hand, during the summer, insects and seeds sometimes become embedded in fresh paint and disfigure it. What kind of paint to use, and the verv im portant matters of when and how to repaint, can he discussed to best advantage after the composi tion and various kinds of house paints have been described. Composition and Kinds of House Paints Only good, durable paint (or stain) should be used on exteriors of permanent structures because the principal cost of painting is the labor. If a cheap coating is desired for temporary structures or surfaces that must be repainted frequently and do not require protection against weathering, cither whitewash or an exterior water paint containing casein may be used. Many commercial paints bear a label giving the name and address of the manufacturer and the com position of the paint. In the absence of previous ex perience with a paint, appraisal of its quality must be based upon the information given bv the formula label. It is wise to buy only paints that give the formula on the label, and to keep a record of the formula so that paint of similar composition can be purchased when it comes time to repaint the building. Paint composition, of course, is a highly technical question with which the house owner and painter are compelled to deal as best they' can in spite of their lack of the necessary technical training. What is needed is a reasonably' simple system of classify ing house paints by kind and quality, much as lum ber is classified by species and grade. It would then be possible for paint users to select the kinds of paint best suited to their individual requirements and to learn to apply' and maintain them correctly. Such a system of classification has been described in technical detail in Industrial and Engineering Chemistry, volume 19, page 1018, September 1937, to which reference should be made for a more com plete discussion of paint composition and classifica tion than is practicable in this mimeograph. That discussion is very' technical, however, and was writ ten for the information of paint technologists rather than for the average home owner. House paint consists of two parts, a solid part (the pigments) and a liquid part (the vehicle). The kind and quality' of a paint are determined bv the nature of its vehicle, the nature of its pigment, and the proportion of pigment in the vehicle. The Nature of the Vehicle The vehicle in house paints consists of two parts, a drying oil and a volatile thinner. The volatile thinner is usually mineral spirits (a petroleum prod- AMERICAN FEDERATION OF LABOR Page Fifty-five net) or turpent paint correct co plication it evap manent part of able quality is p cheaper but it i ing at retail, to because there i: in suitable qual part of the vok : often called "c "emulsifying ag If it amounts tc it may not be j t amounts betray Linseed oil i house paints. . japan drier, the the ordinary pa the paint hard makes little dif boiled linseed 0 correct propori oil may be co raw linseed oil incorporated, seed oil that ht j been increased tions (up to ro ing oil), bodiec in improving t in greater prop which are diset ing. In paint 1 called "heat tr seed oil and si and unbodied 1 I In recent \ . for part of the There is no ob primarily from domestic farm paint hardens p conditions dur drying, a thirc portion, such tung oil, may oils. Fish oil 1 as soybean oi t objectionable < | not be used wrinkles badly bodied or hea very viscous, tions. When ; AMERICAN FED! 1 FLB 001001 imbedded in ic very imrepaint, can he composis have been ; Paints ) should be arcs because labor. If a y structures :quent!y and lering, either t containing ;l giving the ind the cornprevious ex quality must the formula hat give the ecord of the iposition can repaint the hly technical and painter n in spite of ining. What i of classifynuch as lumt would then the kinds of requirements :m correctly. :en described Engineering tember 1937, a more comtnd classificagraph. That .nd was writilogists rather a solid part ehicle). The nined by the pigment, and cle. of two parts. The ' volatile roleum prod- Page Hfiy-hvc WISCONSIN CARPENTER AND BUILDER uct) or turpentine. Thinner is necessary to give paint correct consistency for brushing but after ap plication it evaporates and therefore forms no per in a paint the formula often refers to "vegetable drying oils" or "vegetable oils" instead of naming the oils used specifically. manent part of the coating. Mineral spirits of suit Large proportions of bodied drying oils or var able quality is just as satisfactory as turpentine and nishes (heat treated mixtures of drying oils and cheaper but it is often wiser for the painter, buy resins) are not used in true house paints of good ing at retail, to use turpentine for thinning paint quality. Because of the high viscositv imparted by because there is greater assurance of obtaining it I)eat treatment, excessive proportions of volatile in suitable quality. Some paints contain water as thinner muse be added and, as a rule, the amount part of the volatile thinner. On the label water is of pigment must likewise be reduced in order to often called "colloidal solution", "soap solution", obtain a hrushable product. Moreover, the product "emulsifying agent", or "aqueous bodying agent." takes on the flowing and leveling qualities of enamel, If it amounts to less than 1 per cent of the vehicle as distinguished from true house paint. Such prod it may not be particularly objectionable but larger ucts are sometimes called enamelized house paints, amounts betray a paint of inferior quality. For special purposes, for example, where it may Linseed oil is the principal drying oil used in be the intention to wash the coating frequently, house paints. A small amount of paint drier or enamelized paints may be advantageous but, as a japan drier, the nature of which need not concern rule, they are inadvisable for ordinary house paint the ordinary paint buyer, is also necessary to make ing because they are difficult to apply and maintain the paint harden promptly after application. It correctly. Enamelized paints tend to "pull under makes little difference whether raw linseed oil or the brush" unduly, they must be applied in rather boiled linseed oil is used, provided that there is the thin coating to avoid running, sagging, and forma correct proportion of drier, because boiled linseed tion of beads' at sharp horizontal edges on vertical oil may be considered, for practical purposes, as surfaces, and they accentuate irregularities in the raw linseed oil in which the drier has already been underlying surface, such as raised grain in wood incorporated. Bodied linseed oil, however, is lin or flaked patches of the previous paint. seed oil that has been heated until its viscosity has been increased very greatly. In moderate propor tions (up to roughly 10 per cent of the total dry ing oil), bodied oil may often be used to advantage in improving the consistency of house paint but, in greater proportions, it makes enamolized paints, which are discussed in the second paragraph follow ing. In paint formulas, bodied linseed oil is often called "heat treated" or "specially processed" lin seed oil and sometimes the proportions of bodied and unbodied oils are not stated. In recent years soybean oil has been substituted for part of the linseed oil in house and barn paints. There is no objection to this practice, which comes primarily from a desire to extend the market for- a domestic farm crop, provided that the resulting paint hardens promptly under all reasonable weather conditions during application. To insure prompt drying, a third drying oil of superior drying pro portion, such as pcrilla oil or a small amount of tung oil, may be added to the mixture of drying oils. Fish oil may be used in much the same way as soybean oil provided that in does not imparr objectionable odor to the paint. Raw tung oil can not be used in material proportions, because it wrinkles badly during drying but, when properly Varnish or resin of any kind in house paint has a rather bad reputation because very cheap paints often use varnish together with large proportions of mineral spirits and water. Such paints are un reliable and make it necessary to regard any paint that contains varnish or resin with suspicion. Never theless there are a few paints of good quality on the market in which small proportions of resins of high quality are used. Such paints are called "resinfortified" paints and sometimes they are "quickdrying" paints. They are also likely to he enamel led paints, -unless the amount of varnish used is very small. For most house paint purposes, quick drying has more disadvantages than advantages. For tification, with small amounts of resin is sometimes used in order to dispense with zinc oxide as one of the pigments, resin having some of the action of zinc oxide as a hardening agent in paint. It is still questionable, however, whether there is any real benefit to lie gained from the use of resin in white or light colored house paints. In deeply colored paints like dark green, dark brown, and black, paints in which little or no white lead or zinc oxide can be used, addition of some varnish or of a sub stantial amount of bodied drying oil is often ad- bodied or hear treated, during which it becomes viseable to insure prompt hardening after applica very viscous, it may be used in moderate propor tion and to prevent '.unduly early fading of the tions. When a mixture of drying oils lias been used color. AMERICAN FEDERATION OF LABOR Page l?ifty-scvrn WISCONSIN CARPENTER AND BUILDER The Nature of the Pigment of white lead, zinc oxide, or both, except in deep Durability, opacity (hiding power), color, and, to colors that do not admit opaque white pigments. tenance is a large extent, brushing consistency are imparted to The titanium pigments include titanium dioxide, colors. paint by the pigments. The opaque white and col titanium-barium pigments (25 or 30 per cent titan In recent ored pigments (see next paragraph) provide all four ium dioxide and 75 or 70 per cent barium sulfate), for some * of these qualities. Certain other less expensive pig titanium-magnesium pigment (30 per cent titanium paints are ments that are practically transparent in linseed oil dioxide and 70 per cent magnesium silicate), tiran- sists of alu are used in paint ro improve brushing consistency, ium calcium pigment (30 per cent titanium dioxide dally for tf to reduce cost of manufacture, and to keep the and 70 per cent calcium sulfate), and lead titanate. vehicle may pigments in prepared paint from settling into a hard (The term Titanox that occurs in some formula not more I cake at the bottom of the can. In the interest if labels js a trade name for titanium pigments made very long economy, the transparent pigments are used as gen by the Titanium Pigments Company). Titanium portion of erously as is consistent with durability and opacity. dioxide is so much more opaque than white lead or thinner. T Paints of inferior quality usually contain excessive zinc oxide that the titanium-barium and titanium bought sep amounts of transparent pigments. magnesium pigments, in spite of the large content rnent corns The opaque white pigments commonly used in of transparent pigment, may be considered opaque house and barn paints are: basic carbonate white white pigments fully equal in opacity to white lead I before use. powder of lead, basic sulfate white lead, zinc oxide, the titan and zinc oxide. Lead ticanate is also a very opaque pounds of ium pigments, tiie zinc sulfide pigments, and, in a pigment and, though said to be chemically inactive, to 1 gallo: few brands of paint, antimony oxide. Certain opaque imparts some of the properties of white lead pig slightly' me white pigments, known as leaded zinc oxides, con ments to the paints made with it. Titanium-calcium tain both basic sulfate white lead and zinc oxide but pigment is intended for use in interior paints only is fully as bright in a when they are used it is common practice to report and should not be used in exterior paints of high The Varioi the white lead and zinc oxide separately in the quality'. formula label. The zinc sulfide pigments include zinc sulfide, There ar on the mar I The important opaque colored pigments are the which is very opaque, lichopone, "double-strength" manufactured iron oxide reds, browns, and yellows, or "high-strength" lichopone, and titenated litho- for sale by the Forest the iron oxide earths such as "red oxide", indian red, umber, sienna, ochre, Venetian red (iron oxide and calcium sulfate formed by calcining a mixture pone (a mixture of titanium dioxide and lichopone). (Cryptouc is a trade name for certain zinc sulfide pigments made by the New Jersey Zinc Company). discuss the recognized rough way of ferrous sulfate and limestone), chrome yellow' The zinc sulfide pigments are very useful in interior There ar (lead chromate or lead chromate and lead sulfate), paints but in exterior paints their use, with few or tinted h chrome orange (basic lead chromate), prussian blue exceptions, is confined to manufacturers' second- established or Chinese blue (ferric ferrocyanide), chrome green grade paints and to cheap paints. House and barn eral use ca (chrome yellow and prussian blue), ultramarine, paints containing zinc sulfide pigments of any kind liquid cons zinc yellow (zinc chromate), red lead (lead oxide), cannot he generally' recommended. j raining not aluminum powder, the carbon pigments (carbon For house and barn painting the most widely used resin of an black, lampblack, graphite, drop black, bone black), paints are white paints or tinted white paints. Tinted and mineral black (black oxide of iron). white paints are paints in which most of the pig of volatile the nature The important transparent pigments are magnes ment is made up of white pigmencs with just enough ium silicate, talc, barytes (barium sulfate mineral), colored pigments to produce the desired color. A Products I designated blanc fixe (manufactured barium sulfate), silica, manufacturer's brand of paint that is offered in 32 TLZ (ritai I whiting or chalk (calcium carbonate), calcium sul colors, for example, may consist of 24 tinted white fate, china clay (kaolin), and mica. On formula paints and only 8 colors made chiefly with colored TLZ are a in proporti labels, mixtures of transparenr pigments are some pigments (colored pigment paints). As a rule the each type times ambiguously called "silicates", "inert pig principal areas of buildings are painted with the of opaque ments", or "extending pigments". white or tinted paints and the colored pigment The white lead pigments and the zinc oxide pig paints are used for trim and minor areas. Colored volatile (pi paint. Grc ments are called chemically active pigments because pigment paints made with iron oxide pigments, how division of they are believed to react chemically with the dry ever, have long had a special field of usefulness be ing oils during the hardening of paint. At any' rate cause of the fact that, when properly made, they which is so a number 0 they impart desirable properties to paint that are are less expensive and much more durable than the Pure whi obtainable with no other pigments except red lead best white or tinted paints. They have long been of soft pas and basic lead chromate. For that reason all good used, therefore, for painting barns and other chiefly with more house paints should contain a substantial proportion utilitarian buildings, where low cost of paint main- sired, by tl per cent ba AMERICAN FEDERATION OF LABOR I'age Fifty-nine AMERICAN F FLB 001003 leep ;ide, tanite), ,ium tanxide late, nula lade lium d or tioin itent aque lead aque tive, P>g:ium only high Ifide, gth" ithoine). ilfide nv). crior few ondbarn kind used iuted Pl ough r. A in 32 vhite lored 2 the 1 the ment lored hove ls bethey n the been aiefly uain- ty-nine WISCONSIN CARPENTER AND BUILDER tenance is preferred to a wider choice of brighter colors. In recent years aluminum paint has come into use for some of the purposes for which iron oxide paints are commonly used. Aluminum paint con sists of aluminum powder in a vehicle made espe cially for the purpose. For exterior use on wood the vehicle may be either a bodied drying oil containing not more than 40 per cent thinner or a so-c.illed very king oil spar varnish containing a small pro portion of resin and not more than 30 per cent thinner. The aluminum and the vehicle are either bought separately or are put up in two-compart ment containers so that they may be mixed just before use. From 1 % to 2 pounds of dry aluminum powder of "standard varnish grade" or 1 % to 2 pounds of commercial paste aluminum are added to i gallon of the vehicle. Aluminum paint is slightly more expensive rhan good white paint but is fully as durable as good iron oxide painr and is bright in appearance though metallic in luster. The Various Kinds of House Pamts There are many types and grades of house paint on the market. Until they are classified and graded for sale by some such system as that proposed by the Forest Products Laboratory it is possible to discuss them and to indicate how they can be recognized from the formula labels only in a very rough way. There are three broad groups of high-grade white or tinted house paints whose serviceableness is well established by adequate experience and whose gen eral use can be recommended. In all of them the liquid consists of linseed or other drying oil con taining not more than to per cent of bodied oil, no resin of any kind, and only moderate proportions of volatile thinner and drier. The groups differ in the nature of the pigments used and, in the Forest Products Laboratory system of classification, are designated groups L (lead), LZ (lead and zinc), TLZ (titanium, lead and zinc). Groups LZ and TLZ are available in a number of types, differing in proportions of white lead and zinc oxide, and each type in various divisions differing in content of opaque pigments, total pigments, and total non volatile (pigments plus nonvolatile vehicle) in th paint. Group L is represented by one type and division of paint only, namely pure white lead paint, which is sold in essentially the same composition by a number of different manufacturers. Pure white lead paint is sold chiefly in the form of soft paste paint, in white only, to be thinned with more liquid and tinted, if tinted paint is de sired, by the painter. The soft paste contains 89 per cent basic carbonate white lead, 9 per cent lin- seed oil, and 2 per cent turpentine by weight. If thinned correctly it makes paint of the highest quality'. Because it is essentially a standard article of commerce it is the simplest paint to buy and use consistently in a program of paint maintenance ex tending over a long period involving repeated re painting*. Pure white lead paint is rarely sold in the prepared (ready-mixed) form. Paints of groups LZ and TLZ arc sold in both the prepared and semipaste forms. Many of the prepared paints are of high quality but most of the semipaste paints of the mixed-pigment groups arc either of inferior quality or are so made that the painter is encouraged to thin than with too much liquid, thereby" making inferior paint. It is there fore safer, as a rule, to buy mixed-pigment prints in the prepared form. Lead and zinc paints, group LZ, contain a mixture of one or both of the white leads and zinc oxide or leaded zinc oxide. In addition many of them contain transparent pigments. There are at least 9 different types on the market of which the 3 most important are those with (1) very high con tent of white lead (over yo per cent of the pigment by volume) and medium content of zinc oxide (23 to 35 percent), (2) high content of white lead (35 to 50 per cent) and high content of zinc oxide (35 to 50 per cent), and (3) high content of white lead and medium content of zinc oxide in the pigment. In LZ paints of good quality the sum of the white lead and zinc oxide should he not less than 90 per cent of the pigment and the total pigment should be not less than 67 per cent of the paint by weight. At the present time, paints of group LZ are used chiefly for tinted paints, the white paint of most of die better known brands being of the TLZ group. Titanium, lead, and zinc paints, group TLZ, con tain one or more of the titanium pigments in addi tion to white lead and zinc oxide pigments. In ad dition, they contain very substantial proportions of transparent pigment either as ingredients of the titanium pigments or as additions by the paint manu facturer. There are at least 7 different types on the market, of which the 3 most important arc those with (r) high content of white lead and medium content of zinc oxide, (2) medium con tent white lead and medium content of zinc oxide, and (3) low concent of white lead (10 to 25 per cent) and medium content of zinc oxide. In TLZ paints of good quality' the sum of the white lead and zinc oxide should he not less than 45 per cent of the pigment, the sum of white lead, zinc oxide, and titanium dioxide not less than 60 per cent of the pigment, and the total pigment should be not less than 6j per cent of the paint by weight. Paints AM ERICA N FEDERATION OF LAHOR l'jyc Sixty-otic FLB 001004 WISCONSIN CARPENTER AND BUILDER of group TLZ are now the predominant mixedpigment white paints and arc also used widely for tinted paints. In good iron oxide paints, not less than 30 per cent of the pigment by weight should be iron oxide and the pigment should lie not less than 53 per cent of the paint. If the pigment contains more iron oxide, however, the content of total pigment in the paint should be higher, for example, if the pigment contains 75 per cent iron oxide there should be not less than 61 percent pigment in the paint. What Kind of Paint to Use The kind of paint to use should be determined when the new building is to be painted for the first time or after previous paint has been removed com pletely by painters' blow torch or house paint re mover and the bare wood is again exposed. Once the building has been painted, future repainting should he done with the same kind of paint used the first time. Changing kinds of paint for succes sive paint jobs often leads to abnormally early failure and unsatisfactory forms of failure of the new job. The renewed coating consists of the new paint plus what is left of the old paint and, unless there is past experience with the combination to judge by, no one can tell what the result will be. Certain repainting combinations that have repeat edly been observed to cause abnormal and usually unsatisfactory developments are white paints over yellow ochre primer or paint, white paints over colored pigment paints such as red, brown, green or black, almost any house paint over clear varnish, pure white lead paint over mixed pigment paints that have not aged for a very long time, enamelized paints over softer house paints of the ordinarytypes, and ordinary house paints over enamelized paints. In selecting the kind of paint for a new building, the first point to consider is the length of time that will elapse between paint jobs. In most parts of the United States coatings of white or tinted paint cannot he expected to remain durable for more than 4 or 5 years. If the intervals between paint jobs are to be longer than that, either an ex tremely durable paint, such as iron oxide paint or aluminum paint, should he chosen or, if white or a tint is demanded, the paint should be one that stands neglect well. Pure white lead paint has long been used satisfactorily by owners who paint only at long intervals. White lead paint is no more dur able than good LZ or TLZ paints but the coating gradually wears thin by chalking and very fine crumbling; after it begins to disintegrate there is a long period during which the surface, if not ex amined too closely, still looks reasonably well, and after much neglect the surface can be repainted easily and with assurance that the new job will give the same service over again. When LZ or TLZ paints reach the end of their serviceable life they begin to crack and break up in a coarser and more conspicuous pattern than does white lead paint and, if further neglected, they commonly begin to curl up at the edges of the cracks and to flake or scale off in a manner that leaves an unsightly appearance and a surface that requires much careful preparation for repainting and, even then, forms an uncertain foundation for the new job. If repainting is to be done at intervals of 4 or 5 years the owner may choose a good paint of any of the types described. For such programs, white lead paint has the advantage of being easily pur chased at any time without bothering about careful study of complicated paint formulas and of being thoroughly understood by all good painters so that it is likely to be applied well. During the first year or so of its life it may become somewhat dirtier than other paints bur, when it reaches the chalking stage, the dirt is usually sloughed off and good ap pearance restored. The LZ paints may take some what longer to pass through the dirty stage and be gin to clean themselves by chalking. The TLZ paints, on the other hand, collect notably less dirt than either L or LZ paints and soon begin to chalk freely enough to become clean again. For white paints the TLZ paints have therefore become very popular. The appearance of a tinted paint depends both on sailing with dirt and on retention of the color; when the chalking stage is reached the dirt may be sloughed off but the color begins to fade. For that reason the LZ paints are sometimes preferred for tints. The choice may well depend largely on the particular color chosen. Tints, such as cream or light yellow, are marred more seriously by dirt than by fading, provided the fading takes place uni formly. Tints, such as light green or light blue, however, are seriously marred both by fading and by dirt. In choosing a tint it is well to give con sideration to its probable appearance after chalking begnis.- Repainting at intervals of less than 3 years is rarely advisable because, on sheltered parts of the build ing particularly, the old paint has not aged long enough to become a reliable foundation for new paint and in the course of time the coating becomes unduly thick and of uncertain behavior. As a rule, where it is desired to keep the coating with a cleaner and fresher appearance than is generally customary, it is better to have tire house washed every year or so rather than to repaint it too often. Where wash- AMERICAN FEDERATION OF LABOR l'age Sixty-three repainted > will give ; or TLZ life they and more paint and, in to curl e or scale ppearance reparation uncertain of 4 or 5 nt of any ms, white asily purut careful of being :rs so that first year >at dirtier : chalking good apike some;e and bcThc TLZ less dirt 1 to chalk 7or white omc very ends both the color; dirt may fade. For preferred argely on as cream v by dirt place uniight blue, ading and give con chalking s is rarely :he buildtged long for new 5 becomes As a rule, i a cleaner ustomary, y year or ere wash- e Sixty-three WISCONSIN CARPENTER AND BUILDER ing is planned, paints containing higher proportions what larger container and then begin to stir the rest of zinc oxide have an advantage in that they are of the contents into a smooth paste. Gradually pour somewhat easier to wash. If the washing reduces back the clear liquid in small portions while con : the thickness of the coating somewhat, so much tinuing the stirring until all of the paint is mixed the better, because the harder types of paint do uniformly. Transfer the paint to the larger con not wear awayr as much between paintings as is de tainer and add any additional oil or turpentine that sirable. may be needed. Stir once more and finally pour While climate has some bearing on the choice of the paint back and forth from one container to the paints it is less important than consistent use of other several times. If the paint is a colored one one type of paint, good application, and wise main purchased in more than one container, it is desirable tenance. In the warm, humid climate of the coastal to pour and mix together all of the paint that will plain of the Southeastern States the harder types of be needed for the job, to make sure that the color paint, containing the higher proportions of zinc will be uniform. oxide, are often more durable than are the soft To mix paste paint for application, transfer the paints, such as pure white lead paint. Such paints paste to a container large enough to hold the amount may also he somewhat less seriously affected by of paint that is to be mixed. If the paint is to be mildew, which is troublesome in warm, humid tinted, enough paint to complete the job should be regions. On the other hand, in the dry climates of mixed at one time. Measure out the required the Southwest, paints of the harder types are not amount of linseed oil and pour some of it into the ably less durable than are sofr paints and tend to original container to wash out any paste left cling break up very badly if they are allowed to go roo ing to its walls. Stir the pasre in the larger con long. tainer and add the linseed oil gradually until a How to Use the Paint smooth mixture results. Two blunders that are frequently made in using If the paint is to he tinted, it is best to thin the paint are excessive addition of liquids, especially of tinting colors with turpentine so that they will mix l linseed oil, and stingy application of paints. Painters quickly with the white paint. Add the colors in ' sometimes seek by these means to save paint and successive small amounts, while stirring very thor J manufacturers often recommend maximum allow oughly, until the chosen color is attained. Finally, able additions to convince purchasers that their add the required amounts of turpentine and drier paints "go as far" as any other. and stir until the paint is uniformly mixed. , Good paint is much more durable than linseed Do not. adulterate your paint -- Substitutes for lin oil, but linseed oil is necessary to bind the pigments seed oil, reinforcing oils, sealers, and waterproofing together into paint. Obviously there is an optimum agents, or other concoctions sold for addition to proportion of pigments to oil for maximum dura- paint should be avoided. bility. The optimum proportion has not yet been The volatile thinner in most paints is mineral (satisfactorily established but the best modern evi spirits, a petroleum product, but turpentine is com dence indicates that it is materially less oil than is monly recommended for painters to use in thinning , l generally used. Final coats of paint probably shpoauinldt. Both are satisfactory. No other liquid pos , contain little more than the minimum amount of oil sesses any advantage over these two. necessary to make them harden with a glossy sur New exterior woodwork -- Good prepared paints face. Undercoats should contain even less oil and have usually been made on the assumption that three should not harden with a glossy surface. These coats will he applied to new woodwork. Do not modern ideas, however, are not applied strictly in try to make two coats of such paints suffice. For the recommendations for thinning paints given in the first or priming coat paint i pint of linseed oil succeeding paragraphs. Instead, the formulas are and i pint of turpentine may be added to a gallon ' based upon rhe present practice of good painters, of prepared paint. For the second coat i pint of i For durable painting the stated amounts of linseed turpentine may he added to a gallon of paint. No rj oil may be decreased somewhat hut should not be addition should be necessary for third-coat paint. i f exceeded. If more liquid is needed to make the In recent years certain paint manufacturers have l paint flow properly, add turpentine rather than oil. developed special primers and paints to be used in r General Procedure in Mixing Paint two-coat painting. The best of these should give Prepared paint is not ready for application when very good results if correctly applied, but if they the container Is first opened. The pigments usually are brushed out too thin the results are likely to settle to the bottom, leaving clear liquid on top. he poor. In two-coat work it is desirable, for best Pour off most of the liquid into another and soine- results, to have about the same thickness of paint AMKR1CAN FEDERATION OF LABOR Page Sixty-five FLB 001006 WISCONSIN CARPENTER AND BUILDER left on the wood as in the three-coat method. If pint of turpentine per gallon and the second coat a two-coat painting system is used, both primer and applied without addition. Soft paste white lead p ,,,u finish coat should be made by the same manufac should be mixed as follows: turer for use together. Formulas for Mixing White Lead Paste Paint For three-coat painting on new woodwork soft Soft paste white lead Founds Raw tin- Turpen Paint ' seed oil tine drier Gallons Gallons Pints paste white lead paint should be mixed as follows: Soft paste white lead Founds Raw tin- Turpea- Paint seed oil tine dried Gallons Gallons Pints For first coat .... IOO 2 1% I For second coat.. ioo 3 0 I If repainting of a mixed-pigment paint has been For first coat ___ For second coat... For third coat___ IOO IOO 4 lVt ti/z t'A 3 1 I I With soft paste white lead, a skillful workman can paint new woodwork acceptably with two coats. For this purpose the mixtures may be made as follows: too long deferred so that the old coating is badly shattered and large areas of wood are bared, all loose paint must be removed with putty knife, wire brush, and sandpaper, and bare areas touched up with priming coat paint before proceeding with a two-coat painting job. Even when the surface is carefully prepared for repainting, the new job will suffer in appearance and durability from the neglect Soft paste white lead Pounds For first coat___ . ... IOO For second coat . IOO Raw lin- Tturpen- Paint seed oil tine dried Gallons Gallons Pints 2I 1 2`/2 J4 i of the previous coating. How Much Paint To Apply Although paint coating should be brushed thor oughly they should not be brushed out too thin. Good painters apply coatings of substantial thick Paint coatings do not last so long on heavy woods that have wide bands of hard, dark-colored summerwood, such as southernpine and Douglasfir, as they do on light woods or more even texture. Such woods should be pritned with one coat of aluminum paint of the kind previously described, and two coats of the paint of desired color applied over it. Repainting exterior woodwork, -- If the old coat ing is not too dirty or is first washed, if there are no areas of wood left bare by loss of coating, and nesses, On the other hand, coatings that are too thick wrinkle as they harden. The proper thickness must be learned by experience but the experience can be acquired rapidly if the beginner will observe the amount of paint he applies to measured areas of surface. The following figures for the spreading rate of paint may be used for estimating the amount of paint needed for a job and for gaging the proper thickness of paint coatings: if vigorous rubbing of a small area will remove the superficial chalk and restore a fair degree of gloss, a single coat of paint may be sufficient repainting. For this purpose, prepared paint should be applied without addition of any oil or turpentine. Soft paste white lead paint should be mixed with zx/% gallons of raw linseed oil, % gallon of turpentine, and I pint drier per ioo pounds of paste. If the old coating is chalking too deeply to restore any gloss by rubbing or if there are small patches of bare wood, two coats of paint are needed. With prepared paint the first coat may be mixed with i Spreading rate in square feet of surface per gallon of paint for-- 1st coat 2nd coat 3rd coat Three-coat painting on new woodwork .. 600 700 700 Two-coat painting on new woodwork ... 500 600 Two-coat repainting on woodwork .... 650 700 One-coat repainting on woodwork .... 600 ... ... For QUALITY FURNITURE and Better Prices see The Furniture Co. 1208 TOWER AVENUE SUPERIOR ,.. AMERICAN FEDERATION OF LABOR WISCONSIN 4 TME PROTIDEWT Loan and Building Ass'n Established 1885 Mortgage Loans and Savings Madison's Oldest Savings and Loan Association 117 S. Pinckney Street -- Phone Badger 2690 MADISON WISCONSIN *---------------- ---- ---- ------ ------------------------ Page Sixty-seven Effective floor By I". L. Browne Senior Chemist, Forest Products Laboratory YEARS ago floors were commonly finished with repeated applications of hot linseed oil, each appli cation buffed by hand; and when the surface was saturated with oil, it was waxed and maintained by wax ing at suitable'-intervals. Because unbodied drying oils such as linseed penetrate into wood relatively deep, a good many applications were necessary, making the proc ess rather laborious ; but the finish was correspondingly durable, did not show scratches, and was readily patched at places of maximum wear without refini'shing the en tire floor. The pure linseed-oil finish dried hard enough to be free from any tackiness and made a floor that was very easily kept clean by dry mopping. In time the finish darkened, partly because of the change in color of the, wood itself and partly because drying oils and var nishes/ become discolored with decomposition products as they age. Since the finish saturated a substantial layer of the wood, this darkening effect was more serious than it is with a superficial coating of varnish. As tiine passed, the drying-oil finish was increasingly adulterated with nondrying mineral oils until at the pres ent time floor oils have become cheap products often con taining no drying oil at all. The mineral oils prevent proper hardening of linseed oil, thereby keeping the finish tacky, so that it clings to dirt and the finish ultimately becomes very dark in color or even black. Largely be cause of the adulteration of floor oils the old oil finish fell into disrepute and for a long time has been replaced by vamisb, shellac, shellac and varnish, or shellac and wax finish. There is now, however, a growing trend back to the old oil finish, except that in place of linseed oil, specially designed products known as floor seals are being used because they are obtainable in satisfactory quality and are more economical iri labor of application than unbodied linseed oil. According to a recent estimate, 70 per cent of the floors in large cities in the East are being finished with shellac, 20 per cent with floor seals, and 10 per cent with varnish, in spite of the fact that nearly all who give technical advice about floor finishing rate shellac as the least desirable of the three. The varnish and shellac finishes form coatings of sub stantial thickness over the surface of the wood in con trast to oil and seal finishes, which penetrate into and are embedded in the surface of the wood without forming a definite coating over it. When a coating wears through la a traffic channel, it can rarely be patched without showing the edges of the worn place; and even if the whole floor is reeoated there is usually a difference in color between the worn area and the areas where old coating discolored by age remains underneath. For fully satisfactory refinishing, the old coat must be removed completely either by sanding or scraping or by use of suitable liquid removers. The necessity pf removal can be avoided by taking care to renew the coatings before traffic channels wear through, but with varnish finishes particularly the color gradually darkens as thicker layers of old varnish accumulate. Shellac has much less tend ency to darken with age than varnish hut, on the other hand, water causes it to turn white if the water stands on it very long before being wiped off thoroughly. The modern floor seals may be regarded as thin var nishes or bodied drying oils prepared to penetrate less deeply into the wood than unbodied drying oils. Fewer applications are required, yet they penetrate more deeply than ordinary floor varnishes so that a surface layer of the wood can be saturated and the finish can be embedded in the wood rather than coated over it. Some of the seals contain emulsified water for the purpose of controlling the degree of. penetration and the spreading rate at which the seal is applied. The seals are relatively new products on the market; composition and properties vary widely; and inadequate instructions for application are often given. Inasmuch as the seal finish differs fundamentally from the varnish finish in method of application, it is very im portant that those who use seals for the first time make sure that they learn exactly how the products should be used to obtain the excellent service of which the finishes are capable. Selection of Finish Wood floors can be maintained in good condition by any one of various types of finishing methods, if good materials are properly applied and if maintenance meth ods appropriate for each type of finish and for the de gree of wear to which the floor is subjected are em ployed. No one type of finish can be said to be superior in all respects and none will long continue to give good service unless it is suitably maintained. The secret of good floors lies in thorough understanding of the nature and limitations of the particular kind of finish chosen and in careful following of the appropriate maintenance program. Where the owner's chief requirement is a maximum interval of time between refinishing jobs, during which the floors will be merely kept clean by sweeping and dry mopping, or where the highly lustrous appearance ob tainable only by using a substantial coating of resinous material is desired, coatings of varnish or shellac are N41698.42 FLB 001008 BEFORE: A typical upper floor\orridor in the Broclcman Building at Los Angeles, showing tnfeold fashioned trim and the large areas of glass before\modernization AFTER: The same corridor after remodeling. All of the alterations were made by the building's regular employees, on plans conceived and supervised by the manager BUSH I I r BEFORE: Another view of an old corridor in the Brockmari Building. AlUf the work necessary to effect the trans formation shown at right was done at night / AFTER: Throughout the alterations, all scaffolding and muss Was removed before tenants arrived each morning, and the Whole program was completed in this way i BEFORE: These old elevator entrances were solid, hut antiquate'&rThe old grille fronts were covered with sheet metal \ and this was finished exactly like the walls BUILDINGS AND BUILDING MANAGEMENT--June 1939 AFTER: The modernized elevator fronts are simple and at* tractive. They completely change the appearance of tn^ corridors, and are in keeping with the other work 33 FLB 001009 likely to prove most satisfactory. The coatings should be cleaned and renewed when they begin tp become thin in the channels of maximum traffic but before they wear through to bare wood at these points. Dissatisfaction with such finishes arises most often where recoating has been too long postponed; and this is particularly likely to occur, because those who choose such programs do so largely to escape the burden of watching their .floors care fully. After three or four renewals of the coating, when it has become dark in color, it should be removed com pletely by scraping, sanding, or with varnish remover and a new coating applied to the bare wood. Shellac is used so widely for floors chiefly because it dries so rapidly that a floor may he finished or refinished and put back in service within 24 hours. Varnishes, even the quick-drying kinds, require longer intervals between coats and remain tender for some time so that the floor should be kept out of service for several days when var nishing is beipg done, although they are often used within 24 hours. Where floors can be kept out of service long enough to apply varnish finishes properly, varnish is commonly chosen instead of shellac because of its better resistance to water that may be spilled upon it. Varnish finishes are also tougher and less easily scratched than shellac. The shellac and varnish finish, in which shellac is used as the first coat on the bare woodland the varnish put on over it, is a compromise between the shellac and the varnisfufinlsh. Like so many compromises, it retains many of the disadvantages of both sid^s with some new short comings of its own. Water may still turn the shellac white under the varnish; the floor still needs to be kept out of. 'service long enough to dry thoroughly ; and the finish' is usually very easily marred by scratches from shoe nails or scraping chair legs. The durability of coatings can he improved by keep ing them waxed, renewing the wax every 4 to 6 months according to the amount of wear on the floor. Wellwaxed floors are also more easily kept clean by dry mop ping. Wax over a substantial coating of shellac or var nish, however, tends to make a slippery floor unless the coating of wax is kept very thin. For that reason where wax is to be used, the shellac is often limited to one or two coats and sanded or huffed off so that it acts more as a seal to support the wax than as a coating. Some of the modern floor waxes are made with resinous ingre dients in a further effort to make them less slippery. Those who choose coatings to relieve them of the necessity of paying fairly frequent attention to floor maintenance, however, are not generally inclined to renew wax often enough to gain much benefit from it in extension of the intervals between recoatings, and they might therefore do well to consider the newer floor-seal finishes with or without wax. The modern floor-seal finishes are well suited to the needs of those who wish to keep their floors well waxed at all times, with minimum of slipperiness, and those who do not like the appearance of the very lustrous coating finishes, or who wish to pay a minimum of atten tion to floor maintenance except at an annual or semi annual housecleaning time and then want to be able to clean and patch worn spots without the trouble of moving X all the furniture out of the room and keeping the room out of service for a day or more. Finishing New Floors In new construction, floor finishing should be the last operation performed after all other interior work has been completed. It is advisable to have the floors pro tected by a covering of heavy paper from the time they are laid until the finishing is to be done. The first and most important operation of finishing is scraping or sanding. Scraping by hand has been displaced almost entirely by sanding with electrically operated sanding machines. The sanding machine should be well designed; of rugged construction, with its bearings well aligned and kept in good condition. A machine with badly worn bearings may do more harm than good. It is usually advisable to have the sanding done by a man who spe cializes in floor sanding, not by a carpenter or painter. If part of the work is to be done by relatively unskilled labor, let it be the application of the finish rather than the landing. In sanding, the floor should be gone over several times, first across the grain and then in the direction of the grain. On the first traverse No. 2 sandpaper is usually used on the machine, graduating down to No. J4, No. 0, and No. 00 on succeeding traverses. On softwood floors, however. No. % sandpaper is often the finest grit prac ticable, After the last sanding, the floor may be buffed with No. 3 steel wool. For working close to walls or corners or in closets, where 68][P 1 T q PX 1 3 B B M0 0 q 3 1 q 0 0 q 3 1 q 1 3 + q --June, 1939 35 1 FLB 001010 Effective Floor Finishes (Continued from page 35) the large machine cannot be used, there arc small, poweroperated machines. After the floor has been sanded, it should l)e swept clean and carefully inspected, looking at it across the floor toward the light from a window and remembering that any scratches, undulations, or other blemishes will apjxtar greatly accentuated when the finish is applied. The floor should not he walked on until the first coat of finish has been applied and finishing should he done as soon as possible after sanding. Chicago's Capitol Building, once I f the floor is to be stained, this should he done with a penetrating oil stain at this time. Where floor seal is to be used, however, the stain may be incorporated in the first coat of seal. Some commercial floor seals arc put out in colors as well as in the colorless form. Stained floors require particularly careful maintenance to avoid wearing traffic channels deeply into the wood. Mo stain penetrates very deeply with uniform color and if a patch becomes light in color through wear, it is very difficult to repair it to match in color the unworn areas of the floor. On the other hand, some stain may penetrate very deeply in the large pores of some hardwoods so that the owner, if lie subsequently wishes to sand the floor down to get rid of the stain, may have to remove a considerable layer of the board. Stain incorporated in a first coat of floor seal is less likely to result in such deep penetration in local spots. building eyer torn down Floors of oak or other hardwood with large pores may reejuire filling with paste wood filler before proceeding with the subsequent finishing. The filler may be colorless or it may contain pigment if it is desired to bring out the grain of the wood more contrastingly. Paste filler is al most always used on oak floors before applying shellac or varnish coatings, but with floor seals the practice varies. Some manufacturers of seals recommend that filler be used; others recommend its omission. When filler is used, care should be taken to see that the excess is wiped off very thoroughly to avoid an uneven, smeared appearance of the final finish. Any imperfections left by poor sanding make.it difficult to do a clean job of filling. Varnish Methods of applying floor varnish are commonly un derstood and are usually described on the labels of the containers. Only floor varnishes should b,,e used for floor finishing. Varnishes made for other purposes and the so-called all-purpose varnishes are not so durable for floors as varnishes made specifically for the purpose. At least two coats are needed over paste filler or over a first coat of shellac and at least three coats where the varnish is applied directly to the bare wood. The chief precau tions to observe are cleanliness and reasonable control of temperature and circulation of air. The floor should be clean when varnish is applied, and the brush must be clean to avoid leaving grains and lumps in the coating. The room should be kept at 70" F. or warmer and plenty j of fresh air should be provided, since oxygen is taken ) from the air when varnish dries. Low temperature and Its successor will be a two-story high relative humidity greatly retard the drying of varnish. th Hie future subway 36 June, 19H9--B 0 0 q 3 s1 q B M0 0 q 3 1 q 1 3 + q > B . ; Mq 0 0 00 0Q+ 0 1 q 1 3 + q FLB 001011 Shellac for floors should lie purchased in the form of 5-pound cut shellac varnish and should be pure shellac unadulterated with cheaper resins. It should either be freshly manufactured or put up in glass containers. Shellac that has stood long in contact with metal may contain salts of iron that discolor oak and other woods containing tannin. The correct thinner for shellac is 188-proof No. 1 denatured alcohol. For application, 5pound cut shellac should be thinned with 1 quart of thinner per gallon. It should be supplied with a wide brush that will cover three boards of strip flooring at one stroke and should he put on with long, even strokes, taking care to join the laps smoothly. The first coat on bare wood requires 15 to 20 minutes to dry. It should then be rubbed lightly with steel wool or sandpaper and the floor swept clean. A second coat should be applied, allowed to dry 2 or 3 hours, then gone over with steel wool or sandpaper, swept, and a third coat applied. The floor should not be put back in service until next morning if possible but may be walked upon in about 3 hours after finishing, if necessary. If wax is to be used, it should not be applied less than 8 hours after the last coat of shellac and should be a paste wax, not a water-emulsion wax, since water may turn the shellac white. Floor Sals Manufacturers' directions for applying floor seals vary widely and in some cases are very inadequate. In gen eral, floor seals may be brushed on with a wide brush or mopped on with a squeegee or lamb's wool applicator, working first across the grain of the wood and then smoothing out in the direction of the grain. After an interval of 15 minutes to 2 hours, depending upon the characteristics of the seal, the excess is wiped off with clean rags or a rubber squeegee. For best results the floor should then be buffed with No. 2 steel wool although the buffing is omitted by those who are willing to sacrifice something in appearance and service to save the labor of buffing. If possible, the buffing should be done by a rugged power-driven machine designed specifically for huffing with steel wool. The next best procedure is buf fing with steel wool pads attached to the bottom of a sanding machine. The buffing may be done by hand if a machine is not available. One application of seal may be sufficient, but a second application is generally recom mended for new floors or floors that have just been sanded. A correct interval of time between applications of the seal and buffing is exceedingly important. If the interval is too short, the appearance and durability suffer; while if it is too long, the excess seal "gums" the steel wool badly, is removed from the floor with difficulty, and where, not removed becomes blackened with detritus from the steel wool. If the manufacturer of the seal does not specify the correct interval of time clearly, the user should determine it for himself by trial on samples of flooring or in some inconspicuous places where imperfect results will not prove too disappointing. Once the user has learned how to work successfully with one brand of seal he will do well to stick to it, since he might have to learn the technique all over again with another brand. Floor seals are now offered by a number of inanu- CUTS REPLACEMENT...REPAIR AND MAINTENANCE COSTS, RIGHT DOWN TO THE BONE! Not only will the BEST UNIVERSAL LOCKING SYSTEM cut lock servicing and repair costs to the bone, but it guarantees absolute control of all property and tenant security, gives added, protection... new convenience*., morning, noon and night! Why? Because the entire BEST UNIVERSAL LOCKING SYSTEM, is built around one exclusive,fundamental principle... the INTERCHANGEABLE CORE. This feature makes it possible for any in' vestor or property manager to save cold, hard cash on all locks... regardless of type, size, or where they are used. PIN TUMBLER SECURITY... INSTANT CHANGEABILTY GIVES YOU PERMANENT PROTECTION AT LOWER COST! As shown by the photograph above, the INTERCHANGEABLE LOCK CORE contains both pin tumbler and locking mechanism. It also carries a key-way for the insertion of your regular key. If, for any reason, it becomes necessary to replace a lock, you simply remove the old core with your private CONTROL KEY, recombinate it, or replace it with a core having adiffcrcntcombination.Either method,exclusive with the.BESTsystem,gives theeffectof a new or different lock .. , without added expense, labor cost or time lost. This INTER CHANGEABLE CORE feature applies to all BEST Padlocks, Locks and Latches, for en trance, vestibule, room and office doors.,. cabinet, desk drawer -and wardrobe locks. The BEST system is simple, safe, sure, economical. It can. be installed without changing your present system. Write for full details. Representatives in leading cities arc ready to serve you. BEST UNIVERSAL LOCK CO., INC. 730 East Washington Street : Indianapolis, Indiana REPRESENTATIVES f.V LEADING CITIES ARE READY TO SERVE YOU! B B M0 0 q _ 1 q 0 0 q 3 1 q 1 3 + q --June, 1939 69 FLB 001012 SMOOTH ROLLING ELEVATOR DOORS! The new Wagner Ball Bearing Ele vator Door Hanger brings new quiet ness and new smoothness with per fect alignmentto elevator doors. Get the facts on this new Hanger before modernizing or building. Atk your architect or write # /dr catalog pf Wagner Elevator Accenorles. \ \ \J \f facturers of floor-finishing materials and equipment, who are usually able to give precise and reliable instructions for the proper application, and maintenance of their prod ucts. Seals are also sold by most of the larger paint and varnish manufacturers, although the preference of their dealers is usually for floor varnishes. Waxing Floor* Waxing of floors is done to best advantage with paste flopr wax and an electric polishing machine designed for the purpose. For best appearance and durability there is no satisfactory substitute for the polishing machine; pol ishing by hand is far too laborious for the modern house hold and too expensive for the business building. The paste wax is mopped on the floor, allowed to stand until the volatile thinner evaporates, which may take 15 to 30 minutes, and the floor is then polished with the machine. The most modern type of floor-waxing machine applies the wax and polishes in the same operation. For those who wish to get along without a polishing machine and are willing to accept a somewhat less attractive and less durable wax finish, there are water-emulsion floor waxes that are mopped on the floor and allowed to dry. Refinishing Old Floors Where floors have become badly discolored and worn by neglect or improper maintenance, the most practicable procedure and often the only one that will restore a fine finish is to have the old finish removed and the floor re conditioned by power sanding. Where the floors have been reasonably well maintained but the finish has be come dingy with age, refinishing without power sanding may be practicable- The method of removal of the old finish depends upon the kind of finish that was used. Old Oil Finish An old oil finish, since it is embedded in the wood, may cause some difficulties. If a steel-wool buffing machine.is available, an attempt should first be made to clean the floor sufficiently merely by buffing with No. 3 steel wool. If this is not feasible or proves ineffective, a chem ical treatment will be necessary. Through the action of mild alkalies, the oil is changed to soap. The alkali used may be a water solution of trisodium phosphate, washing soda, or a commercial cleanser. If lye is used, care must be taken not to have the solution too strong because strong alkali swells and softens the wood. (If the oil contained mineral oil, however, there may be no prac ticable way of removing it, since alkalies do not saponify mineral oil.) Application of Alkali In applying the alkali, flush a small area of the floor at a time and allow to stand for a few minutes, then scrub with a stiff brush or No. I steel wool. Next flush with clean water and scrub to remove the soap that has been formed, and finally remove all the water possible by mopping and let the floor dry thoroughly. If the floor turns gray in color as a result of the action of the alkali and water, it may be necessary to bleach it with a satu rated solution of oxalic acid in water (oxalic acid is poi- lune, 1939--B 0 0 q 3 s1 q B M0 0 q 3 1 q 1 3 + q FLB who ctions prodlt and their paste ;d for / lere is ; poixouse- The ! until to 30 chine, pplies those e and d less waxes worn icable a fine Or rehave cs be nding ie old 1. wood, ; maclean steel :hemon of used shing must cause ie oil praconi fy floor scrub With been le by floor alkali satuS poi- EMEHT sonous and must be handled with great care). Rinse off the oxalic acid thoroughly with clean water, mop, and let the floor dry completely. Any raised grain or rough ening of the surface of the boards as a result of the drastic treatments should be smoothed off with sand paper or steel wool before new finish is applied. Old Varnish Old, discolored varnish finish is usually removed most easily by power sanding; but if desired it can be done with liquid varnish remover. Alkaline solutions in water and removers sold in powder form to be dissolved in water should not be used. The directions for using the liquid remover should be followed carefully. Since some old, discolored varnish remains embedded in the wood, complete restoration of the natural wood color should not be expected. Traffic channels where the old varnish has long been worn through and dirt ground into the wood should be cleaned by sanding. Old Shellac Old shellac and wax finishes that have merely become soiled by dirt clinging in the coating of wax may be cleaned by going over the floor with steel wool saturated with clean turpentine. Any white spots in the shellac caused by contact with water may be taken out by rub bing lightly with a soft cloth moistened with denatured alcohol diluted half and half with water, but the alcohol must be used with care to avoid cutting the shellac coat ing. On floors where the dirt is ground into the shellac itself or white spots penetrate all the way through 'the coating, more drastic treatment is necessary. First, wash the floor with neutral or mildly alkaline soap solution followed by clear water, using as little water as possible in each operation. Then scour the floor with No. 3 steel wool and denatured alcohol diluted half and half with water. If the floor boards are level and are not warped or cupped, the scouring can be done to advantage with a floor-polishing machine fitted with a wire brush to which a pad of the No. 3 steel wool is attached. After the scouring, the floor should be rinsed with a minimum amount of clean water and allowed to dry thoroughly before refinishing with shellac. Checkthese CLlP-ER Features before you buy any type of Faucet Repair DQESAWAVWm WASHER AND SCREW NOTHING TO CHATTER mmwmwm WATER CUTSEATAND RENEWS FAUCET HOT OR.COLO WATER, APP10.F0R FAUCETAPART SLIDE CUP-ER ON PENCIL DROP INFAUCI SEAT HOLE; PUSH DOWN NEVER FAILS) TO SHUT OFF \ THATSj c u p -j Ur z in i w a s h e /s e a t IT EXPANDS AND LOCKS TIGHT IN PUCE CLIP-EThis diagram shows a few of CL1P-ERS dut.standing feature^s. Here are others: No washer to wear out A No screw to brhak off utes washer troubles, broken screws and reseating tools forever Reseats it^ to install G-IP-ERS 'save their s;imfa-ll cost many Always easy (mes by e.lim- inafing costly leaks, expensive rep airs and water-si ained fixtures. Don't buy any type of faucet repafir before you try CUP-ERS on those leaky faucets, ball-pocks, globe valves ancf .shut-off valyes in buildings you own or operate, j f Order CUP-ERS today frotjn your supply house, or write direct for samalejf and circular j Floor Maintenance Wood floors with fine finishes should never be scrubbed with water or unnecessarily brought in contact with water except in connection with refinishing old floors as already described. Sweeping or dry mopping should be all that is necessary for routine cleaning. A soft cotton floor mop kept barely dampened with a mixture of 3 parts of kero sene and 1 part of paraffin oil is excellent for dry mop ping. When the mop becomes dirty it should be washed in hot soapy water, dried, and again dampened with the mixture of kerosene and paraffin oil. Exceptional patches of dirt that cannot be ..removed in this way may be re moved by rubbing lightly with fine steel wool moistened with turpentine. Where the finish is a floor seal, badly soiled spots, such as gray spots where Water has been allowed to stand on the floor for a time, can be sanded by hand, patched with seal, and buffed with a pad of steel wool. Varnish finish if kept in good condition offers better protection against water scars; but if it does become stained it is not so easily repaired. B B M0 0 q 3 s1 q 0 0 q 3 1 q 1 3 + q --June, 1939 t t 71 FLB 001014 MACKIN PREMIER BLINDS Consider these TbisUnctott 'JtatuAeA, U/k&n you. iftuy VuuXim fSlitaU Slats removable without disturbing operating parts Mechanically constructed to afford positive level lift Guided t&ynrevent blowing in the wind Longer lifesto the tape.-- no cords to destroy the ladders \ Chain and sprocket used for raising and lowerings not cord and pulley* Ventilator bracket^ attacked to channel guides with out screws Easiest to clean, either by removing slats individually Or the entire body of ikp blind Proven lower maintenai Ball bearings provide for mate of operation Installation on other locations a simple alteration job All materials of highest quality obtainable Rockefeller Center windows throughout -are equipped with over 13,000 Macktn Premier Blinds. Other thou sands in Hotels, Hospitals, .Schools a^d Commercial Buildings. VA few territories available for selected ,jrepresentatives MACKIN VENETIAN BUND COMPANY Factory: BRADLEY, ILL. Mail Address: KANKAKEE, ILL. Sales Ojjiees in Principal Cities How ONE MOP DOES THE WOH OF The CROWN Mop With 28-ply strands, each of which has a tej&iie strength of 90 ibs., th/CROWN MOP outwears three or more ordi nary mopy Leaves no broken strands op floor, or in wringer bucket to clog drains. Absorbs water equal to three times its weigh For /downright economy and dean, quick work, specify foWN, Wide band or nar row tape as desired. Your Sup/ply Dealer will furnish sample or write direct. f r e e s a mp l e THE J. E. FRICKE CO. 40 M. Front St., Philadelphia, Pa. Mills at Hulmevilte, pa. FRICKEa^%-MOPS STRONG DURABLE MORE ABSORBENT / 72 Common Heating Problems (Continued from, page 41) heating boiler being circulated in the shell around the^doil to heat the water which circulates through the cojf and to the tank. Installations of this kind are usually eco nomical, but they must be kept clean. A type at indirect heater often attached to a steam boiler resembles a long cylinder which contains a steam chamber-'surrounding long water tubes or coils, the water being heated in the coils and conveyed to the tank for storage; All such attach ments should be opened up at least otafce a year and thor oughly cleaned out, both in the steajn chambers and in the water coils. Still another form of indirec^heating is the steam coil located inside the water tank; steam being supplied by the heating boiler. Perhaps the most recent type of heater is the coil directly withirythe boiler. This may be either the sort known as a submerged heater or the sort called an instantaneous heater1. The former involves circulation o f the water througly'the boiler coil and back to .a storage tank. The so-called'instantaneous or tankless heater like wise involves a cofl located in the boiler water but not the use of a tank, tne hot water being conveyed directly into the house circulating system. This is the most direct of all systemsy6f hot water heating from the steam boiler and operates on the principle that the entire piping system of the building is a reservoir replacing the usual tank. It is obvious that good circulation throughout the hot wate/ system is necessary if this type of heater is to be fessful. Naturally the hot water cannot be heated from thfe steam boiler by any of the attachments or coils men tioned unless the capacity of the boiler is in excess of the load required to heat the building. . A hot water system which requires steam to be taken from the heating boiler and passed through a coil in the .ank or to any of the attachments mentioned, will prove expensive in the summer when the boiler is not in use foKheating the building, because such a system requires a head of steam on the boiler at all times. The amount of heahrequired to raise one pound of water from freezing point to'boiling point as sea level is 180 Btu. The amount of heat required to push that same pound of water up from 32 degrees and turn it into steam is 970 Btu., or more than five times as much as was required to bring it from 32 degrees to 212 degrees. Therefore, with the use of the submerged or instantaneous type of coil, the boiler need be fired only enough in the summertime to raise the boiler water temperature to approximately 180 degrees, and the fuel required to do this is very much less than the amount required to make steam at the boiler. A proper installation of the instantaneous coil system will include an automatic mixing valve which will intro duce cold water into the line whenever the temperature of the water coming throughNthe coil is higher than the temperature desired for the water in the water lines sup plying bathrooms and kitchens. This, of course, requires aquastats on the boiler water, onAhe feed line, and on the lines supplying hot water to the\building. Air Supply It is usually considered that a chimneyScauses a draft because the gases originating in the combustion chamber are lighter than air and therefore, rising up through the June, 1939--B 0 0 q _ 1 q B M0 0 q 3 1 q 1 3 + q FLB 001015 ms the/oil coil and Hy ecoindirect 3 a long ounding din the { attach ed thorid in the earn coil plied by f heater te either rt called culation storage ter likenot the ;tly into irect of n boiler system al tank, the hot is to be ed from ils mens of the le taken :1 in the ll prove : in use requires amount freezing amount ater up Btu., or bring it rith the ;oii, the time to ely 180 uch less toiler. system 11 introjerature han the les supequires and on a draft hatnber ugh the PAINTING YOUR HOUSE By F. L. BROWNE Forest Products Laboratory Madison, Wisconsin Reprinted from AMERICAN FORESTS May, 1939 The Magazine of The American Forestry Association Washington, 0. C. N41698.43 PAINTING YOUR HOUSE By F. L. BROWNE DISCUSSION of house painting usually begins with a considera tion of the different kinds of house paint. You can buy paint and you can hire a painter but what you want is paint mainte nance and that you cannot buy. The job of putting paint and painting together to make a pro gram of paint maintenance is all yours. Whether you like it or not you cannot dodge the respon The homes we live in form one of the greatest contributions of the forest to hu man comfort. In every house no matter what type its construction there is wood somewhere in large or small amount. With rare exceptions every home owner, there fore, is periodically confronted with the problem of painting and repainting the exterior wooden parts of his home, his garage or his barn. Beauty, serviceability and lasting qualities of the paint to he used are the owner's hoped for realization. Unfortunately most home owners are ig norant of how to achieve this combination of results. The author of this article has without unnecessary expense. Since a worn out coating is not easily discarded renewal rather than replacement is essential for economy. Renewal means that new paint is applied over what remains of the previous paint and that the composition of the renewed coating depends upon that of the old paints as well as that of the new paint. You therefore need good sibility if you are a home owner. Your ignorance of the technical problems involved docs not let you out. You pay the damages spent many years at the Forest Products Laboratory, Madison, Wisconsin, studying paint with special reference to its use on wood. In "Painting Tour House," he deals with the subject from the home-owner paint for your house, not just good paint in general. The latest marvel of the paint industry is no good to you unless you can be anyway if paint, painter, and point of view.--Editor. reasonably sure that it behaves program fail to fit together. properly when incorporated with The new house starts out with the old coating already on your a coat of paint that"is durable for no more than four or house. If repainting every four or five years seems rea- five years. The house may stand for a century or two but sonable to you and you hire good painters tp do the work let us say that it has an expectancy of half a century as tke annual cost of maintaining the exterior paint may a building of pride&L oeeupancy. Ten or twelve renewals well be less than a third of the annual real estate tax pro- of the paint coating within that time are to be anticipated vided the maintenance program is properly guided. Two if you wish to keep the coating always in good condition things should be watched carefully--stick to your pro- ^ | >| 5 | I ' if Ilf l| || . | %{ ^ hS li For economy and good appearance your house should he painted every four or five years. Be sure fhaf in repainting you always use the same hind of paint you start out with when the house is new. Above is shown an excellent reason why. This house was originally painted in color. Then a new sidewall was built on the right side, after which the whole structure was painted white. The detail at left shows the colored paint under the white---at. right the section on which only white paint has been used FLB 001017 gram so that you always repaint a little before the coat ing begins to break up and stick to the same kind of paint with which you start out when the house is new. A systematic written record of the painting history helps materially in keeping the program on the right track. In noting the paint used, an accurate copy of the com plete formula, or better yet one of the labels bearing the formula, should be preserved. The time to consider the many kinds of house paint on the market is when choosing the paint for a new house or when failure of the program of maintenance has made it necessary to remove the old coating to start over again. The rival advertising claims and the eonfleting opinions of experts may then be pon dered carefully.-.Eaeh paint will be found better a n fl m ore durable than any of the others but no paint maker will allow himself to be pinned down to a claim of 1 more than four oi' five years for the durability of his paint. IVh e n the field of possi ble choice has be ea nar rowed down somewhat ac cording to your likes and dislikes among the makers and dealers it is a good plan to look at some houses painted with the paints in question three or four years previously. A survey of neighbors' experience is likely to prove a liberal education in paint maintenance, in the first place unless the neighborhood is very exceptional it will show that few owners stick consistently to one type of paint, follow a systematic plan of maintenance, or keep a record of the dates of painting and kinds of paint used. That is often why they get into trouble eventually. In the second place your survey will show that any one kind of paint may give satisfactory service or very unsatis factory service according to its suitability for the main tenance program and its compatibility with- the paints used previously. When a hodge-podge of different kinds of paint occasionally stands up well for a long time the owner is merely lucky. The wise owner plays safe by making changes in kind of paint only when he knows that past experience justifies the specific changes in question. After surveying the neighbors' experience yon may still feel unable to decide what kind of paint is best but probably will conclude that, for the new house, it is much less important than you originally supposed. Almost any one of the good paints on the market should prove satis factory if you use it consistently in the future and renew it at the proper intervals. Make sure, however, that the paint you select is labeled with a complete statement of composition so that another one like it can again be purchased, even, if the manufacturer meantime changes the composition of the brand you are now choosing. Once your house is erected and painted no further thought should be given to the rival claims of different kinds of paint. The decision has been made. Stick to the kind with whieh you began. If for any reason something goes wrong and you are dissatisfied find out what was wrong and what can be done to set it right. Do not blindly experiment with some other kind of paint for you will merely make a bad matter worse. Many house owners feel that painting every four or five years is unreasonably expensive. As a rule, of course, they belong to groups of lower income level to whom the cost of a paint job is a real burden and who in times of financial de pression find it hard enough to keep posses sion of the house at all. In justifica tion of their expectations there is a long tradition of American practice in house painting according to which mainte nance programs with ten years or even more between jobs were taken as a matter of course. Programs with painting every four or five years are a relatively mod ern innovation perfectly proper where the standard of living permits but we must recognize that large por tions of our population have not yet been lifted above the urgency of immediate necessity. If a man must choose between paint for the house and shoes for the children by all means let the children have shoes. The house will suffer less from worn out paint than will the children from worn out shoes. The choice of suitable paints for programs with more than four or five years between paintings is greatly re stricted. The old red or brown iron oxide paints were durable for as much as ten years but in modern times "barn paints" have deteriorated very seriously in qual ity until it is now difficult to buy a really good one. Two or three coats of aluminum paint are durable for very long periods but the metallic appearance rarely proves agreeable for houses, though it is sometimes at tractive for barns and other' utilitarian structures. For the most part programs with long intervals be tween paintings are based on the assumption that each paint job will pass through a considerable' period of neglect following the break up of the coating before an other paint job is put on. The paint for such programs, FLB .......---- therefore, must be chosen for its ability to retain a rea these reasons the least possible amount of paint should sonably presentable appearance during the period of he applied at a time and the paint used should have un neglect and to leave a surface that can then be re usually high hiding power. No more than one coat painted without danger of impairing the servieeableness should be applied at each painting. of the next paint job. Durability of the paint is not The second difficulty with frequent repainting is that important, in fact the paint should not be too durable incompatibilities between paints of different kinds are because the less of it left when repainting finally is often more pronounced the less the earlier paint has done the better. Weathered before it is repainted. Those parts of the Of the so-called first grade white or tinted white house that are greatly sheltered from the weather are paints on the market pure white lead paint is probably particularly prone to difficulty on this score. Meticu the only one that can properly be advised for mainte lous adherence to the same type of paint for each paint Iis nance programs that presuppose periods of neglect. The old tradition from whieh such programs come was based ing is very necessary in programs calling for frequent repainting. on the exclusive use of pure white lead paint beeause it Those who paint so often may be deceiving them was the only white paint available until comparatively selves through a lack of understanding of the eourse of | modern times. All attempts so far to make white paints less subjeet to soiling and fading of tints and more events in the aging of paint. Soiling of the coating progresses most rapidly during the first year or so, | durable have led to paints that are harder in nature while the paint is still glossy. When gloss disappears than white lead paint. and chalking sets in the dirt may begin to be dislodged Because the newer paints are harder they break up and the cleanest and most pleasing period of the paint's more objectionably when neglected and do not wear off life may continue until the coating finally begins to dis as much by erosion with the result that, when the be integrate. If white paint is repainted when at its dir lated repainting is done, there are thick patches of un tiest stage the period of best appearance may be saeri- certainly adhering old coating interspersed with patches fieed only to start in again with the dirt collecting stage. of bare wood; the painter is unable to apply new paint With white paints, a little patienee while the coating smoothly, and the new job is less durable than the pre sheds its dirt may be better than hastily repainting. vious one. Ultimately, complete removal becomes neces With tinted paints appearance is marred at first by sary, the expense of which is inconsistent with a pro dirt and later, as the dirt is dislodged, by fading of gram of extreme economy. Those who wish to wait a color. If the initial color mnst be maintained exactin long time between paint jobs will do well to insist on frequent repainting may be necessary. A little more pure white lead paint for white and tinted white paints. care in choosing color at first may make it less essen If you belong to the relatively small class of house tial to retain the initial color exactly. Yellows and owners who insist upon superfine appearance obtained buffs can fade rather seriously and still look well hut i>3' repainting every year or two you have selected the when light greens and light blues fade they look shabby. most difficult program of all and must expect to pay Too frequent repainting can often be avoided by con well for it. Complete removal of the coating at inter sidering the faded color as well as the initial color in vals, say every ten years, should be anticipated. Fortu selecting tints at the outset. nately the painter's blow torch is no longer the only Those who are tempted to paint too frequently in or means of removing old paint. There are now house der to keep particularly good appearance at all times paint removers on the market that will do a better job might well consider washing as a substitute for some of with less hazard of fire and usually at somewhat less the repaintings. Instead of painting every two years eost. At best, however, complete removal is too ex wash after a year and a half and repaint with one coat pensive to put up with any oftener than is necessary. after three or four years. For such a program paint of The first difficulty with frequent repainting lies in ' rather hard type should be chosen beeause it lends itself the fact that the coating does not have time to wear readily to washing and since it chalks superficiallr away much between jobs, hence it becomes materially rather than deeply washing restores practically the ini thieker at each painting. No paint behaves well when tial color. After washing it will be found that dirt the coating is too thiek. Cracks appear at an unrea collects less seriously than it did after the paint was sonably early age and take the form of huge gashes. first applied. Use of an alkaline solution of trisodium Coarse scaling sets in at an age when a thinner coating phosphate which removes some paint from the surface would not have begun to break np at all. Each paint making the coating a trifle thinner is advised if washing job becomes less durable than the one before it. For is done. ii FLB 001019 8 NATIONAL PAINT BULLETIN An Open Letter From Dr. Browne lons per gallon of paint. The sum of the white The Editor, Madison, Wisconsin.. April gg, 1989. lead and zinc oxide in formulas A and B is ex actly the same, 6.200. Formula A, which from Table 1 the layman assumes has less linseed oil than formula B, in Table 2 is found to contain National Paint Bulletin. more oil. Comparing formulas A and C, the lay Washington, D. C. man, overlooking the difference in percentage of An item in your Bulletin, Vol. 3, No. 1, page 8 (January 1939), in which, a paint manufacturer's advertising matter comparing formulas for cer tain well known brands of paint is reported, de total pigment in the two paints, assumes that they contain the same amount of white lead and zinc oxide whereas formula G actually contains 25 per cent more. On the other hand the difficulty in serves further discussion because, it illustrates telling the layman how to take proper account of very well some of the difficulties in explaining formulas in their present complicated form to laymen without confusing or misleading them. In continuing the discussion, however, a different set of paint formulas to illustrate the points raised will be chosen so that reference to brands of paint on the market or to specific manufactur ers will be unnecessary. Two common causes of misinterpretation of formula labels are exemplified in the item in the January Bulletin, (1) failure to appreciate the significance of the percentage of total pigment in the paint, and (2) the difficulty in telling from the conventional method of expressing paint formulas when "extending" pigments are used sincerely to control desirable paint properties and when they are-adulterants. The second point is further confused by ambiguous nomenclature for paint ingredients and varying practice in dealing with the composite pigments. Both points can be illustrated to advantage by discussing the formu las of five paints now being subjected to exposure tests on the test fences of the Forest Products Laboratory. These formulas might appear on formula labels, following conventional practices, as shown in Table 1. All of the paints are thor oughly practical house paints the consistency and percentage of total pigment in formulas ex pressed by weight is apparent on comparing the five paints in Tables 1 and 2. Formulas A and E are both relatively low in percentage of pigment by weight but by volume the comparison is 0.200 with 0.268 gallon per gallop of paint. By volume formulas D. and E are practically identical in content of total pigment but by weight they con tain67.8 and 64.4 percent respectively. Formulas B and E illustrate the new position of the "extending" pigments since titanium dioxide came into wide use; Prior to that time the pro portion of magnesium silicate in formula B, about 20 percent of the pigment by volume or 10 per cent by weight, was roughly the maximum for transparent pigment in paints generally accepted as properly "first grade." When barium sulfate is used instead of magnesium silicate in formula B the percentage by weight is 15 rather than 10 because of its smaller bulking value. Formula E, however, which i -unquestionably a first grade paint of the present day, contains more than 21 percent magnesium silicate in the pigment and is much superior in hiding power to formulas A and B, being slightly better even than formula C in that respect. In formula I) there is barium sul fate to the extent of 30 percent of the pigment by weight although the buyer of the paint will not brushing qualities of which resemble closely com mercial paints of the types represented. / realize that fact from the common way of print ing the formula on the label unless he knows that Paints A and B represent a common compari titanium-barium is 70 to 75 percent barium sul son of manufacturers' first grade paints before fate. the titanium pigments became so popular. The Comparison of -the five formulas shows clearly comparison is still reasonably applicable to tinted that it is impossible to tell laymen how to dis paints. The layman, overlooking the difference tinguish between use of "extenders" as adulter in percentage of total pigments in the two formu ants and their use to supply pigment bulk beyond las, assumes that formula A contains more white the requirements of opacity so long as laymen lead and zinc oxide than formula B because the are presented with the complicated formulas by pigment in the latter contains 10 percent of "ex weight. Even in the days when- the lead and tender", The fact is that formula A contains 10.3 zinc paints alone were to be considered, the rule pounds of white lead and. zinc oxide per gallon that "extenders" should not exceed 10 to 15 per % whereas formula B contains 10.6 pounds. If for cent of the pigment was properly applicable only mula B is "adulterated" with magnesium silicate so long as the total pigment was 66 percent or formula A is likewise adulterated with excess ve more of the paint, hut now that the paints con hicle. That the excess vehicle in formula. A is taining titanium pigments must also be included not demanded by requirements of consistency is the rule has no validity at all. shown by formula C, which has practically the To all practical purposes formulas B and E are same consistency as formula A but is made, of essentially the same, yet buyers are likely to be course, with a different type of zinc oxide and a misled by the fact that the label for formula E different linseed oil and contains 12.7 pounds of discloses a large proportion of "extender" whereas white lead; and zinc oxide per gallon. To the best the label for formula B apparently discloses none. of the writer's knowledge no LZ paint with so To the user .of paint "extenders" have exactly high a content of white lead and zinc oxide has the same effect whether they are put in by the ever been sold commercially. Its performance on pigment manufacturer or by the paint manufac exposure will prove surprising to those whose ex turer. Now that the public is thoroughly accus perience with LZ paints of high content of zinc tomed to titanium pigments in paint it would be oxide is limited to formulas such as A. much simpler and more reasonable if- the com In Table 2 the five formulas of Table 1 are posite titanium pigments were indicated on for recalculated in terms of volume, expressing the mula labels just as the composite leaded zinc composition of each ingredient in terms of gal oxides have long been indicated, namely, by stat N41698.44 ic ~< 001020 May, 1939 NATIONAL PAINT BULLETIN measure, developed several years ago at the Bu chemical derivatives. The first publicized use is reau of Standards, has come into, considerable use. for making explosives, suitable for warfare or for The first application of the process in the docu blasting purposes in peacetime. The nitromethane mentary field was by the National Archives of the used is not itself an active explosive, but after be United States, It was chosen as the best, and in ing reacted_ with formaldehyde forms a nitrafri- fact, the only feasible means of laminating the alcohol, which is the basis for nitration to a/om- \vast number of documents received by the Na pound comparable with nitroglycerine. tional Archives, which require such treatment. Nitroalcohols may also be used in coiphnction The process is speedy and has many advantages. with fatty acids to form emulsifying agents likely The sheeting is applied by means of heat and pres to find uses in polishes, of either the oilyor watery sure, no adhesive being used, and a homogeneous type. Market surveys indicate thkt ammonia unit is Obtained, as the cellulose sheeting is ac derivatives of nitroparaffins may command mar tually forced into the pores of the paper. The ace kets in numerous industries, due to their marked tate sheetingxused is very stable, has high trans reactivity, for use in the manufacture of synthetic parency and ^strength, is very thin, is easily organic chemicals. / cleaned with water, and is resistant to insects. Opportunity now exists for the organic chemist These are all properties that are particularly de to use the nitroparaffins and/their derivatives as sirable for documentary purposes. raw materials for industrial derivatives in great Four commercial Operators make a business, of variety. The field is wide, and at this stage ap laminating doeumentsNwith the acetate sheeting. pears to offer good prospect for a healthy new Two of these use only heat and: pressure; the other branch of chemical industry. two use an adhesive in addition. An adhesive " ' /' --Ind. 8idl. No. l/,e. permits lamination at lower temperatures and pressures, but care must bextaken that the ad hesive is stable, and that it will not cause deteri oration of the laminated paper. \ Because of the high stability and other good qualities of the acetate sheeting, as -shown in the Bureau's reports, it is also finding ^Considerable use in the form of envelopes for the protection of stamps and other kinds of sheets, where/amina- Sebacic Acid as a Plasticizer It appears as though B, 0. has another use be sides serving as/kn incentive for the manufacture of soap. Sebacic acid, an important constituent of perspiration/ is now manufactured on a com mercial scale, and is incorporated as a plasticized in certauysynthetics. The final product is said to be practically free from odor. tion is not desirable. A New Set of Chemicals Chemists have long pondered on how to utilise the chemical value of the paraffins--methane^ ethane, propane, etc.--the principal constituents / AS A MATTER OF POLICY The National Paint Bulletin does not usually, publish articles which are anonymous. However, to encourage candid, and hottest expression of opinion in controversial matters, tile Editor will respect the confix dflrtcje of any correspondenEteho prefers to have his ntune omitted from appearing in print. So, if yon have, any pet views or want- to "get sqihetkinff. off ' your chesty' just let us know about it; you will probably *$el better afterwards.--J. R, S. of natural gas. No chemical process has been > found of sufficient activity to break down tly inertness of these paraffins, to attach chemical groupings of controllable reactivity that woffid make them commercially useful;. The very nkme par-affin, "no affinity," was given on account of 4n exceptionally complete their inertness. (Englishmen call certain/liquid: petroleum products paraffin, and Americans call the solid wax of petroleum by this same,name, but this is not inconsistent,: since these, as/well as the line of _ Q X+0 + X 0 gases referred to, are all members /of the long series of true paraffins.) Initial compounds have Black Br Red Yellow now been made which may be handled in conventional ways to. produce a great variety of chemicals IRON X ID E S new to commerce. This has been made possible by the technique of nitration in' the gaseous form. LAMP BLACIS It is understood that Comniep6ial Solvents Corpo ration is to have a production unit in operation by METALLIC BRQWNS the end of 1939. w _ / The nitroparaffins' as the first reaction products OCHRES SIEJ are called* consist so fa/ of nitromethane, nitroethane, and four other individuals. These are UMBERS colorless, mild-odored/heavy liquids which boil in the useful range of/212-S00F. They are direct and and active solvents for nitrocellulose and for a wide range of synthetic and natural resins as well INERT FILLERS as for fats and/some dyes. Mixed with alcohols, \ they are solvents for commercial cellulose ace tates. Nitrdethane is a heat sensitizer which brings abojit the gelling of rubber latex; chlor inated nitroparaffins, on the other hand, have at C. K. WILLIAMS & CO. tracted Considerable attention as anti-gelling agents, useful in rubber cements. Easton * Pennsylvania The great anticipated use for the nitroparaffins is as raw materials for further chemical reaction, to produce a whole family or group of families of i i t c r r s r r) I eu S t: B a v VS XI r> tl li P ii h a: ci m J V v< i is i 0 s 0 s -0p s i+ ii + m FLB 001021 May, 1939 NATIONAL PAINT BULLETIN 9 ing the ingredients of the composite pigments effort to make paint formulas more easily under separately. Formulas C, D and E, which accord standable by the public. ing to the conventional formula label contain basic sulfate white lead and zinc oxide, were made in fact with cofumed leaded zinc oxide. The titan ium pigments might just as well be handled in It is pot always appreciated even by technolo gists that the terms "inert pigments" and "ex tenders" have a double meaning, namely, chemi cal inactivity and optical transparency. The two the same way, namely, by listing the percentages of titanium dioxide, and of barium sulfate, mag nesium silicate or calcium sulfate and letting the public forget that there are pigments with such strange names as titanium-barium, titaniummagnesium, and titanium-calcium. In connection with the resolution favoring for mula labeling adopted last fall by the National Paint, Varnish and Lacquer Association, the Sci entific Section published a special circular on "Nomenclature for Formula Labeling" that de serves more serious consideration by the industry than it seems to have received so far. It recom mends that each ingredient be reported separately and that ambiguous terms such as "titanium white" and presumably "titanium pigment", which might mean any one of the titanium pig ments or a mixture of them, be avoided. It also recommends that "inert" pigments be reported by their chemical names, which would preclude lumping them together under the names "inert pigments" or "extenders." Standardization and improvement of the nomenclature of formula labeling should prove helpful both to the industry properties were at one time nearly always con comitant, at least among white pigments but that is no longer true, Titanium dioxide is chemically inactive but optically very opaque whereas cal cium carbonate is optically transparent in linseed oil but probably is chemically aetive. In the in terest of mutual understanding it is desirable to avoid the terms "inert pigments" and "extend ers", using instead terms that clearly indicate whether the reference is to chemical or optical properties. For chemical properties suitable terms are chemically aetive and chemically inactive pig ments. It should be remembered, however, that chemical activity is by no means confined to for mation of soaps. For further details about the Forest Products Laboratory procedure for expressing paint for mulas in proportions, by volume reference is made to Industrial and Engineering Chemistry, Vol. 29, p. 1018, (Sept, 1937), The system leads to a "technical man's shorthand" by means of which the formulas of the five paints of Tables 1 and 2 can be expressed completely enough for most and to its customers ; it is to be hoped that this practical purposes in the following very concise circular will mark the beginning of a sustained symbols: TABLE 1 Formulas in percentages by weight- Formula A -- LZ55, p/nv 23, division Q. Designation Unit Pigment Vehicle Formula A Percent 62.6 37.4 Formula B Percent 67.2 32.8 Formula C Percent 68.7 31.3 Formula D Percent '67.8 32.2 Formula E Percent 64.4 35.6 Formula B--(LZSO)SO, p/nv 28, division N. Formula C -- LZ54, p/nv 271/2, division L. '* Formulas D and E-- Pigment composition : Basic carbonate white lead Basic sulfate'white lead Zinc oxide Titanium-barium pigment Titanium dioxide Magnesium silicate 50.0 ....... 50.0 ...... ... 60.0 30.0 10.0 . 23,0 , 27.0 50.0 -- 20.0 14.0 26.0 40.0 22.36 15.30 29,70 ........... 11.17 21.47 TL27Z,4, p/nv 28%, di vision L. The system of classi fication proposed by the Fqrest Products Labora tory for giving paint Vehicle composition: Linseed oil Bodied linseed oil Drier and thinner 83,46 16.54 86.76 13.24 89.87 10.13 82.6 7.3 .10,1 users the information 79.8 they need for intelligent 7.1 understanding of the 13.1 composition of paints a- TABLE Z Formulas by Volume according to the Forest Products Laboratory system of classification Designation Unit Basic carbonate white lead Basic sulfate white lead Zinc oxide Titanium-harium pigment Titanium dioxide Diluent allowance Opaque pigment Magnesium silicate Total pigment Formula A gallons 0.091 0.109 ..__ 0.200 ..... 0.200 Formula B gallons 0.125 .... 0.076 .... . 0.200 0.050 0.250 Formula C gallons 0.051 0.064 0,135 -- -... - 0.260 ...... 0.260 Formula D gallons 0,042 0.031 0,065 0.131 .... . 0,269 ....... 0.269 Formula E gallons 0.041 0.030 0.066 0.036 (0.095) 0.268 0.095 0.268 Linseed oil Bodied linseed oil Nonvolatile Drier and thinner Total, paint 0.660 ....... 0.860 0,140, 1.000 0.645 0.895 0.105 1.000 0.670 0.920 0.080 1.000 0.596 0,067 0.917 0.083 1.000 0.593 0.057 0.913 0.087 i.000 would describe the five formulas of Tables 1 and 2 in the following terms: Formula A--Type LZ with high eontent of white lead and very high eontent of zinc oxide, Division O. Formula B--Type LZ with high content of white lead and medium con tent of zinc, oxide, Di vision N. Formula C--Type LZ with high content of white lead and very high con tent of zinc .oxide, Di vision L. Formulas D and E^-Type TLZ with medium con tent of white lead and medium content of zinc oxide, Division L. !! >' /, NATIONAL PAINT BULLETIN May, 1939 FACTORIUM This is a: special department devoted to the interests of technical or business men who- do. not have the time to aid absorb the. mass of. available technical literature. ially, the following statements are a series of pertinent ch have been boiled down by your editor to a con- 3\residue, distilling off the unnecessary or less interestlinthiary discussions. Although the following ieforma- given\in only a few pages, it nevertheless represents a ensation of hundreds of pages of the recent voluminous of fhchnicah paint literature. It should he pointed out also, that tiiOse are riot intended to serve as abstracts, reviews or digests. The primary object is merely to state in con centrated. form, conclusions, of extensive investigations which have come to uur attention. Although we use great care in the selection of t-hestatements regarding their authenticity, it is difficult, of course/to assume any responsibility for the merit or validity of the statements. pigments and~Zd5% t6 3.3% phenol to give 793. The secret of gotuf varnish making, ac cording to Dr. Robert J, Mtiore lies in the proper stable dry mixtures, pastes or ready-mixed paints, dispersion of the oil resin polymerk Those con taining completely polymerized dispersions, un affected by oxidation, give\ excellent films. Resin wax dispersions of increased strength and moisture resistance can be madd, satisfactorily with halowax. Moore also has disclosed a method 797. The'rrpfhing of varnishes can be prevented by the use/of cholesterol and vegetable phospha- tides. Spine of the natural components of rub ber iat^x havc/also been found useful for this purpose. / for making ultraeonie dispersionV Surface 798. In ^Germany, it has been found that the forces, such as surface tension, play a, very im refractive index of emulsion vehicles is a very im portant part in colloids and emulsions. \ portant factor. For instance, it has been con cluded mat the luster of bronze finishes is affected, ' 794. Copper naphthenate is now the paint industry for a variety of being uVed in purposes\ A, /`flic hiding power of pigments is varied and the compatibility''wnth other materials is determined, solution of 20 % copper naphthenate in petrolei (bronze luster of Milori blue is especially af- thinner will control Merulius lacrymans, aj other fungi attacking wood. It can be used pdso ' by the refractive index. in termite control, for preserving shipping'/lags 799. H,ike nitrocellulose, chlorinated rubber and as a anti-fpuling composition in ship bottom ..aeds a plasticizer, but its range of compatibilities paints. Copper naphthenate is made by combin is much wider so that all the usual plasticizers ing copper with the naphthenic acids found ifi and even oils, and soft resins are effective. In petroleum. A uniform product is now on the general\it is not compatible with cellulose deriva market which is soluble in kerosene, tolnene^tur- tives or simple vinyl resins, and its solubility re pentine and in many other common^solvents/ lations make it incompatible with shellac, copal or any resin solubievonly in alcohol. Its paint 795. Red lead paints show a gidat decrease in negative potentials while uncoated steeK shows a decided increase. A steel rod/dipped' in water containing red lead and washed of/any visible traces shows a passive state/ Zin% dust acts as a reducer, while red lead /as aiy oxidizer. To gether they would act rather upon each other than upon the metal 'Surface/ Graphite is an inert pigment and acts well men mixed with red lead. products include thoskmade solely with synthetic plasticizers; oirhlends ;\pil-ree blends; and a va riety of varnished in which chlorinated rubber is only a minor ingredient. Yin the plasticized fin ishes, both plasticizer and, pigment should be chemically inert in okder toVutilize the extreme chemical resistivity of hMorinated rubber. High weather resistance is also achieved in these fin ishes, In the oil blends 'pigmentation must not Iron oxide does not have the lubricating proper exceed a critical value beyond which elasticity ties of graphite, hut/fe much cheaper and can be rapidly decreases. In the resin blends, those' with used with red lead as an anticorrosive. alkyd resins are outstanding, sriying such highly 796;. in Russia/new type paints are being made with albuminous binders, derived from oil seed press cake and/extrac/ion wastes. Promising re sults are alseZ expected with specially prepared water paints. To tnis end, about 98% of cellulosic material is removed from the finely ground elastic coatings that they can bemused oihmetal for stampings. Many of the commercial products are combinations of oil and resin blends. Among the chlorinated rubber primers, those with rectxlead have much faster drying time than led lead\in oil. Many coatings for special purposes are in proved by a small addition of chlorinatedNrabber/ press cake and ^fraction waste by sifting the Aside from high resistance to chemical attack residue and emulsifying with 5% to 10% sodium and good mechanical properties, the chlorinated hydroxide. The emulsions obtained from the rubber paints are useful for rust prevention, pro waste products of castor, soybeans, cotton, flax tective coatings on concrete and masonry, special and sunflower seeds can be mixed with suitable finishes on light metals and wood, paints for 91 Ti yea b>r tim hov old tial wh hat jot) per or ow OIK in ov< the me ap) lor ces gel wt tat ch< o> wi lot me tet sts wi ye to. no pti re a: gr m; sa or is It cn 31 FLB 001023 Painting Problems Answers by F. L. Browne Senior Chemist, Forest Products Laboratory Madison, Wisconsin T HE life of paint is limited to a few years; the coating must be maintained by applying more paint from time to time. From five to six times as much house paint is required, for renewal of old coatings as is consumed in the ini tial painting of new woodwork. Those who make and sell paint are in the habit of thinking of alt these paint jobs as. separate transactions, inde pendent of the jobs that went before or are to come after them. The house owner, to be sure, buys his paint jobs one at a time, but his real interest is in a coating satisfactorily maintained over a long period of years. Much of the misunderstanding and disagree ment about paint comes from failure to appreciate, that paint maintenance is a long-term matter, made up of a suc cession of paint jobs that must fit to gether into a harmonious, whole. Paint. maintenance is successful when it comes up to reasonable expec tations both as to continuance of the chosen decorative effect and as to cost. Owners' expectations, however, vary widely. Some, following tradition of. long standing, expect to repaint no more often than intervals of eight or ten years, Others, whose decorative standards may be more exacting, are willing to paint every four or five years. A negligible few may'be willing to paint still more often, Practically' QX one, however, expects ever to be put to the extra expense of completely removing old coating before applying a new one and any maintenance pro gram. that leads to such eventuality may he regarded as unsuccessful. All of the above expectations can be satisfied with good house paints now on the market, but no. one kind of paint is capable of satisfying all of them. It is idle, therefore, to attempt to dis cuss good paint in general terms--we must discuss it with reference to. the classifying paints, the paint industry kind of maintenance program for has not adopted it. which it is suitable. ''Moisture" Failures and Their Cure The Cure for Poor Paint Access to moisture behind painted Although the writer has rarely en woodwork is the cause of one large countered really inferior paints in the class of early paint failures. The mois cases of paint complaints he has exam ture may get in through carelessly de ined, he is told repeatedly by paint signed or erected joints in. the construc manufacturers and others that much tion, or by condensation of moisture inferior paint is made and sold. The laden air from inside of the house Federal Trade Commission and Better when it comes in contact with the cold Business Bureaus take action against back surfaces of the exterior wood notoriously bad paint from time to work, Trouble from condensation, has time, but they can deal only with paints probably increased materially in. re so inferior in quality that their sale is cent years because of the greater use a downright fraud. Paints that are ot thermal insolation, which makes the merely inferior in quality, but not back surfaces of exterior woodwork clearly fraudulent can be dealt with colder by letting heat escape from in effectively only by deafly .defining side, and because of provision of air good paint. Wien the regional lumber washing and humidification in modern manufacturers were preparing their heating plants. Condensation of this pamphlets on painting instructions kind is more troublesome in the north for insertion in bundles of bevel siding ern parts of the country, but in more they found that there is only one kind southern areas where studs are some of good paint defined in such a way times cpvered with drop siding without that it can be. discussed in general rec ommendations, That paint is. pure" white lead, commonly known as lead and oil. Other kinds of good paint are sheathing and heating is accomplished with inadequately vented open gas burners, condensation on or in the identified for sale by trade brand only, sidewalls or under the roof sometimes vary widely in composition, but- con occurs as a result of the large amount form to no standards by means of of moisture formed in the combustion which the various kinds, and grades of gas. can be recognized by the users. Condensation in sidewalls and attics, The Forest Products.Laboratory lias can be prevented by keeping moisture recently shown that it is perfectly from passing through the walls. This practicable to define good paints of all can be accomplished by the correct in kinds in such a way that they can be stallation of vapor barriers op the in set apart from inferior paints. In fact, side of the studs and underside of attic it is technically feasible to classify floor joists. In houses, already erected paints in. a logical manner. The pro two coats of aluminum paint on the posed "grading" rules, though tech interior surfaces of side walls and ceil nical in nature, are much simpler than ings under the attic make an. effective the various grading rules for lumber. vapor barrier over which other wall While some technologists of the paint decoration may be applied. Where industry recognize the desirability of moisture arises from open gas.bumers 36 September, 1939--N1 R E0 Xq 1 1 st 1 JX q1 N41698.45 FLB 001024 it a< b st w P tl a: tl c 0 s mV t: t: r a 1 r t lowing the same lines as the old central districts (there are exceptions of course), with very little thought given to the automobile or its effect. "Small business districts in them selves, providing for merchandise, services and amusement, will spring up during the next decade, providing beautiful parking facilities and all of the stores, shops, offices and theatres to which a person is accustomed. They will have proximity to the walking shopper as well as to the automobile. "We here in western New York' have attempted new developments in corporating the idea of parking,,and are planning others. In Ken/nore, New York, an entire block of land was taken and the buildings were/set, back seventy feet from Delaware Avenue, providing double-lane /parking in front, with the lot cdncreted, well drained and well lighted. This devel opment will house' a large Loblaw super market arm seven shops, the whole development being as complete a shopping unit as possible, "From our observation, we note that most people prefer to drive up in front of a building, get out of their cars and go into a store, rather than go to the 77 rear and then walk around. Front parking lot to the store, and back. In parking lots aregenerally much.hetter the Rochester development, a variety kept by the merchants than rear-lots, chain is now building and the com and are therefore mbre attractive.\A munity is rounding itself out, and front parking lot is much more cork, while the parking facilities will act as venient fat quick stops and quick pur \ a stabilizer, they are not ideal. chases, ywhich applies to Monday \ "We are attempting another devel- through Friday business. opthent now which will provide both "We have done another develop front, and rear parking, it being the ment in Rochester at Ridge Road and thougfitvthat the rear parking will take Dewey Avenue, where only rear park care of aRoverflow, which is particu ing was provided. In any such devel larly, important during heavy week- opment involving a large frontage aid shopping knd for theatre parking, your principal profit comes from the "In order to nave ideal parking fa shops, since the large stores bring the cilities, there shouM be enough area so customers and the small stores are that you will not have any need to more or less parasites, paying rent worry about congestion. The flow of based on the major attraction. We traffic in and out of your, development have noted that where only rear park should be free of all restrictions. To ing is provided, customers are inclined charge even a nominal sutn'-or require to go into the rear of the large stores, a customer to buy somethin^ is a re do their shopping, go back out the rear striction that keeps people away\Park- into their cars, and away, without see ing must be as free as water in order ing the shops in front; therefore, the to be the most successful. shops do not get the full benefit of the "Because you are providing conven major attractions and it hurts the ience in order to create habits, and in rental value. creating habits you are creating values, "In ordinary parking developments since merchants will pay rent in ac you do not always have the flow of cordance with the business they can pedestrian traffic up and down in front do, and their business is dependent of the stores--rather it flows from the upon the great god`Habit'." N1 R E0 Xq 1 1 J1 X <q 1 --September, 1939 3:5 vuimicu iifTt Tn "the ' broad ' rat outlook I think it is a good thing. would be advisable to,avoid this kind, of ad vertising in. the paint' industry; but it seems Jikplv that ,w, ,oan,,r>i'oneefl,to some rat'asnal WCHBe', "'a "titf or The voalv aminomuinhydroxide^ tNTTT.OTT) and the stmng hydi o ch'oric arirl-tHCI), in water solution gives an * leni rrarrioi, dne t,, 1,,-ff..li, qi. A,I FLB 001025 it should be carried off by means of adequate flues. . Much moisture is evaporated in houses during normal living operations such as cooking, bathing, laundry work,and the breathingof persons and plants. Families undoubtedly vary in their living habits that affect the amount of moisture evaporated and the amount that can subsequently es cape when the house is ventilated by opening windows. House owners should be taught that condensation on windows is an indication that the rela tive humidity indoors is higher than the house can carry safely with the prevailing temperature out of doors and that reduction of relative humid ity by opening windows and adjust ment of the heating plant is desirable until the condensation is re-evaporated. Tn northern climates storm windows are. necessary, whether or not the win dows are weatherstripped, both to save heating expense and to prevent con densation without limiting the house to unreasonably low relative humidity during cold weather. Fortunately the problems of mois ture leakage and condensation are be coming generally appreciated and at. least for new houses and some of those already erected, we now have effective means of keeping the woodwork dry. To be sure there remains the serious undertaking of educating those con cerned with the erection of houses and the house owners themselves, but there ' are reasonable grounds for believing that in time moisture as a large cause of unsuccessful paint maintenance can be eliminated. The Cure for Mistakes in Applying Paint Much, unsuccessful painting comes from faulty technique in applying paint. The most common blunders arise from the painter's very human desire to do the work with the smallest amount of expensive material-possible. In some cases in which the baitnds of safety are overstepped the painter was not intentionally dishonest, he was merely mistaken in his judgment or unfamiliar with the limitations of tlie material with which he. was working. It should be remembered that the painter's judgment is necessarily based on insufficient information because, except in the case of lead and oil, he does not'have practical knowledge ot the composition of the paint he is using, and there are no generally ac cepted standards of correct applica If the paint job (particularly the repaint job) goes wrong, don't blame it alt on the painter. "Mare complaints about paint jobs are caused by incorrect programs of maintenance than by poor lumber, poor paint, bad application, or moisture," The mam thing is a sensible program of. maintenance tion. Commercial paints differ in com position far too widely to conform to any general standards of. application, and since they are not recognized by classes, each paint presents a separate problem iti application. Often the painter is asked. t& apply a paint that came on the market long after he learned his craft and differs seriously as. respects application from anything he has been trained to use correctly. To be sure, directions for application are usually printed on the label on. paint containers. The painter is often chided for paying little attention to such directions, but when manufac turers' directions are studied, carefully in relation to the composition of their products it becomes clear at once that manufacturers' ideas of correct appli cation are just as divergent and illog ical as painters' practices. The Cure for Mistakes in Paint Maintenance In the writer's experience more complaints about paint jobs are caused. by incorrect programs of maintenance than by poor lumber, poor paint, bad application, or moisture. Neither the paint manufacturer nor the painter, as a rule, Ijas much control over main tenance, because the house owner (or his agent) generally decides when painting shall be done, how much work he is willing to pay- for, and often what: brand of paint, shall be. used. Efforts to attain more, successful paint main tenance, therefore, must take into ac count the necessity of teaching house owners how to space jobs'correctly and how to. choose the right lands of paints for their purposes. Many house owners have no definite plan for spacing paint jobs, and merely wait until the old coating goes to pieces before trying to renew it. In this group many have no intention of painting more often than every eight or ten years. Since we have no. white paints that can be relied upon to remain dur able for such long periods, those who follow such programs are more inter- N1 0 Xq 1 R At E1 JX q 1 --September, 1939 37 FLB 001026 ested in the ability of the paint to stand neglect well than they are in its dura bility. They want a soft type of paint that breaks up slowly by crumbling so that it does not look too unkempt dur ing the period of neglect and after neglect can be safely repainted with out expensive removal of the old coat ing. Pure white lead paint, if used exclusively, will behave in this way. and is largely responsible for the fact that so many owners are accustomed to maintenance programs involving long periods of neglect, WioST of the newer paints, however, are made to provide greater durability and superior appearance, which can he provided only by making harder paints that break up finally by cracking, curl ing, and flaking, and therefore cannot be neglected safely. Of course, prac tically all paints are advertised as wearing away slowly by chalking, leav ing a fine surface for repainting, and avoiding the defects of cracking and scaling, but such claims are made on the assumption that repainting will be done before the end of the period of durability and before, neglect begins; they do not mean that the paint is suit able for those who expect to let their coatings go through periods of neglect. There are two ways of successfully linking together the maintenance pro gram and the kind of paint for those with unduly long intervals between painting. One way is to convince the house owner that it will he worth his while to change his program to permit him to' use paints of harder type satis factorily. The other way is to sell him the kind of paint that will serve satis factorily in the program to which he is accustomed. To persuade him to buy a paint unsuited to the program he intends to follow, however, is simply to add one more to the number of those who are dissatisfied. A large propoffhjn of paint com plaints that come to the writer's atten tion occur on houses that have been painted at reasonable intervals with good paints well applied on woodwork that remains dry and yet the paint fails far too soon and often in a manner not characteristic of the normal be havior of the paint last used. In all these cases, however, two or more paints of distinctly different composi tion have been used for successive paint jobs or successive coats in the. same paint job. Some of the combina tions show up repeatedly in different complaints. Some well known com binations frequently occurring in com plaints are white paints over yellow ochre primer or paint, almost any house paint over clear varnish, and white paints over full color paints like deep red, brown, green, or black. Un fortunately technical exposure tests in the past have been confined chiefly to initial paint jobs or repainting with the same kind of paint, but some past records of tests involving combinations of paints differing in type have' been discovered, the outcome of which re veals the same abnormalities of be havior found when these combinations of paints are seen on houses, The evidence that good paints, are not all compatible with one another, is now conclusive, hut there is much dif ference of opinion about the serious ness of the problem. Some hold that incompatibility occurs only in a few extreme cases such as those named in the preceding paragraph. The writer believes, on the basis of both observa tions of houses and of technical ex posure tests, that the principle of incompatibility is very much more far reaching. Combinations of white paints, differing materially in content of zinc oxide, for example, have been observed to deteriorate more rapidly and in a less satisfactory manner than corresponding coats made up entirely of either one of the paints separately. A great deal of research will be neces sary to establish all of the ramifications of the principle of compatibility, but when it has been done many of the present mysteries of house paint main tenance will be cleared up, A large proportion of the Forest Products laboratory's research on painting is now directed toward this problem. Until future technical study dis closes the extent to which paints may differ in composition and still remain compatible, the conservative practice in maintenance is to start out with a good paint when the woodwork is. new and thereafter maintain it at proper intervals with paint of essentially the same composition. Switching from one land of paint to another is doubtful practice unless the particular combina tion so produced lias been tested or found satisfactory by previous expe rience, Certainly those combinations of paints that have frequently led to difficulty should be avoided. At the present time the only white paint that is used consistently by large numbers of house owners is pure white lead because it is the only paint recognized by type as well as by manufacturer's brand. In the writer's opinion the high regard in which white lead paint is held by so many good painters and paint users is due largely to this, con sistency in its use. When white lead is applied over paints of other kinds it often fails prematurely and in an ab normal manner, indicating that it is just as subject to the requirement of compatibility with previous paints as are paints of other kinds. The Heed of Classification of Paints The cure for bad programs of paint maintenance, therefore, lies in a classi fication of paints that will make it pos sible to teach house owners how to buy the right kinds of good paint for their purposes and how to get out of the paints they buy the good service of which they are capable. Consideration of the causes of un successful paint maintenance and con sequent loss of public confidence in painted exterior woodwork shows, that our most serious troubles have come not so much from jerry building and inferior paint as from efforts to im prove building methods and paints that have made the situation more compli cated and unduly technical for crafts men and laymen. Thermal insulation and modern heating plants are distinct improvements over past practices but, unless appropriate precautions are taken to control condensation on cold parts of the structure, they tend to increase the number of houses in which moisture leads to early paint failures and other difficulties. In a similar way modern developments in .paint have given us better paints than we ever had before, but there are now so many kinds of good paint on the market and they vary so much in com position, manner of correct applica tion, an4 compatibility with one an other that painters and house owners do not know how to use them all cor rectly. Merely offering the public good paints that are capable of giving successful service is not enough to re - establish confidence in painted woodwork unless we likewise, make it possible for each good paint to be so. applied and maintained that it will give the good service of which it is capable. To accomplish that purpose the tech nical complexities of application and maintenance must be simplified suffi ciently to bring them within, the com prehension of craftsmen and house owners. 38 September, 7939--N1 0 Xq 1 R 1 E1 JXq 1 Some Causes and Cures for Painting Troubles by F. L Browne Senior Chemist/ Forest Products Laboratory Madison, Wisconsin WQ q paint coatings on wooden walls of Many of them have been cheaply built houses, but on the houses fail unreasonably soon, say in less than two years, other hand many have been relatively expensive houses after they have been applied, the failure is. almost always on which every effort seems to have been expended to due to certain circumstances called, for convenience, build, properly. "abnormal conditions of exposure.'' Failure under such conditions, is not a question of the kind of wood upon which the coating is applied, the quality of. the. paint, qr the craftsmanship of the painter. The staff of the Forest Products Laboratory has observed the troubles in ques tion on all of the kinds of wood commonly used for house siding, with paints of all the varieties generally accepted- as of first quality as well as with cheap paints, In practice, abnormal conditions of exposure almost always involve, as an essential factor, the access of large amounts of moisture to the unpainted sides of the boards. The conditions are greatly aggravated when the tempera ture on the unpainted side is materially higher than that on the painted side, as is the case on the outside walls of heated buildings during cold weather. Causes of ab normal exposure conditions that have been observed re and rarely has there been any possibility that poor work peatedly may be classed as follows: manship on the part of the painter was responsible.. The Type A.--Rain mater, seeping through leaky joints left fault lies in the. abnormal conditions of exposure, and. by. poor carpenter work or faulty design. the only certain cure is to. search out the abnormal condi | tions and change them into normal ones. Attempts to 1. Poor fitting between siding and corner boards, between sid ing and casings of doors or windows,, and between siding and overcome difficulties of this kind by using special prim drip caps over window and door headers or sills beneath such ing paints, special paints, special liquids or unusual openings. I amounts of liquids for thinning ordinary paint are, in 2. Joint's in window frames forced open to permit swollen the writer's opinion, of very doubtful merit. sash to move freely. When the sill and head of the window frame are housed into the jamb, this is an easy way to make the The most common form of paint failure under abnor mal conditions of exposure is that known as blistering sash move freely, but it leaves an opening to admit water. If the jamb is housed into the. sill and. head, the joint cannot be forced open in this way. and peeling. The failure, however, sometimes appears in 3. Omission of metal flashing or, its incorrect installation over other forms that at first glance do not seem at all related doors and windows or at the junction between porch or dormer to paint blistering, such as paint scaling, some kinds of roof and side wall or chimney,' discoloration, of coatings, and blue stain in the wood be neath the coating. Sometimes blistering and peeling oc cur along with the other defects. All such troubles with painted wood may well be discussed together because of their common origin. Present in.formatio,n about the effects of abnormal con ditions of exposure upon paint coatings is based chiefly upon, examinations of occupied buildings, which have 4. Incorrect junction, between shingle side wall and water table where the upper part of the side wall is shingled and the lower part sided. This junction should either be protected by metal flashing or the shingles lapped over the water table- .carefully to see that no openings are left through which rain water can gain entrance. 5. Seepage into the joint between porch column and plinth block or porch floor. 6. Leaking roofs, eave troughs, qr down spouts when so lo cated that the water gains access to the interior of the side walls. given trouble. The staff of the Forest Products Labora tory has been called as consultants in such cases for many years. In addition a limited amount of laboratory 7. Frozen gutters failing to carry off the water from snow melting on the roof and letting it back up beneath the shingles, to gain access to the interior of the side walls. experimentation has been done with miniature "houses" Abnormal exposure conditions of Type A may occur wanned and humidified inside and set out of doors dur on either heated or unheated buildings and, with the ing cold weather. Many characteristic paint defects have exception^of No, 7, in any climate. However, heating the thus heen reproduced under partially controlled con interior of the building during cold weather tends to ditions. aggravate the resulting difficulties with paint coatings. Most cases of paint trouble due to abnormal condi The only sure remedy is to locate the leaky joints and tions that, have been brought to the attention of the For repair them until they are water tight. est Products Laboratory have, been on widely scattered Type B.--Moisture originating within the. building and houses whose neighbors experienced no such difficulties. carried by air circulating within the hollow outside walls. 42 October, J939---N1 R E0 Xq 1 1 1 JX q1 N41698.46 u at i \ tfei d a 0 i} I f 1 1 1 | I | 'S This five-room American Colonial 3one in the cottage style, this month's NATIONAL REAL ESTATE JOURNAL Plan Service design, has but 15,310 cubic feet. It is smaller than most houses done hy Architect Willard Walker for the Plan Service series, yet its rooms, because of their good proportion and convenient arrangement, are thoroughly adequate for the family of good taste and modest means. N1 R E0 Xq 1 1 st 1 JX q 1 --October, 1939 % 41 4 \ ttafeUHM Wi 'tUiWV ij'V _ foTCscc some tonflict but in the broad i'll cutloo\ I thank it is a good thing*. ralJv. the Qiat*ei of uiint coTiMritihiluv brush," 07* ancT^eTike, and I thinfL it would be advisable to^ avoid this kind of d- i vertising: in the paint' industry; but it seems .w^vscau. proceed ,jfcOc same ^rat'fcnal lon<l<-, { a fc-dlt of the ammonium hydroxides fNlLOH) aid the sUonj*; hydro- chloric acul-fHCl), m water solution gives an aci^ reaction due to hydrolysis. An FLB 001029 ML- When moisture laden air comes in contact with surfaces at sufficiently lower temperature, water condenses, 1. Attempting to hasten the drying of wet plaster or other building moisture by heating the interior of a building under con struction without adequate circulation tq carry off the moisture laden air. New buildings should be dried by circulating fresh air through windows and doors. Marked difference in tempera ture between interior and exterior permits water to distil, from , plaster to sheathing and siding through the hollow side walls. By leaving temporary openings at the top and bottom of the air spaces between studding, enough circulation through the side wails can be insured to prevent such action while the building . dries. 2. Designing parts of buildings in such a way that stagnant air spaces, are enclosed by wood walls within which the air may become -moist and wanner than the outside air. Porches built beyond the foundation with skirting extending down to the ground and no provision for ventilating the enclosed air space are common causes of trouble. Hollow ornamental walls extend ing beyond the foundation and hollow columns with leaky joints admitting rain water at the bottom require ventilation, 3. Lack of ventilation in unused attics. During cold weather water may condense beneath the. cold roof and drain down, toward the cornice- If the top course of siding is placed below the frieze board the water' is directed between siding and sheathing, coming directly in contact with the backs of the painted clapboards. 4. Failure to secure a water-tight basement. Building in soil that is not adequately drained and using basement walls, and floors that are not waterproofed may result in a damp, basement and. a circulation of the -moist air through the hollow side walls of the building to condense behind the siding. Plumbing leaks left uncorrected may also produce this result, 5. Activities within the building that humidify the air. The bathrooms and. kitchens of dwellings tend to show blistering and peeling of paint from their outside walls sooner than other rooms. Frame buildings, originally designed as dwellings, when used for purpose's like laundering often give rise to severe blistering and peeling of paint,- THE channels of circulation for air within the hollow exterior walls of frame buildings are controlling factors in abnormal exposure conditions. The subject has not yet been studied carefully and much remains, to be ' learned about it. In general the direction, of movement of air enclosed in the space between lath and plaster on one side and sheathing and siding on the other is upward along the warmer side and downward along the colder one. When the building is being heated during cold weather, the warmer side is the lath and plaster so that the upward air current moves along that side until it meets an obstruction, which may be a plate or a fire stop, where the air current is deflected and starts down ward along the colder sheathing and siding side. This downward current of air is likely to circulate through the joists in the sheathing and building paper (even though waterproof building paper is used) and to pass out between boards of siding. The escape of air between clapboards may he helped or-fliindered by wirxd blowing on the outside wall according to the angle at which the wind strikes the wall. In cold weather the temperature at the back of the siding where air is escaping may easily be below the dew point even though the air may have had a low rela tive humidity when it first entered the hollow side wall from the interior of the building. Thus air chilled from 70 F. begins to deposit its moisture as water or ice at 32 if the initial relative humidity was 25%, at 15 if the initial relative humidity was 11%, and at 1 if the initial, relative humidity was 5%. Since the coldest sur faces. in the side wall with which the circulating air may come in contact are offered by the: back of the siding and the front of the building paper, these are often the fa- . Blistering and discoloration of white lead paint (lower panel) and of a high grade prepared paint (upper panel) produced in laboratory experiments on "minia ture houses." Both troubles are due to excess moisture points at which condensation sets in. The amount of the condensation will depend upon the amount of cir culation and will naturally be greatest near the points in the side wall where the upward current of air is deflected by a window frame, plate, or fire stop so that the air starts its., downward course along' -the sheathing and sid ing side of the wall. The effects, on paint coatings of condensation of moisture behind: the siding are, commonly found most marked on the parts of the'walls correspond ing to. the points of deflection of the air currents. The fact that the effects of moisture condensation are often most marked near fire stops should not be regarded as an argument against the inclusion of fire stops in frame buildings. Fire stops are desirable, often neces sary. Their omission in a, building in which trouble from moisture condensation was experienced would not neces sarily overcome the difficulty, though it might shift the location of its most marked development. Forms of Paint Failure Under Abnormal Conditions Failure under abnormal conditions may appear as blistering, peeling, or scaling, in which the coating is re moved bodily from the wood, or as a discoloration, which mars the appearance of the coating. The discoloration may be due to substances leached from the wood by water, substances carried by water from other places Na t io n a l Re a l Es t a t e Jo u r n a l --October, 1939 43 FLB 001030 within the structure, or blue-stain fungi growing in sapwood beneath the paint coating. Blistering, Peeling, and Sealing The characteristic form in which paint coatings fail under abnormal conditions is blistering and peeling or scaling, Blistering always precedes peeling, though the trouble often escapes notice or fails to arouse anxiety until the peeling is well under way. From their shape it is obvious that blisters are due to a fluid pressure be neath the coating forcing it away from the surface. When observed soon after their formation, blisters are sometimes found to be hollow, sometimes filled with water, hut if the blistering conditions continue they al ways become filled with water. If the wood is of a kind that contains colored substances soluble in water the water hi paint blisters is. colored with them. Sometimes water soluble extracts from the wood dp not become highly colored until they break through the 'coating and come freely in contact with air. Deposits of (such substances over paint blisters often look like resin xudiiig from the wood. The mechanism of the movement of water through wood and the development of pressure behind paint coat ings is still obscure, but the following considerations are ,helpful in gaining an understanding of the sort of forces ghat are at work: From half to more than three-fourths fef the volume of a piece of dry wood: is air that is en closed in the cavities of the wood. Ordinarily this air remains at atmospheric pressure because the cavities communicate with each other and with, the surface through, the openings in the pit membranes, but as soon as the wood becomes wet and there is free water in the cavities, the minute openings in the pit membranes ba ft Paint scaling within a year after painting, in a house examined by experts of the Forest Products Labora tory. The trouble was caused by condensation of moisture behind the siding when the interior was warm and the outside cold come covered with films of water which can be dislodged only by high pressures. It has been shown that pressures of approximately 20 to 40 kilograms per square centi meter are required to force air through wet wood. Once wood begins to hold free water, therefore, its enclosed air is effectively trapped and the pressure acting on the air may rise above that of the atmosphere. Increase in pressure in the trapped air may be occasioned by rise in temperature, by evaporation of some of the free water, or by displacement of air by further amounts of free water. While still turgid or filled with water, paint blisters, can be broken easily and the coating peeled off though it does not necessarily peel of its own accord. As the abnormal conditions give way to normal conditions and the wood dries, the blisters often shrink back into place so completely that the coating may seem to be as sound as ever. The good appearance is deceiving, however, for a few months exposure under norihal conditions may lead to scaling. Since the coating is now thoroughly dry and somewhat aged it is no longer tough and pliable, but is hard and fragile, so that the failure is of a sort easily confused with paint seating under normal exposure. It often happens that scaling is the first sign of failure that comes to the houseowner's notice because the stage of blistering occurred during cold weather when he did not inspect the painted surfaces very carefully. In scaling, the pieces of paint coating that become detached may include the entire thickness of the coating so that the wood beneath is left quite bare, or the separa tion may take, place .between coats of paint, leaving the oldest coats- still in place. In general, intercoat scaling is most likely1 "to be encountered on repainted surfaces, the newer coats scaling from the older ones, though it is occasionally seen on surfaces painted for the. first time, especially if the first coat of paint differs markedly in composition from tire others or if the first coat was allowed, an exceptionally long time to dry before apply ing the others. . The susceptibility of paint coatings to blistering and the size of the blisters' formed, vary materially with a number of factors of which one. of the most important is the age of the coating. Coatings blister most easily soon after they have been, applied and hardened. At that age the coatings are very pliable and the blisters formed are likely to be numerous baf small in size and sharply rounded. If the coating has time to age and become less pliable before abnormal moisture conditions, arise it does not blister as quickly and the blisters are less numerous but larger in size and less sharply rounded. Blisters have been observed that were many inches across and the coatings could be peeled off in strips, several yards in length. Coatings that reach an advanced age before abnormal moisture conditions, arise become too. hard and unyielding to bulge out into rounded shapes recognizable as blisters, but their grip upon the wood may neverthe less be broken so that failure promptly takes place by cracking and scaling. Very old coatings that are chalking or checking deeply or cracking badly do not seem to fail in the manner characteristic of abnormal moisture condi tions; it may be that they are top readily permeable to vapors, for pressure to develop beneath them, or perhaps they do so. fail, but the failure is indistinguishable from. (Please turn to page 54) 44 October, 1939--Na t io n a l Re a l Es t a t e Jo u r n a l let, ilin-t "in the bi u ul `X * and tuC t! ii 'safi,"' ot th" weak ammonium (KB.OTH and the stione hydro- , tilt in 30 daysa ANY SIZE /ANYTYPE have faithfully paid their rent and their MBs, but who have, not been able to gather togethgiPa stake for a downpayment. Outside u~itBtjdiate profit^motive we believe it is our business and dutyHQnutalf people in homes who can afford to pay for them- W<l-ielieve that a nation of home owners is a stronger and more'stable nation than one of renters could eveiribe, arid at the saJne^Utne the plan, malting home ownership more general, offers^oaeof the most effectiw'weapons against social unrest. ^ Durina-the October National Convention our commit tee wfirtle happy to show visiting Realtors, not only our particular project, but what is being done throughout Southern California under the Title I program. makes vacant Some Causes and Cures for Painting Troubles (Continued from page 44) - f*sy t( Of course you bkve vacant! homes on your list--for sale or for rent. But how often have you had the experience of showing a good prospect everything on your list--without making a sale! Nothing met your prospect's requirements. This need not happen any more. Now you can sell a vacant lot and guarantee to have a finished house on that lot--in not more than 30 days. You can guarantee that the house not only will be ready foAoecupancy, but that in every detail it will fit you/ prospect's needs and specifications. It will he a house he/will always be proud of--a house that will stay "new" longer--comfortable to live in and eco nomical to maintain. The house ill be eligible for F.H.A. Insured Mortgage Loan. The Precision-Built method of construction is revolution ary, But it is thoroughly tested- $33)00,000 of PrecisionBuilt Homes have been erected within the past 3 years. You work with your local architecr-W from our archi tect-designed plans.. You work with local lumber dealer, local contractor and local labor. All materials are stan dard, quality materials--bought locally You help your community, while you are building your own sales. We invite hoa to write today for the full facts. You need to know about this up-to-the-minute, fully tested source of new/profits for you! t' O fVl A S C T E COMPANY paint flaking or scaling under normal conditions of ex posure.. Paint mixed with a high ratio, of pigment to linseed oil, which is accomplished practically by substituting turpentine for part of the linseed oil (not by merely .adding turpentine), is more resistant to blistering and finally forms fewer, though larger blisters than similar paint mixed rich in linseed oil. It is good practice to mix paint rich in pigment because it improves, the ap pearance of the coating and makes, it last longer. Sub stitution of bodied, linseed oil or of some kinds of var nish for`part qf.the linseed oil in paint also increases the resistance of coatings to blistering. The addition of var nish to paint by paint users, however, is not to be recom mended without competent technical advice in the selec tion of the varnish because, most varnishes are unsuited for such use. The most resistant paint to blistering so far tested at the Forest Products Laboratory is linseed oil paint made with pure basic carbonate white lead, mixed with a high ratio of pigment to linseed oil, and allowed to age several, months before subjecting it to abnormal moisture conditions.. Moreover on houses painted with, .white lead-paint that have been brought to the Laboratory's attention-.because of abnormal moisture conditions the complaint has been about discoloration more often than about blistering or peeling. It must, be emphasised that, although the composition of the paint does, affect the ease and form of blistering, all good paints are subject-to failure under abnormal moisture conditions so that the only certain remedy for .such troubles is removal of the faulty conditions-. The kind of wood painted is likewise of little practi cal significance as far as paint blisterings is concerned. The Laboratory has seen badly blistered paint on all . kinds of wood commonly, used in building and. has made paint blister experimentally on all woods that it has tested. No differences have been found between wood species in the case of blistering or in the form of the blisters. Within any species, however, some boards or parts of boards seem notably less, subject' to blistering than others. In general paint blisters more readily over heartwo.od than it does over sapwood, under the condi- 54 October, 1939--Na t io n a l Re a l Es t a t e Jo u r n a l Building $3,000 Houses with Title I Financing (Continued from page 31) prospective purchasers, This enlarges the operative buildrs' field considerably, and in conjunction with a iotseHing project such as ours, developer and contractor working hand-in-hand, it offers as nearly perfect a set-up as has been devised to date. This provision is especially valuable mumbling us to have a few "samples" on hand instead of one Our firm, does not handle the construction of the house itself; we merely acf'-as agents for a contractor working exclusively on. houses we have sold. We sell the building job, pre-built, in conjunction with the lot. We must, of course, see to it that all jobs, give satisfaction and this is why the homes are built under the supervision of the Builders' Control Service. This'outfit is in. position to. give prompt attention to the job in hqnd so that the work is not delayed and is properly performed. Building thirty or forty houses at a time makes this\of utmost im portance, \ At the time the purchase agreement is made up we see that the Certificate of Conformity of the Federal Hous ing Administration is properly filled out and signed, as well as plans and specifications, credit statement, anchcontraot with contractor being properly drawn and signs We also accept, from the prospect, a fee of $20, half of which goes to the Federal Housing Administration and which we hold subject to acceptance of the deal by the lending institution, and the other half to the bank; all to be returned in case of failure to qualify. We also, will hold the lots, when necessary, for a rea sonable length of time until the necessary funds are gathered, together to make the down-payment and take/ care o f the initial charges. We see a definite need for housing of this type and are willing to. risk our lots because we believe the/pro gram, under the revised Title I plan, is sound,' practical and of real service. What the Buyer Gets for His Money The figure quoted for the entire cost of the project as it is delivered to the purchaser cpvers/tot, and twobedroom house, garage, incinerator, cement apron from garage to paved alley, public side walk, curbing, as well as provision for all utilities brought to the structure ready for use, such, as sewei> light, -water, telephone, and gas. The model house used for^.demonstration purposes shows exactly what is included/m the quoted price. Land scaping, fences, drive-ways/or walks from kitchen to garage, etc., have not. begn installed as they are not included in the price quoted. We found this saved con siderable. confusion andaefinitely eliminated mis-understandings as to. what the buyer was actually paying for. He gets exactly what he sees, no more, and no less. The contractor is willing to install extra things for cash but most buyers, do the work themselves. The neighbors help one another inrdoing this work. Title I, Grass 3 allows for quantity production of qual ity .homei^Tm terms which the low-income groups can afford to pay. It brings into its fold those persons who Marlite bathroom installations---tike this--create a favorable impression 'with prospects. A damp cloth keeps its glass? smooth surfabe gleaming. Living rooms,resplend ent in Marlite Genu ine Wood-Veneers and. *Carstenite panels at tract a higher type cli entele . . . command higher, rent. When used in modernizing commercial properties these materials impart added, refinement and individuality". . . help to attract new tenants. Avoid vacancies in Residential and Commercial properties by mod ernizing with Marlite. Marlite comes ia wall-size panels, that any good carpenter can cut to size, economically--applying: right over present walls in just a few hours--not days. Over 10Q\calors and patterns give unrestricted choice in selecting the type of wall treat ment desired. Increase the salability and rentability of youk proper ties by uring Marlite l See our Catalog in Sweet's 11/33 for complete product information. Write for FREES hooklet ! \ *Carstenite is the trade name of the ra-tOj unfinished panels. MARSH WALL PRODUCTS, Inc., 107 MarshPlace,Dover See Marlite Exhibit at Nexo York World's Fair, ffome Building Center Na t io n a l Re a l Es t a t e Jo u r n a l --October, 1939 tlO; cor me hoto cai bu t> ta: 1; ps m bi in at cc re si ti .fc w ti n o a n s a a t \ c f FLB 001033 See America's largest and most p Spular home financing agency--see your local Savj igs or Build- ,g and Loan Association J Recommend this friendly, rei f-tapeiess, fast rce of home loans to people v ho build, buy, iodel or refinance. It's easy to understand. It assures lasting satisfaction ! SAYINGS OR BUILDING AND &)AN ASSOCIATION When you support our Local Sayings or Building and Loan Association -You help local business! Look over page 57\ Hie National Beal larket race TWusands of eyes are focused on/it every month. It/s an ideal spot to direct your sales message to the most repre sentative 'Real Estate fi\ms in /the country. If you invite other brokers' co operation, use the NATIONAL REAL ESTATE MARKET PL/\CE to advertise-- Business and Industrial Properties Estates Resorts Farms and Farm Lands Acreage--Lots Suburban am Country Properties1 56 or another on any wood. Moreover, the warei-solublc extractives of redwood and western red cedar give them desirable properties, for the durability of their heartwoods against decay is known to reside in the extrac tives present. Under normal conditions of exposure both woods hold paint coatings especially well and there is good evidence that the extractives exert a favoi able in fluence on the life of the coatings. Discoloration of paint with extractives from redwood and western red cedar is usually more marked on some boards than on others. In part this may be due to differ ences in the amount of extractives in the boards or to their concentration near the surfaces of the boa d-> dur ing drying, but it probably is due still more largely: to details in the construction of the house that make the abnormal conditions more pronounced in some spots than in others. For example, both blistering and discoloration - tend to. occur near windows or doors or just outside oi plates or fire stops in the house walls. Abnormal conditions of a kind that permit water to seep out between clapboards and run over the paim rd surface are likely to produce discoloration even on woods other than redwood or western red cedar because 1 lie water may leach colored substances from building paper or composition shingles, or may carry dirt and deposit it upon the painted surface in irregular patches. Certain fungi grow in moist sapwood of practicahv all species of wood and stain it dark blue or black. Tin. defect is known as "blue stain." Like all other fur si, blue stain organisms can grow only in moist wood. When infected wood dries" the fungi stop growing and remani dormant, though the discoloration persists, Sapwood that has. become blue stained during seasoning may be painted without danger of the stain coming through the paint, provided that the wood subsequently remains, dry. But if abnormal, conditions arise so that, the wood again becomes wet the organisms begin to grow once more and will penetrate through the coating, bringing the stain into view. The fact that a piece of sapwood is. bright before painting does not prove that it will not blue stain if the wood later becomes, wet because it may be infected even though the fungi have not developed far enough to reveal the cqlor. There is no evidence thaf the composition of the paint has any influence on the facility with which blue stain penetrates the coating under conditions, permitting the fungi to grow. Blue stain may occur in the sapwood of any species. A few species with naturally durable heartwood contain no. sapwood in the highest, grade in which the lumber is. sold in commerce. In all but the highest grade of these species and in all grades of other woods, there may be some sapwood. The proportion of the boards of com parable grade in different species in which sapwood may be present varies widely because some kinds of trees contain more sapwood than others in the parts of the logs from which the select grades of lumber are cut. Blue stain coming through paint may be distinguished from mold and lichen growing on the coating itself by the fact that blue stain is confined'to the areas imme diately over sapwood and the color is revealed deeply imbedded in the wood when the coating is scratched away with a penknife. October, 1939--N1 R E0 Xq 1 1 J1 X q1 Te c h n ic a l Bu l l e t in NX . 804 Ja n u a r y 1942 Classification of House and Barn Paints As Recommended by the United States Department ofAgriculture Un it e d St a t e s De p a r t me n t o f Ag r ic u l t u r e, Wa s h in g t o n , D. C. N41698.47 FOREWORD The enormous quantity of paint used on wooden farm buildings accounts for the definite interest of the Department of Agriculture in developing the best methods of selecting and applying paint and maintaining painted surfaces. The va riety and complexity of the paints on the market and the inability of the ordinary user to understand the statements of paint composition printed on the container labels are impedi ments to intelligent paint selection and use. This bulletin, which will be followed by other publications dealing with paint application and maintenance, describes a system of classifying paints by groups, types, and grades. It is based on principles familiar to paint technologists and some paint users. The system is the result of many years of research on the painting of wood by the Forest Products Laboratory of the Forest Service. Its adoption by manufac turers will allow a decided simplification of the technical statements on paint-container labels, and will make it pos sible to tell paint users more clearly and effectively how to identify the many kinds of paints on the market, what the characteristics of each kind of paint are, and how each should be applied and maintained. The classification system places no limitations upon the formulas used by paint manufac turers, and leaves the manufacturer complete freedom to change and improve his formulas at any time. Its adoption will provide a basis for the more intelligent selection and use of paint. Acting Chief, Forest Service. FLB 00103 a wooden farm the Department of selecting and faces. The vamarket and the ie statements of bels are impedi- her publications nee, describes a ies, and grades, ichnologists and f many years of forest Products on by manufae>f the technical ill make it posectively how to arket, what the low each should n system places paint manufacete freedom to i. Its adoption Section and use !& , Forest Service. Technival Bulletin No. 804 January 1942 m Classification of House and Barn Paints As Recommended by the United States Department of By F. L. BX q Senior chemist, Forest Products Laboratory,*1 Forest Service CONTENTS' Page Page Introduction_____ 1----------- -------------------------- - 1 Calculating classification from paint formulas-- Whyclassification isneeded<______________ 1 Continued. Clarification outUned____ --_______ 3 Volume analysis--Continued. Use of classification...... .................--............. 5 Diluent allowance for. very opaque pig fiftlfnilating riftssiffoatinn frompaint formulas-- 7 ments............................---.............. 16 Forms ofpresentinglabel fonnqlas................ 7 Tintedpalnts................--*_______ ___ 19 Example 1,variation A..............- 8 : Colorecfcpfgnieat paints.;.__________ -- 20 EjcamEdal, variation B.-v........^------*-- 9-' Example 1, variation C---------------------- 9 35xample2_.:;,_..................... -___ *---- to Volumcanalytis----- -------------------------- Determining theclassification______ __ 21 Paint groups.............................--.21 Paint types--------- ------------------- ... 22 A10mbPigauinittiegsraidnelsa.b..e..l..f.o..r.m. .u>l.a..s.._.._._. _--.--______________ 24 26 Prepared paints. r.............. -__________ 10 Summary...________________ .... 34 Paste andsemlpaste paints......................... 15 Literature cited............................ 35 4WQ INTRODUCTION !! C1 I N0 ~0 _ 1 0 Xq s The need for classification arises because methods of selling paint either afford the user little of the knowledge of paint composition that is desirable for its intelligent selection, application, and main tenance, or require him to master far more technical detail than is at all necessary {19, p. 6).2 Most paints are proprietary products sold under the manufacturer's trade-mark or brand but, like many other products of commerce, conforming to no generally recognized standards of composition or performance. If paint is bought by brand alone the buyer is not in a position to know of the many kinds of paint available, some of which may be more suitable than others for his purpose. The manufacturer, on the other hand, supplies the paint without adequate knowledge of the individual's needs. This lack of mutual understanding between maker and user of paint gives rise to unsatisfactory paint service, as has been pointed out elsewhere {6, 8). Directions for application are printed on the labels of most proprie tary paints, but the limited space available makes such directions seriously inadequate. It is not possible to compress the craft of 1 Maintained by the U. S. Department of Agriculture at Madison, Wis., in cooperation with the Uni versity of Wisconsin. 1 Italic numbers m parentheses refer to literature Cited, p. 35. 1 2 TECHNICAL BULLETIN 804, U. S. DEBT, OP AGRICULTURE painting into 500 words. Even during apprenticeship or in voca tional schools painters cannot be taught adequately the necessary craftsmanship when they do not know the composition of the paints with which they work or why some of them require different pro cedures. Users' need of knowledge of the composition of paint was appre ciated as long ago as 1905 when the State of North Dakota required by law that proprietary paints, unless composed wholly of white lead, zinc oxide, linseed oil, turpentine, and drier, bear a statement of the formula on the label {16; 19, pp. 188-188). This and a few similar laws in other States are still in effect. It now seems to be widely recognized that such laws have raised the general level of quality of the paints sold in the States in which they prevail {16,17) and prob ably in the rest of the Nation as well. The National Paint, Varnish and Lacquer Association now urges its members to print the formula on the label whether or not the law demands it {1, 2). Most house and ham paints now on the market in the retail trade bear the formula on the label. Formula labeling, however, though it undoubtedly has proved helpful, has not provided the kind of knowledge of paint composition needed for intelligent selection, application, and maintenance of paint by the user. Those experienced in dealing with property owners' complaints about unsatisfactory service know that poor quality of the paint is a relatively unusual cause of difficulty. More often trouble arises chiefly from mistakes in the use of paints of good quality, which in turn come from ignorance of the characteristics and limitations of the particular paints chosen {4, 5). The shortcoming of formula labeling 7 the fact that paint formulas, as will be seen later on, are too compli cated to mean very much to ordinary paint buyers {6, 8), whoneed a reasonably simple interpretation of them in nontechnical terms. Classification simplifies the expression of paint composition for laymen by presenting those few aspects of composition that reveal the major characteristics of the paint and ignoring technical details about which the paint user need not be greatly concerned. Classification merely identifies the many paints by kind independently of trade brand, so that the purchaser can exercise an intelligent choice and so that painters arid other paint users can be given practical advice about proper application and maintenance. On the other hand, classi fication omits many details of composition that enter into the proper manufacture of the paint but can wisely be left entirely to the judg ment of the manufacturer. It should he emphasized that the classification system is designed to deal adequately with the problems of craftsmanship in the use of paint, not with the problems of competence and integrity in the manufacture of paint. The system of competitive trade brands, which identifies the manufacturer with his products and in effect places his seal of responsibility on them, operates to put well-made paint conveniently at the public's disposal. The classification system, in no way alters the significance and utility of the trade brand. The trade brand, however, although successful in making it easy to buy good paint, has not proved helpful in getting good paints so used that they give the good service of which they are capable. Improvement in craftsmanship in the use of paint must be achieved by instruction of those who buy and apply it. Convincing instruction, however understf classes | develop] mainteri prehmii technidf : ^ Ml been re! for pa work, intende metal: Bam _ paintir only ih PaintJet Porch | ehanicj enamel fieatiof chiefly! Panf eludes | These! andna The] group] These! concei users a here <f lead pf Thecf in com is thaf paint I looselj paint white meat CLASSIFICATION OF HOUSE AND BABN PAINTS a however, cannot be purely arbitrary, but must include a reasonable understanding of the principles upon which it rests. When the' many classes of paint are made easily identifiable it becomes possible to ] develop and disseminate sound principles of craftsmanship in use and | maintenance. The highest service of classification, therefore, is as a I preliminary step in the establishment of generally recognized $ techniques of painting and paint maintenance. Cl a s s if ic a t io n Ou t l in e d A broad classification of paints according to field of use has long been recognized in trade practice. House paints are intended primarily for painting the exterior of buildings, especially the exterior wood work. Barn paint often means red paint made with iron oxide intended for farm buildings. Such paints are used also for painting metal roofs and therefore are sometimes called bam and roof paints, j Barn paint may also mean a cheaper grade of house paint for use in I painting farm buildings. Trim paints, which are usually made I only in certain deep colors, such as green or blue, are intended for 1 painting blinds, trim, and other minor areas of the exterior of houses. ! Porch and deck paints are for exterior surfaces subject to the mei chanical wear of traffic. There are also wall paints, floor paints, j enamels, cement paints, implement paints, and the like. The classij fieation according to use is indicated on the label. This bulletin deals s chiefly with house paints and bam paints. | Paints are classified also by color. Each brand of house paint in cludes white, black, and a number of colors up to as many as 32. | These classifications by field of use and by color are, of course, practical | and necessary but they do not go far enough. j The system of the Department of Agriculture adds classifications by ! grdup, type, and grade according to the composition of the paint. These three divisions of the classification are necessary because the ! concepts on which they are based have long been familiar to paint | users and are too well established fcp be easily changed. The concept here called group has led to the familiar distinction between white lead paint, lead and zinc paint, "fcitanium-iead-zine paint," etc. (21,22). The concept of type has Led to the designation of paints as high or low in content of white lead and of zinc oxide (23). The concept of grade i is that expressed by common reference,to first-grade and second-grade j paint (19, p. S). In the past, however, such terms have been used I loosely, without authoritative definitions. It is proposed to define j group, type, and grade precisely. 1 Group is determined primarily by the principal pigments with which 1 the paint is made. Thus pure white lead paint, in which the pigment is 1 white lead, is paint of group L. If changed to gray, cream, or other I light color by adding small proportions of colored pigments, it is still I classified as group L. On the other hand if a large proportion of colored | pigment is incorporated to make paint of deep color it becomes paint | of group CL. Lead and zinc paints contain both white lead and I zinc oxide and in addition they may contain certain inexpensive color1 less pigments and small proportions of colored pigments. Such I paints are of group LZ. Titanium-1 ead-zinc paints contain besides . | white lead and zinc oxide either titanium dioxide or one of the pig| ments of which titanium dioxide is the white ingredient, and in addition .................... . . : ......... .. . .. .... .......... . , .... ...... . V 4 TECHNICAL BULLETIN 804, U. (B. DEPT. OF AGRICULTURE usually contain inexpensive colorless pigments. Such paints are of group TLZ. lied bam paint in which the principal pigment is ferric oxide is classified as group F. In some of the other paint groups the nature of the liquid portion of the paint as well as its principal pigments is taken in to account in the designation of the group. Type is determined by the proportions of lead pigment and zinc oxide in the total pigment of the paint. It has long been recognized by technologists and laymen alike that white lead and zinc oxide are the essential ingredients of most house paints, especially of white paint and paints of light colors, and that their proportions govern very largely the wearing properties of the paint (7, 9, t%, IS, 14)- Some other lead pigments must be considered similar in effectiveness to white lead. Types are defined in terms of the sum of the lead pigments and zinc oxide in the total pigment by volume and the ratio of lead pigment to zinc oxide. They are designated by descriptive phrases and also, for convenience in discussion, by number and letter symbols. Following are some of the more important types: Type 1A: Very high content of lead pigment and zinc oxide with very high ratio of L/Z. Type 2B: High content of lead pigment and zinc oxide with high ratio of L/Z. Type 3B: Medium content of lead pigment and zinc oxide with high ratio of L/Z. * Type 3C: Medium content of lead pigment and zinc oxide with low ratio of L/Z. Type 5: Very low content of lead pigment and zinc oxide. Grade is determined by rules, to be described later, that constitute a rough'estimate of certain paint properties of importance in connec tion with application; for example, the extent to which the paint may be thinned, how thick a coating it may be practicable to apply, how thick the coating will be after it has dried, and whether it will have good opacity (power to hide what is underneath). Six grades are recognized, of which grade 1 contains higher proportions of the more essential ingredients and is suitable for a wider range of adjustments by thinning, spreading rate, and the like, to meet the individual requirements of the job, than paints of.the lower grades. In general, any paint can be reduced in grade merely by thinning it with linseed oil or turpentine. For that reason paints are graded according to their composition after they have been thinned as directed by the manufacturer in the directions printed on. the label. In the past use of the term'"grade" in connection with paints, the significance has been primarily with respect tb selling price. When a manufacturer offers two brands of paint, that at the higher price is first grade and the other is second grade, regardless of com position or quality. One manufacturer's first grade may be essentially the same paint that another offers as seeond grade. In the classifica tion system here described, grade bears only an incidental relation to selling price and is defined basically in terms of characteristics relating particularly to technique of application. Within any one group and type the manufacturing cost will normally prove higher, the higher the grade, but such comparison does not hold, at normal prices ..of raw materials, outside those limits. For example, a paint of group L55, type IB, grade 3 may be more costly to manufacture than another paint of group SLZ, type 4C, grade 1. ; j ; ` | > i ; CLASSIFICATION OF HOUSE AND BARN PAINTS are of ferric ps the ncipal d zinc gnized de are white tavern 1, 14). veness e lead ? ratio iptire letter ) with i high khigh th low titiite innecfc may how : have >8 are more fnents ridual noral, inseed Pg to y the laints, price, ligher com;tiallv sificaiation fistics r one Igher, irmal paint cture Us e o f Cl a s s if ic a t io n ; Under the classification system, paint labels bear the following ; information: (1) The name and trade brand of the manufacturer; (2) a statement of the field of use, such as house paint or porch and deck paint; (3) the color of the paint, as white, cream, dark green; (4) a statement of the formula of the paint; (5) directions for applica- ? tion; (6) the classification mark reporting the classification by group, f type, and grade according to the system of the Department of Agri culture. Of these six items only the last is new and differs from long established practice. The other five retain all of their past signifi cance. A suitable method of stating the classification and formula | is illustrated in figure 1. , | In purchasing paint, the ordinary user continues to give first thought to the tirade brand because he looks to the reputation of the manufacturer for competence and integrity in supplying paint iff good ] . quality, for the reliability of the rest of the information on the label, and for responsible business dealings. Items 2 and 3 obviously come | next in order of attention. Item 4, the formula of the paint, need not be considered at all by the user unless he has special reasons for wishing to buy paints made with certain ingredients, as for example farmers interested in growing soybeans and wishing to buy paints s containing soybean oil. The formula is primarily for the considera tion of technical men and helps greatly m malting the classification system self-enforcing because it facilitates cheeking the classification > mark against the formula. The fact that incorrect classification j marks can be easily detected by competitors, and by paint buyers | with technical training builds up confidence in the system. , Item 5, directions for application, remains necessary under the classification system and may be expected to acquire greatly increased importance. In the past, both makers and users of paint have tended 1 to treat label directions perfunctorily (5), lamely because of the inadequate exchange of information between maker and user and the failure to recognize the relation between paint composition and technique of application. Item 6, the classification mark, makes | it possible to surmount this obstacle by giving the paint buyer the f knowledge he needs without overburdening him with unnecessary | technical detail. j In reading the classification mark, paint users should be taught j to consider first the group and type and to turn to the grade only after I they have settled upon group and type. Group and type are of priI mary importance in determining certain basic tendencies in the bej havior of paint during service, such as soiling with dirt, resistance to j mildew or to hydrogen sulfide, chalking, fading of colors, wearing away | by erosion, checking, cracking, and ultimate form of disintegration if I repainting is postponed too long. Choice among the groups and types ! available on the market is partly a matter of the program of mainteI nance. Paints that are advantageous when repainted at reasonable f intervals may be unsuitable if a very long interval is to elapse. Choice j is also partly a matter of compatibility between paints, since good paints often behave abnormally when applied over previous coatings of paints of very different characteristics. Since all kinds of paint have | their disadvantages as well as their advantages, there will he greater | general satisfaction in the choice if the user's desires in. the matter can be allowed to operate intelligently. FLB 00104: on l .* . - DEPT X~ AGBICULTTOIi , 1 CIASSIFICATION OF HOUSE AND BARN VAUm 6 TECHNICAL BULLETIN 804, U. . ; , , . 4 he considered that, if paints of the same group, type, and color bu After group and type have been settled, graae j. rop6rtiade are applied at say 600 square feet, 'X gallon, a thi Soifnctheeitpdaeintet ramnidnei;ss= important questions therefore intimately about tne connected with the directioied paint and one of greater Th^rade than by low-grade ,v, to produce a dried film opacity will in general be j paint. Putting the mattei of paint of given thicknesi (1 usually be required with a higher grade and the op will be greater. Some paint jobs can be done e h paint of higher or lower grade provided that the tech :ation is adjusted accordingly. Other paint jobs c; perly only with paint of high grade. There may be tim re economical to do a job with paint of rather low gPadl with high-grade paint--for example, when the eonditioi e is such that, to paint it at all, an abnormally large nt must be consumed. The paint grades, therefore, ser echnique of application. .CULATING CLASSIFICATION PROM PAINT I he classification of the paint is calculated from the f ctions for application given on the label, not from tl ed manufacturing formula used in the paint factory, public declaration of the formula should agree with tl . When the label formula is stated adequately the c ulated from it agrees with that calculated from the ma .ula, hut inaccuracies or ambiguities in the label forrm iscrepancies. Formulas that comply with the re enclature for Formula Labeling of the National Pai Lacquer Association (18) are adequate, provided that s-of each ingredient, including colored pigments in tii Stated with sufficient precision, and provided furth tions for application are clear and definite, he remainder of this bulletin deals with the methods of rsificatibn of house and bam paints from the formula < lie label. By following the prescribed methods of calci e or bam paint can be classified provided that a uate statement of the formula is available. ; Fo r ms o f Pr e s e n t in g La b e l Fo r mu l as abel formulas, in conformity to custom and to Stat rted in weight percent. The National Bureau of Star used that they be reported both by weight and by lid columns, as indicated in figure 1. It is recomm practice be adopted by manufacturers cooperating in ion plan. me manufacturers report the percent of ingredients to 1 _es, for example, "pigment, by weight, 63.72 perceni ----I -fication inark1^ off all fractions, thus, "pigment, by weight, 64 per< ^ 1 part of a paint label illustrating how the jsisesinc^i ^ oler practice implies greater precision than is feasible in n "SELta for a popular kaiinudstxoafthmou_steheP8m11^anu^^mrXsr^*aTMde--m{oarmrkuilsa dis^pbperations, whecrelaasssitfhiceatliaotntae.r aIdtmisitsthuenrecfeorrteairnetcieosmlma conspicuousl^ai^^rectLo^^or.apPustomary, and in volume percent, ^percent be reported to one decimal place, as illustrated puuoosced bbyvJ thf National Bureau of Standards. ; ' ,. i (published communication from Lyman I. Briggs, director of the National Bureau -TMar|cf T. Trigg, president of the National Paint, Varnish & Lacquer Association, Octobt for applica.ttiioonn. Detailed discussmu popular press tec`hnnique of^aajpgcation /fflustration it may be poK tion of the subject FLB 001043 6 TECHNICAL BULLETIN 804, tJ. S. DEPT. OF AGRICULTUBE After group and type haVe been settled, grade should be consider,*! that, if p< since it determines important questions about the working properisde are, app of the paint and is therefore intimately connected with the din*< 0 +'0 >1 pun it. m 'h-grade till npHSHw usually b jjlBlM)BoQll turn i. i exly oni> economic + hijti-iri i-> aui-h ti FiermE l^Part of a paint label illustrating how the classification mark; formula for a popular kind of house paint may be printed. On pans nier practice Iahel not shown in the illustration the manufacturer's trade-mark is dispoperatjens, v conspicuously and directions for application are given. 1The formula i>)j , ( b,, both in weight percent, which is customary, and in volume percent, a= ,, posed by the National Bureau of Standards. ;,___' oe royinmr for application. Detailed discussion of the relation between gi ad<* 1 rlf,/' technique of application properly belongs in a more popular pivM 76,81,2 o ,7 tion of the subject (15}), but by way of illustration it may be put * * Us*rj'f . tin-' ui'ti . '' hi ptvf,;:f(p k,r l, r-*v .the qaibilj in^l jr" ii>it >11,IV in luei{ ri 0 q 0i:<- jiMi, pr| FLB 00104 "7 ie considered, ng properties die directions CLASSIFICATION OF HOUSE AND BAEN PAINTS 7 out that, if paints of the same group, type, and color but of varying grade are applied at say 600 square feet per gallon, a. thicker film m dried paint and one of greater opacity win in general be produced by high-grade than by low-grade paint. Putting the matter in another way, to produce a dried film of paint of given thickness, less paint will usually be required with a mgher grade and the opacity of the i film will he greater. Some paint jobs can be done equally satisfactorily with paint of higher or lower grade provided that the technique of ap plication is adjusted accordingly. Other paint jobs can be done properly only with paint of high grade. There may be times when it is more economical to do a job with paint of rather low grade than to do it with high-grade paint--for example, when the condition of the sur face is such that, to paint it at all, an abnormally large amount of paint must be consumed. The paint grades, therefore, serve as guides to technique of application, CALCULATING CLASSIFICATION FROM PAINT FORMULAS The classification of the paint is calculated from the formula and directions for application given on the label, not from the more de tailed manufacturing formula used in the paint factory. Obviously the public declaration of the formula should agree with the classifica tion. When the label formula is stated adequately the classification calculated from it agrees with that calculated from the manufacturing formula, but inaccuracies or ambiguities in the label formula give rise to discrepancies. Formulas that comply with the recommended Nomenclature for Formula Labeling of the National Paint, Varnish and Lacquer Association (18) are adequate, provided that the propor tions of each ingredient, including colored pigments in tinted paints, are stated with sufficient precision, and provided further that the directions for application are clear and definite. The remainder of this bulletin deals with the methods of calculating the classification of house and bampaints from the formula as it appears on the label. By following the prescribed methods of calculation, any house or bam paint can be classified provided that a reasonably adequate statement of the formula is available. lark and Is of the tisplayed | printed as pro- de and isentaiointed Fo r ms o f Pr e s e n t in g La b e l Fo r mu l as Label formulas, in conformity to custom and to State laws, are reported in weight percent. The National Bureau of Standards 3 has proposed that they be reported both by weight and by volume, in parallel columns, as indicated in figure 1. It is recommended that this practice be adopted by manufacturers cooperating in the classi fication plan. Some manufacturers report the percent of ingredients to two decimal places, for example, "pigment, by weight, 63.72 percent." Others round off all fractions, thus, "pigment, by weight, 64 percent." The former practice implies greater precision than is feasible in manufactur ing operations, whereas the latter admits uncertainties large enough to alter border-line classifications. It is therefore recommended that the percent be reported to one decimal place, as illustrated in figure 1. > Unpublished communication from Lyman J. Briggs, director of the National Bureau of Standards, to Ernest T. Trigg, president of tbs National Paint, Varnish A Lactpior Association, October 5,1939. 761892 0 - 47 -2 8 TECHNICAL BULLETIN 804, U. S. DEPT. OF AGRICULTURE The label formula in. weight percent, following long custom, may be expressed in one or the other of two basic forms (18), both of which are further Subject to certain variations. The form most widely used, referred to subsequently as example 1, divides the paint into two parts, the pigment and the liquid (also called the vehicle), each of which is reported in percent of total paint, mid then itemizes the pigment in gredients in percent of total pigment, and the liquid ingredients in percent of total liquid. Example 2 itemizes all ingredients, both pigments and liquids, in percent of total paint. The two forms and their variations can be made clear by using each of them to express typical label formulas for the same paint, namely, the paint already exemplified in figure 1. Ex a mp l e 1, Va r ia t io n A In variation A the pigment or the liquid or both are only partly itemized and the balance of the information is given in footnotes. In the illustration below the composition of the white lend and the drying oil is explained in footnotes. JPercent Pigment, by weight-------------------- -------------------------------------------------------------- 63.8 liquid, by weight.......... .......... .............. --------- -------- ------------------------------------ 36. 2 - ioao Composition of pigment, by weight: i Whitelead.......... ........................................................................................-- 43.2 Zinc oxide 2& 7 Titanium-magnesium-------------------------------------------------------------------------- 33, 1 100.0 Composition of liquid, by weight: 2 Drying oil--,------------------------------------------------------------------------------------- 85, 7 Mineral spirits----------------------------------------------------- Itt 2 Drier 4 1 Footnotes on label 100.0 1 Composition of white lead: Jpereet* Basic carbonate---------- ------------------------------------------------------------------- 70,4 Basic sulfate----------------------------------------------------------------------------------------- 29.6 100.0 ' 2 Composition of drying oil: Refined linseed oil------------------------------------------------------------------------------ 76. 2 - Refined soybean oil---------------------------------------------------------------------------- 24 8 ", 100. 0 It is usually considered unnecessary (though it ia desirable) to explain the titanium-magnesium in a footnote provided that it con sists of 30 percent by weight of titanium dioxide and 70 percent of magnesium silicate, which is the composition of the composite pig ment sold under that name (8, pp. 686-626). The statement in the label formula, however, does not mean necessarily that the composite pigment was used but merely that titanium dioxide and magnesium silicate are present in the proportions indicated. Any additional magnesium silicate or titanium dioxide is itemized separately in the {% \ FLB 00104 DEPT. OP AGRICULTURE CLASSIFICATION OF HOUSE AND BARN PAINTS 9 , following long custom, may : formula. On the other hand the separate Listing of basic sulfate white >asic forms (18), both of which * lead and zinc oxide does not mean necessarily that the two pigments The form most widely used, f were actually used separately; they may represent the component part ivides the paint into two parts, i of the composite pigment, leaded zinc oxide (14) -- in this ease a the vehicle), eadh of which is ; leaded zinc oxide containing 35 percent by weight basic sulfate white then itemises the pigment in- '? lead. Mineral spirits and drier are often lumped together without and the liquid ingredients in itemization in a footnote. Other manufacturers report them separately temizes all ingredients, both in the formula as shown but without indicating how much of the drier tl paint. The two forms and ; is volatile and how much nonvolatile. The content of nonvolatile in ising each of them to express ; drier is seldom reported clearly. it, namely, the paint already i Ex a mpl e 1, Va r ia t io n B on A prid or both are only partly ration is given in footnotes. >n of the white lead and the Patent ------- ----------- .------ - 63. 8 ------ ------ ..-------------------36.2 100.6 Variation B differs from A only in the manner of stating the foot notes. Instead of itemizing them in percent of the composite ingredi ent explained by the footnote, they are itemized in percent of total pig ment or of total liquid, so that the sum of the items is numerically equal to the percent of the composite ingredient appearing in the main part of the formula. Thus the two footnotes under variation A would here appear as follows: 1 Composition of white lead : Percent Basie carbonate white lead__ ._______ ___________ -.- 30. 4 Basie sulfate white lead---- . .----------- -- --------------------- . ------ ---- -- 12-8 43. 2 23. 7 33.1 100.0 --........... _................... 85. 7 --------------------.----------------- 10.2 ----------.1------ ---------- 4 1 100.0 29.6 { 100.0 | 75. 2 24 8 1 100. 0 though it is desirable) to note provided that it condioxide and 70 percent of tion of the composite pig'6). The statement in the essarily that the composite m dioxide and magnesium idicated. Any additional itemized separately in the 2 Composition of drying oil: Refined linseed oil.----------------------,------ ------ ---------------- ....----------... Refined soybean oil-. --....--------------------.-------------... 43.2 64 4 2L 3 85. 7 In printing footnotes the phrase "composition of ----*----- --" is sometimes omitted. ' Ex a mp l e 1, Va r ia t io n C No footnotes appear in variation C: Pigment 63.8 percent of paint, by weight: Patent Basic carbonate white lead-------------. - -------------------------------- -------------- 30. 4 Basic sulfate white lead-.___________---------- ------------- ------ .----------- 12.8 Zinc oxide..------- ---------------------------------------- ,---------------- .-- -- --------- 23. 7 Titanium dioxide---.------------------- ------------- -------_ 9. 9 Magnesium silicate-.____ ----------- -------------- ------------------- ------ 23.2 Total-_______________ __________ ----------------- - ----------------100.0 Liquid 36.2 percent of paint, by weight: Refined linseed oil -- --------- ------------------------------------------- Refined soybean oil--- ------------------------------------ ------------------ Mineral spirits and drier------------ .---------------------- ------------------ .-- 644 21.3 14 3 Total______ ______ _________________ ___________________________ _ 100.0 The titanium dioxide and magnesium silicate might also be reported as one item, titanium-magnesium, as in the illustration given for variation A. If leaded zinc oxide is used it might appear as "35pereent leaded zinc oxide, 36.5 percent." 10 TECHNICAL BULLETIN 804, V. S. DEBT. OF AGRICULTUKE 6 E 1 + 2 . Although example 2 may appear in any one of the three variations described for example 1, it is usually presented as variation C, as follows: Percent Basie carbonate white lead-------------------------------------------------------------- 19. 4 35-pereent leaded zinc oxide j.-------------------------------------------------------------------- 23. 3 Titanium-magnesium_____________ __ .,, - - - L,.... . - - -i;-------------------------------- 21. 1 Refined linseed oil_______ --.______ _____________________________________ 23. 3 Refined soybean oil------------- *.____ ___________________ --. _ 7. 7 Mineral spirits. *.... i_...... ...... ....--. ..... 'J......._i...... .' f 3. 7 Total.______________ _____ ______________ _____________ _____ 100.0 A few manufacturers print the formula according both to example 1 and to example 2 in parallel columns in some such-manner as the following: Pigment 63.8 percent, liquid 36.2 percent of the paint, by weight: Refined linseed oil_______ Refined soybean oil-------- , Mineral spirits and drier. Pigment percent 3a 4 12. 8 23 7 33 1 Liquid percent 64.4 21.3 14. 3 Torn percent 19.4 8.2 15. 1 21.1 23.3 7.7 5.2 Total___ 100.0 100.0 100.0 100.0 Vo l u me An a l y s is . pr epar ed pain t s Paints are classified on the basis of their composition by volume, not by weight. Nat only are the formulas by volume simpler, but paints are usually sqld by volume; and. volume rather than weight is nearly always the dominant property governing the technique of application. The process of converting the formula by weight to the fomrula by volume is called for convenience "volume analysis." It requires knowledge of the volume occupied in paint by unit weight of each ingredient in the paint. This factor is called the bulking value and is listed in tables 1 and 2 for the ingredients commonly used in house and: barn paints. More extensive tables of bulking values will be found elsewhere (11, pp. 466-578). The significance of the column headed "Diluent allowance" in table 1 is explained later under "Diluent allowance for very opaque pigments." The names of pigments listed in table 1 have definite significance and require no additional explanation when used in label formulas except that those names preceded by an asterisk (*) should be des ignated C. P. in the label formula, signifying "chemically pure" and indicating that there is no admixture of pigment of low opacity (see paragraph 6 in the section on Ambiguities in label formulas). When the names so marked are used without the designation C. P., the bulking value given in the table will be used in tne volume analysis but the diluent allowance will be zero. Names of less definite meaning that should be further explained by means of footnotes or otherwise are listed subsequently in table 19, p. 28. TUBE CDASSOTCATION OP HOUSE AND BARN PAINTS 11 T1 < 1.--Data on paint pigments for volume analysis of label formulas and classification. fyariatkms ?ion C, aa Name of pigment and chemical symbol occasionally used Percent 19.4 --- L-- i-- i-- 23.3 21.1 23.3 7.7 a7 i -- 1.5 .l-- 100.0 ixample 1 er as the Opajoptee white pigments: jjtlmony oxide (SbaOs).___________ Basic carbonate white lead---------------- Basic sulfate white lead-----:--------------- Lead titanate (PbTiOO....... Lithopone_______ ___--_____________ Titanated lithopone________________ Titanhim-barlum Titanium-barium ((2350 percent percent TiOj)__ TiOj)__ Titanium-c&lclum---------- ---------------- Titanium dioxide (TiOj)__.------------- Titautam-magnesiun]______________ Zinc oxide (ZnO)-------------------------- Zinc sulfide (ZnS)------------------------ Zinc sulfide-barium-- Zinc suiade-magnesinm----- --.-------- Y weight: |! ' Total patent j 19.4 &2 15. 1 21. 1 23.3 7. 7 5.2 ioao volume, | iler, but | height is | iique of 1 it to the I Sis." It I eight of 1 jg value lused in ! jues will ! column ! \ under { ificance umulas be des!e" and fty (see | Wtea r., the i | f j caning lerwise Aluminum On flake form). Basic lead chromate____________ ____ _______... Black oxide (FeaOd-------- ------------------------Blue lead (basic somite white lead and carbon)-. Cadmium red (cadmium lithopone).:------ --------Cadmium yellow (cadmium lithopone)--_____ Carbon (Cj______________ -------------.-- 'Chinese blue (ferric forrocyanido)------ -------Chrome orange (lead chromate and oxide)--------Chrome yellow (lead chromate and sol&te)-----Chromium oxide (CraOa)__------------........-- Chromium oxide hydrate (Cr(OH)j)........ .......... Copper aceto arsenate.. Cuprous oxide (CujO).......................................... Ferric fenooyamds (F(Fe(QU)eJi)--.---- -- Ferric oxlde (Fe0).-------- ---------------- -------Ferric oxidfi hydrate (Fe(OH)a)............ ............. Ferric hydrpxjdo (Fe(OH)i)------- ------- ----------Graphite-____________ ._________ ___ ____ ... Hydrated chromium oxide (Or(OH)s)-- Hydrated-ferrio oxide (Fe(OH)*)--*........... . Iron blue (Carrie fetrocyankie)....... ............. u-- Lampblack-------------- ...----------------- ---.---------Lead (in flake form)-.--------------------Lead chromate (PbOrfL)--------- ----------------- Lithol red ___ ......---------- --------------- Magnetic oxide (FejOd________ ----------- ------- Manganese dioriae (MhOj)---------- ------------ Mercury oxide (HgO).*----------------- --------------- - Para red (paranitraniline red)..... ...................... -- Paris green (copper aceto arsenate)--- ------------ ... Prassfemblne {ferria forroeyanide)_..... .............. Bed lead (Pb0<)----------------- ....-------------- ... *Red tonra1_____________________________________ TonBdine red...... .....-........................ ..................... Tuscan red.. ___ .-- ----------- -- Ultramarine-___________________ _________ Van Dyke brown* -____ -____ -___ ______---- Zinc chromateCZnCrO*)....................................... Zinc tist____________________ _____ _--------- Pigments of low opacity: Aluminumhydroxide (Al(OH)a)------------------- Aluminumsfficate...___ ____ _____ *___ _______ Barium sulfate (BaSOO --.-- Barytes (barium, sulfate)...------------ -------- Blanc fixe (barium solfate)- Calcium carbonate (CaOOs)----------------- Calcium phosphate, (Ca3(PO<)i)------------- Calcitnn sulfate, anhydrous (CaSO*)........... Calcium sulfate, hydrated (CaS04.2Ht0)-- Chalk (calcium carbonate)-.--------------- China day (kaolin)-------- -------------- ---- Clay (kaolin)___________ ___ Diatomaceous silica___________ ________ _ Fibrous tale------ ------------------- --------------- Gypsum (hydrated calcium sulfate)-..,---. Kaolin_______________ ______________, Magm^om aluminum silicate__________ _ Macnesiom carbonate (MgCOi)------------ Bulking valneper pound Diluent allowance Symbol for use in classifica tion. Gallon* 0.(009 .0176 .0187 .0164 .0279 .0282 .0379 .0283 .0384 .0308 .0387 .0300 .0286 .0361 .0470 .017 .0260 .0189 .0250 .0280 .0660 .0000 .0170 .0200 .0230 .0320 .0370 .0700 .0200 .0660 .0240 .0300 .0300 .0540 .0329 .0300 .0660 .0660 .0240 .0200 .0127 .0800 .0250 .0300 .0450 .0800 .0370 .0650 .0135 .0800 .0800 .0310 .0500 .0720 .0350 .0X70 .0400 .0470 .0270 .0270 .0275 .0443 .0450 0430 6510 .0443 ,0460 .0460 .0510 ,0421 .0610 .0400 .0450 .0660 a 00 0 0 3.00 0 .62: .16 .37 0 3.20 0 0 L4fl .26 0 4.00 zoo 3.00 0 LOO LOO 5.00 3.00 zoo Loo 0 0 0 0 3.00 3.00 4.00 2.00 zoo 4.00 0 ZOO 3.00 5.00 4.00 LOO b 0 loo 4.00 zoo LOO 0 0 .zoo LOO 0 0 0 0 0 0 0 A L L L s ST T T T T T z 9 8 8 c L C L C c c c L L C C C c c c F F F c C c e c c It L C c c c c c c c L C C c c c c c 12 TECHNICAL BULLETIN 804, TJ. &. DEPT. OP AGRICULTURE Ta bLII 1 -- Data on padnlpigmente for Volume analysis of label formulas and ciassi^ccrfioB---Goatmued Name of pigment and c&flinloal symbol ocooatoaaUy used Bulking value par pound Diluent allowance Symbol for use In classifica tion Pigments of low opatity--Continued. _ .__ ^ __ _ . _T__Paris white (calciumcarbonate).,.^------------------------- flfiiM YflinA ... _ Siliceons matter (inearthpigments)----------------------------------------- Slate flour............. --...................-----------------'-------------------------------- Galfana 0.0421 .0420 .0443 .0463 .0430 .0430 Terrfralba (hydrated caicium sulfate) _____Whiting (calcium carbonate)--------------------------- ------ .0510 ,0443 Ta b l e 2.--Bulking valves1 for paint liquids 3 Name ofliqoid Bulk ing Tame Per pound Name of liquid Bulk ing value poPund- Nonvolatile. liquids: CfalUmt OWna-wood oi^seetung oil--__ Fish oU.reftned____________________ 0.1288 : Fish oil; bodied__________ ____ ______ .1260 Linseed oil, raw, boiled, or refined.__ .1288 Linseed oil, bodied, or blown:__--- ,1060 Linseed oil, heavy bodied, or heavy blown..-.... ............... ........................ >1225 Menhaden oil, see fish oil..-------- -- ---- PerlDa oil, raw or refined..--___ ____ .1288 PerUla oil, bodied-.:..----....... .1260 Soybean ofl, refined, clarified, or rdtttered........ ..................................... ' Soybean oil, bodied. -_________ ____ _ .1300 .1260 Nonvolatile liquids--Continued, Tons oil, bodied................. . . Varnish nonvolatile.^ \ Drier nonvolatile-*_. Volatile liquids: Dipontene..-................. --..-iv----. Drier (liquid drier or Jopan drier)-... Mineral spirits......... .............. ......... -. Naphtha (varnish makers and palnfr> era naphtha). Solvent naphtha. - - -_______________ Turpentine...___ ___ .....____ _ Water... .............. .................................. GaSm .1225 .1100 .1225 .1600 .1660 .1380 .1200 ; 1 The bulking values for some of the liquids listed are subject to appreciable variation. When llquids are used ofwhich the hulking values differ materially from those cecordod in table 2, It Is recommended that the manufacturer report the correct specific gravity of the liquid in the label formula as indicated by the following example: `'bodied tune oil (sp. gr. 0.076)." When the specific gravity is so reported the bulking value will be calculated from the equation B*=l-^8.336rip. which is the balking value and Q is the specific gravity. * For alist ofnames ofuncertain meaningforpaintiiquidsandroles fordealingwith them,sectable19,p.28. When the label formula is printed according to example 1, in which the pigments and liquids are itemized separately, the fust step in the volume analysis is to convert example 1 to example 2. The formula ./ given to illustrate example 1, variation A; is thus converted by means of the calculation in table 3. Ta b l e 3.-- Calculation No. 1, first stage, to convert values in formula in example X, variation A, to example $ values Ingredient Fraction of composite ingredient (see fbotnote on label) Step l-- muKipIyby fraction ol pigment or liquid Step 2-- raultiplyby percent of pigment or liquid in paint To get percentof ingredient in paint Basicsulfate whitelead::-.:----.. Refined linseed All ingredients____________ ___ _____ __ _________ 0.701 .288 .762 .248 . 0.432 -432 .237 .331 857 .837 .102 .041 03 8 <18.8 A3 8 <U8 34.2 36 2 70 2 33 2 10.40 8.17 16 12 21 12 23.31 7.71 3.00 1.48 100 00 FLB 3 CLASSIFICATION OF HOUSE AND BABN PAINTS 13 and Symbol tor use is dassiflca- tion If the multipliers in columns 2 and 3 of table 3 are written as fractions (0.704 instead of 70.4 percent) and those in column 4 as percents the resultant figures in column 5, or the desired formula according to example 2, come out in percents again. The results in the last cnlumn are recorded to two decimal places when the com putation is to be carried further, but for printing on the label they would be rounded off to one decimal place. When the label formula is printed in example 1, variation B or C, step 1 of the computation in table 3 is eliminated, as shown in table 4. Ta b l e 4.--Calculation No. 1, first stage, to convert values in formula in example I, variation B or C, to example 8 values Bulktag value per pound Ta&ww .1225 .1100 .1225 .1600 ....1lf2iC5Q0 .1600 .1550 .1380 *.1200 .{quids d that y the liking is the #p.28. rich the tula boos * i. ret it of lent infc i 140 117 i. 12 1.12 1.31 .71 .60 s' .48 Ingredient Bade carbonate white lead Bade sultete white lead-- Zinc oxide________________ Titanimn-magnesmm.----Refined linseed oil............ Refined soybean oil........ Mineral spirits and drier... All ingredient^..___ Step 2-- Fraction of pigment or liquid multiply by percent of pigment or liquid in paint To get lercent of in paint 0.304 .128 .237 .331 .644 .213 .143 63.8 63.8 63.8 63.8 36.2 36.2 36.2 19.40 17 21.12 23.31 7.71 5.17 100.00 After the formula has been obtained in terms of example 2, it is necessary to break down a number of composite ingredients or mix tures that may be reported into their component parts before pro ceeding further with the volume analysis. In the illustration given for example 2 (p. 10) the "35-percent leaded zinc oxide, 23.3 percent" must be broken down into "basic sulfate white lead, 8.2 percent" (0.35 X 23.3) and "zinc oxide, 15.1" (0.65X23.3). It is essential later on to know the proportions of lead pigments and of zinc oxide separately. Other composite ingredients that must usually be broken down to compute the classification are the iron oxide pigments, reduced colored pigments, varnish, bodied oils that contain volatile thinner and mixtures of volatile thinner and drier. Adequately re ported paint formulas contain all the data necessajy for breaking down the composite ingredients; procedures to be followed when necessary data are omitted in the formula will be described later. A few composite ingredients whose proportions are well standardized (3, 8a) need not be broken down. Pigments such as titanium-magne sium and lithopone, for which bulking values are listed in table 1, may be treated as though they were single ingredients. The second stage in the volume analysis is to convert example 2 from the weight to the volume basis (table 5). When the weight- percent of the several ingredients is multiplied by the bulking values of the ingredients in gallon per pound, as listed in tables 1 and 2 (step 3), the volume of each ingredient per 100 pounds of paint is ob tained, of which the sum is the volume in gallons of 100 pounds of paint, or in the case illustrated, 6.397. The weight of 1 gallon of this paint, of course, is 100-4-6.397= 15.6 pounds, which, if the label formula is given accurately to one decimal place, should agree within 0.2 pound with the weight per gallon determined by test oi ft sample of the paint. FLB 00105 14 TECHNICAL BULLETIN- 804, XT. S. DEBT. OB AGRICULTURE If the label formula is given less precisely or contains ambiguities for which assumptions must be made, the calculated and determined Weights per gallon may vary more widely, but if the disagreement ex ceeds 0.4 pound either the formula is very inadequate or the sample is unrepresentative and the classification of the product is doubtful. On dividing each number in column 4 of table 5 by their sum (step 4), the Volume of each ingredient in gallon per gallon of paint is obtained. These numbers multiplied by 100 give the formula of the paint in volume-percent as shown in figure 1. Ta b w; 5 -- Calculation No. 1, second stage, to concert percent of ingtediente by weight to fractional volume per gallon of paint Ingredient Percent weight or pounds per .100 pounds Step 3-^ byfflm To get gallons per value (galP Ion per 100 pounds of paint poand) Step 4-- divide each itemby total to get fractional part of 1 gallon Basic carbonate white lead. .-- ----------------- BMicsoIfatewhite load............ ................................ --_ Titaniuro-magnesfnin--------------------- Refined linseed oil........................ .............. ............. .......... Refined soybean ad-------------- --------------------- --------------- 10.40 3.17 16.12 2L12 sin 7.71 3.69 1.48 100,00 o.om .0187 .0215 .0387 .1288 .1300 .im .1250 0.341 .163 .32$ .8*7 3.002 1002 .572 .135 a. 397 0.0533 ,0239 .1277 .4093 ,1567 .0894 .0289 loom The third stage in the volume analysis is the calculation of the content , of opaque pigment, total pigment, and total nonvolatile matter in the paint after it has been thinned for finish coat according to the manufacturer's directions (table 6). The properties of paint during application and subsequent service are governed by die com position of the paint as used. If the paint is thinned with oil or turpentine before application its composition is necessarily altered. Some prepared paints are so made that they have the desired com position and 'consistency for finish coat as soon as the contents of the container are thoroughly stirred. Other so-called prepared paints are too thick in consistency as they come from the container and must be thinned by adding liquid. (The amount of such thinning directed by different manufacturers varies from zero-to as much as one-half gallon per gallon of paint.) Semipaste and paste paints must be thinned with still larger proportions of liquid: Before paints can be graded, therefore, it is necessary to calculate their composition when ready for application as finish coat in accordance with the manu facturer's instructions. The group and type of the paint, however, are not altered bv thinning and can be determined cither from the composition in tne. container or the composition when ready for finish coat. In the illustration in table 6, all of the pigments are opaque and the drier, in the absence of a statement of its content of nonvolatile matter, is considered entirely volatile matter. It will be assumed that the directions for application call for thinning the paint with one-half pint of linseed oil and one-half pint of turpentine per gallon for use as finish coat. f T1 Ba.4 BQ | ZTioitO* Reft Mm V(J wh Sii. ilh tol sol _ lh ert 1118 eoi wo tic sp an; asTl P* <*h Wf lir, in ad fir H VH fities for |Brmined neat ex| sample .oubtrul. (step 4), Stained, paint in by weight : Step 4-- divide each S item by total to get. s fractional ' Bart oi i gallon 0.0533 .1277 .1587 .0884 1.0000 of the volatile cording* if paint |e com- I ofl or altered, d coma of the paints .dmost pe-half fost be can be | when imanufWeTer, the |dy for kd the patter, 'lit the tte-half |use as CLASSIFICATION OF HOUSE AND BARN PAINTS 15 T1 < 6;--Calculation, No, 1, third stage, to calculate content of opaque pigment, total pigment, and total nonvolatile matter in thinned paint Ingredient Gallon of ingredient per gallon of paint Step 5-- add.oil and spirits for finish coat (J& pint each) Step 6-- divide each item by total to get gallon of ingredient per gallon of finish paint Beflned linseed oil.......... -......................-.................A___---....... - 0.0533 .0230 .0508 .1277 .2557 .2557 .4693 .1567 -8817 .0694 .0286 LOQOO 0.9442 .1519 .0239 L 1250 0.227 .227 0.839 .135 .026 L000 In column 2 of table 6, the total opaque pigment is the sum of the values for white lead, zinc oxide, and titanium-magnesium, all of which are considered opaque pigments for the purpose of classification. Since there are no other pigments present in the paint chosen for the illustration, the total pigment is equal to the opaque pigment. The total nonvolatile is the sum of the total pigment and the linseed and soybean oils, or 0.8817. The small amount of nonvolatile matter in - the drier is ignored because it is not reported in the formula and the error thereby introduced in the calculations is negligible. If the manufacturer's directions called for application of the paint for finish coat as it comes from the can, without any thinning, the calculation would end with the values recorded in column 2, but for the illustra tion chosen the thinning recorded in column 3. is assumed to be specified. When the volumes of opaque pigment, total pigment, and total nonvolatile are readjusted for the thinning (steps 5 and 6), as recorded in column 5, they form the basis for classifying the paint. The instructions to thin the paint for finish coat do not alter the group and type in which the paint is ciassifiedr but in the illustration chosen the paint would be grade 1 if application without thinning were called for, whereas it is grade 3 when thinned with 1 pint of liquid per gallon, PASTE AND SEMIPASTE PAINTS The volume analysis of paste paints and semipaste paints is made in exactly the same way as that for prepared paints, taking into account the manufacturer's directions for thinning the product for finish coat. To illustrate the calculations a semipaste paint of the following label formula is assumed: Pigment, by weight, 81.0 percent: - Percent Basic carbonate white lead------------ ,,----------------...__,,------ ----------------- - 30. 4 Basic sulfate white lead- - -_________________ - - ... 12. 8 Zinc oxide.------ -------- -------------------------------------- ---------- ,----- ,------------- 23. 7 Titanium-magnesium___________________,______________ ____________ 33. 1, Total_______________________________ __________ ______ _100.0 761892 0 - 47 -3 9 FLB 00105 16 TECHNICAL BULLETIN" 804, tJ. 6. DEPT. OF AGKICULTUBE Liquid, by weight, 19.0 percent: Percent Linseed oil----------------------- ------------------- ---------------------- ---------- --, 65,7 Mineral spirits.----------------- -- -------- ----------------------- ------------------- ... 27.7 Drier-------- ------------ --.------------------------------------ - -- ------ -----... . 6. 6 Total-..-- --------.---------------------------------------- ------------------------------- 100. 0 If it is assumed further that the directions call for addition of 3 quarts of linseed oil to 1 gallon of the semipaste paint for finish coat, the volume analysis would he as shown in calculation No. 2, table 7. T1 < 7.--Voly/me analysis of a setnipaste paint (calculation No. $) * 1B ^ I# i SIgfjt Ingredient Frac tion of pig ment Or liquid Step 2-- multiply by per cent of pigment orliquid in paint To get per cent of in gredi ent in paint Step3-- multiply by bulk ing value (gallon per pound) Step 6-- divide Step 4-- each Gal divide Step 5^- item by lons each gallons total per item by of to get 100 total to finish gallon pounds get frac paint of in of tional ob gredient paint part of tained per 1 gallon gallon of finish paint a 304 Basic sulfate white lead. __ .128 Titanium-magnesium. w....... Lm<u.-od ojl.................... ........ .667 Total nonvolatile.-- -r------- Mineral spirits____________ .277 Drier...............:_______ ... : .066 ; All ingredients........ 8LG 24.62 0.0176 0.433 8LQ 10.37 .0187 .194 81. Q 19.20 .0216 .413 81.0 26.81 - .0387 1.038 19.0 12:48 .1238 1.607 -- ............... 19.D 6.27 19.0 L25 .1660 .817 .1250 ,166 100.00 4.658 0.0930 .0416 .0887 2228 .4461 .4461 .3450 ___ -7911 L6411 .1754 .1754 .0335 .0336 1.0000 1.760 0.255 . 255 0.881 .wo 019 . 1.00 \ % ^ 1 DILUENT ALLOWANCE FOR VERY OPAQUE PIGMENTS The volume analysis Leads to a summation of the content of opaque pigment, total pigment, and total nonvolatile in the paint when mixed for application as finish coat. These summations become the basis for classifying the paint with respect to grade. The pigments listed in table 1 under the heading "Pigments of low opacity" contribute practically nothing to the opacity of house and barn paints, although they do add some opacity to water paints and to some flat wall paints for interior use (24). The pigments of low opacity, which were formerly regarded as adulterants by many authorities (28; 20, p. 886), must now he considered necessary ingredients in paints that contain material proportions of very opaque pigments (10). In the volume analysis of house and barn paints, therefore, the pigments of low opacity are counted in the summation for total pigment but hot in that for opaque pigment. The opaque pigments listed in table 1 contribute materially to the opacity of paint but some of them are much more effective in that respect than others. In house and bam paints, which require a rela tively high content of total pigment for reasons other than opacity (7, 9, 12, 13), the custom is to dilute the very opaque pigments by FLB 00105 CLASSIFICATION OF HOUSE AND BARN PAINTS 17 mixing them with pigments of low opacity. This custom is recognized in the volume analysis by counting as part of the opaque pigment a "diluent allowance" representing a volume of pigment of low opacity sufficient to make the mixture approximately equal in opacity to the white leads and zinc oxide on a volume basis. The diluent allowances for very opaque pigments established for purposes of volume analysis are listed in table 1. The composite pigments, lithopone, titaniumcalcium, titanium-magnesium, and zinc sulfide-magnesium, are given zero diluent allowance because they contain the appropriate porportion of pigment of low opacity to make them equal in opacity to the white leads and zinc oxide. Other composite pigments, such as titanated lithopone, titanium-barium, and zinc sulfide-barium, contain smaller proportions of pigment of low opacity and are therefore given small diluent allowances. The diluent allowance for titanium dioxide is derived from the proportions by volume of titanium dioxide and magnesium silicate in titanium-magnesium by the calculations shown in table 8. The diluent allowance for titanium dioxide is therefore 0.762-5-0.238 --3.2, The diluent allowance for zinc sulfide is calculated in similar manner from the proportions by volume of zinc sulfide and magnesium silicate in zinc sulfide-magnesium. Ta b l e 8. --Derivation of diluent allowance for titanium dioxide v Step in calculation Titanium Magnesium Titanium- dioxide silicate magnesium Pounds per 100 pounds titanium-magnesium................ ........ Multiply |>y bulking value in pounds per gallon__ Gallons per 100 pounds titanium-magnesium.................. _...... Gallon ofingredient to 1 gallon titanium-magnesium..... ......... 30 0.0308 .924 3.874 .238 70 0.0421 2.950 3.874 ,762 100 3.874 1.000 Table 9 illustrates the use of the diluent allowance in volume analy sis, with the titanium dioxide and magnesium silicate listed separately instead of the composite pigment titanium-magnesium. The titanium dioxide is listed among the opaque pigments with a space below for its diluent allowance. The magnesium silicate is recorded after the opaque pigment. In step 4 the diluent allowance, 0.0973, is written in parentheses to indicate that it is added in the summation of opaque pigment but not in the summation of total pigment. Thus the opaque pigment is 0.256, but in total pigment the diluent allowance is omitted and the magnesium silicate, 0.0974 added, bringing the rounded off total to 0,256. The results shown in the last column of table 9, of course, agree with the previous illustration of calculation No. 1 in which the titanium dioxide and magnesium silicate were listed together as titanium-magnesium. In table 9 the opaque pigment and the total pigment happen to be equal because the quantity of pigment of low opacity (magnesium silicate) is equal to the diluent allowance for the very opaque pig ment (titanium dioxide). In actual practice, however, the pigment of low opacity may exceed, equal, or be exceeded by the diluent I FLB 18 TBCHNICAX* BULLETIN 804, U. S. DEPT. OF AGRICULTURE Ta b l e 9.--Calculation No. 1 (as in tables 4? 5, and 8) with titanium dioxide and magnesium silicate listed separately Ingredient Weightpercent Stop 3r~ To get gal- multiply tons per 100 by bulsdog pounds of blue paint item di vided by total toget fractional part of i gallon Basic carbonatewhite lead-.------____________ _ Basic sulfatewhite lead- _______ ----. Zinc (wide__________________ ______________--... Opaque pigments___ - .......______ -- 19.40 8.17 16.12 6.32 .0304 0.0176 .0187 .0216 .0308 8.2 14.80 .0421 Refined linseed oil................... --__________ _____ _ 23.31 Refined, soybean oil.................. ..... _ ______ _____ ____ i. 7.71 .1288 .1300 Mineral spirits-_________________ ________ - -_________ _______ ___ All ingredients.----_____________________ 3.69 1.48 iqo. oo i Added into total of opaque pigment, bat not into totalpigment .1550 .1250 It . : .W: . .153 .325 .194 r0973 .823 .872 .185 0.053a .0239 .am .0304 K.Q97S) ,2557 .0074 .2558 .1867 .8817 .0894 LOOOQ : allowance. Calculation No. 3, shown in table 10, illustrates the case ' in Which the pigment of low opacity exceeds the diluent allowance and in consequence the paint contains less opaque pigment than total pigment. Ta b l e ' ofthinned paint values in iahudi the content of total pigmint exceeds the opaque pigment (calculation No. 8) Ingredient Step 4-- Weightpercent : Step 3-- multiply by balking value To get gal lonsper 100 pounds of each item divided by total to get . fractional parts of 1 gallon Basle carbonate white lead_-__________ -____ _ __ ____ Titanium dioxide___________________ ___________ Diluent allowance_______ ____________________ Opaque pigment.. Magnesium silicate..^-.;...TM__..._______________ Silicrt _____________ _______________ ____ _ Total pigment LinseedoiL Total nonvolatile.: Mineral spirits_____ Drier--............... All ingredients^ 19.44 15. 92: ' 5.55 ,0260 0.0176 . 0215 .0308 - 3.2 6:342 .342 .171 >0BdO 0.0500 .0500 .0250 1 (.0300) 14.63 5.28- .0421 ,0453 .616 V" .0001:. .239 .0350 34.16 .1388 4400 3.31 1.71 100.00 .1560 . 1260 .513 joa 0.837 .'0750>:' .0313 1.000 t Added into total of opaque pigment, but not into total pigment. I iiiiW FLB 00105 CLASSIFICATION OF HOUSE AND BAEN PAINTS 19 Table 11 (calculation No. 4) illustrates the frequent case in which the diluent allowance for very opaque pigment exceeds the quantity of pigment of low opacity used in the paint and the resultant content of opaque pigment recorded is greater than that of total pigment. In such cases the content of opaque pigment is a theoretical value and might more exactly be called the equivalent opaque pigment. It represents the volume of pigments of the degree of opacity of white lead and zinc oxide that would be necessary to provide the same opacity. The content of total pigment, on the other hand, is always a real value, representing the total volume of pigments of all kinds actually present in the paint. Ta b l e 11.--Calculation of thinned paint values in which the theoretical content of opaque pigment exceeds the total pigment (calculation No. jj) Ingredient Weight* percent Step 4-- Step 3-- multiply by faulting value To get gal lons per100 pounds of paint each Item divided by total to get fractional part of 1 gallon 18.14 15.80 10.00 .0454 Magnesium silicate--........ .................... ........ ............... 16.81 Xinsecd oil___;__________._______________________..._ 32.74 4.88 1.63 100.00 0.0187 .0215 .0308 3.2 .0421 ,1288 .1380 .1260 0.340 .340 .308 .1453 ,708 4.217 ,673 .204 6.790 0.0501 .0602 .0454 1 (. 1453) .291 .1043 .250 .6210 .871 .0991 .0300 L000 * Added Into total of opaque pigment, but not into total pigment. TINTED PAINTS The volume analysis of tinted paints is made in exactly the same way as that for white paints. Table 12 (calculation No. 5) is repre sentative of paints of moderate depth of tint, such as buff or stone color. In table 12 it should be observed -that some of the colored pigments used for tinting, such as ferric oxide and carbon, contribute to the content of opaque pigment to an extent far out of proportion to the relatively small percent of these pigments by weight in column 2. In reporting label formulas for tinted paints it is common practice to omit the percent of colored pigments in paints of light or medium depth of tint, For example, the National Paint, Varnish and Lacquer Association recommends such omission when the tinting colors amount to "less than 5 percent" (18). In table 12 the tinting colors amount to 4.39 percent of the paint by weight but they account for 23 percent of the calculated content of opaque pigment ; without the tinting colors the opaque pigment would amount to 0.215 gallon in stead of 0,281 gallon per gallon of paint. This indicates why tinting pigments should be reported more carefully. (See item 8, p. 31.) 20 TECHNICAL BULLETIN 804, U. S. DEPT. OP AGRICULTURE r CLASSIFY y T2.-r*-Vbfetwe analysisof tinted pwird, (calculation No.S) D Ingredient Weightperbent Step 3-- multiply by bulking value Tq get gal lons per 100 pounds of paint Step 4-- e&eb item divfdedby total to get fractional part of 1 gallon Basic carbonate white lead-..---........ Zinc oxide........................... .................... ................................ Lead titanate........................ Lead chromate ----------:--. 10.97 19.43 11,77: 1.61 2.68 .10 0.0176 .ms .0164 ,0200 40240 ,0660 0.193 .418 .193 .032 .064 .007 0.0300 .0649 .0300 .0060 .0099 .0011 i Opaque pigment........... -------------------------- -------Magnesium silicate-- : 16.66 ,0421 ,701 Linseed oil----------------------------------- ------------------------Total nonvolatile^--w-----i-i-- Mineralspirits,--,--......... .-- 31.50 ------- : S.71 ino.ho .1288 ,1650 .1250 4.057 .575 .196 6.436 Diluent allowance added Into total ot opaque pigment, but not Into total pigment: For lead titanate, 0.0300X3.0=(0.0900) For lead chromate, .0050X1.0--( .0050) . For ferric oxide, . 0100X4.0=( .0400) For carbon, .0010X5. fl=( .0050) ( -1400) .281 .108; -250 .6304 .880 .0863 .0305 h f COLORED-PIGMENT PAINTS Paints made with colored pigments, pigments of low opacity, and little or no white lead or zinc oxide may well be called colored-pigment, paints. Such paints often contain some varnish in the vehicle. Table 13 (calculation No. 6) illustrates the volume analysis of an iron oxide bam paint. T1 < 13.--Volume analysis of colored-pigment paint (calculation No. (!) Ingredient Step 3-- Weight- multiply percent,. by btuk- . ing;value Step 4-- To getgaV Ions per lOOpounds o( paint each; item divided by total to getfractioaalpart of 1 gallon 16.71 0.500 0.0240 4 0.401 .2000 II O'dO '(.2(1001 .250 25; 09 4.53 7.74 .0430 .0443 .0421 LOTS .201 .320 1341 .0251 .0461 .250 18.88 12.36 4-25 2.33 . 1288 .1300 .1225 .1100 2.432 1.007 .521 .256 3>i0 my o .0649 .03L9 6.34 1.77 160.00 .1550 .1250 .963 .221 8.027 .850 .1225 .0275 1.000 i 1 I r # e As already explain Paints are assigne Inl opaque pigment be following symb< L, lead pigments, as Z, zinc oxide and the T, titanium dioxide a in table 1. S, /.inc sulfide and tl table t. . A, antimony oxide, a; F, ferric oxide or hy< meats, iricludmj <', colored pigments < (e), vehicles Gontainin the total vehieh (r), vehicles containmi rc), vehicles containin of the total veil These symbols ar dients of the paint, titanium dioxide, or bodied oil to the ex There are no symbol; mu; account in assi symbols for unbodie nnd barn paints, th enpii al letters standi Jn combining the and S are used wher which the letters sta The letters F and C, they represent are p of pi oviding color, i paint s may be defm< nients and colored i colored pigments in nients are colored p or exceed the opaq; pigment paints. In group symbol when .i mount to 20 perce (olored-pigment pai paint contains any < ; hould be omitted if pigments by volume Table 14 lists th barn paints on the m ini ended primarily io describe the paini 1 Components of Venetian red. * Added into total of opaque pigment, but not into total pigment. <11 FLB 001058 p4-- * item ided by 1 tO JgQt jtional rt of I .0300 * .0050 .0099 .0011 * (.1400) .1087 .250 LOGO iy, and igment rehicle. i of an ) <>) ; Step 4-- jeach item divided by > total to : get frac tional part of 1 gallon 0.0500 *(.2000) .250 .1344 .0250 .0406 .250 .3030 .2002 .0049 .0319 .850 .1225 .0275 1.000 CLASSIFICATION OF HOUSE AND BARN PAINTS 21 D +0 q 0 q 3 Q C1 0 ~0 _ 1 0 Xq As already explained, paints are classified by group, type, and grade; 1 0 q 3 GX Paints are assigned to groups according to the nature of the princi pal opaque pigments and of the vehicle with which they are made. The following symbols are used to describe the groups concisely: L, lead pigments, as indicated in table i. Z, zinc oxide and the zinc oxide in leaded zinc oxide. T, titanium dioxide and the titanium dioxide in titanium pigments as indicated in table 1. S, zinc sulfide and the zinc sulfide in the zinc sulfide pigments as indicated in table 1. A, antimony oxide, as indicated in table 1. F, ferae oxide or hydrated ferric oxide and the ferric oxide in iron oxide pig. meets, including the earth pigments such as ochre, umber, and sienna. C, colored pigments other than L or F pigments, as indicated in table I. (e), vehicles containing 15 percent or more by volume of bodied oil, based on the total vehicle (nonvolatile liquid plus thinners). (r), vehicles containing resin or varnish. (re), vehicles containing resin and bodied oil to the extent of 15 percent or more of the total vehicle, by volume. These symbols are combined to indicate the characteristic ingre dients of the paint. Thus group TLZ (e) means that the paint contains titanium dioxide, one or more of the lead pigments, zinc oxide, and bodied oil to the extent of at least 15 percent of the total vehicle. There are no symbols for pigments of low opacity, which are not taken into account in assigning paints to groups. Likewise there are no symbols for unbodied drying oil or volatile thinner. For most house and barn paints, therefore, the symbol for group contains only the capital letters standing for opaque pigments. Iff combining the symbols to indicate groups, the letters L, Z, T, and'S are used whenever the paint contains any of the pigments for which the letters stand, no matter how small the proportion may be. The letters F and C, however, are not used when the colored pigments they represent are present only in minor proportions for the purpose of providing color, which is the case in most tinted paints. Tinted paints may be defined as paints that contain both opaque white pig ments and colored pigments with the white pigments exceeding the colored pigments in volume. Paints in which the only opaque pig ments are colored pigments or in which the colored pigments equal or exceed the opaque white pigments " in volume are called colored pigment paints. In tinted paints the letters F and C are used in the group symbol when the respective colored pigments they represent amount to 20 percent or more of the volume of total pigment. In colored-pigment paints the letters F' and C are used whenever the paint contains any of the pigments represented, except that letter C should be omitted if it represents less than 20 percent of the L and F pigments by volume. Table 14 lists the groups that comprise most of the house and barn paints on the market. The list is not exhaustive, however, and is intended primarily to illustrate the method of combining symbols to describe the paint groups, 22 TECHNICAL BULLETIN 8Q4j JX S. DEPT. OF AGRICULTURE T1 < 14, --Groups of home and ham paints WHITE PAINTS AND TINTED PAINTS Group , Major constituents of-- Pigment Vehicle White lead-,___________ XTiihodied drying o3. LZ,,---- White lead, lead titanate, or both, and Do. ziae oxide. TLZ,____ -------------1 White lead, lead titanate, or botb, f Do. TLZ(e)--------------] zinc oxide, and titanium dioxide. \Bodied and unbodied oil. TZ-............-...................... yTitaniumdloxlde, ztocoxide.L__...... Titeniumdioxidfii, white lend.....,........ Unbodied dicing oil. Unbodied oil, bodied oil, and resin. Zinc solflde.white lead,and zinc oxide. Unbodied drying ofl. Irus.'. "'I HI III""'" Zinc sulfide and zine oxide..--______ Ziod salfUlie, titanium dioxide, white Do. Do. lead, zinc oxide. TINTED PAINTS AND COLORED-PIGMENT PAINTS F or C added to any of the.above symbols for white paints, as PtZ or The White pigments indicated by let ters!, Z, T, or S plus F or S3 pig ments, respectively, in the amount ot 20 percent ormere of the total pig ment by volume. Unbodied drying oil, but if resin or much bodied oil is present add tbe symbols (r), (e),or (re), as required. COLORED-PIGMENT PAINTS Lead chromate, red lead, or blue lead.. Unbodied drying oil. Lead chromate and zinc oxide________ Do. Ferric oxide or ferric hydroxide.----.. Unbodied oU, bodied oil, and resta. VZ.____--____----.. Ferric oxide, zinc oxide._____w--___ Unbodied drying oil. cz......................................... G pigqaent aiid zinc oxide.--. . ' DO. CL(re)__________ Chrome green or other mixture of C Unbodied OH* bodied oil, and resin. and L pigments. CLZ-.................................... Chrome gi^n and une oxide or otber Unbodied diyhig oil. mixture of C, t, and Z pigmehts. C(e). ;................................. C pigment.--..--^-.------____ Unbodied and bodied o!L CF<e)_--------------------------- C and F pigments--................................. Do. PAINT TYPES Paints are assigned to types according to the proportion of lead pigment and zinc oxide in the total pigment by volume. Account is taken of the sum of lead pigment and zinc oxide, L plus Z, and of the ratio of lead pigment to zinc oxide, L/Z. Five ranges of L plus Z are recognized as follows: Range 1. Very high content of lead pigment and zinc oxide.. _- -- 80 percent or more. 2. High content of lead pigment and zinc oxide.................... 60 to 79.9 percent. 3. Medium content of lead pigment and zinc oxide. . -- 40 to 59.9 percent. 4. Low content of lead pigment.and zinc oxide---- 20 to 39.9 percent. 5. Very low content of lead pigment And zinc oxide---------- 0 to 19.9 percent. Four ranges in ratio of lead pigment to zinc oxide are recognized as follows: Range s A. Very high ratio of lead pigment to zinc oxide..- . -- Over 3/1. B. High ratio of lead pigment to zinc oxide--- - - - ------- 3/1 to 1/1. C. Low ratio of lead pigment to zine oxide____ _________ Less than 1/1 to 1/3. D. Very low ratio of lead pigment to zinc oxide_____ -- -- Less than 1/3. lead aunt id of plus nore. cent. :cent. icent. nt. .ized 1/3. c ias s if ic at io n o f h o u s e an p bar n pain t s 23 A type is described by naming tbe range of L plus Z and the ratio of L/Z, for example, "type high content of lead pigment and zinc oxide with high ratio of lead pigment to zinc oxide." For brevity this type may be referred to as "type 2B." In type 5, which has very low content of lead pigment and zinc oidde, the ratio L/Z has practically no significance and is omitted. In the paint illustrated in table 5, the content of lead pigment as obtained by step 4 is the sum of the basic carbonate white lead and the basic sulfate white lead, or 0.0772. Since the content of zine oxide is 0.0508, L-)-Z=0.1280, which is 50.1 percent of the total pigment and L/Z= 1.52. The paint, therefore, is group TLZ type 3B. In calculation No. 2 (table 7), L=0.0930-(-0.0416, or 0.1346 and Z=0.0887. L+Z--0.4461, or 50.1 percent of the total pigment and L/Z=1.52. The paint, therefore, is of the same group and type as No. 1. In calculations Nos. 3 and 4 (tables 10 and 11), L+Z=40.1 percent of the total pigment and L/Z--1.0. These paints also, therefore, are group TLZ type 3B. In calculation No. 5 (table 12), some of the lead pigments have diluent allowances which are counted in computing the content of L pigment, thus: Basic carbonate white lead--_______ ___________ ______ ____ __-, Lead titanate,______________ __________--_________________________ Diluent allowance for lead titanate______________________ _______ ____ Lead chromate___ ,_______ ____ --___ --------,------------- ------------Diluent allowance for lead chromate--____- _--------------------- --------- 0. 0300 . 0300 ( . 0900) -0050 ( . 0050) Total L pigment- __________________ ___--,___________________ . 1600 (L-f Z)-s-0.250=90.0 percent of the total pigment and L/Z==2.47. the paint, therefore, is group LZ type IB. In calculation No. 6 (table 13) the paint contains neither lead pig ment nor zinc oxide but does contain ferric oxide. The vehicle con tains resin and bodied oil amounting to 0.0968. The vehicle amounts to 0.750 (1 minus the total pigment), so that the resin and bodied oil amount to 0.0968-^0.750 X100= 12.9 percent of the vehicle. Accord ingly the paint belongs to group F (r) type 5. If the resin and bodied oil amounted to 15 percent or more of the vehicle the paint would be group F (re) type 5. Although in times past house and bam paints of all of the possible types have been offered on the market, type ID is now entirely obso lete, types 1C and 2D are practically obsolete, types 2A, 2C, 3A, 3D, and 4B represent only a few paints that fall slightly beyond the borders of neighboring types, and types 1A and 4A each represent almost entirely paints of a single group. Most house and barn paints, therefore, fall in one of the types IB, 2B, SB, 3C, 4C, 4D, and 5. In practice paints of any one group are made only in a limited number of types, sometimes in one type only. Table 15 indicates the types in which the more important groups of paint commonly appear on the market. FLB 00106 24 TECHNICAL B0I/M3TIN 804, TT. 8. DEPT. OF AGRICULTURE T1 < 15.--Types in which the moreimpoftantgroups of kouse and harn paints are commonlymage droops1 r Remains: Types commonly made * I*_____ White lead paiut in. white or tints, red lead, blue lead, or chrome IA. i.% J yellow paint. IB,2B. CXZorFL^L__ SB, SG, 40, 4D, 8. TLZ.................. TTLZZorSZ _._. _ Wfcfte and tinted paints ofmanufaetorer's first grade.. ....______ Whiteadd tinted paints offered as second grade.*___________ _...... 2B, SB, SC. 4B,40'5. 4D.S. TL ___ 4A,:. >? SLZ ........... 3B, 3C, 4B, 40. 6. SorT.............. CLorOtZ____ 6. cz. i The groups ace listed with reference to the ingredients cf the pigment; only.. Some of thcse pigment combinationa are usuallr ia vehicles containing bodied oil or bodied oil and resin and the complete group symbols contain the added marks (e), (r), or (re). PAINT GRADES r House and bam paints, with the exception of house-paint primers and enainels or "enamelized paints," are graded on the basis of their con tent of opaque pigment, total pigment, and total nonvolatile as revealed by the volume analysis, step 4 or 6, according to whether the paint is intended for application without thinning or with thinning for the finish coat. The rules for grading are given in table 16, A paint I is assigned to the highest grade for which it meets all three requirei ments'. T1 < 16.--(trading rules for house and barn paints Grade MhajtauimQon^otof^- Opaque,pig ment (equivalent) Total pig~ ' -iniebi.t-;' --w (actual) Total pom volatile 1 0.250 0.870 .210 .230 .800 3................................................................................. .170 .210 . 730 4 ..................................................... ............... _ ... : -K130 .100 .060 fll ____ ________ ___________ _________ ______ _________ .090 .170 .090 i Qrade 6 is appliedto soy paint jtaillng to meet reqniremeDts of grade 5. The paint of calculation No. 1, as delivered in the container, con tains (table 6) 0.2557 opaque pigment, 0.2557 total pigment, and 0.8817 total nonvolatile. If the paint were intended for application as finish coat without any thinning it would meet all the requirements for grade 1. When thinned with oil and turpentine according to the instructions, however, the paint contains (table 6, step 6) 0.227 opaque pigment, 0.227 total pigment, and 0.839 total nonvolatile. The highest grade for which it then meets all requirements is grade 3. Accordingly the paint is classified as group TLZ type 3B grade 3. The semipaste paint of calculation No. 2, when thinned as directed for finish coat, contains (table 7) 0.255 opaque pigment, 0.255 total FLB 001062 CLASSIFICATION OS' HOUSE AMI) BABN PAINTS 25 pigment, and 0.881 total nonvolatile, which meets all requirements for grade 1. The paint is therefore classified as group TLZ type 3B grade 1. The paint of calculation No. 3 (table 10), if it is to be applied with out further thinning, contains 0.205 opaque pigment, 0.250 total pigment, and 0.894 total nonvolatile, whien meets all requirements for grade 3. The paint is therefore classified as group TLZ type 3B grade 3. The paints of calculations Nos. 4 and 5 (tables 11 and 12), provided that the instructions call for application for finish coat without thin ning, meet all requirements for grade 1 and are therefore classified, respectively, as group TLZ type 3B grade 1 and group L;Z type lB grade 1. The paint of calculation No, 6 (table 13), if applied without thin ning, contains 0.250 opaque pigment, 0.250 total pigment, and 0.850 totS nonvolatile. It meets all requirements for grade 2 had is i pigment eteKroup accordingly classified as group F(r) type 5, grade 2, House-paint primers and undereoaters made with the property of controlled penetration are graded according to the rules of table 17. The required content of opaque pigment and of total pigment is the fersand same, grade for grade, as those tor house and bam finish paints but materially lower contents of total nonvolatile are demanded because ar coil- | the vehicles used in primers of the kind in question necessarily con tile as | tain larger proportions of volatile thinncrs. Group and type are tier the | determined for house-paint primers in exactly the same way as for Sing for I finish paints. l paint | equiro- t . Ta b l e 17.--Grading rules for hov#e-paint primer* Minifnom cootentof-- Grade Opaque pjgitteat (equiv alent) Total ptement factual) Total non volatile lotalnottYolatUe a 870 .800 .730 pr, connt, and lication rements ding to 5) 0.227 volatile, grade 3. S3. , directed 55 total a 250 .210 ,170 .130 .090 a 250 .230 .210 . 190 .170 0.730 .060 .590 .020 .450 , i Any primer falling to meet grade 6 Is classified as grade ft. Fns.ni els and " enamelized paints" for exterior use are graded on the basis of their content of opaque pigment and of total nonvolatile ^cording to the rules of table 18. Products to come under the rules able 18 instead of those of table 16 must contain bodied oil or resin s bodied oil to the extent of 15 percent or more of the vehicle by :ume and the group symbol will therefore contain the mark (c) or ). In addition the label must indicate dearly that the product has characteristics of enamel or is intended for uses in which enamel enamelized paint" is customary. Porch and deck paints, fpr iiaple, are commonly expected to be enamels, and colored pigmeat As intended for shutters, trim, and other minor areas of house iors are frequently more enamel- than paint-like in properties. Jlite SIS FLB 001063 26 TECHNICAL BULLETIN 804, U. S. DEBT. OF AGRICULTURE 1 Ta b l e 18.--Grading rules for enamels and enamelized paints Qrade Minimum content Of-- Opaque pig. meat (equivalent) Total non-: volatile 2 .............................. *....... .......................a*.-......................................... l Any cpsmeJ fMlB^ to meet grade 5 Is classified as grade 6. .260 *210 .170 .130 ,400 .430 .370 .310 Whl detail| assuml weigh| hand,! Whj positic sulfati 3. i name! white| is une Amb ig u it ie s in La b e l Fo r mu l a s The A number of ambiguities have become widely prevalent in label formulas. Many of these probably arise from the belief that paint Mater Lacqfi I buyers examine the formulas only in a cursory, qualitative manner so that full details are unnecessary. The procedure of classification, Tita) not 1< however, is quantitative and requires reasonably adequate details in the formula. Since all doubtful points are given the interpretation least favorable to the quality of the paint, the paint manufacturer's : titanii j mean Titai men best interests are served by making the formula as complete and s On am accurate as practicable. Tita] Inadequacies and ambiguities in label formulas are dealt with according to the rules given in this section to make sure that the pure t: Chi ai Tita: paint will not receive a more favorable classification than it would pure til receive if the formula were more clearly stated. it show 1. Omissionof statement of content of 'pigment and of liquid percent of paint when the formula is reported by example 1.--Li this case the formula is'inadequate and the paint cannot be classified unless a sample is available with which the weight per gallon can be deter mined. The missing data can be calculated from the weight per gallon if the formula is adequate in all other respects. 2. Uncertain names for white, lead and zinc oxide or incomplete statement of their composition.--Basic carbonate white lead is some times reported under the following names: White lead carbonate, (not ll clearll titanii "tita turert ide pi^me carbonate white lead, lead carbonate, basic lead carbonate, carbonate of lead, and basic carbonate of lead. Although some of these names are incorrect, they will be interpreted as basic carbonate white lead. Similarly basic sulfate white Lead will be understood by any of the following alternative names: White lead sulfate, sulfate white lead, lead sulfate, basic lead sulfate, sulfate of lead, and basic sulfate of lead, except that lead sulfate as an ingredient of chrome yellow may be considered lead chromate for the purpose of the volume analysis. "Sulphate" is an older spelling of sulfate that is still widely used in label formulas. When white lead is reported without further explanation it will be assumed to consist entirely of basic carbonate white lead. Occa sionally white lead is still further abbreviated to lead; if it is clear that the name is applied to a white pigment it will be taken to mean basic carbonate white lead, not metallic lead. Similarly, zinc oxide is sometimes called zinc white or merely zinc. is# pigme as leaf 4. of uni ill Thf Matef quer; Zinc 97 perij Uthopq Lith sulfate sulfide! Zinc pure zi| contain pone" % * FLB 001064 CLASSIFICATION OF HOUSE AND BARN PAINTS 27 When whitelead and zinc oxide are lumped together without further details, sometimes under the name lead and zinc, the mixture will be assumed to be half basic carbonate white lead and half zinc oxide by weight. The terms lead-zinc pigment and lead-zinc, on the other band, usually mean leaded zinc oxide and will be so interpreted. When leaded zinc oxide is reported without further details of com position it will be assumed to consist of equal parts by weight of basic sulfate white lead and zinc oxide. - 3. Uncertain names for titanium figments.--In some label formulas names of indefinite meaning appear, such as: Titanium, titanium white, titanium pigment, titanium-barium, and titanox. When there is uncertainty about the nature of the titanium pigment it will be assumed to be titanium-barium (25 percent TiOa) as listed in table 1. The following names approved by the American Society for Testing Materials (8, pp. 625-626) and by the National Paint, Varnish and Lacquer Association (18) will be interpreted as indicated: Titanium dioxide, commercially pure- titanium dioxide containing on analysis not less than 97 percent of titanium dioxide. Titanium oxide is a synonym for titanium dioxide. Titanium dioxide pigment, however, will be considered to mean titanium-barium (25 percent Ti02) as listed in table 1. Titatnum-ma^nesium or titanium-magnesium pigment, 30 percent of com mercially pure titanium dioxide and 70 percent of magnesium silicate by weight. On analysis it should contain not less than 28 percent of titanium dioxide. Titanium-calcium or titamuni-caieium pigment, 30 percent of commercially ure titanium dioxide and 70 percent of anhydrous calcium sulfate by weight, fn analysis it should contain not less than 28 percent of titanium dioxide. Titanium-barium or titanium-barium pigment, 25 percent of commercially pure titanium dioxide and 75 percent of barium sulfate by weight. On analysis 'it should contain not less than 24 percent of titanium dioxide. When titanium-barium containing 30 percent of titanium dioxide (not less than 28 percent on analysis) is used its composition should be eloarly revealed either by a footnote or by printing the percentage of titanium dioxide by Weight in parentheses after the name, thus, "titanium-barium (30 percent titanium dioxide)." If the manufac turer so desires, the actual content of commercially pure titanium diox ide and of pigment of low opacity in any of the composite titanium Baenfcs may be listed separately in the label formula. ead titanate, for purposes of classification, is considered a lead ' pigment, not a titanium pigment. It should always be listed clearly as lead titanate in the label formula. 4. Uncertain names for sine sulfide pigments.--Zinc sulfide pigments > of uncertain name will be assumed to be lithopone as listed in table 1. The following names approved by the American Society for Testing ^Materials (3a, pp. 638-634) and the National Paint, Varnish and Laei],quer Association (18) will be interpreted as indicated: Zinc sulfide, commercially pure zinc sulfide containing on analysis not less than "percent of zinc sulfide. Zinc sulfide pigment, however, wifi be taken to mean .hopone as listed in table 1. | VjLithopone, 28 percent Of commercially pure zinc sulfide and 72 percent of barium Tate by weight. On analysis it should contain not less than 26 percent of zinc 'fide. .*' $nc styUde-bariUm or zinc sulfide-barium pigment, 50 percent of commercially PC zinc' sulfide and 50 percent of barium' sulfate by weight. On analysis it should ifitain not less than 45 percent of zinc sulfide. The term "double strength lithoA" will be taken to mean zinc sulfide-barium. FLB 28 TECHNICAL BULLETIN 804, V. S. DEBT, OF AGKICOLTOEE Zinc sulfide-magnesium or zinc siMde-magnesium pigment, 50 percent of com mercially pure zinc sulfide and 50 percent of magnesium silicate by weight. On analysis it should contain not less than 45 percent of zinc sulfide. Zinc sulfide-calcium or zinc sulfide-calcium pigment, 50 percent of commercially pure zinc sulfide and 50 percent of anhydrous calcium sulfate by weight. On analysis it should contain not less than 45 percent of zinc sulfide- This pigment, which is not listed in table 1, should be broken down into its two ingredients in computing the volume analysis. Titanated lithopone, 15 percent of commercially pure titanium dioxide and 85 percent of lithopone by weight. 5. Use of trade names for paint ingredients.--Paint ingredients should not be reported in label formulas by trade names subject to copyright. When trade names are so used the ingredient must be identified satisfactorily before the paint can be classified properly. The comprehensive "raw materials indexes" in Gardner's Physical and Chemical Examination of Paints, Varnishes, Lacquers, and Colors (11, pp- 465-678), list most of the paint ingredients by trade brand together with information necessary to identify the nature of the ingredient and with the bulking values. Whenever ingredients reported in label formulas can be clearly identified by means of these raw materials indexes the bulking values reported therein may be used in the volume analysis and classification. A few trade names sometimes found in label formulas are listed in table 19. T1 < 1$.--Ambiguous names and trade names for paint, ingredients Name1 of Ingredient Composition to he assumed when no further explanation is : given in the label formula (proportions are given in per centages by weight), or equivalent of term fleepara. graph indicated In section on Ambi guities ' Albalith........................ Aliphatic hydrocarbons Trade name for lithopone,---------------------------------Mineral spirits_______ ________________________ ___ ,, Alkyd resin---------- - Resin, see table 2---------------------------------- ------------------ ^ Aluminum flake_____ _ Trade name for aluminum silicate, .w Aluminum paste----. Aqueous suspending agent----- W85apteerrc-ent aluminum, 96 percentmineral spirits..__ ._____ ___ Aqueons bodying agent Aromatic hydrocarbons Solvent naphtha. Asbestine_____._________ Trade name for magnesium silicate____ Ash.................... ............. Bakelite resin Brier'iwnvolatile...... ............................. Trade name* count a? rosin, see table 2.. Basic carbonate of load..___ Basie carbonate white lead___-____ --. Basil' le.nl carbonate................ Basie lead sulfate__________ Basic suifate white lead.......________ Basic sulfate otlead.i-------- do. Bone black______ _________ gpercenicarbon, 02percentcalciom phosphate. Brown oxide. ^____________ __ 30 percent ferric oxide, 70 percent siliceous matter.................... Cakrized_____________ ______ Bodied, (descriptive of a drying oil). ...... .......... -.......... Carbonate of lead- - _________ Basic carbonate whito lead----------------------------.,-------------- Carbonate lcaa,,____ __ _____ ___do....................... ..................... ............................. Chrome green-------- -------------- Chrome green, reduced, see below.____________________ Chrome green, c. Chrome green, medium, see beiow. ..................... ......... Chrome green, o. p., light-- 90 percent lead chromate* lO percent femc ferrooyanide^... Chrome green, e. p., medium. 75 percent lead chromate, 25 percent ferric ferroeyanide--. Chrome green, c. p.t dark (or 60percent:lea^.cliromate,4fl:percentferrlcfeiTOcyanide^>_ deep). Chrome green,reduced.___.__. 15 percent c. p. chrome green, 85 percent barlum sulfate_. Celite.................... ..................... Trade name for diatomaceoos silica-............................-- Colloidal eolation__________ _ Water.^.. Crypfcone__________________ Cryptone MS, see below___--,,___ __. Cryptane BA____ _--- Trade name for sine sulfide-barium. - Cryptone _ 1 Trade name for rinc sulfide-calcium____ CryptoneMS-.--.--------- Trade name for sine sQlfidoma^neslam^ Dicalite_______ _____________ Trade name for diatomaoeow silica.--... 4>5 13 M 14 13 5 12 % 2 2 2 9 A 2 2 99 9 9 9 5 U 4,6 4,6 44 6 l The names In thislint either should not be used in label formulas (for example, the trade names) or when used require further explanation of their composition in tencs ^f the.ingredfents Jisted ln itafales 1 and 2. When the further explanation is lacking, arbitrary assumptions about their composition will be made as indicated in the second column and discussed in the paragraph ol the section <m AMBioumss 0 Lq 1 < FX + 1 indicated in the last column of the table. . 'V I 3omOn rally On lent, fcs in and 3D.tS t to ; be srly. tical and >ade a of Juts kese i be ines bateSph Seated Jction Uubiteies 4,5 13 i 14 14 ' 13 5 I 12 |--- >--! i .2 2 2 2 9 9 10 :2 2 5 H : i4>65 5 vhen id 2. le as VJJXL GLASSIFICATION OF HOUSE AND BARN PAINTS 20 Taj bl e 19.--Ambiguous names and trade names for paint ingredients--Continued Nazne of ingredient Composition to be assumed when no further explanation is given in the label formula (proportions are given in per centages by weight), or equivalent of term See para graph indicated in section on Ambi- Drier and thinner,._____ Drop black..--- Drying oil-------------- --- Donnolized-------------- Eaudslfled.ofl------- -- Emulsion-------- Ester gum---------------- aer. Extending pigment---- Ferrite yellow1-..........-- Fixed fatty ofL------------Gloss oil----------------------Glycerol phthalate-------Heat-treated-------- ------- Hydrogenated naphtha-- Indian red----*Inert..-.--*----------Inert pigment-------------Iran oxide--*---------- Ivory blade----,----------Japan drier----,---------Keystone filler------ Lead-------------------- -- Lead and sine-------- ------ Lead carbonate------------------Leaded zinc oxide---- ...----. Lead oxide.-............... -......... Lead paste.............. .............. Lead sulfate............---------- IltlL <SUffix)-_-....... ------ ----- Lithopone, doable strength-- Limeolith--....... ........ - Liquid drier--........--.=-- Metallic brown----- ------------ Metro-Nfte-------------- Monastral bine------- ,---------- Ochre------------------------ *-- Organic color.------------------ - Oxide black----------- ----- Oxide brown--1------- ---------- Oxide of iron---....... ............ Oxide of lead-------------- .------- Oxide of titanium. .............. Oxide of zinc.;___________ Oxide red!.----,--------- --*------ Oxide yellow_____________ Ozlo lead-zinc pigment...... Persian Gulf oxide................ phenolic resin..-------------- ... PanditU-.--------- -------- Prince's mineral............... Processed..------------ ---- Pyrax_____................... Ramapo blue................... -- Red oxide.,.............. ---- Resin ester..... ........... -......... Rosin ester............................ Sesquioxide of iron.-.........-- Sienna, burnt---.------- -- Sienna, raw-----------------~ Silica an<^silicates-_______ Silicatea. Siliceous pigments--.......... Soap solution--------------Solution___--r---1............ Spanish oxide.... ........... Sublimed white lead.____ Sulfate of lead..^..^___ Surfex.................. . Suspending agent_ Assume the drier to be 5 percent of the sum of the nonvola tile liquids and that the balance is mineral spirits* Ose^fki^valu/forui^^d^od!-__pbosp ------ Bodied (descriptive of a drying oil)___ Water- Resin, see table 2---------------- -------------- ----------------------------Barium sulfate..--___ do Trade name for ferric hydroxide______________ __________ Use bulking value for linseed oil----______ --50 percent resin, 50 percent mineral spirits................... ......... Resin, see table 2.--............ ......... .................... ....................... Bodied (descriptive of a.drying oil)-- Use bulking value for mineral spirits- ........... .......... ............... 50 percent ferric oxide, 60 percent siliceous matt.... ........... Barium sulfate-- ______...-- ........ ............. Use buffing value for ferric oxide but no dDoent"dfowanceZ. 8 percent carbon, 92 percent calcium phosphate-__________ Drier. Trade name for mineral black._ Basic carbonate white lead when obviously meaning a white pigment but do not confuse with lead In flake form. 60 percent baste carbonate white lead and.50 percent zinc oxide Basiccarbonate white lei _ ______ 60 percent baste sulfate white lead, 60 percent zinc oxide. Red lead----------- ------------- ----------- ------ -------------- --------.... 90 percent lead in flake form, 10 percent mineral spirits.......... , Basic sulfate white lead bat when part of chrome yellow count as lead chromate* Trade name usually meaning lithopone but see Limeolith below. Zinc sulfide-barium................... --................................. ....... Trade name for calcium carbonate..__________________ Drier. 60 percent ferric oxide, 50 percent siliceous matter___ ... Trade name, use bulking value for magnesium silicate. _ Trade name for copper nhthalocyanine................... ....... 20 percent ferrte hydroride, 80 percent siliceous matter... Use balking value 0.08, diluent allowance 0_...... ............ Blackoride----------- ---------------------------- ------------ ----------- 30 percent ferric oxide, 70 percent siliceous matter.___ Iron oxide, see above.........---------- ------.......... Red lead.. Titanium dioxide........... &.......................... .................... Zinc oxide..........--.............---......... ............... 30 percent ferric oxide, 70 percent siliceous matter......... 30 percent ferric hydroxide, 70 percent siliceous matter. Trade name for leaded zinc oxide....................-.............. 70 percent ferric oxide, 30 percent allpcons matter--.... Resin, see table 2..------.----.------------------------- Trade name for lithopone.- ---........ ---................... 50 percent ferric oxide, 50 percent siliceous matter. ____ Bodied (descriptive of a dryirfgolQ........ .............- Trade name for magnesium silicate.------------------------- Trade name for copper phthalocyanine_______ ______ 30 percent ferric oxide, 70 percent siliceous matter. ... __ Resin, see table 2.............. .................................>------- do. Ferric oxide.--------------- ----- ;----------------- --------.. ....... 30 percent ferric oxide, 70 percent siliceous matter 30 percent ferric hydroxide, 70 percent siliceous matter. Magnesium silicateexceptwhenpart ofanearfchpigment, when it is siliceous matter. Magnesium silicate except when part of an earth pigment. When it is siliceous matter. Siliceous matter--________ ____--,,______ ____ _ WWaatteerr.---------------- --------------------------------- -------,------- 80 percent ferric oxide, 20 percent siliceous matter_. Basic sulfate white lead- ---..... ......... -........-__.-<* Basic sulfate white lead but when partof chrome yellow count as lead chromate. Trade name, consider as calcium carbonate______ __________ Water------- ---------- ---------- ---........-- ------ s-- ------ - 12 9 10 10 14 14 '"*7 7 8 lb 11 *'io 13 9 7 7 9 8 9 T 6 4 8 9 8 3 2 9 9 "H 150 8 9 7.9 L9 9 14 14 9 2 2.9 6 14 y, 3Q TECHNICAL BULLETIN 804, U. 8. DEPT. OF AGBICUIVTOBE T1 < 19.---Ambiguous names and trade names for paint ingredients--Continued Name oftogredlent Composition to be assumed when no furtber i gtvssntatho label formula (proportions are j centagcs by weight), or equivalent of term graph indicated on Ambi guities Syanbtae. 'Tradename tor copper phthalocyanlae.. Cbunt as viritfsh __ ___________ ' Thermoly Bodied (d^criptiteofa dt^iQSoU)^--*--__ Thinner___ Thinner and drier___ Assume $lie drier to b6 iiejeenfc of thelamSTthe zUHtvoiatile' liquids and tbatthe balance is mineral spirits. Ti-Bar_____ _-- Tl-CaL-----Timouor..........:-------Ti-Pore.......... ........... Titanium-- Tradename for titantumbariUiB,.--,-- --. Trade name for tltaptumcalcium.___ ____ _______ _____ _____ Trade name for antirtioiiy oxide.___ _____________ ______ ____ Tradename fortitanitud. dioxide--_____________ ____ Titanfom-bmlum (2S percent TiOf)..--___._______--;______ Titanium dioride pigment.. Titanium, pigment----____ Titanium wMte-________.,, Titanolitb........... ................ Titanox___ _ Titanox A (or AA).____ ... Titanox Titaiwx 330-...^--.*...,*-^Titanox O..________ TitanoxL--___--_ Titanox M.________ Ti-Tint _I--.do---.--i -----_H--------------IZIIII do. Trade name for titauated tLfchopone. Titanox B, see below___________ Trade name for titanium dioxide:____ Titanium-barium (26 percent TiOsl___ __ Titanium-barium (30 percent TiO*)____-- Titanium-calcium-_______ -.................... Lead titanate.______ _____.___________ Titanium-magnesium. ___ --_-- Trade name fortitanium dioxide,(colored) Tt-Tono- Trade name for titanated Utbopone. Umber, burnt____ 40percentferricoxide, lOperoont manganese dioxide, 50 percent : siliceous matter. timber, raw..,____________ __ 40 -percent ferric hydroxide, 10 percent manganese riforiffa Varnlsb.------ Varnish base---- 50. percent siliceous matter. 40perccnt vamisbnoavolatile, OO peromt mineral spirits...^. Varnish nonvolatile..._______________ ___________ ___ _ Vegetable drying . Use bulking value for linseed _________ _.________ Venetian raa..-................. 8 percent ferric oxide, 92 percent anhydrous calcium solfete--_J Volatile. -5..--------------White lead____..._____-- Basic carbonate white lead____________ _____________ .___ White lead and sine oxide. 60 percent basic carbonate whitelead, 50 percent sine oxide--.1 White lead carbonate---- White lead sulfate..-___ Basic carbonate white lead,.--...................................... ........ Basic sulfate white lead. ...._: ______ ;_____________ yellow.odtace.-- 20 percent ferric hydroxide, aO percent silioGoaa matter........ Yellow oxide.---------------- 30 percent ferric hydroxide, 70 percent silioeOtis inattOT____ ... Zinc.................................... Zinc oxide when obviously meaning:a white pigment, biifc do not confuse with zinc dust. ........................ Zinc sulfide-calcium. 60 percent zinc sulfide, 50 peroent anhydrous calcium sulfate.J Zinc sulfide pigment-wL. Litbopone--____ ;___ _______ _______________ Zinc white.___________ Zinc oxide._________________ 5 10 10 13 is M H h 3 3 3 4.5 6 33.,66 3,5 3,5 3.5 8.6 3,6 H 11 ii 10 13 2 2 2 2 9 9 2 4 ,4 2 6. Use of chemical symbols for paint pigments.--Table 1 lists some chemical symbols occasionally appearing in label formulas, that repre sent pigments consisting of a single chemical compound. As a rule chemical symbols are used only to provide supplementary information about the composition of pigments and to make that information as explicit as possible, as for example, "iron oxide (Fe)z, 100%)," as indicating a commercially pure iron oxide. The chemical symbol presumably means the content of the ingredient in question that would be found by chemical analysis. The chemical symbol may also be used to show the proportion of the essential constituent in a pigment that is a mixture of substances for which there are no recognized standards; for example, "raw sienna (Fe803l 32%)." In this example the essential colored^ ingredient is really ferric* oxide hydrate or ferric hydroxide, Fe(OH)3, but the analytical chemist would report it in terms of ferric oxide. Among the manufactured colored pigments known as dry colors, the term "C. P.," which stands for chemically pure, is commonly used, as previously stated, to indicate absence of admixture with pigments of low opacity. For example, "C. P. chrome green" means piL oxide pig itlnued ^para graph raicated * section i Ambi guities 5 10 10 13 22 3.5 3.6 5 3.6 5 3 3 3 4.5 5 3.6 3,6 3,5 .3,6 3,5 3.5 3.6 4.6 0 11 11 10 9 13 2 2 2 2 9 9 2 4 1i CLASSIFICATION OF HOUSE AND BARN PAINTS 31 * that the pigment consists entirely of lead chromate and feme ferro- cyanide. The term "chrome green" alone is less definite because it might mean a "reduced chrome green," which is a mixture of c. p. chrome green and such pigments as barium sulfate and kaolin. 7. Inadequate reporting of pigments of low opacity.--Vague terms such as: Inerts, inert pigments, extenders, and extending pigments will be assumed for purposes of classification to mean barium sulfate. The terms silicates, silica and silicates, and siliceous pigments will be assumed to mean magnesium silicate, except that silicates, siliceous pigments, and siliceous matter, when clearly shown to be part of iron oxide, sienna, umber, or ochre, will be considered pigment of low opacity having a bulking value of 0.043 gallon per pound. 8. Omission of colored pigments in formulas for tinted paints.--In tinted paints in which the content of colored pigments is small- -say, less than 5 percent of the total pigment by weight (18)--it is common practice to report only the white pigments and pigments of low opacity, omitting the colored pigments. Some manufacturers may not have an accurate record of the content of colored pigments in their tinted paints. The colored pigments with high diluent allow ances, however, contribute to the equivalent content of opaque pig ment calculated in the volume analysis to an extent far greater than their actual proportions by weight. Carbon and ferric ferrocyanide, which have high, bulking values as well as high diluent allowances, are especially powerful contributors. It is recommended, therefore, that colored pigments having diluent allowances of 2 or more be reported in the label formula whenever they are present to the extent of 1 percent or more of the total pigment by weight, and that colored pigments with a diluent allowance of 4 or 5, or with, a diluent allow ance of 2 or more and a bulking value of 0.05 or more, be reported whenever they are present to the extent of 0.5 percent or more of the total pigment by weight. If the colored pigments in tinted paints are not reported in the label formula, no allowance for their contribution to the equivalent content of opaque pigment can be made in the volume analysis. This may result in assigning the paint to a lower grade than it would have if the colored pigments Were reported. 9. Inadequate description of colored pigments.--ln colored pigments that are mixtures of a colored ingredient and ingredients of low opacity, such as Venetian red, iron oxide, sienna, umber, ochre, bone black, and reduced chrome green, the proportion of the colored in gredient should be stated in a footnote oh otherwise. If such supple mentary information is not provided, the proportion of colored pigment will be assumed to be as listed in table 19, in which minimum, or nearly miniTnum, contents of colored ingredients are assumed. Thus, failure to report the content of colored ingredient in the label formula will often result in Underestimation of the equivalent content of opaque pigment in the paint, and possibly in its assignment to a lower grade than would be the case if the label formula were more nearly complete. In tinted paints containing only small proportions of colored pigments, the underestimation wul be much less serious than it may be in deeply tinted paints and particularly in colored- pigment paints. Particular care is needed in describing chrome green. Not only are there the c. p. and reduced chrome greens, but c. p. chrome green, FLB 001069 32 TECHNICAL BULLETIN 804, U. 8. DEPT. OP AGRICULTURE being itself a mixture of lead chromate and ferric ferrocyanide, may contain, also lead sulfate or basic carbonate white lead. The pro portions of the lead pigments and ferric ferrocyanide vary very widely according to the color desired. Since the lead pigments are heavy and ferric ferrocyanide is light in weight, the bulking value likewise varies widely. The chrome greens are classified broadly according to color as light, medium, and dark or deep. The light chrome greens contain tike highest proportions of lead pigments and have the lowest bulking values. The composition of chrome green should be stated in the label formula by means of a footnote or other wise and in calculating the volume analysis it should be broken down into lead chromate, ferric ferrocyanide, and, if a reduced chrome green, pigment of low opacity; all of the lead pigments in chrome green, however, may he counted as lead, chromate. The assumptions to be made when the composition of the chrome green is inadequately reported are listed in table 19. 10. Incomplete description of drying oils,,--Unless otherwise indicated in the label formula, drying oils will be assumed to be raw, boiled, or refined oils as listed in table 2. The terms drying oil, vegetable drying oil, and fixed fatty oil, which sometimes appear in label formu las, will be assumed to imply oil having essentially the same specific gravity as raw linseed oil and the bulking value for raw linseed oil will be used in the calculations. The terms heat treated,, processed, thermolyzed, calorized, or durmolized, when used to describe drying oils, win be assumed to mean bodied drying oils as listed in table 2. When tung oil is reported it will be assumed to be bodied tung oil as listed in table 2. The term synthetic drying oil will be assumed to mean a product having the bulking value listed for varnish non volatile in table 2. When bodied oil is reported in the label formula it is recommended that its specific gravity be given as supplementary information either in a footnote or in parentheses, thus, "bodied tung oil (sp. gr, 0.975)." When the specific gravity is so reported the bulking value calculated from it (1 ~s~ (8.33 X 0.975) = 0.123L for the bodied tung oil cited) will be used in the volume analysis. U. Incomplete description of vanish--The term varnish, when not described adequately by a footnote or otherwise, will be assumed to include volatile as well as nonvolatile components. For the purpose / of volume analysis it will be counted as 60 percent by weight of mineral spirits and 40 percent varnish nonvolatile, as listed in table 2. 12. Incomplete description of drier.--Unless the volatile and non volatile portions of drier, liquid drier, or japan drier are reported, all of it will be counted as volatile liquid with the bulking value given in table 2 under the. heading Volatile liquids. When the nonvolatile content of drier is reported, it will be counted in the volume, analysis as part of-the nonvolatile liquid in the paint, using the bulking value listed in table 2 under the heading Nonvolatile liquids. Very often the drier and the volatile thinner are lumped together as a single item in the label formula under some such description as thinner and drier, or merely drier. In such case, the drier, as listed in table2 under the heading Volatile liquids, will be assumed to amount to 5 percent by weight of the sum of the nonvolatile liquids and the FLB CLASSIFICATION OF HOUSE AND BARN PAINTS ' 33 remainder to be volatile thinner. For example, if the composition of the liquid is reported to be: percent Linseed oil------------ --------------------- -- - ---------- --------------- ----------------- ----------Tung oil---- ,,--------------------*----,--------- ---- -- ---- ,,-------------- Resin-,-,--.--.--------- --.------------- ----------------------- --- --------------------------------- Thinner and drier (or, drier)_________ ____________ ___________ ____ _-- -- 45 15 5 35 Total____________ -__________---___________ ________ ______ -- 10D the drier will be assumed to amount to 3.25 percent and the volatile thinner 31.75 percent. When the term turpentine and drier is em ployed, the balance in excess of the drier will be accepted as turpentine. Sometimes drier and thinner are reported separately but the amount of drier is disproportionately large. Thus the foregoing example might read: Peremt Linseed oil____________________ _____________ -______ --________________ - Tung 0)1------,_______ ______________ -- --____ -,-- - .Resin___.-------- ------- ------------------- ------------------------------------------------------- Thinner-----,---------------- -------------------------------- ------------------------ ------ Drier-.-,.!-;----------------------------------------------- -----------, 45 15 5 20 15 Total--------------________ ______ ______________ 100 If the drier exceeds 6 percent by weight of the sum of the nonvolatile liquids it will be readjusted according to the above rule before making the volume analysis; that is, the drier credited will be limited to 5 percent of the sum of the nonvolatile liquids and the remainder added to the thinner, 13. Incomplete description of volatile thinner.--Unless otherwise clearly indicated, the volatile thinner will always be assumed to be mineral spirits as listed in table 2, Naphtha will be understood to mean varnish makers and painters naphtha obtained from petroleum, unless it is called solvent naphtha or is otherwise shown to be derived from $oal tar. The terms aliphatic hydrocarbons and aromatic hydro carbons will be assumed to mean, respectively, mineral spirits and solvent naphtha. When the thinner used has a bulking value that differs materially from the one that would be assumed for it from these rules, it is recommended that its specific gravity be reported in the label formula. 14. Sophisticated names for water.--Ingredients reported under such names as: Emulsion, emulsified oil, suspending agent, aqueous dis persing agent, aqueous bodying agent, colloidal solution, soap solution, and solution will be considered to consist'entirely of water. 15. Lmcertainties in the directions for application.---Label directions for application usually include instructions for the first painting of new exterior woodwork and for subsequent repainting over old paint. In addition, separate instructions are often given for painting new wood work in three-coat and in two-coat work. Occasionally instructions are given for repainting in one-coat work. As a rule the various in structions differ only with respect to thinning of priming and under coats and call for the same thinning or for no thinning for finish coat in all cases. If, however, they differ with respect to thinning for finish coat, the volume analysis will be computed for each set of instructions and the paint may have to be graded differently according to the pur pose for which it is to be used., ~ If separate thinning instructions for finish coat are given for use of the paint in warm and in cold weather the volume analysis and grade a 4 FLB 34 'TECHNICAL BULLETIN 804, XT. S. DEPT. OF AGBICULTUSK will be calculate for the directions given for warm weather, provided that the extra thinning for cold weather, beyond that for warm weath er, consists entirely of volatile thinner and does not exceed % pint per gallon for prepared paint and 1 pint per gallon for semipaste or paste paint. If the thinning instructions for finish coat specify a permissible range of thinning proportions, for example, "thin with 1 to 2 pints of turpentine per gallon" or "thin with not more than 2 pints of turpen tine per gallon," the maximum addition of liquid will be assumed in calculating the volume analysis and grade. If the thinning instructions for finish coat 'call for thinning but set no definite limit, for example, "thin with turpentine as required," it will be assumed that prepared paint will be thinned with 1 quart of turpentine jpor gallon and that semipaste and paste paints will be thinned with 1 gallon of linseed oil per gallon. If the directions make it clear that less thinning than would be assumed by applying these rules is preferred by the manufacturer the volume analysis and grade will be computed on the basis of the preferred procedure. For example, directions sometimes read: "The paint has the correct consistency for finish coat as it comes from the package but it may be thinned------- i If directions printed on the label conflict with directions given in a color card or other sales literature the directions printed on the label will be followed in the volume analysis and grading. If no directions for application are printed on the label it will be assumed that prepared paint will be thinned with 1 quart of turpentine per gallon and semipaste or paste paint with 1 gallon of linseed oil per gallon. SUMMARY This bulletin presents a procedure for classifying house and bam paints by group, type, and grade, evolved as a result of more than a decade of research by the Forest Products Laboratory of the Forest Service. The system of classification described is recommended by the Department of Agriculture as a step toward obtaining more lasting and satisfactory service of paints on wood, and as an aid to paint users in identifying correctly the kind of paint needed for specific purposes, the characteristics of the paint offered, and how me paint should be applied and maintained. The information presented here is of value primarily to paint technicologists concerned with determining the paint classifications to be printed on labels or with checking the printed classifications to see that they agree with the formulas. Paint users wflf in the main depend on less technical information based on this material, but those who are willing to master the technical details will be able to use this bulletin in the classification of any paints that bear a formula on the label, or for which the formula can be obtained. The procedure proposed involves the addition of a simple classi fication mark to each paint label, which will indicate (1) the main group to which it belongs, such as "white lead" or "titanium-leadzinc"; (2) the content of white lead or zinc oxide; and (3) the relative quantities of opaque pigment, total pigment, and total nonvolatile. The bulletin presents the necessarily intricate calculations upon which this simple system of classification is based. (1) (2) (3) A) (3a) (4) (5) (17 (1 f FLB CLASSIFICATION OF HOUSE AND BABN PAINTS 35 LITERATURE CITED (1) ANONYMOUS. 1938. RESOLUTIONS ADOPTED [AT NATIONAL PAINT, VARNISH AND LACQUER ASSOCIATION' MEETINGl DISCODEAGING FREE DEADS AND RECOM 2 MENDING ~X + 1 1 < . Amer. Paint Jour. Conv. Daily 23 (3D): 15], 22, 24. (2) ! #1939. MORE Q1 q ,<1 ~ < q X . q X 3 Q [Editorial] Amer. Paint Jour. % &' ( )& * +24(8): 44-45. (3) A S T+ 0 _ 1 q X_ 0 ~X M .0 q 3 1 0 1 s 1939. STANDARD SPECIFICATIONS FOB TITANIUM DIOXIDE PIGMENTS. , - ( .0 1 3 4A. S. T. M. Standards 1939, pp. 025-626. (3a) A S+ 0 _ 1 q X_ 0 y ~X T M .0 q 3 1 0 1 56 7 89 : 81939. 1 q 1 _ 0 ~0 _ 1 0 Xq ~X< e ;<0 q _ ~0 = >?0 3 + q . A. S. (4) @ AB X q T. M. Standards 1939, pp. 633-634. , F. L. BC D E F G H I J1935. 1 X < - QXX 's 0 X~ Q 3 1 +< KL0 q QX M1 0 q t. Paint, Oil, and Chem, Rev. 97 (21): 28, 30, 32, illus. (5) NO P QR S TU V WW X Y1937. THE QX ZZ [ \ ] ^ _ `1 1 _ 7 0 1 0 qt X< + : 's Xp 1 0 q 3 Q < _7 1 q _ XX 1 0 . Oil, Paint, and Chem. Rev. 99 (4): 9-12. ab a c d f gg h ij k(6) 1937. X X s y s + ~X _ 1 0 ~ 0 q 3 QX 1 0 q t s. Indus, and Engin. Chem. 29: 1018-1026, illus. (V) 1938. CLASSIFICATION OF HOUSE PAINTS AS A GUIDE TO THE STUDY OF l m n~X + 1 0 Xq . Drugs, Oils and Paints 53: 92-95, illus. (8) 1938. WHAT CAN BE DONE TO MAKE PAINT MAINTENANCE MORE SUCCESSFUL. Amer. Paint Jour. 22 (22): 22-26, 54-60, illus.; (23): 21-23, 55-67, illus, o() B q 3 , E. H. p q1935. .0 q _ 0 3 + q t s / Amer. Soc. Testing Materials, Symposium on Paint and Painting Materials, pp. 73-80. Philadelphia. r s t(10) F , W1 q R. u v w f19401 0 q r t +1 0 1 ~X x y z M q1 +0 t ur .0 Q 1 0 q t 0 3 + q t s Amer. (11) @ @ { |.* Soc. Testing Materials Bui. 105: 35 38. G1 q , H q y A~ . } ~1939. Q 0 _ 1 1 q _ Q +0 _ 1 1 +0 q 1 0 Xq X~ 1 0 q t s, 1 q0 Q , p. c, A_ r s 1 q _ XXr s . Ed. 9, rev., 578 pp., illus. Washington, (12) H1 3 1 r , 1. D. 1935, 0 1 q 0 .+0 3 + q t s In Amer. Soc. Testing Materials, Symposium on PainLand Painting Materials, pp.88-95. Philadelphia. (13) H1 , R. L., and RX , C. H. 1935. 1 0 3 + q . In Amer. Soc. Testing Materials, Symposium on Paint and Painting Materials, pp. 81-87. Philadelphia. (14) HX , C. D. X e q1932. Q .0 q _ 0 3 + q t s Fed. Paint and Varnish Prod. Clubs Official Digest (118): 957-964. (15) HX+1 q , H. P. 1925. 1 0 q 0 q 3Xq Q ~1 + , D. S. Dept. Agr. Farmers' Bui. 1452, (16) 33 pp. K 1 0 q 3, K, JV 1928. 1 0 q t 0 q 0 31 0 0 q 3 1 1 X XqX~ q X Q Q X 3 Q D1 7X 1 : X+ Q qX Q X~ Q D1 7X 1 0 q M 1 0 q t1 (17) (18) AND THE PAINT TEST FENCES AT THE NORTH DAKOTA AGRICUL TURAL _ X 3 . Paint, Oil, and Chem. Rev. 85 (24): 10-11; KX q (25): 10-12. < , L1 q _ t . ' 1938, '" 1 0 1 q 1 ." Amer. Paint Jour. Conv. Daily 23 (3-D): 7, 21,A Paint, Oil, and Chem. Rev. 100 (23): 42, 44, 46, 161. N1 0 Xq 1 P1 0 q , V1 q 0 Q1 q L1 _ A X_ 0 1 0 Xq, Iq _ ., S_ 0 q .0 ~0 _ S _ 0 Xq . 1938. q X+ q _ 1 R ~X< ~X + 1 .1 < 0 q 3 6 pp. Washington, D. C. FLB 36 TECHNICAL BULLETIN 804, TL S. DEBT. OF AGEICULTUKE (19) RX< , F., and L1 , C. S. 1938. PAINTS AND VARNISRES. ACCELERATED EXPOSURE TESTS. N. Dak. R^gulat, Dept., Div. Foods and Chein. Bnl, 53, 190 pp., illus. (20) S1 <0 q, A 1 Q HX< Xq . 1927. THE INDUSTRIAL AND ARTISTIC TECHNOLOGY OF PAINT AND VARNISH. 4S9 pp., illus. New York and London. (21) Uq 0 S 1 T 1 D 1 + q , P X_ + q t S E _ 0 ~0 _ 1 0 Xq _ C0 X++0 . D , F0 0 0 Xq 1 1936. PAINTS, TITANIUM-ZINC AND TITANIUM-ZINC-LEAD; OUTSIDE, READY- MIXED, Q0 . 12 pp. Washington, D. C. 1938, PAINTS^ LEAD-ZlNC BASE, READY MIXED AND SEMI-PASTE, WHITE 1 q .0 q 14 pp. Washington, D. C. (23) V1 q V1 _ 7 , C. H. 1939. _ 0 q 3 1 q 1 0 q 3 1 0 q s. Iowa State CoL Ext. Serv. Cir. 261, 46 pp.> illus. (24) W1 Q , A<0 q H., and B X q , F 0 _ 7 L. 1939. ._ 1 0 q 1 0 q t s In Sutermeister, Edwin, and Browne, Frederick L., Casein and Its Industrial Applications, ed. 2, pp. 315-353, illus. New York. i t U. S. GOVERNMENT PRINTING OFFICE 0--1947 FLB 001074 Mat, /y'/ jg. ;;i " " ' - * i-f*. if / >- ......... ** # * ^Mmmmimm ., s,... jf *>*9 ,*r> - !' "' 1 1 `, Gi J:. - - * f *,i **TW3TOIWfl3fBW"iUr'' *-' ,. i t ', -'". J" <P,t ft'-1 .- --. -* f l> ,.:, - -*.1! J*.t V.. /*._'** L ``j?''* *.* ^ ,,., f *" - ` '!'^.s - * 5-L V ' . ' |,.|rf|W-| f ^ J +* ' j ; `> * IIHiy Q KM ^Iv^S Paint for Your Job t>mm aww 8*0^Q v i[cOU'LL find paints have changed since your last paint ing job. For one thing, nearly all paints now bear a state ment of the com position, or formula, on the label. Understanding what that composition means in terms of the performance to be expected of the paint, however, is difficult because most paint formulas are complicated. The Forest Products Laboratory proposes a system of classifying paints into groups, types, and grades based on composition which would make it easier to explain.. The simplest white paint and by far the oldest is pure white lead paint, often called "lead and oil." It is usually purchased in the form of a soft paste rather than a liquid paint and. by weight rather than by volume. Soft-paste white lead is sold in white only; to obtain light colors it must be tinted on the job with colors-in-oil. Soft-paste white lead usually contains 89 percent white lead, nine percent linseed oil, two percent turpentine; and is so labeled. No other paste paint should be called "white lead" or "lead and oil." The new development in white lead paint is its sale in the prepared form, in light tints as well as in white, and >y the gallon instead of. the pound. It costs more that way but may be mare convenient for those not accustomed fp thir ting paste paint on the job and tinting it. The formula : for ; quid white lead paint of good quality should read:' '/ . dwi.y;: nr; by weiK.b.1 fy.-dc c a i bon lie 'vhm lend)..................71% --j Limned oil. ................... 86% wcUlu...............................................20 --^ Tur^eulmc and drier................. 14 ions? 100% The important figure is the one in boldface type, which should not be less than 70 percent: if the paint is to be con sidered of good :quality. VSiJCeESSFUL FARMING, MAT, 1941 J- Pure white lead paint, which belongs to Group L of the Forest Products Laboratory's classification, still has some important advantages over newer kinds of paint. First, when bought in paste form, it is essentially a "srand.ard" product, is therefore easy to buy with assurance of good quality, and at retail prices is usually cheaper in net cost than other white paints of comparable quality. Second, for those who do not paint often enough to keep the paint coating from disintegrating seriously between, times, wlilte,, lead paint: is-the wisest-chaiee 'bcia.use inbreaks down very slowly and by a fine crumbling that, always leaves an easy surface to repaint. ST paints of good quality sold in the prepared form, . in white and. the lighter colors, are now paints of Group TLZ. The name "titanium pigment" as used in paint formulas means a mixture of titanium dioxide and ex tending pigments in unspecified proportions. Titaniummaghesimn means a definite mixture of titanium dioxide and magnesium silicate. Titanium dioxide is a brilliantly N41698.48 FLB 001075 ifflik. . >v - & % ' "t-i p ..... * , Ad" ^ S2** 'Hs' $ **<> <#' * * a,. UH ECK.ING in to trac cor-opra.ting habits, I find that a good maryV tractor owners are the victims of a/fnisfit be tween the engine and the fyfel they are burning. It is not an argylrient of one fuel against another, i oral tank wagon prices and the state gasoline tax in many cases make oncylype of fuel the logical choice. Rather, it is a case of adapting your tractor 10 the fuel you select. You needn't beyit engineer to con duct a fuel clinic /if your own for your tractor this spring. You may be sur prised at what/Vou learn. In this story, ni try to luring to light the simple, fundamental points of harmony be- 1. 1W\ %<* oXt; fV "*d' _e >: <artioiVs>e* l" rfccoYly^V>P*p^''ei'S JSsto' 'u \ . w,, a. , *C<SV oi otfa . k,,ocV ,,t foe of1] ,,, sAe<eie' * ^'.l a<e ^ W* 8 \ **'* \ By Carlton Stoddard Uveen your traeto'f- engine and !he rations in its fuel tank. If your tractor- rnulor is "sweet," it walks away with the load and con serves fuel. If it is off-key for the fuel you are burning, the signs to look for are a knock or ping, overheating, sluggishness, or too big an appetite. One factor to consider in your trac tor fuel clinic is compression. Fuel-air vapor in. the cylinders is like a coiled spring--the more- it is compressed, the greater the recoil force. The basic compression ratio of different tractors varies, to begin with. Compression ratio is simply the volume of fuel-air mixture in the cylinder at the bottom of the'ylown.stroke in proportion to its volume\compresse.d at the top of the upstrokcX Low-compression tractors have a ra\^o of four to (trie or less, medium-compression tractors about live to on.r.Yprnd high-compression tractors six to One or over. l'o got the irfaximurn power from any fuel it should, be compressed as much as it will sfitncl. Beyond that point it will detonator explode vio lently' in the cylinders\You hear it as ping--ignition with a "Tang" n flier t.hart. a "push." Prolonged, ping nav hammer and heat your motO^unt. (he pistons or connecting rod 'Year ngr break down. \ TJ \ f I l.dl.S are rated by a scale of octimc numbers which arc simply a mcasurV rnenl; of "anti-knock.'' Here is a rou.glK octane scale [ Continued on page 52 \ SUCCESSFUL FARMING, MAY. 1941 FLB 001076 13 By Dr. F. L Browne, U. S. foresi Produces laboraiory vF' '.jk-A-jf ,, ^ i v-'1 1 *,; i , ', *' * j^-' i ---- & 'f 4f$yr Lki^rf white pigment having several times as much opacity as white iead or zinc oxide; hence a little titanium dioxide in paint goes a long way. *CQ RMT.CALLY titanium dioxide resembles silica,'orsand, and in paint-making titanium dioxide, except for its great opacity, has die same effect as the extending pigments, ft has none of the chemical effects of white iead and zinc oxide. A titanium pigment in linseed oil makes a paint that, chalks away completely in a short time; to make it a durable paint reasonable proportions of white lead and zinc oxide must be. added. The real novelty of the TLX paints is not that they contain a little titanium dioxide but that they contain much more extending pigment and yet have' as much or even greater opacity than the old LX. (lead-zinc) paints. Paints high in content of white lead and zinc oxide waste away slowly by chalking but they hold'dirt and be come gray in consequence. By reducing the content of while lead and zinc: oxide, chalking is speeded and the paint stays cleaner but. of course chalking must not be allowed to go so rapidly that: the durability is impaired. .Figures A, B, and C illustrate the development of checking and cracking in TLZ paints as the cuntent: of white lead and zinc oxide diminishes. Paint A is classified as type 215, which has a high content of white lead and zinc, oxide, with the white lead predominating- over the zinc oxide. Paint B is of type 3C, having medium content of white lead and zinc oxide with a little more zinc oxide than white lead. Paint G is of type 4C, having low content of white lead and zinc oxide with considerably move zinc oxide than while lead. These three paints rep resent reasonably well the range in types of TLZ paints now on the market. Note that paint A after 30 months facing south shows fine checking in a "reticulate" (network) pattern, but no coarse cracking. The checking began, however, after only eight: months.' Paints B and C remained entirely Tec from checking and cracking for nearly 24 months but: after 30 months drey' both show much coarse cracking, which is fairly conspicuous. Paint B is beginning to curl at the edges of the cracks, which leads very soon to flaking. Paint C is not yet curling and may nor do so, but on the other hand it is ch.al.king away rapidly. W0 choice among the paints of types 2B, 3Cl, and 4G should depend, upon the program of main tenance the buyer expects to follow. If he repaints every three to lour years, type 4C offers advantages accause of its cleanliness and long freedom from checking and cracking, but it docs not hold tints well even when special "chalk-resi.sianl" kinds of titanium dioxide arc used. If the buyer repaints every four to five years, type 3C offers good cleanli ness, fair tint-retention when made with chalkresistant titanium dioxide, and fairly long freedom from checking and cracking; but a good deal of scraping and sanding to remove loose and curling paint must be done if the intervals between paint ings are too long. Type 2B holds tints still better, is reasonably clean, and is fairly easy to prepare for repainting. Its early checking, which may be con sidered a temporary disadvantage, is in reality an important protective measure against more serious difficulties later on. Those who may wait more thau five years between paintings will probably be better satisfied with type 2B than with either of the others, hut they will be still safer if they use. pure white lead paint. Palms-can be classified accurately from their formulas only after certain, complicated calculations have been made. A rough estimate can be made, however, by com paring formulas with the representative formulas given in the table (page 30) which illustrate typical palms of types 2B, 3C, and 40--presumed to be prepared paints. For paint of type 2B- the white, lead and zinc oxide amount to 41 + 14+27 -- 82 percent of the pigment. For paint of type 3C .the white lead and zinc oxide come to 17 + 17 + 32 -- 66 and for paint of type 4C to 15+25--40 percent of cite pigment. If on examining the formula of a. paint you find that the sunt of the white lead, and zinc oxide falls above 55 but below 75 percent of the pigment, the pai.ru is probably of type 3Bor 3C, (3B if the white lead greatly exceeds die zinc oxide). If the paint is of good, quality the percentage of pigment in the paint should vary with the proportion of white lead and zinc oxide in the pig ment as indicated by the three examples.; Continued on page 30 successful FARMING, MAY. mi FLB 001077 Thfc shift to tractors on the Guy Gee fajm, Livingston County,. Illinois, left waste space in the 32- by 40-foot born. Altho now 50/years old. Its loft was made into a snug poultry house for 370 hens at a cost of $250, incAvdtng electric wiring and weatherproofing. An/elevator at one end makes the handling of fp4d and bedding easy. There is a cleanout chujb at the other end. During season, eggs go to a local hatchery, at other times to auction/or the local market Poultry Adopts the Old Horse Barn Number 2 of a Series on What to Do With Old Horse Barns By F. J. Keilholz, Universily of (Hinot's t OR RF.NT" signs have gono up on even some of (he finest horse barns since almost 12 million draft animals disappeared from the American farm scene. Fred Adams and Guy Gee, farming near For rest., Illinois, have demonstrated how this otherwise waste space and expensive overhead can be turned into profit with poultry. Adams rents his .plac'd, but his landlord told him if he wished to convert the barn into a poultry house to go ahead. The flock is now one of the farm's major enter prises. Guy Gee made his hayloft into a poultry house which, like lhat made by Adams, is electrical ly lighted and soon will be equipped with convenient running water. /. / Fred Adams and Daughter Ruth in J their poultry house made from a barn. A renter, he spent J69 on job X d trrgrcn oz <n fiTrrrrH nlr | 1 XLJ <2=r wJ07 -------------------------------- 1 ---- BOOSTS i .............................................i i rf| Fred Adams, Livingston Coun ty, Illinois, tore the horse equipment out of this 4Q*yearold barn and used half of it for hens in 1939-/Returns were so pleasing he Completed the other half an/ went into the winter of 1940 with 300 White Leghorns. Lumber from an old granary was used to make an inside wall. Straw is blown into the top of the barn SUCCtSSFUt. rARMING. MAY, 194. FLB 00107 * MICHIGAN ARCHITECT AND ENGINEER # AUGUST 1941 Durability of Paint Jobs Studied ISCUSSING data obtained from a series of D experiments conducted by the Forest Prod ucts Laboratory at Madison, Wis., Dr. F. L. Browne reports that the durability of paint on the exterior of houses has been found to depend on the they had ever been before. To meet the demand for two-coat initial application, painters had to invent a new technique in winch the full amount of paint previously applied in three coats was put on in two by greatly re ducing the spreading rate of both coats. The new tech nique was one of painting in thick coats. The economy depth of the coating, regardless of whether this was was effected entirely in labor, not in material. obtained by two thick coats or three thinner ones. When modern paints of high opacity are used, it has been discovered that the thickness needed for good durability is much greater than that merely needed to hide the wood. The greatly diminished spreading rates, however, in volved the further requirement that the paint for both coats be unusually high in content of total pigment so that the consistency would be favorable for application in thick films without running and sagging and without wrinkling during drying. Two-coat painting, where one paint is used for , both applications, or a combination of special primer and conventional prepared paint for the finish is employed, often gives, rise to short-lived paint jobs because the necessity of building satisfactory film We may call this technique of initial painting the twocoat system with self-priming. When done honestly by workmen who had mastered the technique, it proved far more than a temporary expedient and compared favorably in durability with good three-coat work. When done incompetently, the shortcomings were usu thickness has not been fully appreciated by paint manufacturers, painters and paint users, it is ex plained. Two-coat systems consisting of a special primer and a finish paint made for application in heavy coats are, however, less likely to be applied ally apparent before the painter could escape responsi bility for them. Study of special primers overthrew the traditional theory that priming paint for wood should be low in content of pigment and high in content of volatile thinner to -promote deep penetration into the wood. too sparingly. Deep penetration, in fact, proved to be wasteful and Experimental research has demonstrated a superi ority of well-designed special primers over selfpriming for painting such woods as Douglas fir and southern yellow pine, but it has also been shown that even harmful because it consists of vehicle alone, separated from the paint film, -and isolated in the cavities of wood cells beneath the treated surface. Use ful penetration is limited to the filling, with pigment and vehicle together, of those wood cavities that open primer and finish paint should be. designed carefully for use together, because a primer may give good results with some finish paints and prove incompati ble with others. Declaring that the two-coat system of house directly into the surface on which the paint is applied. When used according to the self-priming technique, ordinary house paints penetrate wastefully and can be improved by restraining undue penetration. One means of controlling this is to incorporate bodied oil in the vehicle. Another means that seems to be less widely painting has changed in the last decade from a prac appreciated is formulation with a high level of pigmen tice ignored and condemned by the industry to one recommended by a majority of paint manufacturers, Dr. Browne continues: tation favoring application of low spreading rate--that is, in thick coatings. Complete elimination of zinc oxide from special primers is recommended by one school of thought on Some of them advocate it enthusiastically, whereas the subject and is opposed by another. Conclusions others accept it in public but regard it in private with about its use must be subordinated to the more funda misgiving or disapproval Much painting with, two-coat mental problem of compatibility between primer and systems has been thoroughly satisfactory and much of finish. The finish paints on the market differ so widely it has proved seriously lacking in durability. The suc in properties that no one primer can be expected to cessful work demonstrates that a substantial economy prove compatible with all of them. When the finish is realizable from the practice. The unsuccessful work contains no zinc oxide, the primer should be zincless; demonstrates that the conditions necessary for a .satis on the other hand, some zincless primers produce alli- factory two-coat job are not yet understood thoroughly gatoring (intersecting circles) and intercoat flaking of by all manufacturers and users of paint. finish paints containing zinc oxide, which is corrected Accepted practice formerly required a minimum of when zinc oxide is incorporated in the primer also. three coats for initial application and two coats for re Since the special primers With controlled penetration painting, In the course of long experience and competi lend themselves readily to a high level of pigmentation tion, materials and procedures were adjusted so that favoring application in thick coats, may be made With three coats would supply sufficient paint to ensure satis a high content of Opaque pigment, and offer great pro factory results but would avoid any wasteful excess. tection against spotted chalking and fading, they Serious rebellion against these standards began about were proposed as a particularly effective means of meet 1920, when a boom in house construction following a ing the demand for two-coat initial painting. long stagnant period found labor costs far higher than Careful attention to spreading rate in its relation to 70 N41698.49 FLB 001079 3 MICHIGAN ARCHITECT AND ENGINEER thickness (if coating is now more usual than it was in 1920 because of the much greater opacity of modern paints. With many special primers and finish paints of the present time, satisfactory hiding can be obtained with only half the thickness of coating necessary for good durability. Hiding, therefore, can no longer be relied upon to gauge adequacy of film thickness. The logical development of two-coat initial painting is one-coat repainting. So far there scorns tu be little commercial exploitation of the possibility on the part of paint manufacturers, although one maker of a twocout system recommends it to some of his customers but docs not yet print it in his label directions. In practice much one-coat j-epainting has been done for many years. When repainting is done at reasonable intervals, before the old surface starts to crumble or flake seriously, one generous coat of highly pigmented material, such as is suitable for the finish of a two-coat system, is sufficient. In the series of exposure test* at the Forest Prod ucts Laboratory, the. three-coat jobs with self-priming were materially more durable than the two-coat jobs, as was expected from the difference in the estimated thickness of the coatings. Tt. is pointed out, however, that the two-coat jobs, even without the 'benefit of special primers with controlled penetration, held gloss uniformly just, as long as the three-coat appli cations or the two-e.oat jobs with special primers. Uneven gloss and spotted chalking were found to be caused hy inexcusably scanty application and did not require special primers for their correction. The most durable coatings by far worn discovered to be those* done in three-coat, work with aluminum primer. This proved true with each of the. eigtit finish paints. The average; durability of fifty months was nine months greater than the next best average durability recorded, and fifteen months greater than the durability with self-priming. Mica primer im proved the durability of three-coat work by five months on the average, but Hake lead impaired the durability slightly. It was noted that substitution of a suitable unpigmonted priming oil for the priming layer of threeeoal work may leave, the. durability practically un impaired, veu though the film thickness is somewhat reduced, thus permitting a slight saving in cost of material for the job. However, it was warned that' under such conditions there is serious risk of early development of conspicuous alligatoring. The durability of the two-coat jobs with the different special primers varied greatly, from twentysix to forty-one mouths. Five of nine special primers with controlled penetration made two-coat jobs equal or superior in durability to the three-coat work with self-priming, even though the estimated film thick ness in the threc-eoat examples was materially greater. It is believed that still better durability would have been obtained if these primers had been used for throe-coat, work or if the finish paints had been designed for and applied in deeper coats to build up the film thickness to that, of the threecoat jobs with self-priming. Only responsible firfns our JOHN H. FREEMAN FINE HARDWARE Architects Bldg. Detroit, Michigan TEmple 1-6760 GEORGE W. AKERS COMPANY Sales Agents for Modine Manufacturing Company Patterson-Kelley Company V. D. Anderson Company Korfund Company Electric Air Heater Company 16525 Woodward Ave. TO. 8-5640 Power Light HAMILL ELECTRIC CO. Contracting Engineers TRinity 1-2650 6544 Beaubien B. F. STURTEVANT CO. Western Division, Inc. Fans--Blowers--Steam Turbines Air Conditioning Equipment Forced and Induced Draft Fans Vacuum Cleaning Systems Planing Mill Exhaust Fans Phone Cad. 9260 812 Michigan Theater Bldg. Detroit, Michigan C. A. PAVEY, District Manager r--Patronize them FLB 001080 30 The Right Paint for Your Job [ Continuedfrom page 73 ] The liquid in house paint of good quali primer and finish paint together arc caLlcd ty should contain not more than 15 per a "two-coat system" and the recommenda cent volatile thinner and drier (mineral tion is made that new woodwork may' be spirits and turpentine arc acceptable painted with two coats, one of primer and volatile thinners but water is not) and the one of finish paint. Figure E shows that the balance should be linseed oil--except that special primers of good quality when so soybean oil may be substituted for not used arc in fact much superior to the older more than one-third of the linseed oil. A method of using the finish paint for both small proportion, of lung oil is likewise coats. The left-hand halves of the four acceptable. boards shown were "two-coatcd" with I.NOTHER new development of recent primer plus paint but the right-hand halves simply received two coats of the years is the special priming paint for use ordinary house paints. On Douglas Fir and with house paint. Formerly one paint was Southern Yellow Pine, however, the "two- used for all coats of any one paint job, coat system" is not so durable as three-coat tho the paint was thinned with a little work starling with aluminum primer. extra linseed oil and turpentine for prim If five years is considered a reasonable ing coats. The old practice is slightly interval between paintings for the house, cheaper than the modern one but better the service buildings (because of farmers' results arc obtained with the special prim tendencies to let (hem go-twice ns long) ers whenever the. job calls for more than need 10-ycar paint. Red paint cun be made THIS BOOK ON one coat of paint. to-last 10 years, hut no white paint will do The special primers are of two kinds, so. Another good choice for service build each for a different purpose. Aluminum ings is aluminum paint (two coats) of the FARM BUILDING priming paint is especially useful for the first paint job on new woodwork of such woods as Douglas Fir and Southern Yel kind already described for priming wood. R ED paint has great opacity. It does not Free low Pine, which have wide bands of hard, take a great deal of it to hide wood and I dark-colored summerwood from which give it a red color. To last 10 years, how paint tends to Hake off loo early. Figure D ever, at least one gallon of red paint of che shows the advantage of this use of alumi very best quality must be applied for every num priming paint. The left-hand halves of 250 square feet of surface on new', smooth the four boards were painted with one coat woodwork. Rough, weatherbeaten wood 'TpHE Federal Extension Bureau, of Oregon Agricultural College has published this valuable booklet to help solve your farm building problems ... In it you'll find the answers to almost all of the common ques tions regarding materials and methods for constructing new and repairing old farm buildings: proper methods for poultry housing; suggestions for grain storage; how to avoid heat loss in livestock barns; how to apply new toofs right over the old . . . these are just a few of the 160 subjects covered. Askfor'*FederalExtension Bulletin No. 540." Write Red Cedar Shingle Bureau, Seatde, U.S.A., or Vancouver, B.C., Canada. of aluminum priming paint and two coats of white paint; che right-hand halves were painted with three coats of the white. The first and third boards were of Douglas Fir and the second and fourth of Southern Yel low Pine. They were cx posed fachigsoulh for 45 months before the photograph was taken. The label should indicate clearly that the aluminum paint is designed primarily for painting exterior woodwork. Aluminum paints offered for many painting purposes including wood merely incidentally have not, in the writer's experience, proved capable of giving the results shown in figure D. The second kind of special primer for work takes still more paint, at least one gallon for every 200 square feet. If the painting is done in two coats, the first coat should be applied at 450 square feet per gallon on smooth wood and 350 square feet per gallon on rough vvood and the second coat at 550 square feet per gallon on smooth wood and 450 square feet per gal lon on rough wood. Red barn paint of the best quality can be so applied but most of the barn paints on the market cannot. Red barn paint of good quality should contain not less than 55 percent pigment, of which at lease 33 percent should be ferric oxide. The balance of the pigment is usually described as calcium sulphate, REMODEL FARM BUILDINGS WITH RED CEDAR SHINGLES house painting is commonly described as "house paint primer" or "house paint undcrcoruer'5 with che properry' of "con trolled penetration." Primer and finish paint should be made by the same manu "silicates," or calcium carbonate. A few red barn paints contain a small porportion of zinc oxide, which is a desirable ingredi ent. The liquid should contain not more than 15 percent mineral spirits and drier S. C. Frosty Michigan farmer, says . . . facturer for use together. Very often the and there should be no water. The balance ltl am remodeling my farm, I would not think of the liquid should be large ofusing any roofmaterial but CedarShingles. ly linseed oil, but as much as 'They give positive protection to my bams and Representative Formulas for Paints of Group TLZ and one-third of it may be soy } comfort to my stock. Economy means a great deal as the cost per year with Cedar Sbtngles is negligible. AU farmers should use Cedar Shingles as they are the best in the long run." Types 2B, 3C, and 4C Ingredients as usually reported Type 2B Type 3G Type 40 (High content (Medium con (Low content of white lead tent of white of white lead bean oil and it may contain a small proportion of resin. When part of the liquid is reported as "varnish" it and zinc ox lead and zinc and zinc ox should be assumed that 5-POINT SATISFACTION ide) oxide) ide) somewhat more than half of When you use Certigrade Red Cedar Shingles on your farm buildings, you're sure o f getting the maximum protection pf any roofing material against hall, wind storms anclrusr, plus insulation, long life, economy and fine appearance. Here is a material that will serve you well for new construction or remodeling. Ask for figment in paint % by weight 66.0 % tov weight 62.5 % by weight 59.0 rigment composed of: Basic carbonate white lead Jinsic sulfate white lead '/inn oxide 41 ) 2174 yf (82) Titanium-magnesium 18 100 17 ) 17 > it/!) 32 \ 34 100 --) 15 y {40) 25 ) 60 100 the "varnish" is mineral spirits. The term "varnish solids" or "fixed oils and resins" means non-volatiie material containing no min eral spirits. Varnish gives red paint a higher degree of gloss and somewhat more resis tance to mildew, but too Liquid in paint 34.0 37.5 41.0 much varnish or varnish of CERTIGRADE Liquid composed, of; I.insccd oil Mineral spirits and drier 85 IS 8S 85 15 15 poor quality impairs dura bility and makes it difficult lo apply enough paint. RED CEDAR SHINGLES At Lumber Dealers / -------------------------------------------- SUCCESSFUL FARMING, MAY, T94I 3to SEE . . W . Total 100 100 100 Note: The italicized figures in parentheses are lo be calculated by the buyer bv adding together the figures in the formula as indicated by llic brackets. The sums so obtained should ilicn be used to gauge roughly the minimum content of pigment io the paint, indicated by boldface type, if the paint is of good quality. The higher the italicized figure is found lo be, the higher the boldface figure should be. . PAGE 85 Good red paint may be made for a somewhat lower price than good white paint but not for the extremely low price that has become cus tomary for red barn paint. N41698.5 FLB 001081 29 IN OPERATION, IN UPKEEP First inThrift S'K New York. N. Y. Sun y Cir. D. 312,112 JUL 25 1941 ^ % V If %941y /. The Tarn I0W TO APPLY COATS OF PAINTUnited States s. build up its o\v would s"-ikeaTiBrowne Reports Durability! destroy United i in war. The oth on Exterior of House the interdepend! of ideas and pr Depends on Thickness. said the defcatc COATS OF PAINT ! Browne Reports Durability on Exterior of House Depends on Thickness. N 1 ~ 0 + Q ---designed to prevent a Hat tire from rolling off the wheel --to protect you In case of blowout or puncture. iawrea ^f rrccdomrterDtourraobfilihtyouosef spdaeinptenodns tohne tehxe-ll Durability of paint on the ex-1jr^5e"meM^------33a'M3S&ari area ot lrccdomth. k of coating- whether thel tenor of houses depends on the strate a supei.iority OJf 1 tr. ade .can ,be av thickness is provided by two there is a large thjclc coats or by three thinner dom. For such stoneSi according to _ report by incurred the ivnD___r _ F___L_ __B__ro__w_n__e o. f_ the Forest Republican P-Products laboratory, Madison, politicians were WIST,' to the American CiwmtCal Lease Bill. -SaiguiifCty. which wilt hold its 102d "WiUkie canno national meeting in Atlantic Despite tiie n City, N. J,, September 8 to 12. party member, When modern paints of high out backing of topacity are used, the thickness hit with many of coating needed for good dur-` Said the Chrability Is much greater than that "Wendell Willkrequired merely to hide the wood of the most un<Dr. Browne says, in our time." Two-coat painting where either "An pvir'inrdirone paint Is used for both coats, c fice and couragor * combination of special t primer and conventional pre-,n ~ t. A / a .pared paint for the finish is em-,r QU . "'a <As ployed Often gives rise to short-' r subjects do you |tvej paint jobs because theiT<| about among yoneceggity of buying satisfactory ances these dayfjlm thickness has not been fully appreciated by paint manu-ee The Answer: facturers, painters, and paint.ee users, he explains. Two-coat sys-u The war......... terns consisting of a special- . Farming. .... primer and a finish paint made18' Politics, nation;for application in thick coats areje Money, cost of jess likely to be applied too, thickness of coating whether the thickness is provided by two thick coats or by three thinner ones, according to a report by Dr. F. L. Browne of the Forest Products Laboratory* Madison, WIs., to the American Chemical Society, which will hold its 102d national meeting in Atlantic City, N. J., September 8 to 12. When modern paints of high opacity are used, the thickness of coating needed for good dur ability is much greater than that required merely to hide the wood Dr. Browne says. Two-coat painting where either one paint is used for both coats, or a combination of special primer and conventional pre pared paint for the finish is em ployed, often gives rise to short lived paint jobs because the necessity of building satisfactory film thickness has not been fully appreciated by paint manu facturers, painters, and paint users, he explains. Two-coat sys tems consisting of a special primer and a finish paint made for application in thick coats are be applied too { signed special primers over self- i i priming for painting such woods j as Douglas fir and southern yel- ` lw pine. Dr. Browne adds, but ] j they show also that primer and | finish paint should be designed carefully for use together" be| cause a primer may give good | I results with some finish paints and prove incompatible with | others. 'The two-coat system of house ' jj painting during the past decade jjhas passed from a practice j ignored or condemned by the in dustry to a recommendation, made .by a majority of paint manufacturers," Dr. Brownes paints out. "Some of them advo cate it enthusiastically whereas others accept it in public but regard it in private with mis giving or disapproval. "Much painting with two-coat systems has been thoroughly satisfactory and much of it has proved seriously lacking in dur- 11 i ability. The successful work- 1 demonstrates that a substantial" economy is realizable from the e practice. The unsuccessful work Weather...........sparingly. demonstrates that the conditions i I'anel ueumj...< necessary for satisfactory two-M (Asked of women): In general, what subjects space wirh unusual i coat painting are not yet under- do you think are most often talked about t u n e m ma io r bo w es . stood thoroughly by alt rnanu- -T- among your women friends and acquaint HH Lowest-Priced ot mr*- --ances these days? facturers and users of paint." __ Q The Answer: All Farmers The war...................................... 56% The dtaft...................................... 16 Household activities................ 14 Gojfsip............................................ 13 F/mily, children............................... 10 on Many Models PLYMOUTH / Percentages total more than 100 because ^ most respondents named more than one subject. (Only leading subjects listed.) SUCCESSFUL FARMING, MAY. 1941 . ; PAGE 85 FLB 00108 N41698.51 FLB 001083 PAINTING ARliY BUILDINGS Prepared ty F. L. Browne Principal Chemist Forest Products Laboratory Madison, Wisconsin for Army Service Forces Corps of Engineers Repairs & Utilities Branch 1944 FLB 00108' PAINTING ARM? HOLDINGS n ' mi ..... M FOREWORD The policy for interior and exterior painting, as published in War Department Circular No. 269, 27 October 1943, amended by WD Circular No. 237, 12 June 1944, is as follows: 1. GENERAL--a. Serious shortages of manpower and material as well as present limitations on funds make mandatory the exercise of strictest economy in painting and repainting of War Department owned, leased, controlled, or sponsored buildings, structures, and facilities, and machinery and equipment for their maintenance, b. Only the most urgently needed painting and repainting will be per mitted, Serious physical deterioration of building, particularly interiors and vertical exterior surfaces, will not result from lack of paint; there fore, peacetime standards of appearance and maintenance will not be upheld, 2. EXTERIOR PAINTING.--In the case of theater of operations and mobilization type troop housing and appurtenant installations, painting and repainting will be limited to sash, doors, and trim. Wood construction at Govermaeut-owned'manufacturing plants may be one coat of creosote oil stain , -1- FLB 00108 or cottonseed oil gum stain, and doors, sash, and trim may he painted unless already stained. Untreated gypsum siding may be painted on the exterior where practicable with two coats of exterior resin emulsion paint (Civil Aeronautics Specification No. 577). 3. INTERIOR PAINTING.--a. In temporary buildings, interior painting will be limited to hospital buildings used by patients, bakeries, cold storage rooms, service clubs, guest houses, exchanges, induction buildings, weather forecasting rooms at base weather stations,- and chemical warfare and ordnance plants where necessary to reduce hazards resulting from the handling and processing of explosives and explosive and toxic gases. When considered necessary and approved by the commanding officer of the installation, materials and equipment may be furnished to organizations desiring to perform the work of whitewashing or painting their kitchens, kitchen storerooms, and mess halls. Amy Engineer Service funds may be used for this purpose, except where Amy exchanges are concerned. Interior painting in exchanges will be paid for from nonappropriated funds. Use of War Department funds for labor for such projects is not contemplated. (A.G. 600.12 (1 Jun 44).) b. Necessity for painting and repainting in permanent buildings should be determined on the individual merits of each case, taking into consideration the use of the room, fenestration, and existing wall finish. Jn addition to painting of hospital buildings used by patients, bakeries, cold storage rooms, service clubs, guest houses, induction buildings, and weather forecasting rooms at base weather stations, painting in other permanent buildings may be justified in the following instancess I FLB 001086 (1) In rooms whose use requires a high degree of sanitation and whose present condition falls below the minimum set by the post surgeon, (2) Ihere conditions, such as excessive water or condensation in shower and toilet rooms, cause rapid deterioration of unprotected materials, (3) In rooms such as shops, office, and classrooms where difficult visual tasks require a degree of illumination which otherwise would have to be obtained by rewiring and/or the installation of additional or new lighting fixtures, (4) In chemical warfare and ordnance plants where necessary to reduce hazards resulting from the handling and processing of explosives and ex plosive and toxic gases, c, Ko painting will be authorized even in the above excepted cases where improved appearance is the only consideration. In any case, painting will be limited to a minimum number of coats, 4. ' PAIIOTG OF MINTBMKCh Kf^HIKERY AKD SPIRENT,--Repainting of machinery and equipment used in the maintenance of buildings, structures, and facilities will be approved only when existing coatings will no longer protect surfaces against deterioration tending to impair functional character istics, and when necessary as a safety measure. Fine finishes will not be specified. Quality of finish will be the minimum required to prevent rapid -3- FLB deterioration of equipment, (A.G. 600.12 (23 Oct 43)) The decision to suspend exterior painting for the duration of the emergency was based on the results of research made by the Forest Products Laboratory, U. S. Department of Agriculture, in cooperation with the Repairs and Utilities Branch, O.C.E. The report of the study by Dr. F. L. Brown, Principal Chemist, which concludes that deferred painting will not impair the useful life of Amy buildings, is published for the information of all concerned. J. S. BRAGDOM,Brigadier General, U.S.A. Chief, Military Construction Division. Office of the Chief of Engineers, I I 1 '.'v i FLB 001088 PAIIn'TII.'G . ARIT BUILDINGS The original plan for the wood buildings of cantonment type erected at Amy posts in I94O to 1942 was to leave the siding unpainted* For that reason, southern yellow pine lumber of common grade, which contains many knots, was considered to be suitable. After construction had been started, consider ations of appearance and morale of the men (the United States was not yet at war) led to the decision to paint the buildings despite the adverse paint behavior to be expected over the knots. There were many other conditions un favorable for good paintings much of the lumber was green, the painting had to be done in haste amidst construction and occupancy of the posts, much painting had to be done in the winter, and serious changes in the painting specifications were made during the progress of the work as materials and labor became critical. Nevertheless, paint jobs of very satisfactory quality were generally obtained. On the whole, the quality of the paint work was equal to that commonly dons on new residences, either publicly or privately. owned. Except for the defects that were bound to occur over knots, the paint jobs on cantonment buildings have proved as durable as those done in other programs of mass construction. Cantonment painting has proved to be almost entirely free from the early blistering and peeling of the coatings that are caused by moisture in sidewalls and have plagued so many privately owned buildings ; The paint jobs on cantonment buildings are now from two to four $ FLB years old. On the difficultly paintable woods such as southern yellow pine, . good maintenance of paint calls for repainting after 3 to 4 years. If, in the midst of war and a serious shortage of manpower, it is considered necessary to maintain a well-painted appearance on cantonment buildings, a program of repainting might well be started during 1944 or 1945* On the other hand, if appearance alone is not considered sufficient reason for repainting at this time, there is no reason why it cannot be deferred until the need for improving appearance is deemed urgent. Postponement of repainting until the war is over, even if that takes another 4 years or more, will not impair the usefulness, shorten the life, or increase the overall cost of maintaining cantonment buildings. Painting of wood buildings with protective oil paint is not as customary in other countries as it is in the United States, In Switzerland, wooden buildings, including wooden buildings of the Swiss railways, are commonly left unpainted to weather naturally. In Sweden, farm buildings are decorated with a 9red wash", which is a water paint somewhat analogous to whitewash or to casein paint, but lacking in protective power against wood weathering. Sven in America painting with oil paints was not generally customary in colonial times. It is reliably reported that-a barber in Massachusetts Bay Colony was driven from the Colony because of his arrogance in having his house painted. The oldest wood buildings in America, the Fairbanks House at Dedham, Mass,, and the old Schoolhouse at St. Augustine, Fla., have stood f l?/' FLB 001090 more than 300 years without paint or other protective treatment. The House of Seven Gables at Salem, Mass., has never been painted. Christ Church at Cambridge, Mass., thou# now kept well painted, reveals a long history of paintlessness in the weatherbeaten condition of its siding. Yet the Yankees always have been reputed to be a thrifty people. ' Painting of barns and other farm buildings is still far from universal practice in most parts of the country. In any of the longsettled sections of the United States and Canada there is no difficulty in dis covering barns that have remained in constant use without paint for half a century or more. Where the exterior wood was an inch or more in thickness and was kept from contact with the ground or other sources of continued dampness, it usually has required little or no replacement. Strained efforts have been made to show by statictical surveys that paint maintenance prolongs the life of farm buildings, but such conclusion is reached by including in the unpainted group buildings that are not maintained in any way. Neglect to make needed repairs may min a buildingj one of the major benefits of paint maintenance comes from the periodic inspection and repair that usually precede painting. It is practicable, however, to make the inspection and repair at suitable intervals without painting. Paint is not a wood preservative; it is not used for the purpose of preserving wood against decay. Wood rots only when it remains damp for considerable periods of time. Wood freely exposed to the weather does not rot when conditions permit it to dry out rapidly soon after each wetting. I -7- FLB Tfheii there are poorly designed .joints into which water may seep and be held for a long time, rot may take place. Tood that is continually in contact with dampness cannot be kept from becoming wet, because paint coatings merely retard the absorption of moisturej they do not prevent it. Experience shows that coatings on continuously damp wood soon blister and peel. Poorly de signed joints seldom can be kept tight with paints since paint retards the drying as well as the absorption of moisture by wood, painting woodwork with poor joints may hasten rather than retard decay. The cantonment buildings that the writer has seen were planned care fully with regard for the prevention, of decay. Foundations are usually concrete capped with -termite shields. The space between ground and wood floor is usually ample and well ventilated. The wood, skirting, fencing off the space, is kept from contact with the ground or with the concrete foundations. There .should be practically no decay of the woodwork in such cantonment buildings whether or not they are kept painted. In a few cases, regrading of the land near the buildings has been.done.in such a way as to partly cover the wood skirting with, soil. This may eventually result' in rotting of the skirting, but painting will not prevent the decay. The wood steps with handrails at the doors of. the buildings involve some joints that are hard to keep tight and may in time cause some decay which would be hastened rather than retarded by frequent paint ing* Unless some of the cantonment buildings -continue in use for many years, the replacement of steps and handrails will be an item of trivial importance. ITood, exposed to the weather is subject to weathering which can be \ FLB 001092 pace, here gs and d g, but e doors in time paint- | I I I ars, nee. ' | be prevented by adequately maintained coating of protective paint. Tfeathering results in a slow erosion of wood from the exposed surface at the rate of roughly 1/4 inch a century for softwoods such, as the pines. The process also involves strains within the wood that tend to cup or warp thin boards and loosen nails. The 1/2-inch bevel siding that is widely used for pri vate residences is too thin to stand weathering well over very long periods of time and, if left totally unprotected by paint or other treatment, may need replacement in 30 to 50 years. Even so, it is considerably cheaper to replace such siding every 30 years than it is to paint it every 4 or 5 years. Painting, therefore, is not a means of reducing maintenance costs but is an expense that is justifiable when the appearance of weatherbeaten wood is considered unsatisfactory and protection against the weathered appearance is deemed worth the cost. Cantonment buildings are sided with ship-lapped or tongued- andgrooved drop siding well nailed over lumber sheathing. Even if left entirely unprotected, the siding should last many years with little or no replacements* Paint maintenance, therefore, should be regarded strictly as a matter of appearance. If it is decided to repaint at this tin, there will be an increase in the overall cost of maintaining the buildings which can be justified only if the improvement in appearance is considered to be worth . the price. If it is decided to defer repainting for another two or three years, the cost of repainting at that time will be slightly greater than it would be -9- FLB 001093 m now, becatise more work will be needed to prepare the surfaces for repainting and more paint will be used. The increase in painting cost, however, will be less than the depreciation charge for painting done now. (All of the photographs that follow, except figure 4, were taken by the author. The signboard shown in figure 4 is now in the possession of Mr. George K. Hunt of the Forest Products Laboratory). 1 I 1 # : FLB 001094 Pina signboard free from decay after 25 years exposure, unpainted except for the durable black paint used for the letters. By measuring the difference in level between the protected letters and the unpainted back ground on thi^ and other signs of known period of service, it is calculated that unpaintesi softwood weathers away at the rate of approximately 1/4 inch a century. FLB 001095 FLB 001096 LEFT* The Fairbanks House at Dedham, Mass., erected in 1636 and never paint ed. Some of the thin siding was replaced in 1903 (photograph taken in 1936) butthe window frames, corner boards, and barge boards and all structural woodwork are believed to be the original. i One of the houses of the Amana Colony built at Amana, Iowa, in 1958 (photograph taken in 1927) and left with the siding unpainted for reasons of economy, but window sash and doors were kept painted. FLB 001097 bnpainted exterior woodwprk in nodern architecture: A hotel at Bend, Oregon* the upper stories of which are covered with vertical siding of ponderosa pxn left unpainted to obtain the weatherbeaten apoearance* FLB 001098 I FLB 001099 ' "COVERHMEXt Ml* 15 OfF,CE' 1547 FLB 001100 First cantonmenttype barracks erected at Ft. Meyer, Va. Dry lumber of a select grade, free from knots', to gether with pure white lead paint combined to make a paint job in almost perfect condition 18 months after the painting was complated. Compare with figure on next page which shows-the effect of knots in the common grade of lumber used for most of the canton ment buildings * < j I !; 5 ' FLB 001101 Ifipip aMIfgfslliti illlilSJt --HMQ | ****** jHt B' H;*$ H> ! HHBHHHHIHHi iSilliwi m ++ I SSflgtltl MHK: How knots in common grade of lumber mar the appearance of a job less than 1 year old at Camp Lee, Va., although special oars was taken on this hullding to spot-prime the knots with aluminum FLB 001102 FLB 001103 ;;g FLB 001104 ll, hospital building tfii Pt. Bliss, Tex. on which paint has failed unusually com pletely because of a ^ combination of wood of 'high density and : ^ ^omission of a third Coat paint that was initially contracted for. Bren with the advanced paint flak ing, however, the boards remain straight, fit tightly, and the nails remain |firm. It makes little |differenoe whether |this building iis re|painted now or is |al lowed to remain as |it is for some years. FLB 001106 Southern yellow pine lumber, similar to that used in cantonment buildings, still in good condition on the test fences of the Forest Products Labora tory, Madison, Ms*, 11 years after the last painting. These panels were erected in 1924 and painted with three coats of pure white lead paint (left panel) of of lead and zinc paint (right panel), re painted with one coat of paint in 1927, and not again painted until photographed in 1938, FLB 001107 One of a number of unpainted buildings moved to Camp Wolters, Texas, after many years of service in the Civilian Conservation Corps. The Post Engineer at Camp Wolbers reported that these buildings were considered very satisfactory. FLB 001108 By F. L. BROWNE, Chemist US* Forest Products Laboratory Madison/ Wis. Some Tiling A as gqapljBfflpre-war? Why are house paints made with ich shtUpKioat of paint be? What about so-called plastic UestiSpi such as these are here given in an informative for the Journal by a chemist who has done exhaustive research On paints at the U. S. Forest Products Laboratory. This is the first of a series, and will be of special interest to property managers and operative builders FIVE years of shortages of mate rials and labor for civilian paintiHg'plus a need for much new nous ing are expected to result in great activity in house painting as soon as paints and painters, are again freely available. At the same time the cost of applying paint has in creased, making it more than ever desirable to use paints of the best quality and to apply them with the least labor consistent with dura bility. "Plastic paints" The post-war paints for main taining houses do not differ greatly from pre-war paints. No startlingly new materials for paint making have been discovered or are known to be in prospect. Rather, the past five years have been a time of sub stitutions and shifting of formulas to deal with scarcities of customary raw materials. Nevertheless, public interest in technology Etas been stimulated by wartime develop ments in synthetic rubbers, resin glues, resin sheet materials, resin impregnated materials, molded products, and other synthetic sub stances that are popularly lumped together under the general name of "plastics." It is therefore widely supposed that there are or soon will be radically new paints. Alive to this expectant frame of mind, a few manufacturers have marketed so-called "plastic paints" or plastic substitutes for paint, often with spectacular claims for their per formance. Investigations of "plastic paints" by the National Paint, Varnish and Lacquer Association and by Better Business Bureaus have revealed most of them to be ordinary paints sold under the new name. They may be paints of good quality at higher than customary prices or paints of inferior quality at the price of good products. Some are paints of thick consistency to be applied in coatings of several times the usual thickness, consuming several times the usual amount of paint, but alleged to be durable "for. a lifetime." It happens, how ever, that coatings of house paint last longest when they are 'about 0.005 inch thick to begin with; much increase in film thickness be yond that optimum tends to pro duce shorter life and a more diffi cult surface to prepare for repaint ing. Calling paint a plastic does not alter its behavior. Although the name plastic in connection with paint or varnish should warn buyers to be cautious, it is only fair to point out that there is no authoritative definition of plastic as a kind of material. All coating materials are plastic in the sense that by suitable methods of application they can be made to conform to the shape of the surface on which they are spread, and in service, must usually retain enough plasticity to submit to moderate changes in shape or dimensions of the substrate. Late in the 1920's, paints were called plastic if they could be tooled after application to produce decorative surfaces of rough texture, chiefly for interior walls and ceilings. The vogue for plastic paints of that kind passed when it was found that they are hard to keep clean and hard to re paint, but stippling paints, which are still popular, may be considered plastic paints of that type. A new variety of plastic paint may be molded on surfaces of plywood or other materials in a hot-press at the time the plywood is being glued together; it may prove useful in making prefabricated houses but is unsuitable for painting on the job. Some technologists consider it proper to call paints or varnishes plastic if they are made with "syn thetic" drying oils or resins. Var nishes, however, are frequently made with mixtures of synthetic and natural materials and it is diffi cult to draw the line clearly be tween the synthetic and the natural products. Ester gum, which is manufactured by combining resin from pine trees with glycerol from 20 March, 1946 -- Na t io n a l Re a l Es t a t e a n d Bu il d in c Jo u r n a l N41698.52 FLB 001109 Features Aluminum moulded over insulation board form its roof shingles Heat-absorbing window glass in the bedroom Exterior walls of redwood plywood, joined bV splines, and varnished with new chafing Soundproof slidihe^doors Flush lighting designed on principles of sealed-beam headlights Germ-killing sterile lamps New spec'nim lighting in greenhouse Aluminum root, redwood paneling, horizontal lines , . . Television, record - change conduit. A continuous electric out A new type of circular concave intcr-communica'ion systei let strip is installed in the base mirror lighted from the rear by a % Rubberized plastic walls for bedri boards. Plastic push plates are circulayfluorescent lamp magnifies equipped with tiny bulbs which the fate. An electrical toothbrush Packaged bathroom, with peat-ska. glow at night. witiyspecial heads for various mem tub, plexiglas revolving turret-typfl Every room has radio reception bers of the family is attached to a shower door equipment. Standard, F.M., phono spring cord which pulls out and graph or Muzak (music over tele hen automatically goes back when Electrical toothbrushes, hair-driers, phone wires) may be dialed, in 'not in use. An electrical shaver is and special- compartment for dry eithhr the living room, master bed. attached to a similar cord. Directly i ing hosiery Neon-lighted linen closet shelving room,''second bedroom, kitchen ani` overhead is a sunlamp permitting patio A, all four types in various suntan treatment while shaving. rooms at'one time. A television re Immediately behind is another Structural translucent corrugated glass ceiver is b\ilt to the right iff the lamp for drying milady's hair. A partitions 1 fireplace. An automatic /record special compartment for drying la I Miniature inside gardens in living changer is connected to rne radio dies' hosiery is also provided. The iooni - installation by'''relays. A'home re medicine cabinet is large enough corder permits the recording of to hold even a half-gallon of rub Roller-type doors On kitchen cabinets voices or radio programs. bing alcohol. Immediately below ^Grease filter in kitchen suction fan Plastic sink top and drain Console-type refrigerator, with draw ers that pull out Automatic package receiver Innumerable appliances, including Precipitrpn, clothes drier, rnoduflow thermostats, frozen food cabi net, garbage disposal unit, and dishwasher, radiant infra red gas heater An inter-commumcation system connects master b^rflsun, kitchen, barbecue, front floor, service door and hobby shop: \ Bedroom walls are covered with a rubberized/plastic material\imi- lar to wallpaper with designs Im pregnated/into it. " \ The master bedroom, 13 feet by 20 feet/ has high winflows which prevail in other rooms. Instead of wall/in closets, storage walls are provided with sectional drawers is a storage space for towels. The water closet flushes by merely lean ing back. A miniature radio is ad jacent. A feature of the entrance hall is the structural translucent corru gated glass partition directly in front of the doorway, and two mini ature inside gardens. Living arid dining areas are com bined, divided only by( a U-shaped (Please turn to page 40) apd compartments. The dressing A new type of flush lighting, /able is equipped with an 11-foot Utility roam, air conditioner, precipitron wnrhiiivc.hlt uutwiliiznevsu ,. the priunvcvii^p>lae>su ovra. / w(YildUeb 1mUiUrrUoMr. -IMnI. CaL UcadUbiUneVt - bUebdsliUdCe i> sealed-beam headlights, diffuses z/ the bed a master switch controls all A 5 high percentage of light into roonfs lights in the house, without wastage. Fluorescent indi The master bathroom resembles rect lighting is used in the living the "packaged" or ensemble type, room. Neon tubes light bookcases, and if it proves popular, may be and can be regulated to law, me manufactured for general use. The dium or bright by turning a dial. Bums model was forged without Continuous strips of neon and flu dies. The tub is pear-shaped, with orescent lighting are u/ed in kitch the wide end usable for a shower. en cabinets and linen .closets. Gerin- The shower door is a revolving tur kiiling sterile lamps/re provided in ret-type, made of translucent plas the kitchen and b^fhroorns. In the tic. greenhouse a new,type of lamp, con A hamper for soiled linen is built taining spectrum'colors in the glass, under the lavatory. A full-length, brings out the full beauty of the radiant, infrared gas heater gives flowers in natural colors, A new instantaneous heat for early morn type of swjfch which works in re ing hath or shower. It is designed lays perijrits the use of bell wire to heat the body not the air in the to the switches, eliminating costly room. Na t io n a l Re a x . Es t a t e a n d Bu il d in g Jo u k n a l -- March, 1948 FLB 001110 Second. the high cost for labor in painting on the job together with the relatively thick coating neces sary for durability on exterior woodwork, makes it economically necessary to use paints of maximum content of nonvolatile ingredients and minimum content of volatile; thinner in order to build the re quired 0.005 inch of coating With the fewest possible applications. Good house paint of a decade or so ago, when three coats were usually considered necessary for painting new woodwork, was likely to consist of approximately 23% pigments, 67% linseed oil, and 10% volatile thinner and drier by volume. (The percentages by weight, as reported in the formulas printed on paint labels, vary considerably according to the specific gravity of the pig ments used.) The: nonvolatile in gredients, pigments plus linseed oil, amounted to 90% by volume. For the first coat the paint might be thinned with one pint of linseed oil and one pint of turpentine per gallon and applied so that one gallon covered 600 square feet of surface, which left about 0.0013 inch of coating after the volatile thinner escaped and some of the oil was absorbed by the wood. The second coat might be thinned with one pint of turpentine per gallon and applied at 700 square feet per gallon, which brought the thickness of coating to 0.0032 inch. The final coat applied without thinning at 800 square feet per gallon brought the coating to 0.005 inch. Enamel could scarcely be made with as much as 21% pigment and 44% resin and drying oil, requiring 35% by olume of thinner and drier. If applied in the same way three coats would build only 0.0037 inch of coating, making a fourth coat neces sary to reach 0.005 inch. On inte rior surfaces that are not exposed to the rigors of weathering, 0.003 inch of coating is enough provided that the enamel is made with highly opaque pigments. For painting at the factory where application costs are much lower, it is usually cheaper to apply four coats of fastdryine enamel than three coats of slow-drying paint. The third reason for preferring oil paints for houses is that oil paints, made with a high propor tion of pigments including reason able proportions of white lead and zinc oxide, dry satisfactorily under a far wider range of weather condi tions and wear out in a manner more suitable for repainting than enamels do. Painting on the job must frequently be done in colder or damper weather than is best for the drying of coatings. Extremely bad conditions should be avoided, of course, but practicable house paints must withstand much varia tion from the ideal. Oil paints have marked advantages over enamels in that respect. The manner in which coatings Of house paint wear out is important in view of the fact that the coating probably will be re newed at least seven or eight times during the life of the house. Re moval of the old coating before repainting is much too expensive to be considered except as a last resort in cases of great difficulty. Good house paint, therefore, should wear out in a manner requiring minimum effort to prepare the sur face for repainting. The ideal would be a coating that remained everywhere firmly adherent and un broken, merely wearing gradually thinner until it no longer concealed the underlying woodwork com pletely. Some oil paints approach the ideal under favorable circum stances. All coatings, however, lose their plasticity and become brittle after exposure to the weather for several years. Once embrittled they are inclined to crack, after which they may curl and come loose along the cracks and flake or scale off. The safest paints for economical long-time maintenance are prob ably those oil paints that develop many fine but inconspicuous cracks with little or no tendency to loosen or curl along the cracks. Sudipaints can be recoated with confidence and little expense for scraping off loose paint. Paints formulated to de lay cracking unduly are inclined to crack conspicuously, forming an un certain foundation for repainting. The resin in enamels, which pro duces greater hardness of coating early in its life, causes increased brittleness later on which tends to aggravate cracking, curling, and uncertainty of repainting. (Next month Mr, Browne will dis cuss oil-restricted house paints and the pigments used in house paints, as part of the series of three articles,) Good house paints should wear out in such a way as to require minimum prepara tion in preparing the surface for repainting. The best oil paints for long-time mainten ance develop many fine but inconspicuous cracks with little or no tendency to loosen 22 March, 1946 -- N1 R E0 Xq 1 1 B J1 1 q 0 0 q 3 X <q 1 IS 9P6I `yowffl -- TVNHnof ONitnina Xq aj.vj.sa ivaa TVNOixvjSi 0 6pasn waM auid ||aJ pue ty se| no<j 4 331 135 fospnoy aisles - x sqluaui g (. iaiyaue jo--toj pooS |||)s ate lauijid juied-asnoy tyiM scan? ayi )nq Sayuiedai Suipaau )u;od ay) o) pa|iej axey scale <tpauiud-j|as,, ay) 9)ey) Moys asay) 'ipnos Buiaej ainsodxa jo stpuoui lays paqdctBojoyj yuied ysiuy jo )eo> auo Ay paxxojjoj lauijid )uied-asnoy jo )eo auo y)i pauiud 3 8ai M }y il ay) uo spued ayp -pauuiy) 1)503)oi|Mamos fiutqsiuy ay) 0 X4 pasn 111lujed ay) y)iM pauitid aiaM ydeiSojoyd siy) jo )jaj ay) UMoys seats )sa) ay -saqsituaiq sir aremuaa -3B pUB `Xp3BX3 ISOUIJB D3EJJTIS 31)1 jo 4IIO3U03 sip Mopoj `sqjEUi qsnjq OU 3AB3[ SpUlBlta Supured 3JOJ3q Ajarejpauiun paqiooms XqnjajEa uasq iou seq jnqi jaquirq ut ju;> -sajd s A 1 [B XpiBau are qoiq.vi `0 S4 pasrej puB isqjEca jaiuureq `sqiBUi i3UE)d rpns saqsituaiq 3-inDS -qo leqi sqjEui qsnjq iqSqs S3AB3) puE 33Ejjns SuiApapun sqi u; sap -ijBp-iSajji iqSijs jjo s[3A3[ mred UO 'spjEoq jo saSpa dreqs uio.ij AEME MEjp OJ Spuai II pUE A[SnOJ3 -u-:.S eog Eqwatuos paqddE ji <(sS ,, puE ,,SUTU,, SUIJOJ A[ipE34 pUlEU3 jnq ir speaids jajured aqi ajaqM isnf S 0A 0 4 X XiijEnb aqi seq lured uo lanpojd J6[tiyp.red aqi jo DpsijaiSEiEqo saiEj SuipBSjds jo aSuEJ MOJJEU E A[UO UiqilAA XpSEA paqddii aq u e d puxnua inq qof aqi 01jo spaau aqi SutpjoiiE X [4 3 jad 01laaj aJEnbs pQg` i ireqi ajoui oog s e apiq s e u io j j aiE4 Suqreajds Xu e 0 <paqddE aq u e j jured po ,/qnd,, oi spuai iauiBua seajaqM qsnjq aqi Japun ,,di[s,, apjEijojuioa < SBq lured UO "spuiBua ui appiuiEi -lEun 34 < pus saaiuied Aq pszpd ajB lEqi sapjadojd uopBDqddB ureuap SAEq spo SuiX.ip qijM apEili siured `isqq Supured asnoq j o j pajjajajd 34 siured po Xq. sues -E3J lUBiJoduii aaiqi 34 ajaqjj siured asnoq ui po paasuq SuiDEjdaj 4 X4 aqqEims spo " SuiXjp spaqiuXs ou uaaq iaX 1 0 4 ajaqX "siured asnoq uo laajja spin AJ3A pBq aABq inq sJEaX Qg rsEd aqi Suimp sjanbaEj puE saqstuJEA paziiioptqoteJ aABq suisaj art aqi -uXs u.iapojq X0.0 _ X 0 1injasn 0 <uop -iqos 0 J3]S3 3S0[npa3 pas uisaj aqi daaq oi jaSrej jpis aq isnui spinbij apjE[OA jo uopjodojd aqi janboEi ui Saiajduioa si uopBjodjpDjii amp aqi Xq snoosiA XpiuaJixa s; po puB uisaj jo ajtiixiin aqi asnEDaq aSjE[ aq ismn qsiujEA ui jauuiqi api -E[O1 jo uopjodojd aqx `siuaA[os aiqBims ui 3SO[rqp30iira iptls J31S3 asofnjpj puB uisaJ SuiAfOssip Xq apBin si janbaBq -jauiiiqi api -<4 X1 jo uopjodojd aSjBi SuippE uaqi puB `iaqjaSoi xuaqi SupEaq Xq Xqensn qro SuiXjp qitAt uisaj SupEJodjoDui Xq apEtu st qstujBA -janbaEj jo qsiujEA XpSjEi s; apjqaA aqi qaiqM ui sjaureua ajB sjonpojd apBUI-XjOPBJ JOJ SlUIEd pUE `SlUIEd" joop `spuiEua jouaiui `siured pEAv jouaiui < qans `sasodind jaqio isoui 4 X4 0 0 -4jaup puE jauuiqi apiBjoA jo uopjodojd [puis qiiM. po SuiXjp jEptuis jo po paasuq uaaq ssq lutBd aqi jo uop -jod pinbq 4 X opiqSA aqi inq apsui 3J3M Xaqi tprqM. qiiM siuaiuSid jo lunouiE puE putq aqi ui XpsajS pajajjip a.AEq Aaqp -siuiscf [ro paasuq Uaaq s X 1 4 < aAEq sasnoq jo sjoijaixa aqi 4 X4 aiqElius siureq HO paasun WIA. apniM 3JV S)U)Dd asnoH XyM sjonpojd X4 X0 3 4 0 0 < aq X 0 uiaqi jo auras inq saoud 4 X SUIIBp 3[qEUOSB3JUn JOJ X[[E3piJD pauxniExa aq pinoqs siujEd ipns Iiured anse[d uopEuSisap aqi jo peapdaqs aq pjnoqs `ajojaiaqi `siasn lureq Ajisnput satisEjd Suipjoui aqi Xq uisaj opaqiuXs inq sjaqEui qsiu -4 1 Xq uisaj jEjniEU e paJoptsuoa X{U0UIUI03 si srej jo uoiiEoqiuodEs ( I1 FLB 001112 Some Things You Should Know About Protection is paramount -- but lasting life and beauty are also going to be demanded of post-war house paints.'In this second article of a series of three a noted chemist discusses oil-restricted house paints; the percent by volume of oil, pigment and thinner to insure maximum coverage, thickness and life; and the basic proportions of white lead and zinc oxide pigments that should be included in oil painfsto provide firm drying and durability under all conditions ; TJAINTS of a decade ago,' con- Paint containing 25% pigments, ments and 62% raw linseed oil by % JL taining typically 23% pigments 47.6% raw linseed oil, and 27.4% volume and having a consistency f apd 67% linseed oil by volume, volatile thinner and drier would known to paint technologists as "90 which is about 5.2 pounds of lihseed be thin and Watery to the point of Krebs units." When such paint is oil per gallon, were somewhat too impracticality. To restore normal applied as a finish coat it is apt to rich in linseed oil. Several genera- consistency it is necessary to thicken be spread over 700 square feet per dons of painters have been taught part of the linseed oil by heating it gallon, which forms a coating as Apprentices that "oil is the life at 550 to 600F. for several hours. 0.0020 inch thick when dry. Assume B of paint" and painters are still in Such thickened oil is called bodied further that, to comply with the clined to overload their paints with oil; it is not to be confused with wartime restrictive order the paint 5 it. Thorough technical research, boiled oil, which contains metallic was altered to contain 25% pig e however, proved that most oil driers but has about the same vis ments, 24% raw linseed oil, and l paints perform better when the pig cosity as raw oil. The wartime oil- 23% bodied linseed oil and that x ments form a higher proportion of restricted paints, therefore, were by selecting suitable grades of pig V the dried coating than the 25.6% made typically with 25 to 26% pig ments and bodied oils tire consis \ by volume represented in the fore ments, 24% raw linseed oil, 23% tency of the paint was about 65 i going composition. For best results bodied linseed oil, and 27 to 28% Krehs units, that is, noticeably thin i the pigments should occupy 28 to volatile thinner and drier. ner or more watery in consistency i 30% of the yolume of the dried The oil-restricted paints are in than the oil-rich paint. In that case i coating. In enamels the proportions termediate in composition and the oil-restricted paint probably B should be 30 to 40%. The maxi properties between oil paint and would be applied at 700 square feet S mum proportion of pigment in the enamel. For that reason they have per gallon but the coating would be X wet paint at the time of applica sometimes been called enamelized only 0,0016 inch thick, roughly } tion, however, is usually limited to paints. In ease and flexibility of four-fifths the thickness of the coat I 25 to 26% by volume in order to application the oil-restricted paints ing of oil-rich paint. The customary i } keep good brushing qualities. The are distinctly inferior to oil-rich amount of paint would be con i i best house paints during the five paints but are much superior to sumed in painting a given building, j years prior to July, 1943, therefore, true enamels. If oil-restricted paint only three-fourths of the usual j ' commonly contained 25 to 26% pig Is applied at the same spreading amount of oil would be used, but ments, 61 to 65% linseed oil, and rate used for oil-rich paint the oil- there would be a significant sacri 10 to 13% by volume of volatile restricted paint vyrll form a thinner fice in the durability of the paint thinner and drier. Such paints con and proportionately less durable job. tained 4.75 to 5.05 pounds of lin coating than the oil-rich paint. The In practice, however, the oil-re seed oil per gallon. tendency, however, is to apply oil- stricted paints were made at nearly During the war linseed oil, in restricted paint at a lower spread the same consistency as the previous common with Other vegetable oils ing rate, in which case it may foim oil-rich' paints, namely at 90 Krebs and fats, was in short supply. As a as thick a coating and give practi units for the example cited. To the means of conserving oil the War cally the same performance as oil- painter stirring his paint to make Production Board limited the rich paint but a larger amount of it ready for application the modi amount of vegetable oil in house oil-restricted paint will be needed fied paint seemed to be the same as paints to a maximum of 3.75 for the job. the paint he had previously used. pounds per gallon, which would be To illustrate, let us assume an Nevertheless, the effect of the bod 47.6% of the paint by volume. oil-rich paint made with 25% pig ied oil was such that he was apt to 194626 April, -- N R E B J1 0 Xq 1 1 1 1 q 0 0 q 3 X q 1 N41698.53 FLB 001113 apply it at 575 rather than 700 square feet per gallon, in which case the coating formed was 0.0020 inch thick. The oil-restricted paint then gave a paint job equal in coat ing thickness and in durability to that previously obtained with oil- rich paint but nearly 25% wore paint and labor were consumed and almost as much linseed oil was used to do it. The oil-restricted paints, therefore, make painting more ex pensive. Although large * proportions of bodied oil are disadvantageous in house paint, small proportions may serve useful purposes. For many years it has been common practice to make paints with about 5% of bodied oil and 57% of raw oil rather than with 62% of raw lin seed oil. When used in moderate proportions that do not make it necessary to increase the propor tion of volatile thinner the bodied oil is helpful in adjusting the con sistency and application properties of the paint. The proportion of bodied oil may be increased to as much as 9% with 58% raw linseed 'oil before the paint acquires enamel-like properties and increase in ' content of volatile thinner'',becomes necessary. Some authorities, there fore, believe that post-war paints probably will be made typically with 25 to 26% pigments, 8 or 9% bodied oil, 52 to 55% raw linseed oil, and 10 to 13% thinner and drier by volume. They will prob ably contain about 4.75 pounds of linseed oil per gallon. The 25 to 26% by Volume of pig ments in house paints may be made up of any one of a great number of combinations of available pig ments. The period between the two World Wars was one of active ex ploration of the numerous possi bilities during which there was great diversity in the pigmentation of the paints offered by different manufacturers. Competition, how ever, has gradually eliminated ob solete combinations until it seems likely that most' of the post-war paints will be comparatively uni form in the essential aspects of pig mentation. White Lead and Zinc Oxide in Paints Oil paints require a certain pro portion of white lead and zinc ox ide to provide firm drying under all conditions of weather in which painting must be done and to make coatings sufficiently durable. Zinc Oxide and the white leads, includ ing basic carbonate white lead and basic sulfate white lead, are be lieved to react chemically with lin seed oil or with products formed from it during drying and aging. Although the chemistry is not fully understood there is no doubt about the need for white lead and zinc oxide in house paints. Opinions differ, however, about the mini mum proportions necessary for good service. Formerly it was thought that 70 to 90% of the total pigment (18 to 23% of the paint) should be white lead and zinc oxide. It is now realized that paints with such high proportions of the chemically active pigments become unduly dirty after a year or so of service and that the coating begins to check or crack sooner than is necessary. Paints in which 40 to 50% of the pigment consists of white lead and zinc oxide are less inclined to become dirty, are much slower in developing checking or cracking, and yet are even more durable than the older paints with high content of chemically active pigments. A few experts recom mend as little as 35% lead and zinc pigments in the total pigment, (about 8,75% of the paint). A con servative view is that the white lead Should be between 5 and 8% and the zinc oxide between 5 and 6% by volume of the paint when the total pigment is 25%. The minimum proportions of white lead and zinc oxide required for their chemical effects provide less than half the opacity demanded of modern white paints. The bal ance of opacity needed to make a coating of 0.005 inch thick com pletely hide the underlying surface is imparted by incorporating one of the very opaque white pigments, titanium dioxide or zinc sulfide. About 3.6% of titanium dioxide or 6.3% of zinc sulfide suffices for the purpose. It is undesirable to add much more than the required opacity because some painters will then apply too little paint for good durability. Titanium dioxide is usually preferred to zinc sulfide for the best paints, probably because the reputation of zinc sulfide has been impaired by its wide use for many years in the cheaper grades of house paint. (Next month Mr, Browne will dis cuss chalking, deep color paints, and new special house paint primers in the last article of this series.) Paint test panel fences of the U.S. Forest Products Laboratory at Madison, Wise, -- April, 1946N R E B J1 0 Xq 1 1 1 1 q 0 0 q 3 X q 1 27 FLB 001114 Some Things You Should Know About Post-War House Paints Less paint <-- longer life. New paints plus new methods give more value for your paint dollar. In this, the last in a series of three articles Mr. Browne tells property managers and operative builders how new controlled-penetration primers plus one coat of finish paint are more durable than the old [penetrating primers plus two coats of finish. Also discussed are the types of light paints than can :be safely tinted without chalking, the wearing qualities of chemicals that go into "deep color" paints, and methods of classifying house paints By F. L. BROWNE, Chemist U. S. Forest Products Laboratory Madison/ Wis* OF the 25% by volume of total pigment in good paint, 10%. has been assigned to white lead and zinc oxide and nearly 4% to titani um dioxide, leaving a balance of 11% still to be accounted for. In white paint the balance is made up of inexpensive pigments of low opacity, commonly called extending pigments or extenders. The more important extending pigments are: magnesium silicate, magnesium aluminum silicate, silica, mica, and barium sulfate. Certain mixtures of very opaque pigments and extend ers are treated as though they were single substances and given names of their own. Among such com posite pigments are: titanium-bar ium pigment, which contains ti tanium dioxide and barium sulfate; titanium-magnesium, which con tains titanium dioxide and mag nesium silicate; lithopone, which contains zinc sulfide and barium sulfate, and zinc sulfide-magnesium, which contains zinc sulfide and magnesium silicate. The oldest of the composite pigments, lithopone and titanium-barium, were actually manufactured as mixtures but some of the more recent ones are merely mechanical mixtures. Since the ex tending pigments were used gener ously in cheap paints long before the very opaque pigments were de veloped, many paint manufacturers have been reluctant to report ex tenders in the formulas of their best paints. By lumping the extend er together with a very opaque pig ment under the name of a com posite pigment direct reference to the extender is avoided; In modern paints the extenders are not to be considered adulterants unless they are used to the exclusion of the requisite proportions of chemically active ana opaque pigments. The time has passed when any apology need be offered for the presence of extending pigments in good paints. Tinted paints, a term that in cludes nearly all colors commonly used for buildings except deep shades of red, yellow, green, brown, blue, and black, are white paints to which small proportions, rarely as much as 1% by volume, of the necessary colored pigments have been added, replacing a correspond ing proportion of titanium dioxide or extending pigment. Most,of the colored pigments, even in very small proportions, add materially to die durability of paint On the other hand, chalking must be kept within closer bounds in tinted than in white paints because the color apparently fades as soon as chalk ing begins. Paints containing high proportions of white lead and zinc oxide fade less markedly than paints low in chemically active pig ments. For that reason some manu facturers use more lead and zinc and less titanium pigment in their tints than in their white paints. The kind of titanium dioxide pre ferred for white paints, which has the crystalline form of the mineral anatase, leads to objectionable fad ing of tints. White paints contain ing titanium dioxide, therefore, should not be tinted on the job by the painter. Instead he should use cream or light gray paint for tint ing or,better,use the``white base for tinting" sold by many manufactur ers. For tinted paints there are other kinds of titanium dioxide called "nonchalking" which are either specially treated anatase titanium dioxide or titanium dioxide with the crystalline form of the mineral rutile. The term nonchalking is an exaggeration. All house paints should chalk as they wear away but the rate of chalking should be held within reasonable limits. The colored-pigment paints or "colors," which are deep shades of red, yellow, green, brown, blue, and black, necessarily differ greatly from the white and tinted paints. The requirement of color excludes the opaque white pigments in any but minor proportions. The chemi cal effects of white lead and zinc oxide are thereby excluded. Iron Oxide, however, seems to have some of the desirable effects of the chemi cally active pigments. The most im portant red, yellow, and brown pig ments are rich in iron oxide. Lead chromate, an important but ex pensive brighf yellow pigment, seems to be similarly effective and basic lead chromate, which is bright orange in color, is a basic pigment like white lead. These pigments, therefore, make good oil paints that can be made much like white paints except that iron oxide or lead chro mate replaces the opaque white pigments. Pigments of low opacity play the same part in colored-pig ment paints as they do in white paints. Red and brown paints made with iron oxide, however, often con tain a substantial proportion of varnish, replacing part of the lin seed oil, to make them dry faster and harder and to make the coating more glossy. Addition of the var nish makes it necessary to increase the content of volatile thinner, which results in coatings somewhat thinner than those of good white paints but the great durability of the colored-pigment paints makes the loss in film thickness of minor importance. Green paints.are commonly made with chrome green pigments, which are mixtures of lead chromate and ferric ferrocyanide, often with sub stantial proportions of pigments of low opacity. Green oil paints of good quality would be relatively ex pensive, consequently the content of chrome green is generally limited to the amount needed for color and opacity and the vehicle consists largely or entirely of varnish in stead of linseed oil. Blue paints are made similarly with ferric ferro cyanide and black paints with one of the carbon pigments or with one of the carbon pigments together with a considerable proportion of iron oxide pigment. Such paints, (Please turn to page 85) 32 May, 1946 -- N R E B J1 0 Xq 1 1 1 1 q 0 0 q 3 X <q 1 N41698.54 FLB 001115 Expenses -- Home Purchaser: one year. In other words, he must its purchase, it could perhaps be s- The purchaser of a home will be carry forward as a prepaid item shown that the property was not/ entitled to deductions for interest amounts paid on insurance beyond purchased with the idea of paid on mortgage and real estate Taxes. All such expenses as insur ance, repairs, maintenance, clean- the one year in the same manner as one on the accrual basis must do. Losses -- When. Deductible: Loss demolition of the improvements/in mind. It would depend entirelyupon all the circumstances surround ink etc., are considered personal expanses and are not deductible. Expenses -- Renter: Although the rent paid by the renter of ne cessity includes the factor of taxes paid by thkmwner, these taxes are not deductible by the renter except in the case of\he stockholder-ten- es must be deducted in the year in which the loss was definitely ascer tained. A partial loss can some times be made where it can be shown that the assets from which payments will be received have been reduced to a point that only a small percentage of the claim can be col ing the situation to determine as to whether it is a proper deduction. Intra-Family Transactions: Dif ficulty often arises when an attempt is made on the sale of exchange of property when the/transaction in volves directly or/indirectly mem bers of families/Or where an indi ant of a co-operative apartment. Stockholder-tenants are now per mitted to deduct from their per sonal returns amounts paid or ac crued to a co-operativV apartment lected. In the case of corporations, all losses ascertained during the tax able year are deductible. Individuals are limited to losses vidual is deaUng with a corpora tion in whichhe and his family own more than 50% of the value of the outstanding stock, or between two corporations if more than 50% of corporation to the extent,that such amounts represent such, stock holder-tenant's proportionate share of real estate taxes paid or in< by the corporation, on the apart ment building and land on it is situated and of interest pail or incurred by the corporation on its indebtedness contracted in the acquisition and construction of Such property. Depreciation: Depreciation ' is not allowable as a deduction on a home that is occupied by the owner. If, however, part of the building is rented, a prorata part of the depre ciation is allowable if this part of the property is used in a trade or business or used as an investment property. In investment property, deprecia tion is deductible against other income of the owner if the income from the property itself is not suf ficient from which to deduct the depreciation. It is, of course, nec essary that a division be made be tween cost of land and the cost of improvements. Depreciation is al lowable on the improvements only. occurring in a trade or business or transactions entered into for profit. Individuals, however, are en titled to deduct casualty losses even though they have no relation to a trade or business or transactions en-/ tered into for profit. Casualty losses are-losses frefm accidents, casualties, and theft/not msated for by insurance/such as: aiito accidents; jewelry aitd auto theft; fire to home, furniture, and other household articles;/and losses due to storms. Demolitioriof Buildings -- When Deductible: AXloss/is usually al lowable on the voluntary removal of a building if/me property has been held for a/considerable time by the taxpayer, HoWver, if the building has recently1, been ac quired, it \s usually contended by the Bureau that the property was purchased with this in miHdyand, therefore, no loss is allowable's,If, however, it can be shown that son change has occurred with the of /the property which could not ive been foreseen at the time the value of the outstanding stock in both are owned by the same in dividual, or if one of the corpora tions was a personal holding comjany, or between the grantor and 'the fiduciary of a trust, or between a fiduciary of one trust and the fiduciary of another trust, if there is a common grantor, or between the fiduciary and beneficiary of the Same trust. It is contended in these situations that it is not an arm's length trans action and that the transaction may be for the purpose of securing the tax deduction and is, therefore, not a bona fide transaction. Lance Joins Association Ormie C. Lance, for 13 years sec retary of the iNforthwestern Lum bermen's Association, joined the National Door Manufacturers' As sociation on April 15, as secretarymanager. Mr. Lance succeeded W. M. Steinbauer, former secretarymanager, who recently resigned to become associated with the Wabash reen Door Company. Capital Expenditures: Capital ex penditures are never deductible at. the time they are incurred.. The; Construction CostTIfnltolQeXxes must be depreciated over their life. On leased property they maybe amortized over ' the term of/ the lease or their life, whichevei/is the lesser. Costs of repairs are an expense or a capital charge, depending upon whether the life of the asset has been extended or matte more use ful. Where a new property has just been purchased, it/is held that all repair charges necessary to make it usable are capital expenditures. Insurance Bremiums: Under the most recent/rulings, a taxpayer, even though on the cash receipts and disbursements basis, may not deducfmore than one year's insur ance premium in his return for any Statistic* compiled by (J> S. Department of Commerce. 1946 Jana~ ary American Appraisal Go.: Average, 30 cities.......... .1913 equals 100..., New York. ..................... do......... San Francisco............. da....... St. Louis...................... ........ ;............ da____ Associated Uenerai Contractors (ail types) . 1913 equals .100.... JE. H. Boeckh and Associates, Inc.: Residences: Bride: Atlanta.........U. S. Average 1926-29...... equals 100.... ____ .do......... San FVancisco........ _____da........ St. Louis.................. .....................da....... Frame: Atlanta................ .. ..............._...da........ New York............... ...... .............. do........ San Francisco.,___ St. Louis....... .......... ......................do....... ; Federal Home Loan Bank Adaunatraticra: Standard 6-room frame house: Combined index....1935-39 equals 100.... Materials...... ........... Labor.--.................... .................... do........ 283 293 280 249 278 241.0 140.8 173.1 ISO. 6 157.7 142.6 173.7 147.7 158.3 138.2 335.3 144.2 Janu ary 266 271 270 241 256 226.8 129.4 1ST.9 145.3 146.7 131.2 159.5 143.4 146.2 134.5 I3L.7 140.1 \ 1945 March' ----- July Sep Novem tember ber 267 273 270 241 259 227.8 268 - 274 270 243 2S9 229.3 \ 270 >276 271 244 266S 272 279 272 245 270 230.0 f231.0 27S 248 275 238.0 131.6 159.5 145.5 150.1 133.6 161.1 143.6 149.3 131.6 159.5 146.3 153.2 133.6 161.1 144.4 154.3 132.4 160.1 146.3 153.8 134.4 161.7 144.4 154.9 134.1 \|3b.5 162.6 165.1 146.3 148-0 154.8 15o\6 135.3 163.0 144.4 155.4 137.l\ 165.0 ' 145 ..8 157.6 135.0 132.3 140.4 135.1 132 5 140 4 135.5 133.0 140.6 136.3 133 3 142.4 137,3 134.2 143.5 !" " # $% -- May, 1946N R E B J1 0 Xq 1 1 1 1 q 0 0 q 3 X q 1 SI FLB 001116 I Past-War House Paints-- (Continued from page 32) which are really enamels, should seldom be used for the priming coat on woodwork; instead the wood should be primed with gray prim ing paint made with' white pig ments and linseed oil and the col ored-pigment paint should be used for the finish coats only. Florida Developer Plans to Get Group Bids On Homes Planned by'Site-Buyers \S AN ADDED incentive fonbuy- XX inghome sites in Davis Islands, a Tampa subdivision, W. Howard Frankland, president of the/owner corporation, has announced a plan to facilitate construction j of new homes by a group contract to a single contractor. / Families planning new homes may select their own architects, and turn in the blueprints/to the com pany for a formal bidyletting. Con tractors bidding on the home units will make both a group bid and separate estimate of/the cost of each ' individual home. /These will be submitted in separate envelopes. a gfcoup operation, as operative builders know. Davis Islands was planned and developed by D. P. Davis, a former Tampa, newsboy who foresaw a new suburb built by dredging land from the bottom of Tampa Bay. At a municipal election in April, 1924, approval Vwas voted for develop ment of the project. Six months later, whenVhe lots were offered for sale, all records for land sales in Tampa were'broken. Within a few hours $1,683,500 had been spent on 306 lots. The'Florida land boom was underway. \ Davis Islands withstood the col The second envelope, containing the estimates cm the individual homes, will no/ be opened until after the lowybidding contractor has been selected. Prospective new home owners' may sit in on the bidding session, and, of course, will be shown Hie bids on theif new homes after the contractor has been selected, / Mr. Frankland believes group bidding/will result in a saving on materials because of large scale buy ing, but in today's tight market, the amovmt of such a saving may be questionable. When houses are con structed in close proximity, a cer tain labor saving can be effected by lapse of the boom, and has con tinued to develop\as a residential district. Its 832 acres now contain many fine homes, apartments and hotels, as well as municipally-owned tennis courts, yacht basin and hos pital, all within five minutes of the center of Tampa. Its\ streets, the narrowest of which are 60 feet wide, are all paved, and all utilities are in. Mr. Frankland heads\a corpora tion which acquired the property from absentee ownership three months ago. Other officers are F. H, L. French, vice-president; Wallace C. Tinsley, vice-president, and Alfred Dana, secretary-treas- ma. / & '( (/ N1 0 Xq 1 . B 1 .E 1 1 q ) *B J0 0 q 3 X 7q 1 -- Muij, 1946 House Paint Primers The old practice of priming new woodwork with a priming paint made by thinning the finish paint with linseed oil and thinner is wasteful because much of the oil penetrates relatively deeply into the wood, where it does little good, and negligible progress is made toward building the required 0.005 inch of coating. House-paint primers were designed to prime bare wood more effectively and to make it possible to build satisfactory coat ing thickness With only two coats of paint, one of primer and one of finish paint The modern primers contain as much pigment as good finish paint, namely 25 to 26% by volume. About 40% of the pigment or 10% of the paint by volume is white lead and 3 or 4% is titanium dioxide to give sufficient opacity; the remaining 11 or 12% is extend ing pigment. The linseed oil amounts to 40 to 47% of the paint by volume, about half of which is bodied linseed oil. The thinner and drier amount to 27 to 34% of the paint by weight. The bodied oil together with the generous amount of pigment provide the characteris tic known as "controlled penetra tion," which prevents excessive penetration of oil into the wood. The substantial proportion of thin ner is necessary to make paint spread properly on hare wood. House-paint primer of this kind can readily be applied at 450 square feet per gallon and followed by one coat of good finish paint applied at 550 square feet per gallon to build a coating 0.0045 inch thick. Such two-coat work has repeatedly been shown to be even more durable than the older practice of building similar coating thickness with a thin, penetrating primer followed by two coats of finish paint. Classification at House Paints Although most house paints bear a statement of composition, or for mula, on the label, the composi tion is reported in percentages by weight rather than by volume. Paint ingredients vary so greatly in specific gravity that a general discussion of paints in terms of percentages by weight becomes 35 FLB 001117 stimated 50,000 People Attend Memphis Home Show Panoramic view of die Memphis Home Show *-- a display of model homes, home appliances and buildins materials at Ellis Auditorium NAHB Southeast Area Conference held at Memphis are s frontrow, left to risht, Frank W. Corfright, Wallace R Johnson and Joseph W. Meyernolf. Standing at left is John B. [Good win and On the right is Sam An estimated 50,000 people viewed the Home Show in Mem phis, Tenn., held in conjunction with the Southeast Area Confer ence of the National Association of Home Builders annual conven tion, April 19-20. The Home Show, open to the public from April 18 to 24 featured 87 exhibits of new , homes, home appliances, new mate rials and treatments. The two-day home builders con vention featured panel discussions and talks by industrial and govern- oental representatives. Main speak ers were Joseph W. Meyerhof!/ preifdent of NAHB, and Raymoi M, Foley, commissioner of FHA. Panel discussion topics were home financing, moderated by Cttrt C. Mack, assistant underwriting com missioner, inA, and materials for G.L homes, chainnannea by Wal lace E. Johnsork regional -vice-presi dent of NAHB, and moderated byRobert P. Gerholzizi former presi dent of NAHB. counting department records the period of the lease, the amount due per billing period, the decorating or other charges or aUowances, apd any special clauses. All this is done from the office copy of the signed lease. The tenant's card contains a digest of the terms of the lease, recorded at the time of die original drawing of the lease from the ten ant's application. It is used there after as a source of/billing, as well as the accounts receivable record. It is also used bythe manager as a basis for setting-up his earning rec ord of commissions. The' owner- upon receipt of this monthly statement, proceeds to make entries in his books of ac count. No matter what method of ting he uses, such informa tion As simple to record when re ported, as follows, in columnar fashion: 1. Space occupied (Suite No.) 2. Tenant (Name) 3. Arrears (From last report) 4. Current Rent (From billing record) 5. Other charges (Details, per symbols) 6. Adjustments (Details) 7. Received (Cash) 8. Arrears (To next report) 9. Remarks (If any) All this should be set forth upon a statement which conforms to standard typewriter spacing, and should be on a single form of uni form size for filing. hopelessly intricate. For that reason the United States Department of Agriculture has proposed that paints be classified by group, type, and grade according to their com position by volume and that the classification be printed on the la bel. The oil-rich white paint de scribed in this article would be classified as group TLZ type 3B grade 1 if it was made with the higher proportions of white lead and zinc oxide suggested and as, group TLZ type 4C grade 1 if hr contained the lower proportionspi white lead and zinc oxide. The clas sification system is described in de tail in U.S.D.A. Technical Bulletin No. 804, "Classification o(/House and Barn Paints As Recommended by the United States Demurtment of Agriculture," which can be pur chased for 10 cents from the Super intendent of Documents, Washing ton, D.C. Another/helpful publica tion on paints is/U.S. Department of Commerce,/Building Materials and Structures Report BMS 105, "Paint Manual with Particular Ref erence to Federal Specifications." Monthly Reports- (Contintuid from page cost for checks and stationary and bookkeeping expense. However, in my opinioriV it would prove more practical to ha die the/income for each building of a separate ledger sheet. The income^ coula be classified separately with th/aid of a few columns because tjfte same bank from which disburse- lents were made in connection with this group of buildings would control all deposits. One entry per day would represent the total re ceipts of that day, as accounted for on the duplicate rent coupons. On this same sheet the closing entries for the monthly statement could also be posted. For instance, receipts less disbursements would show either the check to balance for account of owner, or the credit balance which would constitute a part of bank balance and trial bal ance at the close of the month. When the property manager's leasing department informs the ac counting department that the lease has been properly closed, the ac Classification of Disbursements. In my opinion, the following ten categories are adequate to cover the analysis of the usual monthly operating charges: , 1. Advertising 2. Wages 3. Commission 4. Decorating 5. Electricity Fuel Maintenance and repairs 8.\Management fee 9. Miscellaneous 10. lAiifonn expense and upkeep Below\ and separately may be shown sum items as: 11. Real estate taxes . 12. Water 13. Federal ahd state pay roll taxes 14. In 15. Mortgage interest 16. Building improvements If the owner desires a further analysis of his expenses for deco rating, repairs, supplies, insurance, and commissions, the manager may detail them to meet ms. require ments. Since the owner is regularly sent all receipted vouchers, he may (Please turn to page 88) 36 + ,- ---May, 1946 N H E1 0 Xq 1 1 1 1 q B.0 0 q 3Journoi FLB 001118 ease, jinal tentierewell :ord. as a ; rec- this : to : aed o rinat remar ) ling per pon to and uni- ten >ver thly | eep be % .xes her xolce, aay ire.rly lay \ Photographs below and right, taken in 1944, show paint behavior as tested at Forest Products Laboratory's "farm," Madison, Wisconsin BY F. L. BROWNE U. S. forest Products Laboratory el and 2 Paints get dirty, clean themselves Painted with three eoats on the north side of the test fence in 1936, later repainted as follows: 1A & 2A. One coat every 3 years, last time in 1945; IB & 2B. Two coats every 3 years, last time in 1945; 1C & 2C. Two coats every 4 years, last time in 1944; ID & 2D. One coat every 5 years, last time in 1941. The dirtiest paint, A's and-B's, is only 1 year old. Two-year paint on C's has begun to clean itself. Five-year paint on D's has been clan for two years or so. White paintlooks'best in the last half of its life. Pure, white-lead paint on lA to ID. Titanium-lead-zinc paint of Group TLZ, Type 3B on 2A to 2D, White-lead paint gets dirtier than TLZ paint but, like most other paints, it cleans itself by chalking as it gets older. 3 4and Tinted paints (light colors) fade Painted with three coats on south side of test fence 1939. Redcedar and white-pine siding. Paints on 3 tinted to match a gray color. Small pieces now tacked* to the boards show the color at the start. The pain, - on 4 were the same except they were tinted to mate! 0 a bull color. All the paints were of Group TLZ but tl i< y dif fered in amount of lead and zinc pigments or in kind of titanium pigment as follows: A's & B's. High in Irad and zinc pigments. Type 2B; C's & D's. Low +0 lead zinc pigments, Type 4G; A's & D's, Titanium pigment of the chalking variety; B's & C's, Chalk-resistant v&i riety of titanium pigment. A's and B's faded 1< -ft, C's faded badly, D's faded most, in fact they soop; turned almost white. V and 0 Wear and color changes in red barn paint Painted with two coats on southside offence, 5 in 1940, 6 in 1939. Douglas-fir and southern-pine siding ~> \. Best paint sold by Maker'X; pigment 54 % by weight of which factory-made iron oxide 22 %, zinc oxide 5 %. Wore fairly well, color faded. 5B. Cheaper paint by Maker X; pigment 51 % of which iron oxide only 15%; much varnish in liquid. Color good but did not wear well. 5C. Best paint of Maker Y; pigment 54% of which natural iron oxide 25%; some varnish in liquid. Wore well, color darkened. 5D, Cheaper paint by Y; pigment 50% of which iron oxide (Venetian red) 15%; some varnish in liquid. Wore well, but more paint was needed for a given area. 6A, Pigment Spanish oxide 56 % of which iron oxide 83 %; varnish in liquid. 6B. Pigment Spanish oxide 64%; no varnish. Paints in 6A and 6B had too much iron oxide for best wear and best color, 6C. Pigment 53 % of which iron oxide (Spanish oxide) 25 %. Wore well but faded badly. 6D. Pigment 59% of which iron oxide (Spanish oxide) 50%. Best wear shown but color darkened slightly. .| , fi# _ ' See the author's how-to discussion of paints and painting on page 52 ---- ----1--^ SUCCESSFUL. FARMING, SEPTEMBER, 19t4 N41698.55 FLB 001119 Pointers from your paint farm (Continued from picture pagre tt-29) By F. L. Browne II > I r Jl II M >' Kl II I II I !> 1 iv w piuos dtvslopid duting thi war, s 4 / vs ill he v i U aflv iv <1 to va it no Iongi r bm io l* muti-iii with (jOOll punts ihu ihielly on ml iil> punt u lidi ohiiel i ifLsc r ill tn io <^ro it* ff ui to turn out w\ in ul i qulU ib f J foi i cough lut lif tod to 11 d ubsntut s joi <anit of lilt- ni it nils usUctliy uif (l fin making ciWli.in paints ]'()! fanp paini., roconwi inn U noisily i TDitur of puking up vshrt pnvri w was luokc n of1 Mot pints foi outsidt > o< (f rfwi itu talm butiftinc,'! -rt oil punts t h tl is (J7 * v'lu ' (U Itspud pm Hon nt di< paml IS chiflb Itti'tdtul Orhr chymg oil uth wyfn m oil imy v pi i< c iin g\i tit + hi coimsumy lor I >i ubhuiL. or 04 7 tying. Wiy small proportion* ot dntis Ar nt rdid to miki punt dry I'ist i i i bi I lit i 11 h li i * ' -in onlci ol tin War Pmduetion Boird liiiiituig ih'" rinioiint ol diying oil to housi paints to 1 75 pounds per galIon m ord. i to ronsei ve vejp ubh oils Good oil paints nmm illy couum 4 75 to a I ill i i n i i i il ni i1 on 1 ariiniini of drying oil left out Muv-ei d oil is ti /f in short supply \ltho tilt ristmtiti oid< r is no longii in eflcet, most in uiul ii luri rs still mtke oil nstuttid someulut elieapoi to iuiki and theiefore n i ly rt main on th' mat ket as lony as they i 11 i tin ii I i I il in i paints Competition will es* ntuallv drive^ them back to tin field of iow-piitid pamis, win re thi y stat 'cd house paints of good quality sold at that time Ltiay i.ui desiribtil m letm ol a rl isiihe iiton propos d bv out Toust 15 r rluets I iboiatoi atil sueqistiom oi loLnlt tli U will rlisvilw in Linvtri oil PuM d t ri (I fo t< iiiomi tl ipph of wiLitit* tliiniins **0 that a him thulv, , i un^h io Iv 1 Win r < in lit hui)t mill H 1 i uls a p i-sibfa ( and pimI dlti shuil'l ht if4U io In wit id id tl> on s non 1 nr roii'h sUilm ind should I si I nil li il diqai soons in binds si i' nIv 11 ll is pul without ` nui " or , .s' lu-i sligh' `luul mark, ' which irid ui th ,i id 1 4 )1 s ot in si buildups dry -itt-1 V inrth m dl kinds of wi lthi i in ahull punting is dom, and iuai m dt suitable ini> ts ils (,<nxl oil punt will dr, all du'si ilirnft-r lor you I'ailiis e 111 h melt m whu it tin + hieli i (insisti pat tly of raw IinsiedoiUnd ol < IdJsifitation is non published m lUlad I I si i \ I 11 il I il i 11 ( hiurJoUui uf Hl'tSi f 7i'/ 7/iW`P di li i nit m> i in' b} tin l nl d Slu'et l)ej> irt- m t nf Ayiatlluri., Svhit li c tn be boitf'lu fi r 10 111'ts fiom till bupi rinU nth nl of Ihi white or light lolond pamts de- sirilvd at that time wm puis wlute- liatl paint uhnh is paint ol Group f. (|i id) Typi t,\ (.itade 1, and foifi kinds ol nn\id-pi*'nn tic p nuts ol tiurtip LL/ (Utaniiini, letd, and /int 1 1 >pe ill Gride I of Caoup LIZ, lype 31', Gndx 1 md of Gump 1 Ll lype 4( , ii Lb I i i 11 11 t 11 v ill not differ from ilum vi n gu ttlyr, a id 1 nn n'lnn thtin In ic to uhrsh your quin s ulueh evia nimeial spit its to old st kind ot whin punt is still oni of 1 map lint i ithi t moi< rujis ot ihiitu t J0 4 _ 0Ui nt p unring qn llttu s it holds Unta i n(mi'll dry putu on the slirfad to wear Mam i (lot t, liusi I7 en n'dile to ni lki sinli p dins p ipuLir hv c ill my them synt'lt tit puns quit k. drs nip palms oren,ir'u li/' d punt, So Mr. Iiussisii thou disidvimi? >ia'i oiiiMiqlud my ad\ Hit nri s t lamu d t t itu m t si'i pt m i < rl ttn p + its ll d i p t dors liM chi k gu +0 , 1 ui si i Jnit i put tin no.ii nukis use of I'll limn ` pia.UL pahi*,'! or pisl by slow eh liking uid i line dm king and erumbl.nn that liases a goodsurfact [ i p n 0 0 I | i i ' it ' in 1 postpum d fan sivu li > ai bevond tnt nuut. il fourth or tilth seal v ithout prnliiji mg an unkempl appearance ot lcaiing i difficult tntf iv[Xrisise surface to prt pan- foi i(-painting. Such delay in re painting is common m trim work 1 he she rtf omi*ig ot pun w hue lead with dm during Ihe lust yeat or two mi, I. St in dll nnldtd pjihtws she. ts. ' filieis, mhlieis ami giu*' lbe plastic mon htasrlv slndi d ui is of buddings i paints no tin uniii' suitable for upki'i p You'll notin' lliis on page 28. punting than hey win. 'vl <n tiny win You maylruy pme w utt 1 adpnntin > r dli d A i* I I7 Hi paint* lire form of sotr pad's- lOLitatnyig 89 ptisent white lead, 9 pertenlL lum tu pa.it'.if Pointers From Your t'. Paint Farm f rram [ <i"i 52 ] In st i d oil and 2 peici nt turpentine hv weight 1 n make 61 s eailons of Or tdi -1 punt, mis 10O pounds of thi pisti with y* f qillons of I usttd oil and 1 pint ol fvpiirl punI dm i Io nuke light eoloi5, ih. wlnti inui-t be tint'd with colors moil Pun v.Iulefi id paint ini" also he linuiilit 1'1 the piepated foim in white, ind aho in a sanity ol light 1'dors (Jride-1 pauil in die piep ind foim, ion iums poi le s th in 71 prist nt pigment bv wiighi, and not liss th,m 86 peiemt of ifii liquid is Imserd oil 1 hi UL / p unts, as toinpaierl to thi white-le l paints you'll- pist r( id iliout, li.ivt the ul\r intaqe of a blighter appiaiaitci piitnulaih' In while, and Its, gnsing fiom colLilion of dul l'tn dtaid von II li ive to take iny ssortl lor u hi e uiv th p clun s on p i"' * and 29 s.oii tshu.- tin mini ihHiunie betwim L md 11,7 paints Yon neid to see the ai tnal (Hints out in thi d iyrliqlit in rlic k tl i it il diilen in i, ToOWS 1 L7 punts ma/hase lossir pi jpoilions of s.luLe leid mil nne oxidt thini'in gi uei ills ust d in 1941 lin.n- mg l111 piopoitL'm of tlv lead md rinc pi'inint, imj,roves vinn- propiitns ol 11 /, pamis Im nukes otlu r propi 11 n'S v oi si Tlv n is, lluulori much difler- enn ot opinion ibnui lust pioptnlions Mo hull le id md /mi riusts too ripul ehilkair and i ulv l tilurt of thi J 1Z paint lhi s<-ty loac l proportnm i innol In sin\n tls, but the wlnu hail fiiiit rim cisidetoplni mtainis ,liould not I7 hss ihan 40 p-itinl of the piqm at bs w'lgltl Piiuls ueai the mini mun piopoiliiiM which bi Ion; io Type 4( stiv ukiisilv ih an ind nuv not ilnik 'U ei irk fill a long turn, but lliev milk wq lr<els, do tuU hold mils will, i id if tin v in- re "li t *d they may c raek and a tli bull* \, th( ininuiit of fa ad md 7in< is mueisid, thi te is gtsilti giir ui rn dii t ami e uh r cheeking anil tin h im bill h s sivm ill ilkmg hs, t idlin' ol mas and fa's oli|i i noe ible 11 ltkin Roll fl dm" if in i*li i led \ sifa ,i-r fin sou to tale i< tint I !,,/ pamts i f medium eoiiient nf white fa ail and /mi aside (i- hit h lieloti" to J spi 5B if (Ivy hi mon li id than /me oi to lype it it tins hast mon /im tl an fa ad pii,in< mj iipuv in i good eompionuse In twi eii tin ads ml v;' s and disidsantiei s In sui h puiu,, tlv i lute fa id and /me usi'fa n o lii i is usuillv hi r nn oil and di p neut of thi lot il pn'un nt bs \,i i 'lit Some tilamuiu pigin nl, i halk nio.e I i h than min is Ilv i lialkuM v in (ns nr Inst fin innhin" s.lule ivunt Incauv the p Q0 + bi-emni i fa ss qsisid wnh dm, liut foi luifad [jimis tin ilulsii i taut s ii ulus m hist to Isold f idol' V'i id IbZ |, unis nl 'Mp 115, >1. oi 1C shot fa not bi tl Old on thi (of) Il ml able colon 1 p suit ol tlio-e tspe, r innol Ij i pun-lii ^d, a cn i nt is Iv tuiihii timid on tin (ob or belt-1, a sp-riil wlnti bn fan liuline," oflen il bs soon- iii.iuul LClun i i, mav be Il is s i i ill ki oping in iiu ik I ill tl lulled paint-ill .-tat faini'ei lit ill s/Iuie |sanus. V a lule, tiv bull or guy tints Jiov n in tin pliorogi qilii on paly 29 will 11-1 6 sous whin tin nine jinulin" sslule SUCCESSrUL fARUING sanri-WHER 1946 FLB 001120 Above: Doctor Browne explains sections (such as those below and left) on the many exposure "fences" set up to test paint life and performance FLB 001121 n;^ aturaslly, any one brand of hybrids cannot win all the time, but when Pfister Hybrids win 8 out of 10 yield checks, that is mighty conclusive proof of superiority. Figures based on 2,325 competitive yyield checks made over a period of 8 years in 9 states show that Pfister Hybrids actually win 83.13' of the time. In the few cases , where Rfisters do not win, they lose by an average of less than 5.5 bushels per acre. Remember, it costs you just as much to plant, ) grow and harvest a "fair-to-middling" hybrid as it does a winning hybrid. And, every extra.bushel of shelled corn is extra profit . ... clear profit! Your opportunity for making extra profit is better when you ask your Pfister Dealer to help you select the hybrids that are WINNING 8 out of 10 10 2+ in your locality. Call him today! FflEC f NEW l947 C0RN OHE " N* * contain iryjf valuabte information on corn, colorfully illustrated. Available from Pfister Dealers or write: Pfister Associated Growers, l-ac , flo* H, El Paso, III. &MORE c0RltUSS c0B bred that * PFISTER ASSOCIATED GROWERS, IHC. BOX H. EL PASO, ILLINOIS YIELD CHECKS are made in farmers* fields where Pfister Hybrids have been grown alongside of competitive hybrids under the seme conditions. A predetermined number of hills of each hybrid is picked from adjoining rows and the corn accurately k weighed. This gives EAR CORN YIELD. THEN THEAR$ of eacftaybrid are shelled Into separata containers/The shelled com is accurately weighed. This gives the S H EL LEO CORN YIELOA MOISTURE TESTS are made and weights reduced to No. 2 corn. This determines the winner on the basis of 4ry ifceiled cere field per acre. And in 2,325 such checks. Pfister Hybrids WIN 8 out of 10 TIMES. FLB 00112: i 4 0 0 0fill tKpn i l" f down m httleTnare ftfli 4 ai X4rm pruputj surface loi p-unl ri' tf'.ilw" ' ' t Mnr',vrn.Meii*f*ijii.f.-r*''d*r-. {frcidesonwuftwrffoioximpk yield pool I I'liclwawr soilwoud' I0W 1 )ol7,5 or and sOulWrn ydlw pin< dn not hold 1 Ss Ill'll' ! 1 ' I 11 " lik ifcctl*f aud vine pirn- VVhni i fi in the n 3 4urate i <0 1 vxhllt <> ' 1 1 11 " 1 "" 1 toinplctely, il iswoiih thuil >, lth llUlIllllUKU II I 1 * I-IT M> I1 I I I 1 1 1 ilcvRMd for p l ^ WT tal) iwn ofwhitr a* light ,rtfJ Ovtr th< almiumini fnmm plvtfOQrJ ij bi >r niinnii with iluinimiL'i hyu^ pamf b "h ivi n^xU ilu. p uni U+ Iciuqu a`H ti> " plywood is inui h pi<>- cixbuti Mtaui,,l ihukim* as po -^lbli 5Three toaiH 'miniily wire innsidir<cl rt*<o,ar> 0 0 panning n \\ v ooduoik Modtru pints huvivti, ai< ul lui,hu i,l il i i i I I ii ' 1 !| prevent fJ'-tdi* 1 punts anti pcciaLhousi- pajm piHiKis 0 Q / wuixlixoik 1,1 ht pami*d adiqumh with 7+0 to us om ul utrrur md om of tinnh punt Thf punt 1 ould b* spu nl tht<k<t liowtvi luciusc t>o<ni w< Ji i<qniits a roatiTj tboul iKlf5 ' h-iimk, vvhtilm it pul on in Uo cueits oi m ihn < In tlurt* f >it p* irtn< tli< tir 1 toiliirt b< spi* id if 000, ilu H'cond a* 700, ind tin than n8U(>squiu 1+ tp 0 gallon Modi m, 2-< o u pi *t tu 11 to apply X0 7* X 1 ol sp<_f utl puma wuhoui ?ui' duniiiri at 4-10 squirt* l* a pi i dlon and mu coat oHuiisli 4 +0 U0 at "> 0 lqiMi* f* tt 6]70 tallnn Hu< is no -uvinu in th< amount ot p I but thin is a ' iv- ui<; ol l Jior ol upLyiut, i tlurd coal 1^1 D bam p inL ul trood qu dits in pufu ul uly sun ilil< lot Linn build.m,s I0 + uisf of il t 0 0mode t m <*r n u dm i!>nif', md pl< isimj iolu U JI * isoin of ill \( u Lnf +0 mauly ininv Inm p mils un iht iii ukt tli \ b i n of pout quililv in an tfloii tu ni ik< iht rn loo 7clieiply loi 11 itu is is no misiakinh put fov<o4'1 pi gallon X 0 t iou^-lmu suv- !C S<C loloi ]) lilt is Oil pn,f V tin s iu idr \\ jlli 11 rl un n u ur il n >n 8uMck (not lilxn u iv- arxl ta< uny-pio- duitd non o\idt J s ich <4 Spanish o\idef 'M'aihn In i duLn bonusshit [>urpk iliadf as slio\ n sjnu iinv t/tn< oxidt is idilul io non o\id< /incoxidt ishdp- lul in itnihili i 'OtnviU ol uuldiu <>i bun p'liMs a dillft uhv uhuh \ou 11 I'licl v lit it vi i (In it 0 null h d iinprn Vt uUdii i<d 1 umipar d to Spin i h non o\idvJ mi i punts ih il hold i bu'lib 7 rl (i]or Vivuum nd is i uiiitmfu inn d pi muni ill it ioniim> 9 i in o id( m<l( ih mm sulitl Jla noi o\ifl* in flu* bi it \ + Uan n lU auioum U> IH pill (tu Oi till' p"UUUl li\ Uili-lli Hui > litihri \mi w>s)i ihi puiph ml :ol Sp * Iic r<d-itd of VtU Uan ll1^ mul 0 7 ol Tl / it flu sclffh lnlu,, ot u Into Ii id m ml in lru I uu i y< iis ol its Ion ul tin fin muli mi I he I ih* I ind lo him \ Ii Li il mi in o ih U you m knovwhu voua * bii< inq aud us< n m voni |v st nU mtnf Phaso don't ihink. illai lovv piici- per qdion otpiint nn ms low cost foi th< job oi lov ro>t pi r vi-u of S* I \ K ** ENO SUCCESSFUL FARMING SEPTEM ER 1946 W*' i* i\ [-)" Lasts Iwiger,tof Anto-hitc fill'' Battery ftay mute Ilian 3 timey the liquid icser\e of ordinalv hattenes Iu noim.il tar use,the plAtes arc kept siilinierjp'd to help deliver full life and pouci lonq after the plates in oidinaiy battciicy are exposed and inactive. In addition, oversize elechical tapanlj^ pins Tibie glass insulation, gives lougui life than lialteiies without the Aufo-Lite "Sta ful'' fcatuies. lo get the best monej ran liuv, hc suic jour nevl balkij is an Auto-rate "S*ta-ful *' AUTO-LITE BATTERY CORPORATION ' TOLEDO 1 t OHIO Mam/facturirff PJonti ol* Nioqoro Toll* Indlonopolit Atlanta Oill i I *. 4 OH il Tity Tr |> HERi'S WHAT MAKES THE DIFFER ENCf 111 li B: ,5j Utnqui'n vwdi icjn ( nd contliurtinn Auto-Lite 1 Sta^ful morn than 3 time? the liquid reserve of ordinary batteries pthr Batteries hired / Uqfcid level Afr*r Equal Evaporation JL * g jj ii Hluitraiiani dbovo Show the result of equal evopcroiMn in Ihe AutoAite tSw-hl" Bull jry unit Olio r bull- m s As shown fay iRusi ution on tbo for right, plans of (Adninry battvrisv oi* expand Moiter by wntor Ion and then bosom* irtastioe tasty iSs 55 FLB 001123 BREAK" out of Farm Work Do Your lifting And loading With A TRACTOR LOA! H* lifts. toads, forte, scoopsJ It pulls. <iigs. grades Ievels.'-Jb.oisul Equipped with combination "forh-bacfi:* et,V Afc budIes manure, sand, gravel,.dirt or snow. For FatraalliHiM, F-12 and F-20; John. Deere A and B; Oliver 7Q; Case SO: Allis Chalmers WC; Miune&Dotis Molina UTU: and Masse? Harris 101 Jr- The DVSr-ALL is an IMPROVED TYPE of tractor loader with ''balanced twin hydraulic lift.4* No t^rlsU strain or wear on hydraulic mechantem. No belts, seats, cable or pulleys to cause tniublja, Lifts 2.500 Us. 11 feet Clears lowest bam doors! Easiest of ail loadws to attach end detach. Drive under to attach, drive out to detach ' LIMITED TEME1:. .... Try this loader on your farm for UPays AT DUB BISK! Mail coupon, today for . Complete Descriptive Litoroturo .rad Free Trial .Offer. FREE 10 DAY TRIAL COUPON ISIEBRING MFG. CO* X1 ; 0 <0 =Xq lOltt MAIN STREET GEORGE, IOWA ?Send complete kfonostfoo en Dizz-Ail Loader nd 10 Day Free (rial offer. Iq 1 + L. fADDRESS _ ROTY_>i Ait-------------------------S---T--A--T--E------------------------ g MMWWWWMfS * y,- ^ , s MAN WITH CAR iewiaBgwaara*wraw>ig* No Time Like New to Get In Mctiess Business It's no trick, to make goodjttoriey when yon __ . U3eyourcaraaaMcNesaMStore L'seYuura .Wheels;" Farmers buy veryfchinff ; they .canfrom McNess. Men because McNcsn Products are tope in quality* representextravaluea. Attractive buai- CAR : ness-Bettiogprizes.and premiums; also monev-saving deals to customers make lo Raise YourscdingMcNess daily accessitieaasnap.. We Supply Capital--Start Now! There'a no better wortanywhere. Pays : .well, permanent, need no experience.to PAY smoaeyifirst day, look, i/s FREE. Tells all--no obligation. / (1) THEMcHESS CO., 241 Adams St, Import, 111. Now Many Wea/ FALSE TEETH With Little Worry Bat, talk* laugh or sneeze without fear of insecure false teeth dropping, slipping or wab- . bhng FASTFJRTH holds plates firmer and more comfortably. This pleasant powder has no gum my, gooey, pasty tiste or feeling. Doesn't cause nausea. It's auutUnc (non-acid). Checks `'plate odor" (denture breath). Get FASTEETK at any drug store. / OTTAWA Wood Saw FOR TRACTORS Fast wood sawing.tjuiddy pays fof self. Easily moved while attached. Bigblade. Freedetail*, OTTAWA MFC. CO. W*32l Oak Avow Ottawa; Kam; 56 Good Tiling Will Boost Your Farm i From page 33] wise, this field was farmed in the regular drained soil, 19.9 bushels over the shal rotation. The first season after the field low die, and 15.6/ bushels on the un was tiled, corn was planted, with the re drained land. sult that no part of the crop was lost. In Layouts like th6 one on the Wolf farm; fact, ponds have completely disappeared. test the ingenuity ofthe engineer. As Mr, Field B was in pasture from 1936 until Mdss points out; "You just can't run a this Spring, when it was plowed and tile fine thru ar rise of ground, and hit a planted to com. The wet spots were tiled pond on the/Other side by following the in 1943. However, it was not until this water-flow level. You absolutely 'need a: year that the soil had opened enough for level and must know what you arb doing. the planting of tilled crops. If you tile by eye dr follow the flow of B _ 1 >? Field C was wet iii spots, it water your tile will be laid to an uneven 'and invariably you will come Out was considered good only for pasture, and too jfigh or too low on the far side." no attempt was made to farm the land ifith the exception of a slightly higher before tile wax put thru. Last year, this finer, Field D was covered with laterals, field was planted to corn and averaged 100 feet apart and extending thru the 65 bushels to the acre, ' fence fine into Field B, Laterals 1,100 add For many years, when it wasn't tot 1,200 feet long are 6-inCh die, while later wet. Field I) averaged 45 bushels ofcor; als only half this long, are 5-inch. These or 20 bushels of soybeans. But in 1944, laterals connect into Main Ho, 1 which the first season after tiling, corn in /this runs about 130 feet in from the end of the ' field averaged .55 bushels, and last/year field. Main Np. 1 starts as 15-inch tile, the soybeans went 33 bushels to the acre. - and steps down to 10 inches, then 8 inch One of the most noticeable diffidences is es, and finally to 6 inches as the carry-off that before tiling, the crops ofttat stood by out on the fai end of the main decreases. ... while operators waited for tile field to Sizes ofmains and the laterals, too, are in dry off enough to harvest the crop. proportion to the amount of water they A quick look at the drawing qfthe farm are expected to carry. Carrying capacity give you an idea of/the plan that is affected directly by slope qf fall and the neer Moss worked/out. While the size of tile used. jt is far from the ideal solution, there was nh choice but to drain this side of the D0 AB1 q _ A recommended between farm into a marsh running into the south eastern corner of/field C. laterals vary according to the type ofsoil. For instance, on the heavy, day Soils, Carl points out that, all top often, pro laterals should be placed from 40 to 60 tection aOaNimuntenance- of tile outlets feet apart. On the lighter, silt-loam soils, have resultedMn plugged and ineffective distance between laterals may be 70 to 90 systems. Frequently, he has found that feet. Laterals on sandy loams may be 100 ditches, long neglected, have silted and to 125 feet or more apart, and in most filled in tq/such amfxtent that the tile out muck soils the lines maybe 150 feet apart. lets havtebecome plugged. Thus, eventu That character of the soil also has a ; ally, tfie entire drainage system lies use bearing on the distance laterals should be less. 7?o safeguard ag^nst oudet trouble spaced is shown by a comment from Vir on the Wolf farm, a tsement headwall gil Overholt, extension agricultural en witfi apron protects the tile opening. gineer in Ohio, "Most of our tile in this it is not at all uncommon to .plow up state were installed 30 to 60 years ago. At Tf- and 3-mch tile that wereNaid 60 to 80 that time drainage was satisfactory with Xrears ago. But today, drainagh specialists the lines spaced 4 to 8 rods apart. But in /recommend 5-ineh tile as the smallest, recent years, water is not moving thru the / be used anywhere m the drainagosyslem. soil as rapidly, and many farmers have / WQ @ tile was buried scarcely^ feet found it necessary to split this distance by laying new lines between the oldla terals. " beneath the surface 50 years ago, ert And small wonder, since a cubic foot of has now reduced this depth to as littlAas this soil weighs from 15 to 20 pounds 18 inches. Tile at this depth was in little more than the original virgin soil. This danger when horses and lighter machim change has been brought about by too ery were used, but the heavier machinery' many cleanly cultivated crop3." now used on farms has broken and dis The Wolffarm-layout diagram on page located many lines. In planning tiling 32 shows that Main No. 2 extends into systems, Carl aims, to have tile buried Shields C, B, and A where it is joined to from 3 to 4 feet deep in mineral soils. In sin No; 3. Laterals trom Mains 2 and the case of muck soils, which have been 3 cut across or tap low spots in these fields. drained previously, he recommends a "an drainage systems be repaired depth of at least 5 feet profitably, and put into good working In addition to more protection for the condition? That's the question we asked tile, greater depth of tile lines lowers the drainagh experts from Minnesota to New water table and results in an expanded York State. Drainage specialists agree root system for the crops; The value of that whileVsome tile can be repaired at suitable depth is shown by an experiment little cost, in other cases it may be far on the Jennings County Experiment Sta niore satisfactory to install a new system. tion in Indiana, where drainage has been studied since 1921. Production from un I~ THE old system is plugged at the out drained land has been compared with let because of a faulty headwall or silt in that from land tiled at various depths. the drain ditch, \he outlet can be re In all cases, the land with die laid 42 paired, or the ditch can be dredged. inches deep gave the greatest production. Broken tile in the Ime can be repaired; Eight crops of com have averaged 57.6 "Where tile lines, laid up a draw, have bushels over tile 42 inches deep, 51.3 been broken by erosion," Mr. Lynes, bushels over tile 24 inches deep, and 40.8 trouble shooter for they Mason City bushels on the undrained land. Wheat has (Iowa) Brick and Tile Company, points averaged 25.6 bushels on the deeply tiUt, "repair is useless; [ Turn to page 125 SUCCESSFUL FAPMING. StFTEMBFR. 1944 9 bushels ov. ci the ,sh il 15 6 bushel, on itn nti- || the nut On the Woli laim if. ``Vim |ust can't tun i rise (if i'ioand. anil lnl a lid uli bs follow in'* tin 1 "Von ilisoliiteh lie'll i .rani wh it ion uc d mil! * sc oi lollovv thi flow of mil 1y* laid to an lira \ i n in ibis nm villi mu um lull nil lilt f Ll 111 piiuicil isli'dnli lii<rhir V.ii imi' lid until in t ih uni (,\itiulint> lhin tin icJdK 1 duals I I'M) and Is loi't; die t mil* Uv't into MQX NX 1 "huh Icit m Horn thi end i>t di 1 stall, as lo-inih tile > b inih' i` *ht <-i is ofl tid ot iln lit tin dun as. s id tin 1 in ra's, too u c m ir am mill of watei ihe\ U l_r slopi of tall a id the ii uiiJin' ndi d lx tl ten oidi I-; to the l\l> of soil n ilu hi i v lias mis j pland horn Id to fill he Ivlin i silt-ln im -oils 11 itn ds nu> lx "0 to no sands loam' in o lx IdO lore ip H , md 11 run i 0 s mas hi 1 >0 t i r ip u l i nt tin oil also h is i isu m U u dssii mill t)` b\ i loiiiriu nt (min X nii nsioa tgi tcuhiii al 11"Most ol our li'< m tin ue \ a Siuslarto.s vtill 1 to s mils tpm Uni in a isiiol niotmp, thin iln \ to s| lit ihisdis'iivi hv lj in11n ilu old 1 in ial i ii, sun( i ( ubn foot of Ircun 1 "i tn -10 pounds UU.UI ll Ml III soil I Ills i In on'hi 11 unit bi too ilt iv in d imp isymi dtaj run < n pi" T u "V ' ( +0 ivls into \ \ in it is 1 mi d to uals noin M mi - mil >lov spots in iI7 ( fn Ids sssi ii I c mviind pul n In 'find (iiiii.iii^ , tin 0,0 n m i isKi d Imn Minin s it to Ni \\ || I4 J0 I I 1 1)1 i p 1 I'd !t If c I I l ll 'Ills O' I ll to imt dl * in " s '< nt in is pin* l{ il i* l i fmlaulis ii uiti dl in sill in the null t car b ni'fih i i" lie iJi d' (d litae i n I i n p mi d UNITED STATES DEPARTMENT OF AGRICULTURE Miscellaneous Publication No. 629 Washington, D. C, issued July 1947 N41698.56 FLB 001125 CONTENTS Density and texture....................... Resins and oils............... .' Moisture content. . ....... Knots and other defects. .; .... Selecting the best wood for painting.. Selection by species......... .. Selection by grade..,........ Selection by kind of grain. . . .. . Selection by density and texture. Page 1 1 5 5 . s; 6 6 8 8 '8 8 For sale by the Superintendent of Documents, U. S. Government Printing Office, Washington 25, D, C, Price iO cents WOOD PI By F. 1 The long ing costs holds pa: new woo S OME kinds . longer than othe: sQnie stay coated the original grain as shown in figu. the painting cha selected fpr paint first time the wo. wood. This pub1 some suggestions i Other factors be coatings, such as c done, number of ti the sun and rain Under highly unfa before there is tim Publication, howev behavior of coating ordinary conditions woo PA The. -properties of content of resins, oil; Among softwoods pend primarily upon year of its life a tree 1 Supersedes Leaflet N Others. ' Maintained at Madisc 749958--i7 ^`"rcerr -0f t, *rt-**; it ni,'rgus ,,1{0 stands out among whffl .,.i , ,, lLr ^ebuni 1 Ills SllC'gcdt ivd ,> FLB 00112. WOOD PROPERTIES AND PAINT DURABILITY1 By F. L. C DB X q , chemist., Forest Products Laboratory,2 Forest Service The longer a coat of paint lasts the lower the over-all paint ing costs will he. Information about how wood takes and holds paint is therefore of interest to all who use paint on new wood. S oME kinds of wood hold coatings of outside house or barn paint longer than others. Even when all boards are of the same kind of wood, some stay coated longer than the rest. Moreover, when coatings wear out, the original grain pattern of the board is revealed by the sloughing paint, as shown in figure 1. The reasons behind this behavior largely explain the painting characteristics of wood. "When the best woods cannot be selected for painting, careful choice of paints and painting methods the first time the wood is painted will partly offset the shortcomings of the wood. This publication explains how paint is affected by wood, and offers some suggestions for painting the more difficult woods. Other faGtors besides the nature of the wood affect the durability of paint coatings, such as composition of the paint, skill with which the painting is done, number of times the surface has been painted, degree of shelter from the sun and rain (fig. 2), and climatic and local weather conditions. Under highly unfavorable conditions of service, the coating may wear out before there is time for the nature of the wood to show its effect. This publication, however, is concerned mainly with how wood affects the behavior of coatings of good paint, well applied and maintained, under ordinary conditions of service. WOOD PROPERTIES THAT AFFECT PAINTING CHARACTERISTICS The .properties of wood that affect paintings are density and texture; content of resins, oils, and moisture; and defects, such as knots. DENSITY AND TEXTURE Among softwoods (conifers) the painting characteristics of a board de pend primarily upon the amount and distribution of summerwood. Each year of its life a tree adds an annual ring composed of summerwood and 1 Supersedes Leaflet No. 62, Why Some Wood Surfaces Hold Paint Longer Than Others. 2 Maintained at Madison 5, Wis., in cooperation with the University of Wisconsin. 749958--47 I springwood, but the oi does not help to hold tl springwood and summe it comes loose from d securely on the spring enough the coating mabut if the hands are wi boards with narrow ba: Figure 1.--Paint fails soonest over the bands of summerwood in softwoods. A, These two boards were painted with white paint and exposed to the weather for 5 years. B, The same boards after remaining paint was taken off with paint remover, showing the dark bands of summerwood, indicated by the paint-bareareas in A springwood, Summerwood is the dense, homy, dark-colored portion of the annual growth ting, formed in the tree late hi the growing season. It has Wood cells with thick walls , and small cavities. Springwood is the softer and lighter (in weight and color) portion of the growth rings, formed in the early part of the growing season, and has wood cells with thin walls and large cavities. Paint oils penetrate farther into summerwood than into 2 Figure 2,--Paints last Ion paints (one at the left, at yellow pine, after expo: B, facing south; FLB 001128 springwood, but the oil that penetrates is separated from the coating and does not help to hold the coating in place. New paint sticks firmly to both springwood and summerwood, but when the coating becomes old and brittle, it conies loose from thp smooth summerwood, though it usually is held securely on the springwood. If the bands of summerwood are narrow enough the coating may bridge over the summerwood and remain in place, but if the bands are wide the coating breaks loose from them. Therefore, boards with narrow bands of summerwood are best for painting. Figure 2.---Paints last longer in the shade than in strong sunshine. Two house paints (one at the left, another at the right) applied on Douglas-fir and southern yellow pine, after exposure to the weather for 8 years; A, facing north, and B, facing south, 3 FLB 001 The width of the summer-wood bands in softwood usually varies with the density (weight per unit of volume) of the wood and the rate of tree growth, Hcing narrower when the density Is low or the tree growth is slow. The density of softwood lumber is low when the proportion of summerwood is grnall If a tree grew slowly, however, the bands of summerwood may be narrow'We^jSSaJii^Is high because there are then many growth rings per inch of radius of the log (fig. 3), The manner of cutting the boards Figure ?.--Paint-holdihg characteristics depend on wood texture' and density. Boards A and B held paint Well; boards C and D, poorly, when they were painted with house paint and exposed to the weather. Board A had 36 annual rings per inch of radius of the log and at 6-percent moisture content weighed 25 pounds per cubic foot; B had 27 annual rings and weighed 30 pounds; C had 6 rings ' and weighed 30 pounds; D had 15 rings and weighed 46 pounds. from a log also affects the width of the summerwood bauds exposed on the painting surface. Edge-grain boards (called quarter-sawn in hardwoods) have narrower bands of exposed summerwood than flat-grain boards. They are cut from the logs at right angles to the annual growth rings, and the edges of the growth rings appear on the painting surface of the boards. In flat-grain boards, which are cut at a different angle, the faces of the growth rings appear (fig. 1). In flat-grain boards, the side that was nearer the bark often holds paint longer than the opposite side. Hardwoods (broadleaved trees) differ in structure from softwoods. Hardwoods have fibers and pores. The size and arrangement of the pores, which are much larger than the fibers, g6vem the painting character istics of the wood. Hardwoods such as oak, with pores larger than those in birch, are poorly adapted to painting with ordinary house paints because pinholes are left in the coating over the large pores. The pinholes not only are unsightly, but lead to early failure of the coating. The best hard woods for painting are those of medium to low density, such as yellowpoplar, with pores no larger than those in birch. 4' RESli l Resins and oils in -well-season! | is generally supposed. The resi | the life of paints containing zinc | prevented by using modem pr | essential oils in cypress and son | some paints, but they prolong the j In green lumber, however, fh Resin may exude when the pai) wise, and either push through < {. wood may completely prevent dr Occasionally on dry wood, hi partly dried or has become mo: ! of white or light-colored paint pines. The discoloration pomes i heartwood, which are evidently when it is dry. MOIS' Paints last longest on wood regained some moisture so its rr applied to very dry wood are j it is best to paint wood when that is expected to prevail durinj Wet wood, the moisture coi Uncertain condition for paintii of the coating by blistering (f result from pressure against th air and water trapped in wet redeedar, which contain colore paint applied while the wood but later absorbs enough mo danger of blistering, peeling, or KNOTS A Knots in wood produce sei lumber the paint over knots i stances from the wood. Endabsorbs enough oil from pair discoloration and oil absorpti< other spirit varnish over the 1 to crack badly and m*ay flake likely to crack even after they to fill with new paint. Pitch streaks or pitch pocke paint or crack or bake off, orb t; RESINS AND OILS Resins and oils in well-seasoned wood have less effect on painting than is generally supposed. The resin in pine lumber seems to shorten slightly the life of paints containing ape oxide, but this unfavorable effect can be prevented by using modem priming paints free from 2dnc oxide. The essential oils in cypress and some of the cedars may delay the drying of some paints, but they prolong the life of the coatings. In green lumber, however, the effects of resins and oils may be serious, Resin may exude when the painted wood is warmed by the sun or other wise, and either push through or loosen the coating. Oils in unseasoned wood may completely prevent drying of some paints. Occasionally on dry wood, but more often on wood that has been only partly dried or has become moist after seasoning, there is a discoloration of white or light-colored paint over the heartwood of ponderosa or white pines. The discoloration comes from brown substances in the resin of the heartwood, which are evidently more active when the wood is damp than when it is dry. MOISTURE CONTENT Paints last longest on wood that has been well seasoned but which has regained some moisture so its moisture content is 12 to 15 percent. Paints applied to very dry wood are slightly less durable. As a rule, however, it is best to paint wood when it has about the average moisture content that is expected to prevail during service. Wet wood, the moisture content of whifch is over 25 percent, is in an uncertain condition for painting because there is grave danger of failure of the coating by blistering (fig. 4) and peeling. ' Blistering and peeling result-from pressure against the back of a coating caused by expansion of air and water trapped in wet wood. Moreover, woods like redwood and redcedar, which contain colored substances soluble in water, may discolor paint applied while the wood is wet. Even if wood is dry when painted but later absorbs enough moisture to .become thoroughly wet, there is danger of blistering, peeling, or discoloration. KNOTS AND OTHER DEFECTS Knots in wood produce serious blemishes in paint coatings. In pine lumber the paint over knots is often discolored by yellow or brown sub stances from the wood. End-grain wood in the knots of any wood often absorbs enough oil from paint to destroy the gloss of the paint- Both discoloration and oil absorption can be prevented by applying shellac or other spirit varnish over the knots before painting, but the paint is likely to crack badly and may flake from the knots fairly soon. Large knots are likely to crack even after they are painted, and the cracks may be too large to fill with new paint. Pitch streaks or pitch pockets in wood mar paint coatings by causing the paint or crack er bake off, or by exuding.resin. 5 FLB 001 f Blue stain in sapwood can be concealed by paint as long as the wood can. be kept dry. If at any time die wood becomes damp, however, the fungi causing the stain may become active and push through, discoloring the paint. nr , *I 1 . Sis M-zsaiP figure 4.--Blistering of paint coatings on wood siding caused by condensation of water behind the siding during cold weather. The badly blistered coating at the left consisted of three coats of a good-quality house paint. The slightly blistered coating at the right consisted of two coats of the same house paint applied over a priming coat of aluminum house paint. Paint failures of this kind can he entirely prevented only by permitting no water to get behind painted woodwork. SELECTING THE BEST WOOD FOR PAINTING Wherever wood is to be kept well-painted for a long time the cost of paint maintenance can be reduced by selecting kinds of wood that hold paint coatings most satisfactorily (fig. 5). . SELECTION BY SPECIES Since paint-holding qualities are affected by the kind of wood, and woods are marketed by species, the easiest method of selecting woods for painting 6 - mmn Figure 5.--Paint wears longer on ! after 8 years of exposure to thi at left), on eastern white pine upper boards at right), and on s is by species. Species alone, 1 selection because there are wide boards of any one species. 1 when purchased in lumber of characteristics into five groups; Group I: The cedars, baldc woods. Woods of group I hi barn paints well. Group II: Eastern white pit which are softwoods. On woe are slightly less durable, but < group I. Group III: White fir, the h the softwoods; aspen, basswoO1 of the hardwoods. Paints de of group III than on woods of containing zinc oxide are less c Group IV: Douglas-fir, sou softwoods; beech, birch, the g deteriorate more rapidly on W( II, and III, On southern ye less durable than paints free fro Group V: Ash, chestnut, eh hardwoods with large pores, the pores before smooth eoatir FLB 00113: M-Q3226F Figure 5.--Paint wears longer on some woods than on others. A good house paint, after 8 years of exposure to the north, on western redcedar (two upper boards' at left), on eastern white pine (two lower boards at left), on Douglas-fir (two I upper boards at right), and on southern yellow pine (two lower boards at right). is by species. Species alone, however, is not the most effective basis for selection because there are wide variations in painting characteristics among boards of any one species. The commercially important native woods, when purchased in lumber of the higher grades, are classified for painting characteristic^ into five groups : Group I: The cedars, baldcypress, and redwood, all of which are soft woods, Woods of group I hold ah of the common kinds of house and barn paints well. Group II: Eastern white pine, sugar pine, and western white pine, all of which are softwoods. On woods of group II, paints containing zinc oxide are slightly less durable, but other paints are as durable as on woods of group I. Group III: White fir, the hemlocks, poixderosa pine, and the spruces of the softwoods; aspen, basswood, cottonwood, magnolia, and yellow-poplar of the hardwoods. Paints deteriorate somewhat more rapidly on Woods of group III than on woods of groups I and II. On ponderosa pine, paints containing zinc oxide are less durable than paints free from it. Group IV: Douglas-fir, southern yellow pine, and western larch of the softwoods; beech, birch, the gums, and maple of the hardwoods. Paints deteriorate more rapidly on woods of group IV than on woods of groups I, II, arid III, On southern yellow pine, paints containing zinc oxide are less durable than paints free from it. Group V; Ash, chestnut, elm, hickory, oak, and walnut, all of which are hardwoods with large pores. Woods of group V require wood filler to fill the pores before smooth coatings of paint or enamel can be applied. .7 FLB 001133 rf SELECTION BY GRADE Most lumber is graded for sale. In softwood lumber the better grades for painting are the select grades. ' Select grades of lumber permit few knots, pitch streaks, or pitch pockets. Common grades in which defects are numerous cannot be expected to hold paint as well as the select grades. SELECTION BY KIND OF GRAIN Some woods are cut into lumber in such a way that the boards in the highest grade are always edge-grain. The term "vertical grain" is some times used instead of edge-grain; among hardwoods the term "quartersawed" has the same meaning. For good painting, edge-grain dumber should he purchased whenever possible. When fiat-grain boards are used, it is desirable to turn them so that the bark side will be the surface exposed for painting. The bark side is the side toward which the annual growth rings are convex. SELECTION BY DENSITY AND TEXTURE In commercial shipments of many kinds of lumber there will be found a wide range in density, and in width of growth rings. Paint maintenance can often be improved by setting aside those boards that are much above the average in weight or in width of summerwood bands. The heavy, wideringed boards may be used for construction that will not be painted, for less important parts of the structure, or for parts that receive little sun shine. (Paint will last longer on any board if it is in-a shaded rather than a sunnyiplace.) As a rule, the tame for repainting a house is determined by the vfearing out of paint on the poorest boards. . SUGGESTIONS FOR PAINTING THE HEAVIER SOFTWOODS The forests of the United States produce much more lumber of species classed in groups III and IV than of Species in groups I and II. For that reason woods that tend to shorten the life of paint coatings often must be painted. In such cases the unfavorable effect of the wood can be reduced by careful selection and application of' paint the first time the structure is painted. Painting should be done as soon after erecting the woodwork as is practicable, usually within a week, it is not good practice to allow wood to weather for weeks or months before painting. The first of priming coat of paint may be applied, if convenient, before the lumber is delivered at the site of the building. If this is done, both sides of the boards should; be primed to avoid the cupping or warping that might otherwise occur from unequal rate of change in moisture content on the two sides. Al though priming of butt ends is often omitted, the best practice is to 8. paint the butt ends v before fastening them If woods of groups before applying house their paint coatings i Figure 6.--Aluminum woods that have wid fir were exposed to t were painted with tlwith ode coat of alu: paint that was used t Aluminum house pa paints or enamels i wood. The paint j< lowed by two coats paint or any of the li; III or IV before fui last 2 or 3 years long paint. Next best to alum IV are modem hou FLB 001134 I h% fti-- ' ' ' paint the butt ends with primer after cutting and fitting the boards, but before fastening them in place. If woods of groups III ..and IV are primed with aluminum house paint | before applying house paint of the' desired color, they can be made to hold | their paint coatings nearly as long as woods of groups I and II (fig, 6). M-69224F ! Figure 6.--Aluminum priming paint improves the durability of house paints on I woods that have wide bands of summerwood. These painted panels of Douglas| fir were exposed to the weather for 5 years, facing soudi. The left-hand halves were painted with three coats of white paint; the right-hand halves were painted i with one coat of aluminum house paint followed by two coats of the same white paint that was used on the left-hand halves. Aluminum house paint is made for use on exterior woodwork; aluminum paints or enamels made for other purposes are unsuitable for priming wood. The paint job consists of one coat of aluminum house paint fol lowed by two coats of house paint of good quality. So applied, white ;i paint or any of the light colors should last about 4 years on woods of groups ! Ill or IV before further painting is necessary. Paints of dark color may I last 2 or 3 years longer. When repainting, apply only the white or colored T paint. . I Next best to aluminum house paint for priming woods of groups III and | IV rare modem house-paint primers that contain no zinc oxide and that 9 FLB 00113^ have the property commonly called "controlled penetration" (fig. 7). Many manufacturers of commercial house paint now make such house-paint primers. The painting may be done in either three- or two-coat work. If three coats are applied, the house-paint. primer may be thinned with a small proportion of turpentine or mineral spirits and applied so that 1 gallon of the mixture covers about 600 square feet of surface. After that. f'igure 7.--Special house-paint primer makes it possible to paint all woods satis factorily, even those of group IV, with only two coats. Panels at the left and S at the right are adjacent areas of the same boards of Douglas-fir (first and third boards from the top) and of southern yellow pine (second and fourth boards). The panel at the left was painted with two coats of white paint; the panel at the right was painted with one coat of special primer and one coat of the same white paint. Panels were exposed to the weather, facing south, for 3 years. two coats, of house paint in white or a chosen color should be applied, and each coat spread over 700 square feet to the gallon of paint. In two-coat work the house-paint primer is not thinned and is applied in a thicker coating so that a gallon covers no more than 450 square feet of surface. A single coat of good house paint is sufficient over such a primer coat; provided it is applied so that a gallon covers no more than 550 square feet of surface. s - Thus, although the best paint service is most easily obtained When wood of the most favorable kind has been selected, good paint service is possible even on the less suitable kinds of wood if the right kind of paint is applied properly the first time the wood is painted. V V. S.JQ GOVERNMENT PRINTING OFFICE? r.OAKD'S DAIRY M A IV Failure of red barn paint less than a year after the barn was built and painted, caused by Insufficient ventila tion within the barn during winter weather^ Moisture from the cows con densed behind the painted siding until the wood became wet, whereupon the paint blistered and peeled. I'1 * if $# 0 % BARM by BROWNE HREE objects conspicuous in the American T countryside Jong wore painted red, the country schoolhouse, the railway freight car, and the farmer's barn. A generation ago the little red schoolhouse largely dropped from the trio, except in poetry and the biographies of political candidates. The country school house now is less often little; even when it is the paint is usually white, in harmony with the note ot cheerfulness that has replaced iho hickory switch in modern teaching. Rail roads have toyed with colors other than red for freight cars but. in recent years they have re turned to red for their first choice. Now it is the red barn that is threatened by a change in style as some farmers switch to brighter colors, particularly to white paint. The dominance of red paint in the past did nol come by accident. There were sound reasons for it. To begin with the combination of red paint for the barns with white paint for the farm house has always seemed to establish a suitable sense of proportion. White is pretentious, it at tracts attention, and makes a house look larger. Red of the shades used for barns is modest and paring; it tones a large building down until it erges into the background. A white farm house -'is out prominently among red barns but g white barns it is overpowered by the - and less attractive buildings, present popularity of white for farm builduggests that farming is coming to be con i more as a business enterprise than as a _>f living. Perhaps it should be; but, if so, EF in white bams must be prepared to pay rent for their quarters than cows that re contented in red barns, for it costs more >ep buildings white than to keep them red. '< Red Paints Have Longer life hite paint is costly because it contains exsive white pigments such as white lead, zinc ,de, and titanium dioxide. Red paint seldom jntains any white pigments; instead it is made of iron oxide pigments which are moderate in cost. Cost of the paint itself, however, is a lesser item in the cost of painting because it usually takes three or four times as much for labor as for the paint. The main economy in favor of red paint comes from its longer life. Good red paint lasts twice as Long as the best white paint. To keep white paint in good condition it is usually necessary to paint every four or five years but red paint can be made durable enough to go ten years, though it must be admitted that it takes a better grade of red paint than the majority of those now on the market. The plain fact of the matter is that most farm- The author. F. L. Browne. Is chemist with the U. S. Forest Products Laboratory, Madison, Wisconsin. ers in the past have not succeeded in keeping up a schedule of repainting their barns every ten years. Often the painting is done when farm crops bring good prices rather than when the old coaling has worn out. For that reason the man ner in which paints wear out is important for farm painting. Paints that wear away slowly by a tine crum bling remain more presentable in appearance and are easier to prepare for repainting than paints that crack badly, curl up, and fall oil in large scales. Good red paints are more likely to take the favorable way of deteri rating than are most of I he present day white paints. Moreover, a partly worn-out red paint presents a much less offensive appearance than a similarly worn-out white paint, for the white paint calls attention to its shabby condition whereas the red paint shrinks into the background. Fainting Weathered Wood Wood that is allowed to go long after the paint has worn out becomes roughened by weathering; the once smoothly planed surface gives way to a fuzzy, splintery one, channeled by ever deepening cracks. The deterioration proceeds slowly, for it takes a century for one-fourth inch of the wood to weather away. Because of the long time so often allowed to pass between paintings of farm buildings, such, weatherbeaten wood is the rule rather than the exception on American farm buildings. Wood weathering has two consequences as far as further painting is concerned. First, twice or three times as much paint is needed to paint a given area once the wood has become weathered, for the roughened surface takes up extra paint. Second, the new paint job lacks the spick and span appearance it would have on smooth wood. Whenever new boards are inserted among weath ered boards in repairing a building before paint ing it, the new boards stand out conspicuously by their glossier, smoother, and brighter appearance. There is a trick in painting weatherbeaten buildings by which time and money may be saved. Instead of applying two full coats of paint in the attempt to make it look as nearly as pos sible like paint on. smooth wood, thin the paint to the consistency of a rich shingle stain and apply only one coat, just enough to saturate the wood surface and to impart a uniform red color. The result should be a stained appearance with little or no glossiness rather than a painted appearance. For use as a stain, a red paint of good quality is needed. It should be made with plenty of iron oxide pigment and with a vehicle containing much linseed oil and little or no varnish. It may be thinned with a quart of linseed oil and a quart of paint thinner to a gallon of paint. The red barn paints now on the market are seldom of the best quality. The manufacturers seem to strive to make the cheapest red paint that will last about, as long as good white paint will. Iron oxide is such an excellent paint pig ment that a red paint of decidedly inferior quality wiU equal good white paint in durability. What the farmer really needs, however, is red paint; capable of lasting twice as long as the best white paint. Such red paint, of course, will cost more than the paints now generally available but it need not cost more than good white paint docs. During recent years some of the farmers' coop eratives have sold red barn paints of distinctly better quality than is obtainable from other suppliers. Commercial Point Standards A serious obstacle to the improvement of the general quality of barn paints is the lack of ac cepted commercial standards of paint quality. To be sure, most paints made by reliable manu facturers carry a statement of composition, or formula, on the label. Faints, however, are com plicated materials. Most paint buyers know too little chemistry to gain much information from paint formulas. The United States Department of Agriculture has proposed that the paint industry adopt a system developed by the Forest Products Lab oratory for classifying house and barn paints by group, type, and grade. If paints were labeled according to some such clearly defined classifica tion, buyers would have less difficulty in finding paint of the quality they need. In addition, makers of best quality paint would find it easier to get a fair price for it despite the competition of inferior paints. So far, however, the paint In dustry has been opposed to the establishment of classification or other forms of commercial standards. The proposed classification system, recognizes six grades of paint numbered from grade 1, the best, to grade 6, the poorest. There is no real need for so many grades; some of them certainly would disappear if the industry adopted commer cial standards of any kind. Before the war many of the brands of house paint in white or light colors were of grades 1 or 2. During the war "oil-restricted" forms of house paint were de vised in an effort to conserve scarce linseed oil. The best of such paints were of grade 3. Present house paints are still mostly of that kind. Red bam paints were nearly all of "oil-re stricted" varieties long before the war. Few barn paints offered under the brands of paint manu facturers are classifiable better than grade 5 except among those sold by farmers' cooperatives, some of which offered paints attaining grade 3. The high grade red barn paints can usually be recognized from the formula printed on the label. As a rule, the formula gives (Turn to page 527) N41698.57 FLB 0011: 518 HOARD'S DAIRYMAN Jiil> 10, 1948 Club Heifer to Herd Owner D. T. GRUSSENDORF PUREBRED Holstein heifer set the course A of young Jim Witte's life. In a way, the two grew up together'. The heifer, chris tened Snowball by Jim, was only a caff when he received her as a gift from his father on his thirteenth bii'lhday. lake countless thousands of dogs and ponies given to young boys by their parents. Snowball soon became the focal point of all Jim's teen age interests. His proprietary pride in her erased any adolescent doubts he may have had about the future, aroused in him an enthusiasm for dairy farming that has carried through the last 12 yoars. Jim, County Agricultural Agent D. t. Grussendorf, and Valeria discussing production figures Ownership ot' Snowball led directly to Jim's enrollment in 4-II club dairy work back during the dark depression days. He was active just three seasons before he and his heifer developed Jim built up a herd now numbering 21 head. He milked her eight years and site gave birth U> eight calves before she finally threw a siifie furm." With the Wittes, and others like them, rest Northern Minnesota's hopes for a rehabili tation of its agriculture. into championship material. In a state nationally known for its high qual ity cattle. Snowball, under the hoy's careful joint. At present, Jim's herd includes 19 registered Hoist<?ins. St. Louis County agricultural offi The present market places the value of Jim's herd at approximately $10,000. The furm, which has under cultivation about 100 of its 260 acres, management, achieved the best milk production record among all Minnesota 4-H animals. Jim's part in this accomplishment was rewarded with a trip to the National Dairy Show. lie decided to increase still further his `'know how" of the dairy gamo. So, upon graduation from high school, he and his brother, Charley, enrolled at the University of Minnesota's North cials unhesitatingly term it one of the ten top dairy herds in northern Minnesota. Some nearequal cattle have also been developed by his brother. Young- Jim Witte is married now. He met his wife. Valeria, at a 4-H club party in January. 1944, She, too, had been a 4-H'er since her first days of high school, turning her talents into the would soli for an equal amount. Life at the Wittes today centers around those purebred Holsteins, Snowball taught Jim an early lesson that successful dairying is a threeway combination of good cattle, liberal feeding, and careful management. That combination is practiced rigidly at Stoney Brook farm. The cultivated land is given over almost en Central School of Agriculture. Two years later the boys were back, looking lorward to the day field of home economies. On Stonev Brook farm, Jim and Valeria dem tirely to hay crops, yielding about 75 tons per year. Jim mixes the hay and grain ration for they could start their own farms. Today the Witte name is synonymous with quality herds, quantity production in the farm ing area immediately adjacent to the head of the Great Lakes. from l to 28 Snowball was the nucleus around which young onstrate daily that a 4-11 background can and does provide rich dividends in adult life. Still more important, they are proving that farming holds an attractive future for enterprising youth. Their example stands as a defiant disavowal of a long-accepted fallacy in St. Louis County, that, ``you can't make a living on a cut-over area his herd according to his own formula. He knows from experience it pays to feed his cattle well, because they possess the inherenl ability to convert the major share of that feed into rich milk rather than flesh. Uuod Herd Average And, us Snowball did, his Holsteins show the results of Jim's knowledge. Last year they av eraged 538.6 lbs. fat. per cow. compared to the Minnesota mean of about 190 pounds. Scrupulous cleanliness is the rule in the VVti barn. The same maxim applies in ihc new mi' house, whore every morning a cooper creamery truck stops to pick up the production. While dairying is Jim's main source come, lie has added a lucrative sideline cent years by keeping pace with the rupi. creasing interest in artificial bleeding, are now tour bulls in his herd, led by a nn.mt h-old, ! ,700-pou nd regisl ereri He named Si. Louis King Rue Ormsby La purchased from the* St. Louis county poor i purebred herd. Because of his reputation for high, qu high produeers, Jim's insemination service i constant demand. At $5 ix>r service, he a\ aged two a day during 1946, all within a . mile radius of his place. His own herd increases by about 10 cahes pi?r year, but he usually sells most o them after selecting the best two or three heifers. Since he slaried his Stoney Brook farm, Jim has reg istered 30 calves. Requests lo buy his purebred s*ock ervyyio front a}] over the N-'rtkwrm Average age of the Witte herd today is lour years, as young by usual standards as its owner is in the dairy game. Bui its managemenf has been such that T.he ton present produeers should maintain their record herd average for' another six year*. At 25, Jim keeps an open mind on dairying, is a constant caller at government agricultural of fices, stands ready to institute new procedures on his farm at any lime. He is enrolled In pas Jim and Ormsby Bessie Minnie, a lop producer, at milking time ture improvement pro- i Turn to payi: 521) FLB 001 I EYER aie LOADER HOARD'S DAIRYMAN Painting the Barn PICKS IJP 75 BALES IN 1 i MINUTES Loads ywr bales --- save* yoi r back I You Just atadk 'emI Saves you] baler, too. Frame doesn't strain or brd k from pul ling loadej] skids or wagons.j EASY TO HITCH Saves timej changing loads. Hitches to fi truck bumper or to f alongside ^Bgon. GROUND DRIVEN Light dre^t Picksupbalea just as drop-', ped -- guidel^ Twp models Buie deck heights 6` 9!' and li' -_Wri7e for literature and name i nearest Meyer dealer. THE MEYER MFC. CO. Boa 63, Marten, lit. MEYER ELEVAIORS SHOW-SALES THE MOORE BROS. CORF. Albany 6, New York it Your Deafer Does Not Hand/e Goods Advertised In Hoard's Dairyman-*-* Ask Him Whyl Made by DAIRY SANITATION SPECIALISTS MANUFACTURERS OF 99-YEAR-OLD LEWIS' LYES 48-page book points way to extra profits Get bigger milk checks by producing more and higher quality milk. Tlie timetested Lewis' Lye sanitation plan has helped others to do this. A favorite of dairymen for many years, the 'fclan is fully explained in the booklet. This booklet tells in detail how the Lewis' Lye plan can help you keep bacteria count lo\tf and keep cows healthy, by re ducing spread of contagious abortion and mastitis that may be transmitted by contamifiated surroundings. It tells you how. for about lc a gallon, you can make a dependable Lewis' Lye solution to disinfect your dairy barn and milk house and sanitize milking machine rubbers. Lewis' Lye is made by the makers of famous B-K dairy bactericides. So dip the coupon and send for your free copy of the booklet today I TIME TESTED L G 'In some place* LEWIS' Lye 1* known at 1 0 0EAGLE Lye FILL IN Pennsylvania Salt Manufacturing Co.. Dept. 13-G 1000 Wictcner Building, Philadelphia 7, pa. Please send me my free copy of your lye booklet. NAME________________________________________l----------------- STREETi----------------- CITY AND STATE_________________________ OfHBl PENNSALT PRODUCTS DOT INSECTICIDES Sprays Pawdsri Duals for Novi* Barn * Livestock * Garden (Continued from page 517) the percentage of pigment and the percentage of "vehicle" or '`liq uid" in the paint, and then it gives the percentage of each ingredient in the pigment and of each ingredi ent in. the vehicle. A red paint of grade 1 contains at least 54 per cent pigment, and at least 30 per cent of the pigment is "ferric oxide", which is the chemists' name f^r iron ox ide. At. least 85 per cent of the ve hicle is linseed oil, soybean oil, or Other "drying oil" and "resin." A red paint of grade 3 contains at least. 48 per coni pigment, at least 26 per cent of the pigment is ferricoxide, and at. least 70 per cent of the vehicle i.s drying oil and resin. Those who wish detailed, though necessarily technical. instructions for interpreting painl formulas will find it in "Classification of House and Barn Painl.s as Recommended by the United Slates Department of Agriculture", by F. L. Browne, Tech nical Bulletin No. 8U4 of the U. S. Department of Agriculture, obtain able for 15 cents from the Superin tendent of Documents, Washington, D. C. What Kind of Red Paint There are two popular preferences among many farmers lhat work against development of a 10-year bam paint. One is the desire for an unduly bright red color. The other is a leaning toward unduly glossy or shiny paint. Among many kinds of iron oxide pigments suitable for paint making the brightest reds are usually those known as Venetian red. They are made by healing together limestone and iron suJfat.e, a wasle product ot the iron and sled industries. Not more than 40 per cent of a good Ve netian red pigment is iron oxide. The rest is calcium sulfate, which acts in the paint as an extending or cheapening pigment. The lO-year red paint probably needs more than 40 per cent iron oxide in its pigment. It may con tain extending pigment, but calci um sulfate is much less desirable lor that purpose than other extend ers sucli as calcium carbonate and magnesium silicate. The preferred iron oxide pigments are often darker in color than the Venetian reds, tend ing more toward maroon. New syn thetic iron oxide pigments are now being developed that may match the Venetian reds in color withoul their disadvantages. Red paint made with linseed oil or linseed and soybean oils has only a moderate degree of glossiness. To make it highly glossy a large part of the oil must he replaced with var nish. The high gloss obtained in that way seldom lasts very long and is likely to give way to a dingier con dition of Jaded dullness than is ever reached by the high grade paints made chiefly with oil. The very glossy paints have other shortcomings. They produce an cnumet-like surface that accentuates the imperfections in the lower grades of lumber commonly used for farm buildings. They are unsuitable for use like stains on weatherbeaten wood and they fall far short of the 10-year durability of the best red paints. Applying Paint Long-lfved paint jobs require good application as well as good paint. The most common mistake of work manship in farm painting is that called stingy application. Not enough paint is applied to make a coatingthick enough to wear a long time. Smooth wood such as new lumber needs about 3% gallons of grade 1 paint on 1,000 square feet of sur face. It may be applied in three coats of a little over a gallon each or in two coats of 1% gallons each. If the paint is of lower grade, however, it usually takes more of it to make the required thickness of coating. Instead of 3!e gallons of grade 1 paint, it may take 4VI gal lons of grade 3 paint or more than 5 gallons of grade 5 paint. Not less than 3 coats are needed to apply such large quantities of paint. Of course the absence of recognized grading of paints leads most painters to treat all paints alike, with the result that the low grade paints are almost sure to be applied stingily. Spray Painting Farm buildings usually offer a chance for substantial savings in coat of applying paint by using spray guns Instead of brushes. When skill fully done, spray painting is fully as satisfactory as brush painting. Too often, however, spray painters have tried to save on paint as well as on labor. When paint is to be sprayed it should not be thinned much more and certainly should not be spread less generously than when it is brushed. There are times when the best of XJaints, competently applied, soon fail through unsightly peeling and scaling. It is not unusual, for exam ple, to see a cow barn with the paint scaling badly from the siding out side the cosv stalls but with the paint in good condition outside the haymow. Such paint failures com monly result from insufficient venti lation inside the barn during the winter season. Moisture from the animals, instead of being carried oil in the air escaping at vents, con denses behind some of the wood sid ing. When painted boards become wet in that way the paint may be expected to blister promptly and la ter on to peel or scale off. A report discussing means of preventing con densation in barns is obtainable from the Forest Products Laboratory, Madison, Wis. Our past practices in farm paint ing on the whole have fallen short of the standard of reasonably good paint maintenance. Material im provement in painting practice should be economically attainable provided that the most durable kinds and qualities of paint are selected and used wisely for the purpose. TRACTORS USING PAPER OIL FILTER ELEMENTS With this specially designed AC Paper Filter Element, you can wait three itimes as long before changing elements and make a cash saying in element cost. You save Qil because of fewer oil changes. You save time in the held. And you can be sure of AC's " 5-Star Qual ity" through and through * . . tough filtering paper stock of even texture,-resin impregnated to give maximum Service and efficiency. Try this'; AC Paper Element and save time . . . save trouble . . . save money. AC also has 4 complete, line of trac tor oil filters for field installation. To Study Trace Minerals The Associated Press carried a story recently to the effect that Johns Hopkins University has re ceived a half-million-dollar endow ment for the study of the physio logical effects of the so-called "trace elements/' Known as the McCollum - Pratt Fund, in honor of E. V. McCollum, an authority on nutrition, and John Lee Pratt of Fredericksburg, Va., university trustee and donor of the gift, the sum will be used to study the function of copper, boron, cobalt, manganese, and other minerals in living organisms. Dr. Isaiah Bowman, president of the university, said the principal and interest will be expended over a ten-year period. Known as trace elements because living beings con tain them only in very small quan tities, the minerals so designated must, nevertheless, be present to avoid deficiency diseases. AC SPARK PLUG DIVISION GRN1RAL MOTORS CORPORATION FLB 00113 N 528 HOARD'S 5. JOBSIN1 COES .^OttfANT j o b s 5fM 1 S,NGLE IN JL APPLICATION 1. PAINTS WHITE 2. KILLS GERMS 3. KILLS FLIES Why pay for two or three spraying jobs in barn, poultry house or cellar--first for whitewash ing, then for disinfecting, then for DDT--when Carbola does all in ONE EASY LOWER COST OPERATION DISINFECTANT In Carbola destroys otx contact the germs of many profit-taking discuses, including MASTITIS BRONCHITIS WHITE DIARRHEA BANG'S DISEASE CHICKEN CHOLERA HOG CHOLERA TUBERCULOSIS HOO FLU (Copies of independent laboratory fatl'reporfs oo reffueif) CONTAINS DDT DRIES WHITE Kills spiders, 90% less cobwebs for 8 to 10 months. Better sanitation. Lower bacteria Used for 32 years by farmers everywhere to help control livestock disease's and Co feet white walls, and In recent years (since DDT was added) to kill dies us well. Never put DDTln or on wet hydrated lime, which destroys DDT; Carbola contains no lime. MAKE SURE YOU ARC <3ETON CARBOLA ASK TO SEE THE PACKAGE Hardware, feed, seed, drug, fann stores. 1 1b. 25^, 5 ib. 75<, 10 lb. SI.25, 251b. $2.75, 50 lb. 4.85. Price* xlightiy higher in Rockies J S. TV. For name of nearest dealer write to CARBOLA CHEMICAL CO., Inc. Natural Bridge 108 N. Y. L. Established 1916 Other Products By Carbola Chemical Co. CCC 3?f> DDT Garden Dust CCC 25% & 50% DDT Wettable Powders CCC 3-6 (DDT & Copper Insecticide &. Fungicide Dust) CCC 25-31 (DDT & Copppier Insecticide 6c Fungftiicliid. e Spray) CCC 31 % Copper Spray CCC 25% DDT Cattle Spray cod iO% l>I>T (Powder lor roaches, bedbugs, lice, etc.) CCC Garden Kntcnone CCC Copper Kotcnouu HT LITE 5% DDT Wall Paint (for homes St milk houses) MVLJTE Cement Paint HYLJTE Water Putty CCC i*at Destroyer r/qnF/flfhenea Jet coaling' 'Can-Top" strikes right at the most vulnerable point of bacteria forma tion - the neck of the milk can. Protect your profits this easy, economical way. ,,ii ,-f 3f -iCj I THE SARGENT-ROUNDV CORP. Randolph, Vermont For literature, write Dept. B | If Your Dealer Does Not Handle Goods Advertised in Hoard's Dairyman -- Ask Him Why! DAIRYMAN July 10, 18 Holstein Convention at Kansas City HE 63rd annual convention of public schools at Topeka, Kansas. T the Holstein-Friesian Associa His pleasing blend ofr' information, tion of America, held at Kan inspiration, and gooff humor made sas City June 1-4, attracted mohreim a lasting favorite with the -con than 700 delegates, members, and vention group. friends of the world's largest dairy In the secretary's annual report breed association. The hosts from it was pointed out that applications Kansas and Missouri were generous for registry during the year reached m their hospitality, providing an tn- a total of 166,830, a gain of 10.20'" icresting program for the ladies as over 1946. Similarly, transfer appli well as the men. cations totaled 112,939, a gain of Highlight of the convention was 5.1% and membership applications the "open house" at the world fa totaled 1,624, a gain of 6.5% over mous Clyde Hill Farms at Clyde, the previous year. Other activities Missouri. There more than one showed the same upward trend. thousand visitors saw with a great Advanced "Registry made a 12.8% deal of interest the progress and de gain, while herd test moved up from velopment of one of the greatest 874 herds in 1946 to 1,083 in 1947, Holstein herds in the country, made a gain of 24%. The upward spiral possible through the combined ef in herd classification was even more forts and conscientious work of the rapid. During the year, 18,835 ani industrious herd manager, Joseph mals were classified, a gain of 31.5% Gemmeke, in charge of the herd tor over the previous year. Despite the he past 25 years, and of the Sisters Increase in business in all depart >f the Benedictine Convent of Per ments, increased costs were also re petual Adoration. ported and the net result was a fi Most remarkable in the building nancial loss for the year of $11,686.04. f this herd has been the splendid In the report of the director of development of great cow families, extension, Glen Householder pointed deluding the 30 females m the herd out that during 1947 a new all-time today descended from "Old Zuba", 'high" was established for regis 16-year-old queen of the Clyde Hill tered Hnisteins sold in public auc herd. Zuba, now in her 13th lacta tions when 14,926 head were sold in tion, has 207,781 lbs. milk and G.735 238 sales in 29 states for an average lbs. fat to her credit, and was not of $418. One of the major efforts of tested during her first two periods. the extension service, including more Her best record was 766.4 lbs. fat service to breeder-group managed at 14 years of age, and she now lias rales, has been to bring would-be 625 lbs. fat :n her first 232 days, buyers in contact with breeders hav milking over 100 Lbs. milk a day and ing surplu seed stock for sale. making 116 lbs. fat in one month. An all-time high was also recorded All of the females in the herd and in 1947, both for number of organ most of the herd sires used have ized Holstein clubs functioning been home bred. One could go on throughout the nation, and their to indefinitely about the breeding pro tal membership. Householder em gram and management practices phasized that the most helpful sign carried out at the Institution, but for the future in organized Holstein most visitors agreed the herd com activity is the fact that the junior bines type, production, longevity, Holstein club is making progress. and reproduction In a manner that Newly elected president of the is Lhe dream of most breeders. Association is Owen D. Young, of Clyde Hill has received the pro Van Hornesville, New York. Other gressive breeder award seven consec officers include S. B. Hall, Trout- utive years and the herd holds the dale, Oregon, vice-president: H. W. all-time Hill average for herds of Norton, Jr., executive secretary, and 590.4 lbs. l'at on 39 head. The herd Glen M. Householder, director of ex is'milked three times daily. Since tension service, both of Brattleboro, 1944, the herd has averaged 547 Ihs. Vermont. or better each year. The last classi New board members include Carl fication score was 85.8 on 50 head. G. Wqpstcr (retiring president) New At the convention proper, the dele gates went on record in favor of an York; Frank Pellissier, California (rc-elected); Howard Clapp, Wiscon amendment which makes -the offi cial formerly called secretary, now executive secretary, who shall be the sin, to fill vacancy created by John Wuethrich, Wis., (resigned); T. H. Benton, New-Jersey; and T. Hobard chief executive officer of the cor McVay, Kansas. poration, subject to the direction and control of the board of directors and f the committees thereof. The by'aw* wore also amended to the effect that an assistant secretary shall be provided. Although some difference of opin ion was- voiced, the association went oh record placing the director of extension subject to the direction and control of the executive secre tary. Also included in the reorgani zation setup is the discontinuing of the title, "Superintendent of Ad vanced Registry." Following the annual . banquet Wednesday evening, the conventiongroup turned out for the- national convention sale Thursday, in which 71 animals sold for an average of $1,250 a head, with the top female, Pabst Reburke Rag Apple, bred heif er consigned by Pabst-Knutson, Wis consin, bringing $4,500 to top the sale. She was purchased by Signor Jose Leon, Buenos Aires, Argentina. Top bull of the sale, Pabst Roamer Gallant, also consigned by Pabst Farms, Inc., sold for $4,000 to the Manning Creamery Co., Iowa. Throughout the convention the California delegation provided a great deal of enthusiasm for holding next year's meeting in Sari Francisco and a resolution to that effect was passed unanimously. An effort to cut down convention expenses was made when Secretary Norton proposed art amendment to increase ibo active member requirement for additional delegates from any district from 150 The occasion was an amateur musicale. The kind-hearted hostess spied a lonely ' looking little man huddled in a corner of the room, and paused to make conversation. "Tell me," she finally asked, "do you play any musical instrument?" "Not away from home," the little man replied. to 250. but the amendment was "How peculiar," remarked the defeated. hostess. "What instrument do you A very excellent speaker was heard on the open forum, Dr. Ken neth McFarland, superintendent of play at home?" "Second fiddle," replied. the little man COPY (from The Mississippi Valley Lumberman, January 7, 1949) FORMAN, FORD AND CO* ANNOUNCES GRADE 1 HOUSE AND BARN PAINTS Grade 1 paints, offering, for the first time in the history of the paint industry, an advanced, scientific grading of paint as an aid to the consumer, is being announced by Forman, Ford and Co* of Minneapolis at this year's Northwestern Lianbermens Association convention. Ihile grad identification is not new to the marketing of products in America, being common on many farm products, it is an innovation with paint. In some respects it ranks with legislation introduced in North Dakota by Ladd in 1905 requiring publication of formulas on all paint sold in that state* The background of grade labeling in paint is primarily the story of the Forest Products Laboratory in Madison, Wis* a unit of the United States Department of Agriculture. For SO years this labora tory has maintained exposure test panels and, in many cases, men from the Laboratory have scrutinized the test panels maintained by commercial manufacturers. In recent years this work has been primarily under the jurisdiction of Dr. F. L* Browne, senior chemist of the Forest Products Laboratory, > Based upon the many years of records maintained by the Laboratory, end on his cm experience, Browne, in January of 1942, authored Technical Bulletin No. 804 of the United States Department of Agriculture. In this bulletin, he published the components and their proportions for various grades of paint and established the actual grades of paint that would define the quality of paint. Dr. Browne, in his Bulletin No. 804, emphasizes that the classification system simply gives paint users information that they can understand as compared to the difficulty of comprehending a paint formula. Forman, Ford and Co. feels there can be no conflict over the use of such a classification system that supplements Trade Brands as compared to recent attempted legislation that called for virtual elimination of branded products to be supplanted by grade classification only. They present classification of paint as a means of providing greater under standing and satisfaction to paint users. So important does Forman, Ford and Co. believe this program to be, they brand these products tinder their firm name, Forman, Ford, the first time in the company's 66 years they have honored a product with their name, it was pointed out. They further establish this new brand with the addition of Grade 1 on the label (see illustration). At present, the Forman, Ford Grade 1 label will be applied only to outside white, exterior primer and red barn paint. N41698.58 FLB 00114': The United States Depar-fenenfc of Agrioulture specifies that use of the classification system requires presentation on the label of the Classi fication Seal* Bach can of Forman, Ford Grade 1 paint displays this seal* On it is shewn the group (which applies to the pignents and vehicles used), the type (which indicates the content and ratio of lead and zinc) and the grad of the paint* ' Comparison of certain paints now on the market under the tJ*S..D.A* i classification system has produced some startling results* Forman, Ford says* Of a number of paint formulations, examined on cans purchased through normal ccramsrcial channels* there was no house paint higher than a Grade 2 with the average of the better known brands a Grade 3 classification, some even as low as Grade 6, it is claimed* Forman, Ford and Co* believes the American people are entitled to buy paints of highest quality and feels paint of such quality can be offered under the classification seal of the United States Department of Agriculture* They likewise say their Grade 1 products will retail at a price equal to or below that of certain nationally distributed brands graded and found to be of lower classified grade* For dealers or any person interested in the comparative grades of paint, the Forest Products Laboratory at Madison, Wis*, mil analyze and grade any formula submitted to them on the basis of their classic fieation by group, type and grade. All that is necessary is to mail a copy of the formula and directions for use as shown on the label to the Laboratory* % FLB 001142 CU*TiV ^{(u Ja l J fV)!^ '/ y A Standard of By F.L. BROWNE Chemist, forest Products Laboratory* Forest Service, U. S. Department of Agriculture YOU can now buy paint labeled plain symbols that can be ex Thus, paint of group TLZ(e) is by, the maker with both his plained easily to the public. titanium-lead-zinc paint contain trade' brand and a classification Paints are Classified by group, ing much thickened* oil; but paint recommended by the U, S, De type, and grade. The words stand of group TLZ with no added small partment of Agriculture. The for ideas already familiar to those letter contains little or no thick classification is a form of quality who have learned anything at all ened oil. In the paint trade, thick standard. It tells briefly what kind about the wav paint is made. ened oil is called bodied oil, and grade of paint you are buying. The trade brand tells, as it always has, who made the paint and ex pects to be held responsible for it. Together, classification and trade brand supply all that is needed to buy from reputable sources with an eye to quality as well as to price. The USDA classification plan was suggested by the Forest Prod ucts Laboratory after more than 20 years of research in the paint ing of wood. Under the plan there is a classification for every kind of house or barn paint for wood buildings. Any maker or dealer in paint is free to use the classifica The idea of "group" comes from the common practice of speaking of white lead paint, lead'and sjhc paint, titanium-lead-zinc paint In thus alphabet age, such terms are soon shortened to initial letters, such as L for white,lead paint, LZ for lead and zinc paint, and TLZ for titanium lead-zinc paint. L stands for any of the lead pig ments, Z for zinc oxide, and T for titanium dioxide, Other letters needed for some paints are S for zinc sulfide, F for iron oxide, and C for the remaining colored pig ments. In classifying a paint, then, the group symbol first tells the kind of pigments of which it is . Some paints, especially colored paints with little or no white lead or zinc oxide, contain more or less varnish. Varnish is a combination of resin with bodied oil. Good red ham paint, for example, often has some varnish in it. The classifica tion by group shows the presence of varnish by the symbol (re). A bam paint may belong in group ,F(re); if it contains a little zinc oxide to help keep it free from mil dew, as some of them do, it may belong in group FZ(re). Some times there is resin but little or no bodied oil, in which case the group would be FZ(r). tion on his labels. No law requires chiefly made. it, however, and no agency of gov ernment need be consulted about it. But when the..classification is used the paint must conform in fact to the classification claimed for it. Misbranded paint is unlaw ful. The law in some States requires the composition, or formula, of paint to be printed on the label. The policy of most of the industry is to print the formula even in States that do not require it. Such formulas, however, are much too complicated and too technical to mean much to the average buyer. The USDA classification is based on the printed formula. It merely shows what the formula means in Second, the group symbol tells what kind of liquid or vehicle is in the paint. In the best white paints or paints of light color, it is taken for granted that the liquid is ordi nary linseed oil or a similarly use ful oil. But if much of the oil has been thickened by special process ing, the brushing and spreading properties of the paint are altered. The paint works more nearly like enamel. Such paints are called, enamelized paints or, since they contain less oil and more thinner, oil-restrjicted or oil-conservation paints. They are classified by group by adding the small letter e m parentheses after the capital letters for the chief pigments. THE idea of "type" in classify ing paints, comes from the practice of speaking of paints as high or low in lead pigment or in zinc oxide. These pigments act chemically on linseed oil in a way necessary to make paint last a long time outdoors. The type symbol tells how much lead ana zinc there is in the pigment part of the paint without going into tiresome detail about it. There are five ranges in content of lead and zinc, counted together. There is the very high range, the high range, the medium range, the low range, and the very low range. They are represented, in the order named, by numbers 1, 2, 3, 4, and 5. There are also four ranges in * Maintained; at Madison. 5, Wisconsin, in cooperation with the University of Wisconsin. ratio of lead to zinc, the very high, MARCH, 1949 N41698.59 37 ; <. ' ^ ? the high, the low, and the very low. They are represented in the order named by letters A, B, C, and D. Thus, paint of type 3B has "medium content of lead pigment and zinc oxide with a high ratio of lead to zinc." Paint of type 4C has "low content of lead pigment and zinc oxide with low ratio of lead to zinc." In type 5, the letter is left out because the ratio of lead to zinc is of no interest when there is so little of them present anyway. THE idea of "grade" in classify ing paints comes from the practice of speaking of paints as first grade or second grade, meaning as a rule that the first grade is more expensive but better m quality than the second grade. In the USDA classification there are six grades. They are numbered from grade 1, the highest, to grade 6, the lowest. When paint of grade 1 is prop erly mixed for application, each gallon contains at least 0.25 gallon of equivalent opaque pigment, at least 0.25 gallon of total pigment, and at least 0.87 gallon of total nonvolatile. The exact meaning of the terms may be left to the paint chemists. The equivalent opaque pigment tells how well the paint hides the surface underneath. The total pigment gives information about die spreading properties of the paint and about the structure and durability of the coating it makes. The total nonvolatile shows how much of the paint remains in the coating after it Has dried. For the grades lower than grade 1, the requirements are scaled down ac cording to a published table. In general, the higher the grade of the paint, the less paint and labor are needed to do a job of given quality. Some jobs, such as painting new woodwork with but two coats of paint, require the highest grade of paint if they are to be done properly. Other jobs, such as painting new woodwork with three coats, can be done equally well either with the high est grade paint or with somewhat more paint of a medium grade. Still other jobs, such as painting badly weatherbeaten wood, take so much paint because of the rough surface that money may some times he saved by using a wellmade paint of low grade. Paint buyers should think of grade chiefly as a guide to the way paint should be used for best and most economical service. Although grade 1 of suitable group and type is likely to be the best purchase for most work even if it costs a little more, good work can still he done in many cases with paint of grade 2 or grade 3. On the other hand, a grade-1 paint can be a bad choice if it is of a group or type unsuitable for the purpose. Another point to remember is that the painter lowers the grade of a paint when he thins rt with either linseed oil or paint thinner. It takes good workmanship along with good paint to get good paint- fug. The classification mark .on the label of a paint, therefore,, must state three things, the group, the type, and the grade. It should also bear the statement, "Classified ac cording to the recommendations of the United States Department of Agriculture, Technical Bulletin No. 804." For several years past, many brands of white and light-colored house paint have been of the clas sifications group TLZ(e) type 3B grade 3: or group TL7.(e) type 3C grade 3; or group TLZ(e) type 4C grade 3. Sometimes the grade is as low as 4. At present there is a gen eral trend toward less bodied oil, represented by (e) in the group symbol, and toward higher grade Some brands have fully resumed prewar quality and are classified as group TLZ type 3B grade 1 or with type 3C or 4C in place of type 3B. Among paints of group TLZ, those of types numbered 1 or 2 would be unduly expensive. They would also get dirtier and stay dirty longer than paints of types numbered 3 or 4. Paints of group LZ must be of type 1 or type 2 if they are to be of high grade. Al though such paints were once widely sold, they are now uncom mon because they are costly and get dirty. Pure white lead paint, usually classified as group L type 1A grade 1, is an excellent paint for some uses, especially where re painting may be put off longer than is generally desirable. Part or all of the titanium di oxide in group TLZ paints is some times replaced by zinc sulfide. Such paints are of group STLZ or `group SLZ. There are also leadless paints of groups TZ, SZ, or STZ for use particularly where there may be hydrogen sulfide in the air, which blackens paint contain ing lead. The leadless paints are type 4D or, if they are low-grade paints, sometimes type 5. White or light-colored paints of high gr ade should never be made in type 5. To be sure that they contain enough lead pigment and zinc oxide, the buyer may well in sist upon one of the types num bered 3. Those of types 4C or 4D may be satisfactory but there is less assurance that they are. The house-paint primers now sold by most paint makers are usu ally of group TL(e), TL(re), TLZ(c), or TLZ (re) and of type 4A or 4B. Most of them are of grade 3 but a few are as high as grade 1. The primers nearly al ways contain bodied oil or Tarnish to give them the desirable quality called "controlled penetration," It is usually wise to buy primer and finish paint of` the same trade brand, because each should be made properly for use together. Paints of dark colors cannot have much white pigment. Except in bam painting, their chief use is for trim and minor areas on build ings. The best trim paints of dark colors are usually enamels to be used over house-paint primer. Some of the groups in which they may classify are c(re), C(e), CF(re), and CFZ(re). The type is generally 5, less often one of the types numbered 4. They may be made in any of the grades. Red barn paints may be of groups F, F(e), F(re), F(r), or, if they contain a little zinc oxide, Z after the F in any of these groups. They are nearly always of type 5. For many years most brands of barn paint have been of low grade to sell at low prices. Grades 5 and 6 are, common. Until recently a bam paint better than grade 4 has been rare. Now, however, there are a few brands of grade 1 on the market. LASSIFICATlON is new in paints. Few brands, yet, have the classification on the label. But from the formula printed on the label anyone may calculate the classification if he can do simple arithmetic and has the patience to learn the method. All the neces sary details are printed in a pam phlet that can be purchased from the Superintendent of Documents, Government Printing Office, Washington 25, D. C., for 10,cents. It is called "Classification of House and Barn Paints as Recommended by the United States Department of Agriculture," by F. L. Browne, U. S. Department of Agriculture Technical Bulletin No. 804. 38 BUILDINGS FLB 001144 HOUSE PAINT AND OUTDOOR FURNITURE By F. L. Browne? fe ore publishing this excerpt from report not because we think of many ur readers as house painters, but for Reasons. First, much of what applies puse paint will have- an application for our readers interested in outdoor fur niture. Second, this: development is the result of more than 20 years of research in painting wood and of real interest to all connected with the paint industry. ,, YOU CAN NOW buy house paint labeled by the maker with both his trade brand and a classifica tion recommended by the U. S. Department of Agri culture' The classification is a form of quality stand ard. It tells briefly what kind and grade of paint you are buying. The trade brand tells, as it always has, who made the paint and expects to be held responsible for it. Together, classification and trade brand supply all that is needed to buy from reputable sources with an eye to quality as well as ta price. Any maker or dealer in paint is free to use the classification on his labels. No law requires it, how ever, and no agency of government need be consulted about it. But when the classification is. used, the paint must conform in fact to the classification claimed for it. Misbranded paint is unlawful. The law in some states requiries the composition, or formula, of paint to be printed on the label. The '. policy of most of the industry is to print the formula even in states that do not require it. Such formulas, khowever, are much too complicated and too technical to mean much to the average buyer. The USDA , I Writing Advertisers Please Mention WOOD WORKING DIGEST 111. N41698.6 FLB 00114 E_ u'g.Sg ns .~b N -S C ra a o 8! a- " C C " S-l" 4S n B <*4 g* *00 o oj >>*U X co ^ 'J w s 0? g t; -- X. A cc `3 ^ .5? 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S3 tIvsS*1*j.Sa*'aa.2a? o&-SSt ? 0) I w Is s, iO l1 l SI* CO VI FLB 00114' 3`3'sre agp ou,fi, oSeI,M^ Pia diei? 6181 >|ins lBig gao^ ..................................................................................................... ^K) ' .............. *.............................................................................. 8S3jppy ' *............................... ..............................................................dltlS\[ *p9SOpUO SI spoip 4C4 Q *00`f$ jo 93ud uoiiB0ijqnd*9J:d pjpads oq* *o <tsqsnit^ poo^ jo iiaaiog aqjLw J ^3 c >ui puos osca^ : uamapua^) !HO 'z uoiXoa `zo 'l<fea 'w*l$ Auaj *m /! q 0 'ssiud Hauvasay (ajep uoixBorjqnd j aunf ja^jE 00*S$ 3CI adud aq}) 'OO'f'S J aapd uoijBDXjqnd-ajd jBiaads aqi ye ^saqsmiq poo^\ jo aanapg aqj^, jo Xdoa moi jsqwo ox iqSu aqi xe uodnoa 4U3IU3AU03 aqj ssf| I mm3ms i i FLB 001148 a pamphlet that can. be puirhaied ftom the Supu int^ndent oi Documents Gov ernment Pi Kiting Office, Washington 2> D C It is cdlUd "Classification of HQI ` ai'ct Ham Paints as Recom mended by the United States Depot t- fiiint ol Agucultuu,' by F Biowi U b D pniluu.nl of AgiU-iiItu.li Toe1 meal Bulletin No. 804. *"\Ar LVownr* i, j rhein ,t at the rorcot Pri lutz Labuiuloi/, F^iOat Service, U S Dcpc mrni of Agu< ultirc, Madison, Wis. WOODWORKING DIGEST'S NEW ADDRESS 222 EAST WILLOW AVENUE WHEATON -- ILLINOIS Tool Up with Woodworkers KN0UREK-SCHM1DT Combination Enables You to Shape with Ease and Safety Knourek Patent Ball Bearing Shaper guide Collars and Schmidt patent lock edge shaper collars. Eliminate friction caused by old style rotating collars. Prevent burning of patterns and stock. This friction imposes extra exertion on the part of the operator and there is an element of danger involved in the constant tendency of collars to force stock back in the opposite direction to whic'* it is fed. Sometimes stock is kicked back violently. Schmidt collar insures absolute protection against knives flyinc out when operator fails to tighten knives securely. Collars have screw adjustmen enabling ope rat o to set knives to c thousandth part o an inch. Serrated edg shaper steel is usee and this we stoc. in all sizes. Yo need not discari the steel and knive you now use. W serrate these edge at small cost. j WOODWORKERS TOOL WORKS, IN '220 S. Jefferson St. Chicago 6, III. 124 WOOD WORKING DIGEST FLB 001149 jit. by F L. Browt l oi Agncul1 1 .. 804." hemisf at *he Forest Pres; t.t Jar. co, U S Dope , Madison. Wit .... i 5 HE to use natural wood finishes -kers i to Shape with cars cmd Schmidt >n caused by 'oldi s and stock. This, he operator and ' onstant tendency trection to which fly- '. . f nst knives flying ;ly. Collars have ew adjustment| doling operators set knives to ai. tusandth part of - inch. * irrated edge iper steel is used;'; d this we stockiall sizes. You/ ed not discard; i steel and knives,/ ; n now use. We; rate these edges";.; small cost JODWORKERS' OL WORKS, INC. 120 S, Jefferson St. Chicago 6, W. April* j| tnere J0 the jw in , have 1. But >n the e the imple ace to necespam- from nents. ffi.ee, cents, 3ouse anded tment owne, ilture qGS :||| jj M 1pi iii 1 i M m H . - 5 it m By F. L. BROWNE* With the trend to modernize traditional architectural styles, natural wood finishes have become increasingly popular for home exteriors. They can add substantially to the appearance and salability of homes built for sale if they are correctly applied and properly maintained NATURAL finishes for wood siding on the ex teriors of houses have become increasingly popu lar during the past 15 years. Woods that have a rich brown or red color of their own, such as redwood and western red cedar, lend themselves particularly vyell to natural finish, though woods of paler color, such as cypress, pine, knotty pine, and Douglas fir are sometimes finished in that way. Those who have learned to use suitable materials for a natural finish and to apply and maintain them correctly have usually found them pleasing and satis factory, On -the other hand some who have tried natural finishes without first learning what they re quire have been disappointed and have changed back to the older practice of hiding the wood under a coat ing of house paint. The first thing to learn about natural finishes is that they are much less durable and therefore must be renewed much more frequently than coatings of house paint. House paint should go at least four years before needing renewal but natural finishes nearly always need renewal at least once a year. On parts of a house that are fully exposed to 'sunshine and rain, natural finish usually needs renewal every six months until it has been done three or four times, after which the intervals may be somewhat longer, though seldom more than 12 months. On more shel tered parts of the house yearly renewal may suffice and in deep shade the intervals may he even longer. As a rule the lowest courses of siding on the south side of the house are most severely exposed and need most frequent renewal of natural finish where as the highest courses of siding and the overhang under the eaves of the north side are the most sheltered and can go longest between renewals. Trees of neighboring houses, however, may shift the locations of greatest and least exposure to other parts of the house. Need for renewal of finish becomes evident when the luster or glossiness originally imparted to the wood by the finish fades to toe dullness of unfinished wood. Another test is to splash water on the surface to see whether the water rolls off quickly in droplets or spreads on the wood and is soon absorbed. In the latter case fresh application of finish is in order. Needed renewal of finish must not be delayed too long, for if it is postponed unduly the wood begins to acquire a gray color that turns still darker gray when more finishing eventually is done. To restore the desired color titer serious grayness has developed the surface must be scraped or sandpapered until the wood is bright again. If the wood is allowed to become roughened and cupped as well as grayed by weather ing, the restoration of a smooth, bright surface be comes very laborious. For that reason the timely re newal of natural finish simply cannot he neglected. Similar neglect of coatings of house paint is less serious. There is no way of keeping wood very long with exactly the color and nearly complete absence of gloss with which it comes from the lumber yard. A finish that could do so would enjoy a good market. But any protective finish that can be applied neces sarily penetrates slightly into the wood, displaces air from wood cells, and seems to deepen the color of the wood e-ven if the protective material has no color of its own. Moreover, by filling the pores in the wood, the protective material makes the surface smoother and therefore imparts at least a moderate degree of luster or glossiness. As time passes there is further change of color because sunlight gradually darkens the color of most woods by changing yellows and reds toward brown. Even the weakened sunlight that gets through windows eventually darkens interior wood work. If, in addition, the protective finish itself dark ens with age, as most of them do, still more change in color must be expected. Fortunately, aged wood is still more attractive than freshly cut wood. Natural finishes may be divided into three broad types, the oil finishes, the wood sealer finishes, and the varnish, finishes. They differ in the composition of the rnatSKal used, in the appropriate methods of application, in the resulting appearance, and in im portant characteristics of performance. The paint in dustry, however, has no such generally-recognized classification of finishes; the trade names of com mercial products do not necessarily indicate the type to which they belong. Thus a material may be sold as a "log cabin oil" and yet turn out to be either a sealer or a varnish. The user must judge from such information about the composition as may be given on the label and particularly from the way the prod uct behaves when he starts to apply it. OIL FINISH. The natural finish with the lowest degree of luster or gloss is the oil finish. It also dark ens the color of the wood more than other natural finishes do because the oil penetrates farther into wood. Moreover the oils are inclined to continue darkening with age more than most seals or varnishes * Chemist, Forest Products Laboratory, maintained by . the Forest Service, FT. S. Department of Agriculture, at Madison, Wisconsin, in cooperation with the University of Wisconsin. 36 November, 1951 K LM M N OP-- N1 0 Xq 1 R 1 . E B J1 1 q 0 0 q 3 X q1 \ N41698.61 FLB 001150 Imagination converts run-down structures into profitable investments From Shamble to EQ r y community has white elephants those rambling structures that serve no particular purpose. They take up valuable land/ They may be a blight on the community. Bi/t with imagination,, they can be converted into useful dwellings . . . and at a profit. / Realtor-Builder H, E. Russell of Richmond, California, does just that. He searches for old, run-down structures that have possibilities. He converts them into new, attractive quarters. He landscapes the lot, He improves the Appearance to such an extent that property values in the surrounding area are increased/ making the venture profitable for him and/for neighbors. As a sample of his imagination, Russell just finished converting ah agedystructure, once a chickenhouse, into a modern dwelling. When Russell took on the task, the building was a blot on the landscape. Its ancient paint was peeling, boards were rotting, and the site was strewn with debris. From thesfe apparent ruins, Russell built such an attractive home that even after a 10-day public showing it still draws sight-seers from the surrounding area. "Operation Chickenhouse" began when Rus sell saw that the location had possibilities , . . a panoramic/view of a near-by city park and a sloping lot jined with acacia and fruit trees. Major ^structural changes started by sheath ing existing wood with fireproof asbestos in order to meet rigid building codes. The lower half of the exterior walls was then covered with Johiis-Manville Flexboard and the upper half Tiriished with kiln-dried, rough-sawed, clear r heart tongue and grooved redwood. New sup porting columns were set on steel plates, and the original beams were replaced with; heavy new ones. The lot is high at the hack and slopes gently 'to the avenue at the front, A paved parking space, large .enough for three cars, now com mands the lower part of the lot. Trees which partially- blocked the view were cut down, the \larger ones being retained as part of the land- caping plan. A brick patio, 12x50 feet, was alt on the high portion of the lot back of the house. ting interior feature is an open mezza nine studio above the main living area. Access to the Brick patio is from the studio, which ad joins two\small bedrooms and a half-bath, also on the mezzanine level. Total floor space on this level is 74b Square feet. Non-glare vrindows now overlook the patio on the sunny side of the dwelling. These win dows flood the open studio with sunlight and provide additional light for the living area below. Another unusual feature is that the mezzanine 'rtiay be reached by stairways at both ends of the downstairs area, which, with the open studio, help crea/ a feeling of spacious ness. One-quarter-inch II. S, "Plywood was used for all interior walls and partitions. Beams in the main living area are exposed'tind painted a pale yellow. Interior redwood panels are waxed to bring out the fine grain. The main floor includes a dihing area and kitchen, which are under the mezzanine, a shower room and a large storage area, Total area on the main floor is 1250 s.quare'feet. The house is heated by a Lennox High-boy gqs heat er, 75,000 btu, located at one end of theNmain floor. .\ The entire project required 58 actual working days for completion. Total cost of remodelling' the house was $9,500. Russell sold the converted property for $17,500. R ST T U VW November, 1951N1 R E0 Xq 1 1 B J1 1 q 0 0 q 3 X q1 -- 35 FLB dp. The darkening, however, can he largely correct' If linseed oil or a commercial product not contain ed by incorporating a little" pigment in the oil as is ing preservative is used, there are two ways of in described farther on. corporating suitable preservative. One way is to buy The simplest and oldest oil finish is ordinary lin one of the concentrated solutions of ponlachloro- seed oil, either raw linseed oil or boiled linseed oil phenol or other chlorinated phenols sold at lumber Unless the work can be done in warm, dry weather yards for preserving wood and to mix it with the lin it is best to use boiled oil or else to add about one- seed oil instead of adding turpentine or paint thinner. sixth of a pint of liquid paint drier to a gallon of raw If the directions on the preservative say that it is to oil Most painters also like to add some volatile thin be mixed with three times its volume of fuel oil for ner to linseed oil, thinking that it makes the oil pene use as a wood .preservative, it may be mixed one trate deeper. That is not the case, but thinning the volume of concentrated preservative to three volumes oil helps to avoid leaving any excess oil on the sur of linseed oil for a linseed oil finish. face. Turpentine, mineral spirits, or other thinner The other way of accomplishing the purpose is to sold for mixing with paint may be used but do not buy one of the water-repellent preservatives now add more than a half gallon of thinner to a gallon sold at many lumber yards and some paint stores and of oiL apply it to the wood before the linseed oil finish is The oil may be applied by brushing, spraying, or put on-; In the second case most renewals of the finish mopping. Two good coats are needed for new wood. can be done with the linseed oil alone, for the treat But it is most important to see that all of the oil sinks ment with water-repellent preservative need not be into the surface of the wood. If, after the second coat repeated for three or four years. has been applied and has stood 20 to 30 minutes, The oil finishes may be further modified to ad there are any glossy places where excess oil stands vantage by incorporating a small amount of pigment on the surface, it should be wiped off before it has in them. Usually a pigment of reddish brown color time to harden. Coatings of linseed oil are unsatis is desired to simulate the color of the heartwood of factory not only because they are too glossy hut be redwood or red cedar. The pale color of any sapwood cause they are inclined to run or to wrinkle when present in the lumber is thereby changed to resemble they dry. In any event, coatings of oil are too soft, the heartwood more closely and such woods as pine teasid to hold dirt, and become mildewed easily. or Douglas fir are given a richer color. Moreover, In renewing the oil finish after it shows signs of better maintenance of color is `achieved because the wear, one fresh application should suffice. Again, presence of the pigment tends to mask the gradual any excess not drawn into the wood should be wiped darkening in the color of the wood itself. off. (Do not forget that oily rags are a fire hazard. If renewal of finish should be delayed until some Bum them promptly or keep them in a tightly closed boards become slightly grayed from weathering, the metal container until they can be burned.) pigment helps to restore the desired color, provided Trade-brand 'products may be purchased at paint the'graying, has not been allowed to go too far. Fin stores. They are often called log oils or log cabin oils ally, presence of a little pigment usually adds appre because the natural finishes for exterior woodwork ciably to the durability of the finish. Of course, the first became popular for summer cottages built of amount of pigment must he small, well short of the peeled logs. The commercial products are usually point at winch it could give a painted or even a stain made of bodied linseed oil, lung oil, or other drying ed appearance. oils and thinners. Bodied oils have been heated or A number of the trade-brand oil finishes on the treated chemically to increase the viscosity greatly, market contain pigments. Such products, of course, after which a greater proportion of inexpensive thin should be stirred thoroughly before use and should ner must be added to restore suitable viscosity for application. The bodied-oil finishes do not penetrate (Please turn to page 47) so deeply into wood as raw or boiled oil does and therefore do not darken the color of the wood so much. The product approaches the properties of a wood sealer more and more closely as the degree of bodying is increased. The trade-brand oils should be applied and main tained just as has been described for the raw linseed oil finish. Since a bodied oil is more apt to leave an excess standing.pn the surface than raw oil is, special care should be taken to wipe off the excess before it becomes hardened. The oil finishes give their best service in dry places where there never are any prolonged periods of dampness, such as southern Arizona. Where damp ness may linger for some time the oils are subject to attack by molds, the fungi that grow on surfaces. On finishes the condition is usually called mildew, A dark, almost black discoloration may result. Mildew can be prevented by incorporating suitable preserva tives in the oil finish. Some, though by no means all of the trade-brand oil finishes, already contain pre servatives. If so, the kind and amount should be stat ed on the. label, Mere statement that the product it self is a preservative, however, is meaningless because the paint industry's use of that word may have no such significance. Oil finish may be. applied.by brushing, spraying* or mopping, Two coats are needed for new wood. If .excess oil stands on surface after second coat, it should he wiped off before it has time to harden. X YZ Z [ \] November, 1951N1 R E0 Xq 1 1 B J1 1 q 0 0 q 3 X q1 -- 37 SELLING is. "making the other -High occupancy rates of recent years have caused some property person want to buy what you have to offer," and renting apart managers to become lax in their apartment merchandising methods, ments is a selling job. Some prop But vacancies are on the increase in some cities and experienced erty managers have forgotten that in the past few years of a "sellers' managers recognize the need to revitalize renting techniques now market," but they're realizing the importance of it again as apart ment vacancies increase. In many apartment buildings the methods used in showing and 1. Approach. There are two kinds of personality----pleasant and unpleasant. Cultivate the former. Greet prospects with a smile. Make in an apartment. Know your neighborhood, including all its lo cation advantages. Know the loca tion of schools, churches, transpor renting units leaves much to be desired because they are frequent ly handled by operating employ ees -- '`superintendents, janitors, elevator operators -- who have not been properly trained. Where a trained rental agent is available, or where operating employees, have been given careful instructions, the yourself attractive to people who come into your building. Be clean and presentable. If people like you, they- will want to rent in your building. 2. Introduction. "The voice with a smile wins." A pleasant, courteous introduction makes pros pects feel at home. If they feel at tation facilities, playgrounds. These things should be brought out intelligently in the course of presenting the space. Don't over whelm your prospects with infor mation, but let them know as many advantages as possible dur ing the course of the conversation. Sometimes it is possible to indicate results are usually much hetter. home, a good start has been made, an advantage without saying any The problem is of particular im 3. Creating interest. Point out thing about it, portance in the smaller building, the good features of the apartment 4. Creating desire. At this stage and in connection with those pros and building. These include ex of the game your prospect has be pects who shop from'building to posure, light and air,, cross venti.-, come really interested in the build building before approaching a rent lation, ceiling heights, convenience ing the course of the conversation. ing agent. In such cases, the first of layouts, closets, laundry, drying Sometimes it is possible to indicate part of the job falls upon the oper facilities, transportation, parks, an advantage without saying any ating employee. If management shopping. thing about it. officials only realized how many Points of interest in public spac If husband and wife show a de prospective leases are lost because es include house telephone, door sire for privacy to discuss certain of an initial bad impression creat interviewer, mail boxes, garbage items, give them plenty of oppor ed by the discourtesy, lack of in disposal, fire towers. The main ad tunity within the apartment. If terest, delay, or slovenliness of an vantages of these and other fea you force them to wait until they employee they would pay more at tures in the suite should be stress are outside of the building, you tention to training their men in ed. Radio and television outlets, may lose them. However, be con the fundamentals of renting work. size and arrangement of closets, sistently available in the adjoining Even if first impressions are convenience of bathroom are room, ready to provide any infor favorable, there is a right and among the numerous features that mation they may wish. Do every wrong way to present the unit to have sales appeal. thing to facilitate a decision oil the prospect. Its advantages should Kitchens and bedrooms are ex tfespot! V1 be presented in such a manner ceptional sales features. In the Here are some practical pointers that they will outweight its disad kitchen you should be able to talk for the renting employee: vantages in the prospect's mind. intelligently about the good points Always obtain the name of your This calls for a certain amount of of the range, refrigerator, cabinets, prospect. . sales technique and a thorough floor covering. If the kitchen con See that your prospect receives knowledge of all the talking points tains special lighting over work a pamphlet by the management of the building and the suite. spaces this should be stressed. concern describing the building One of the first, essentials, is to In the bedroom, point out size and suites. keep, your building in spic and and equipment of closets, especial Make a report to the office of all span condition inside and out. ly linen and cedar closets, the prospects who call at the building. Many a lease is lost in the lobby. amount of space and how it can be Don't promise more than you Lobby, halls, and elevators should used for twin or double beds. can and will deliver. be kept spotless. Vacant apart Call attention to laundry facili Don't smoke while showing ments should be kept in first rate ties, automatic machines if provid apartments or talking to prospects condition. One vacant apartment ed, space set aside for storage in or tenants. Some people object in each line should be decorated as the basement. strongly to smoking. a show apartment. Be able to answer prospects im When in doubt, find out. Don't The person who handles rentals mediately about the sizes of rooms, make mis-statements. should be thoroughly familiar with cubic capacity of refrigerators, Follow up your prospects close these five steps in the sale: kind of current, how many closets ly, but don't high-pressure them. ^ _ `a a b cd38 November* 1911 --N R E B J1 0 Xq 1 1 1 1 q 0 0 q 3 X q1 B TATURAL FI NAsiding h: popular, and tained correct) attractive and hand, natural the knowiedg often have be that have a i their own, sue red cedar, Ien well to nature paler color, su pine, and D< finished in tha Natural Fit Frequent li The first th finishes is tl durable and, t much more fr paint. Paint years before n ral finishes ne at least once building that shine and ra; needs renewal has been done which the ini longer, thoug months. On n building, year in deep shade, longer. Need for i evident whei originally ini] finish, fades tc wood. Anotiu the.surface to off quickly in wood and is s ease, fresh e order. Needet be delayed t< unduly, the gray color tl when more fi To restore th grayness ha must be sen the wood is 1 allowed tobei 196 FLB 001153 J) *1 , n t/ 2< NATURAL FINISHES FOR EXTERIOR WOOD ByJF t. Browne*Chemist, Forest Products Laboratory, Madison, Wisconsin 1 efg1 ~0 q 0 hQ h for exterior wood as well as grayed hy weathering, the N siding have become increasingly restoration of a smooth, bright surface popular, and when applied and main becomes very laborious. For that reason, They differ in the composition of the material used, in the appropriate meth ods of application, in the resulting tained correctly usually have been found the timely renewal of natural finish appearance, and in important character attractive and satisfactory. On the other simply cannot be neglected, Similar istics of performance. hand, natural finishes applied without neglect of coatings of paint is less serious. the knowledge of what they require, often have been disappointing. Woods There is ho way of keeping wood very ' Oil Finish long with exactly the color and nearly that have a rich brown or red color of complete absence of gloss with which Oil finish' has. the lowes| degree of their own, such as redwood and western it comes from the lumber yard. A finish luster or gloss. It also darkens the color red cedar, lend themselves particularly that could do so would enjoy a good of the wood more than other natural well to natural finish, though woods of market. Any protective finish that can finishes do because the oil penetrates paler color, such as cypress, pine, knotty be applied necessarily penetrates slightly farther into wood. Also, the oils are in pine, and Douglas'fir are sometimes finished in that way. into the wood, displaces air from wood cells, and seems to deepen the color of clined to, continue darkening with age more than most sealers or varnishes do. Natural Finishes Need Frequent Renewal the wood even if the protective material has no color of its own. Moreover, by filling the pores in the wood, the protec The darkening, however, can be largely corrected by incorporating a little pig ment in the oil as is described later. The first thing to learn about natural finishes is. that they are much less durable and, therefore, must be renewed much more frequently than coatings of paint. Paint should go at least four years before needing renewal, but natu ral finishes: nearly always need renewal at least once a year. On parts of a building that are fully exposed to sun shine and rain, natural finish usually needs renewal every six months until it has been done three or four times, after which the intervals may be somewhat longer, though seldom more than 12 months. On more sheltered parts of the building, yearly renewal may suffice, and tive material makes the surface smoother and, therefore, imparts at least a moder ate degree of luster or glossiness. As time passes, there is further change of color because sunlight gradually darkens the color of most woods by changing yellows and reds toward brown. Even the weak ened sunlight that gets through windows eventually darkens interior woodwork. If, in addition, the protective finish itself darkens with age, as most of them do, still more change in color must be expected. Natural finishes may he divided into three broad types, oil finishes,, wood sealer finishes, and the varnish finishes. The simplest and oldest oil finish is ordinary linseed oil, either raw oil or boiled. Unless the work can be done in warm, dry weather,, it is best to. use boiled oil or else to add about one-sixth oka-pint of liquid paint drier to a gallon of raw oil. Most painters also like to add some volatile thinner to linseed oil, thinking that it makes the oil penetrate deeper. That is not the case, but thinning the oil helps to avoid leaving any excess oil on the surface. Turpentine, mineral spirits, or other thinner sold for mixing with paint may be used, but not more than a half gallon of thinner should be added to a'gallon of oil. in deep shade, the intervals may be even longer. Need for renewal of finish becomes evident when the luster or glossiness originally imparted to the wood by the finish fades to the,dullness of unfinished w ood. Another test is to splash Water on the surface to see whether the water rolls off quickly in droplets or spreads on the wood and is soon absorbed. In the latter case, fresh application of finish is in Older. Needed renewal of finish must not be delayed too long. If it is postponed unduly, the wood begins to acquire a gray color that turns still darker gray when more finishing eventually is done. Portion of a Forest Products Laboratory test panel at Madison, Wis., treated with a To restore the desired color after serious "redwood finish," It has been exposed to the. weather for 7 months, facing south. The grayness has developed, the surface top board is redwood followed by white pine and cypress. Experts recommend re- must he scraped or sandpapered until the wood is bright again. If the wood is finishing once a year after the second application allowed to become roughened and cupped 196 ARCHITECTURAL RECORD * * f mmm. " . . . . . N41698.62 FLB 001154 WARM AIR PANEL SYSTEMS several years. In the crawl space warm air system, it will take place in the first year.X Warm Air Panel and Split Systems Some engineers advocate panel heat ing, or, the Hsplit" system in. which the air follows a sbhmus pattern in the floor or ceiling panel ahd then is " bled " into the room through small openings near windows. \ For large houses wherhthe total heat loss exceeds 106,000 Btu/br, one inde pendent heating system can take care of the total heating load, if a panel or "split" system is used. But with\peri- meter" systems, when the heat IX Jr is greater, two or more independent sy: terns are required; and the systems can then be zone controlled. These engineers also believe that most of the heat from the air should be dissi pated in floor or ceiling panels, resulting in surface temperatures around 85 F and 100 F respectively. Temperature of air to rooms approaches that of the room. One consulting engineering firm de scribes their floor panel heating system for residences, comprised of cellular clay tile topped with 234 in. of concrete, as follows: The residential installation is con trolled by room thermostat and conven tional warm air bonnet control except that continuous fan circulation is not used. When the thermostat signals for heat, the burner provides constant heat input to the slab until the thermostat has been satisfied. The fan is controlled by a high-low limit setting. If the fan ran continuously after the thermostat shut off the burner, the slab would con tinue to store heat, and the house would become too warm. Night set-back is not recommended because then the system is forced to operate in the morning for a good while after sunrise when the outside tempera- Tx4" !2'0.C. to asbund 4 p,m/E(uring thisperiod', the/' solar heat is absorbed l?j the .floor slall/ Irrni/lh ftAnoitrf^AT o Ol iX A+X 1 I<1 nf1 1 low heat storage. High W prevented. Other systejhs making fisfefof noncritioal materials inqladq/^-Tlocir panel systemwith'woods^bpemaid on&poncrete floor slab, and a/plywood subfloor above. Ceiling parrels are being com, structed with gynsmSTboard furred down from ceiling joisfs, and the furring strips act to guide the air in a sinuous pattern. See the two/sketches on this page. Below: layout of a typical ceiling panel system. Furred down ceiling is used sim ilar to photo (note reflective insulation!. Gray fane indicates large distribution duct to front panels. Slots admit air near out side walls 195 Natural finishes for major areas of wood exteriors are a relatively new .develop ment. This report deals with the various misunderstandings and difficulties that have come up in the Forest Products Laboratory's consultations with architects and others. When the requirements and limitations of natural finishes are considered in advance, and the necessary precautions have been taken, natural finishes have been found both practicable and pleasing. The oil may be applied by brushing, spraying, or mopping. For neiv wood, two. good coats are needed. But it is most important to see that all of the oil sinks into the surface of the wood. If, after the second coat has been applied and has stood 20. to 30 minutes, there are any glossy places where excess oil stands on the surface, it should be wiped off before it has time to harden. Coatings of linseed oil that stand on the surface are unsatisfactory, not only because they are too glossy, but because they are inclined to run or to wrinkle when drying. These coatings of oil are too soft/ tend to hold dirt, and become mildewed easily. In renewing the oil finish after it shows signs of wear, one fresh application should suffice. Commercial products are often called log oils or log cabin oils because the natural finishes for exterior woodwork first became popular for summer cottages built of peeled logs. These commercial products are usually made of bodied linseed oil, tung oil, or other drying oils and thinners. Bodied oils have been heated or treated chemically to increase, the viscosity greatly, after which a greater proportion of thinner must be added to restore suitable viscosity for application. The bodied oil finishes do not penetrate so deeply into wood as raw or boiled oil, and, therefore, do not darken the color of the wood so much. The product approaches the properties of a wood sealer more and more closely as the degree of bodying is increased. The commercial oil finishes should be applied and maintained just as has been described for the raw linseed oil finish, Since a bodied oil is more apt to leave an excess standing on the surface than raw oil is, special care should he taken to wipe off the excess before it becomes hardened. The oil finishes give their best service in dry places where there never are any prolonged periods of dampness, Where dampness may linger for some time, the oils are subject to attack by molds, usually called mildew. A dark, almost black discoloration may result. Mildew can be prevented by incorporating suit able preservatives in the oil finish. Some, though by no means all, of the commercial oil finishes already contain preservatives. Ifso, the kind'and amount should be stated on the label. Suitable Preservatives. If linseed oil or a commercial product not containing preservative is used, there are two ways of incorporating suitable preservative. One way is to mix one of the concen trated solutions of pentachlorophenol or ofher chlorinated phenols with the lin seed oil, instead of adding turpentine or point thinner. If the directions on the preservative say that it is to be mixed with three times its volume of fuel oil for use as a wood preservative, it may be mixed one volume of concentrated pre servative to. three volumes, of linseed oil for a linseed oil finish. The other way of accomplishing the purpose is to apply one of the water-repellent preservatives to the wood before the linseed oil finish is put on. In the second case, most renewals of the finish can be done with the linseed oil alone, for the treatment with water-repellent preservative need not be repeated for three or four years. Adding Pigments. The oil finishes may be further modified to advantage by incorporating a small amount of pig ment in them. Usually a pigment of red dish-brown color simulates the color of the heartwood of redwood or red cedar. FEBRUARY 1952 Some natural finishes whiten (loss of adhesionI and scale when applied to rather large areas, of exterior siding. At left is a 3-year-old house in. Arizona which had been rdfin/s/ied 1 year before the photo was taken. Above is an 18monfh-ald hcuse ir. Madison. Wis., which had been refinished only 6 months before 19T NATURAL FINISHES FOR EXTERIOR WOOD The pale color of! any sapwood present in the lumber is thereby changed to resemble the heartwood more closely, and such woods as pine or Douglas fir are given a richer color. Moreover, better maintenance of color is achieved because the presence of the pigment tends to mask the gradual darkening in the color of the wood itself. If renewal of finish should be delayed until some boards become slightly grayed from weathering, the pigment helps to restore the desired color, provided the graying has not been allowed to go too far. Finally, presence of a little pigment usually adds appreciably to the durabil ity of the finish. Of course, the amount of pigment must be small, well short of the point at which it would give a painted or even a stained appearance. A number of the commercial oil fin ishes on the market contain pigments. Linseed oil or prepared oils without pigment can be pigmented just before use by adding a small proportion of burnt sienna ground in oil. About onehalf pint of sienna-in-oil to a gallon of oil may be right, but the exact propor tions are best determined by trial on sample cuttings of the wood. Wood Sealer Finish Like the oil finish, the wood sealer finish is a penetrating finish that should not be permitted to build up on the surface into a glossy coating. Sealers do not penetrate wood so deeply as oils do. For that reason, the sealers usually darken the wood less and give the surface more luster or glossiness than the oils do. The sealers, however, are less glossy than varnish finishes unless too much sealer is applied and the excess is not wiped off. In composition, wood sealers are much like varnishes except that the sealers contain more thinner and lessnonvolatile matter. Both are made as a rule by cooking resin and drying oil together in suitable proportions, incorporating dri ers, and thinning to proper consistency. Many kinds of resin, both natural and synthetic, may be used. The differ ence between a sealer and a varnish lies more in the method of application than in the composition. Wood sealer finish, like the oil finish, sinks into and satu rates the wood surface without forming a continuous coating of appreciable thick ness over it, as varnish finish does. If excess sealer finish is not wiped off, what may start out as a sealer finish will end up, after one or two renewals, as. a varnish finish. A good spar varnish or marine spar varnish will give sealer finish if thinned with about an equal volume of turpentine or other paint thinner and applied like the oil finish. Although most wood sealers are more resistant to mildew than the oils are, sealer finishes are more readily attacked by fungi than are paints. Wherever there may be lingering dampness, it is advisable to have a preservative in the sealer finish. Some of the commercial products already contain preservative. Otherwise, preservative may be incor porated in a sealer finish by either of the two methods suggested for oil finishes. Some commercial wood sealers contain pigments for the same desirable purposes already described for oil finishes. The. user may also add pigments to sealers lacking them by following the methods suggested for pigmenting oil finishes. Varnish Finish Unlike either oil finish or sealer finish, varnish makes a highly glossy coating of appreciable thickness covering the wood. Varnish may not darken the color of the wood to begin with much more than a sealer does, but with the passage of time, there may be more darkening caused by change in the varnish itself than would be the case with a wood sealer. Varnish is applied by brushing or spraying. At least three coats are needed for new wood, but for renewal, one coat at a time is sufficient, Qn new wood, the first coat may be thinned moderately with turpentine or other paint thinner. Shellac must not he used for the first coat on exterior surfaces, even oyer the knots in knotty pine, Succeeding varnish coats are expected to stand out without penetrating the wood and, of course, none of the varnish is wiped off. Wherethere is dampness at times, var nish finishes need preservatives against mildew much like sealer finishes. Unless the varnish already contains, a preserva tive, it is advisable to apply a waterrepellent preservative to the wood before starting to put on varnish. It is seldom practicable to add a concentrated pre servative'to a varnish because varnish cannot stand much addition of thinner. Similarly, it is not. good practice to add pigments to varnish. If pigmentation is. desired, it is best to apply a pigment oil stain to the wood first and then to varnish over it. On the whole, experience with varnish finish on large areas of exterior wood work such as siding has not proved satis factory. Often the varnish finish develops milky, opaque patches where the coating has lost its adhesion to the wood without breaking open. Some varnishes craze or crack in an unsightly manner, after which renewal of the finish is difficult. Finishing Hardwoods The methods of natural finishing de scribed so far are suitable for all of the softwoods and for hardwoods with pores no larger than those in birch. Hardwoods with pores larger than those in birch, however, usually need special treatment for the pores after water-repellent pre servative, if used, has been applied, but before oil, sealer, or varnish is put on. The treatment for pores is the applica tion of a paste wood filler! Paste,wood filler is applied by thinning it with paint, thinner to a consistency suitable for brushing, like paint, but brushing across the grain of the wood rather than with the grain. For varnish finishes on hardwoods with large pores, use of wood filler is necessary to avoid danger of premature failure of the finish. For wood sealer finishes, the use of filler is strongly recommended, though it may not be essential. For oil finishes filler may be omitted. Finishing Doors and Windows Doors and windows usually need more careful maintenance of protective finish than is necessary on wood siding. Paint or trim enamel affords the most reliable means ofmaintaining the needed protec tion. Careful consideration should be given to- the choice of paint or trim enamel for the exterior surfaces of doors and windows even when natural finish is selected for, the siding. Paint of a color matching that of the naturally finished siding may be used if desired. But if natural finish is wanted for doors or windows, it is probably best to apply a full varnish finish consisting of three or four coats, because, varnish gives better protection against weather ing than oil or sealer finishes do. Rust Stains Woods that contain tannins, such as redwood, red cedar, oak, and chestnut, readily produce a black color when brought in contact with iron rust and a little moisture. Other extractives, present in many woods may also form strongly colored compounds with iron. Exterior woodwork, therefore, should always be fastened in place with corro sion-resistant nails, screws, or other fastenings. 198 ARCHITECTURAL RECORD WiSCdNStN STATS-JOURNAl/ StfMPAf, SEPTEMBER ft 19 L Studies Natural Finish^ <ftT JAIN Mt'fK'l-.* MMBp||W8p8i|M^^ top ii*1 if. 'i> , 1 - dull. oi h hf i- \ no\, o t 1 pt ri> i i * -i a #rcfctl ' p-inin't )>; 1 4$ aft(i Hlt'> iifMd i'W U W* *H 11 I'Tr < M l 1 *&,$ \ i w i 14 t pVt* * vju*l 'l1 * i A"fU &>, bc*' i o i ^ L Bo fn* j0 l$tyi \* # * 1 i k*K c ? 4* ( i *^ n** J III (it i * l> 41 Ftwr t<> lm Shot $y kQ &j& ^*- * /, -- I-J 0 ' -U<. - ' ' #v#h t s *ia 1 M,o'J rv r1 r ^ F^'*"-*1 PnJdttcls- ?-afetriiiyi^ at ?v^d^`4 14N i^\.ed t iitoaphicx lit tfrt us* f urTiuiai <>( *. ?* iyr vood Jid*ng #>n ^o^;4\iir> > 1 T Brown t }ihor t> u."Pr w it* t H < ui -- sr^si i n rn >i + in jho o t I 4 0 t 0 v sjiow v v in n ns; + i Ii iiavt s < n [Mini d > u! oti i i o'w i iin no * +* w *110- u, thr son; 0 irr 1 a u v l* i t rt`i i t iartm rurliiet f*ruj tL- ltiy. r?r Pft !<;< h!i. m* k?i*i}H r hotiMCs TMp i mUs * .v i 1 iifrItIffIRl!'n."|r.f fI Sfi1 M l.^1!b'"\ in<*Oip?o"ra..ft?PTf f-^gJ 'i I*rv*jr4v i tnp c. t m he oti Greater Durability !tfabn spar catnip tends, to bet Burnt ?'emia ^lounii in oi! mat. mors datable than irntmarv snarl far; m"'i"?' Jt^" r-t'K" J ,--:raaH....l....r..t.r.o..a....o..f...j.y..a..r.f.i.i.s..fat,w9-1Hsbik*altMT.teitts ii 01 a!Jfl ,lfl<ietl ' ' *0 farjfei (litarv.-.SlMit tfat*fr ats *" xn ^u, e Oil, .1 lift!* color arl 'nt-rflwl to no**..*n!>ml, .Mji otily a 'icaiv> durabilirv single coat lusrdcd ter renewals It s m flmnmdedv hoveter tin fcew ssoofi the i rst out ran J inseesd Oil t ted I tint the user e\peionsnt vrild'.&e tbianed nmderatcty mtb tar- S npi"s ir.it oldest oil u . o is hamp!<_ cut,tui,n or stood t,,o Jiafce1l]|reiitl^ ot` ofiirr paint tfiinner , I'm osi1 oil raw Or boiled t'^iri ,'Ore tue decree of eoloration iv ttben io*ie. in: ti'tvetei i i, '| 1 i nm b\ I'be voife is ilorjo in vraa'ni, dry iliat desired, `idirfuntt tv. limit Hie rcueama !p ntliej'. it 15 best (o u-e bolietin Ii tic nl fun b ie noad seat Hlic jfo1, v`itr tti * rMiti Mi ut <7 10I aibouf uflt^ta'tifi / *i, l> ^iiiiiirai^p*' n1''" ppophales atid ^houli > ili^v tke iiC'.T'h aot*Jj'f, vaieti fe! 'i.wfi j rs\- nij "'icftKe healpre do no pen^frr^tei ard fl^s Ufe?^der"Ci-aiife This :n u.<i' tie a .died lit pru h i1' steeply as oijs, and henre loirt] Ose eots-e u^Jt 'jius bn ;e.-ev' ' ns, sci awn;;, m mt>Opa.g be. t`" m0 Q7 nivln? hittre gioss theoah ssturo of "He tarj'-h naj *e. i.eod, t.tp peats ard jst'edrd Nirrc are mazit sealers on /lie still be dood V.S <i4io t:*`V ,', 1 impelwn> to sir that the 0). tt,.jsel sotd nndet \anous tiji'e _ tTnen j pte*so.i,,l<vc i` i"*ed>'<! iklhtu rl- spi iii If then* art 114 m ' no.'umti . ssis the lab d > .uhis 1. - tp app's i \ if rms.' plates after the e.lhas bean <>rj-0.j :it0, ,,. P'^'-'rksti'e 'a the itnor SiMi'd'ie'wrp'ed ofT'be&'e^be otf'rM.,jitls ^ > ji j J; };L, nit Lie 3>nn,e,rr li** -ua,f' f anno si in i tie 1 TI * t* *110 ^ h'tdScr.s" ' * '<w '"' ' er m~ a- y net M'ure s n'p'no. ihu ns ! ^ 93 '^aliu~ 'i<#tSJ,1 ``-L the oil imssces give their best lev . non id b-t.peo r.h t>- no' ?J , ,,u^" ^ fi 15 "seKIce. says "the ehiirMsi, "tn ffiS it'c* tie U't' ri3' sis I oil* i * ''t ' 'Jf \ 1 n 1ici11 0 ' '' p t * ** n *V antu tfca Of1 Idaees where Uie are, never,my- a semi miss , t nf.ed nenods if Jlainpness Vfhen iintTi fli-, v*.'c fet' r>, st , ,i W the moo f. ,t aid )p.r f^ftsf . a*h! over ii it dampness lingers, die oils are sufr- type linn tarni^i. haweter, has out prot- j-itt in attack b$ molds, the ituigi tnai grin* nu sun in s nut av \ltulv I1 Iao^i ed parlleutaHy neat'ts^al nn tnre areas of e&terior fromlrrark, su.-ti de\ `bar oi' s'ale<* is B ,,, as sioirt?. It may develop mithj k h it peed oil. rey a romifiereiai ie..thj al-arkm l,\ 1 ujii ihao i upd opague palcbes Where ihr ro-itip* I *' * 1i 'fv's \ > 'iSIpi i od PPP- i est h, e not contain 'a hw l o' , i l e * prwnatim. >v:<r>de to a* t on tpre it], > S .ip, .he use- tan add one of the coo- r.i the ioiuumriat oionuett !>aie hat tost its adhesion *, the vioci without tkeatdng open. Some '. airttsfie. eu;f o e-jil,, rctura'lid sDiotKts of pcntfiath- sniseti iti> e* udued, j. ' *'< s making tt <UrrietTlt to lenen Vieti 6ro{flien'i>r avaitaW ,'"MS^ei`4jii?nieuT''..... `" ' .................. ' tSaraiC f .<Jl otic, of * uLhe orat o 1 u ftttr--aalnr. iepcyati.ii.sb makes a hirnl, i ea**i ir i loss ro.i im,I Coal develops vihico pricks a'j I s,,cfu*te.si aa.n!Xdi.>iItitth"ee7n bbeeccoommeess uneeetCes' I nevvills mat! *' *btt* h>sirt trHBBr i*>l&` *f> tilt- Sa||||||| rt-i, u* ti'tor ov*H |||||i IprfeSWsaliyoa'jaip-* tor hou^ir Si.ivi *be scrfree o' tb<- wood Ti.oighl latM lttrfttjj+*- .V6i^Se asi<6 4f>^od ;tbr 1 arnish *jwt rot kt-n ibr j-Urhne wood iie,<it die-Imte<roiliviO(.d nutc'i -ii.v tiia.i j sealer ' emsh is pm" 5ouii Ml Tfflreasc, re-fit may darhcji nKsro p'iili Jie bjs- i * *) 'l /'* i;i * * iVV't -sit atone ha be made of imsedd iing of the lieanneill a.ftj'hl the time, due 0 nchances ' au)i-h t<sL!" wiiL- S,,, , !he e,|rp wattu '*'Ul1 'Stni'b. remmci. hb * / ! /f ,, N / 0~VX/ly) / ' 1, ,,* k. ** " * *. V (lc A*ts M ** *fM iMtj hMi 0 I1l0 inp -. i.l + i'ei lToellarr! picsens'ise li-t frr tilrep or ff, ir je.i-1 N41698.63 FLB 001158 loth C fl'llMSe - IHI l.lllOI! r`l iviiu h tiin mi tannins sum u 4 0 ed-| worn! led redoi, oak mid rhf si nut Inn an so a Mail air i Jill dot plop m the pi ''.enoc of i*#n1 mt and Mfelnliitf -wpi ait. ((i iimiiu'nrfptl xi Hi i uniint'juii ! rt s not a good plan to srM iiilli a tiatuial finish on a m", linusii q i expeninenr sith the . nioa ot changing ( > paint I itn il in c> saiy the Ulioiatoii wiins It 16 heftei, it says, to (hookI ith peisotK u till ime hsd i/wd (i.pr'iitti<t mill a sfitnn mite1-!U and method oi application i tlio change can usilulh. be m.i'lo. ii a ii i Hi i in i 11 n* i it 1 n i s 0 0 0 i has In cn allotted In actumuiul. lo a mating, strip ihn surface of ,,11 - tic 0 0 rnatonal *ith tarnish it Remove any remaining wax fiom (ini n.' i > i ip . i i * e, i ,,t. paper lightly, and paint as a new If a sealer was u^ed and is with in f&e v4* surface, it may bo pia.H, ibl..W||.Hb* without laidtiuii itTs. him- ver , ,t0 let * -yea* elapse s The bulletin on natural wood fjnIshei tor exterior finishes is Xo 1HWO8. and may tie obtained free ! testae. \ *on. 5* tVfe.0 FOREST PRODUCTS LABORATORY (Madison 5, Wie,) . FOREST SERVICE 0 S. DEPARTMENT OF AGRICULTURE Approved Technical Article tfsr- One of the houses of the Amana Society at Amana, lov/a, as it appeared in 1946 with poncferaso pine siding that had never been painted except hr windows, doors and trim. The house was at least 40 years old, but probabty was much oider than that WOOD SIDING LEFT TO WEATHER NATURALLY By F. L Browns, Ckemisi Forest Products Laboratory,* Forest Service U. S. Department of Agriculture QIWCE op<0 q_ 1 0 Xq of the article on O "Natural Finishes for Exterior Wood" -in rA _ Q0 s _ str1 uR _ X (February 1952, page 196) a number of inquiries have been received about the possibility of leaving exterior wood entirely unfinished, toweather naturally. If suitable precautions are taken it is practicable to do so, i>ut whether this is desirable is a question the architect and * Maintained at Madison, Wis,, in coopera tion with the University of Wisconsin. owner must decide. Painting, though, is likely to remain the customary treat ment for exterior surfaces of smoothly planed wood, and staining for rough wood. Nevertheless, the practicality of weathered wood is adequately demon strated by much past experience. For the first century or so of the American Colonies, particularly in New England, wood was the predominant building material and the exterior surfaces were The new house of architect Winston Elting has unfinished rough sown redwood siding. A water-repellent preserva tive was applied to millwork, exterior beams and columns left unpainted to weather naturally. It was not merely that paint was an imported luxury. To the puritan mind of the time painting was An ungodly arrogance for anyone but a high crown official or a very wealthy merchant. There is record of the expulsion of a barber from the Massachusetts Bay Colony for aspiring beyond his station in life when he spent part of a small in heritance for painting his house. Many of the wood buildings of the early colonial period still stand. Most of them, of course, were painted when it became socially acceptable to do so, and they have been kept painted since. But some, including two of the oldest houses that remain, have never been painted. New Englanders claim that they have the oldest wood house in the United States, now known as the Old Fairbanks House at Dedham, Mass, The first part of Die house was built in 1636. Most of the clapboard siding, however, was replaced in 1903 but has now stood nearly 50 years without paint. The oldest portion of Hartwell Farms at Arlington, Mass., also built in 1636, is still covered with the remnants of the original clapboards. From 1858 to 1932 the Amana Society owned communally seven villages in Iowa County, Iowa. The houses were of wood and were left unpaSirted except for window sash and doors, which were painted. When I saw them for the first tame in 1927 the houses were well main- NOVEMBER 1952 197 N41698.64 FLB 001160 I Part of a 25-year-old signboard made by stenciling letters on an unpainted background. Eroding of the unpro tected wood background by weather ing left the letters embossed Vis in. From this and other suitable evidence, I it can be predicted that wood wastes away about 'A in. a century due to weathering tained. The chief carpenter told me that the Vi by 6 in. bevel aiding lasted from 30 to SO years before they found it advisable to begin making replacements. In 1946, fourteen years after the residences passed into private owner ship, I again visited two of the Villages, By far the most attractive, and neatly kept houses were those that remained loyal to the old customswith tho-siding unpainted hot with comer boards, facia boards, and window and door carings, as well as sash and doofa, decorated with paint. ' The houses mentioned so far were all very modest dwellings, left unpainted for economy or to conform to local cus tom of the time. But there are at least a few examples in recent years of more pretentious buildings for which weath ered wood was chosen strictly for its .appearance. Two of those I know are hotels that must attract patrons to remain in business. Pilot Butte Inn at Bend, Ckre., send the Redwood Inn at Scotia, Calif., are the leading hotels in their communities. Both have been in operation for several decades. Jha Process of Wood Weathering Wood such as siding and trim on braidings, if left freely exposed to the weather without protective painting or treatment, changes materially in ap pearance for a few months or years, after which it stays nearly unaltered far a long time. The color of the wood is affected very soon. Woods like redwood andred cedar, thatowe theircolor largely to substances soluble in Water, may first become bleached. Woods of lighter color, such as pine and spruce, may first become somewhat brown from the action of sunlight. Later all of the woods turn gray unless the building is high in the mountains, where the brown color asso ciated with the Swiss chalet develops. Smoothly planed wood Boon begins to acquire a rough surface. First the gram becomes raised, that is, the hard bands of SummerWood rise above the softer springwood between them. Then minute checks or cracks begin to appear in the surface and steadily increase in number until the surface becomes decidedly rough as the fibrous structure of the exposedwoodisgreatly loosened. Finally the wood substance erodes away very Slowly and the boards gradually become thinner. Wood Wastes away by such weathering at the rate of approximately in. a century. Besides the many minute checks in the surface, most woods soon develop some larger arid deeper checks or cracks that are easily visible and may become conspicuous. As a rule, the woods of moderate tp low density acqrare fewer of the conspicuous checks than do the woods of high density. Edge-grain boards check less than flat-grain boards of the same variety of wood. As a result of the weathering proems there is a tendency for boards to clip, Warp and poll at their fastenings. Firmer nailing may therefore be neces sary when wood is left to weather them would he required if it were kept well painted. The cupping tendency varies with width and thickness of the boards. The greater the width in proportionto the thickness, the greater is thetendeney to cup and pull at the fastenings. Although Mby 6 in. bevel riding was considered satisfactory by the Amana Society, % by 6 in. siding would serve much better. For best results the width of the boards should not exceed 8 times their thickness. Cypress, hemlock, white pine, ponderoaa pine and spruce usually weather to a light-gray color that often has a silvery sheen. A darker gray with little or no sheen is developed by red cedar, Douglas-fir, fir, southern yellow pine and redwood. Red cedar, cypress and redwood commonly acquire fewer con spicuous cheeks or cracks than other woods do. Similarly, cypress, red cedar and redwood generally have the least tendency to cup and poll at fastenings; Whereas pine, fir, hemlock, spruce, Douglas-fir and southern yellow pine require firmer nailing to hold them in position. Development of Weathered Appearance Takes Time Although the appearance ofweathered wood is attractive for suitable archi tectural effects, there is a difficulty in malting use of it for new construction, in that much time is required for the change from new to weathered lumber. Moreover, thechange seldom takes place evenly over the different parts of a ride wail. Those boards that receive most rain and sunshine become weathered first. Usually the lowest courses of siding on the south wall become fully grayed and roughened sooner than the top courses of riding under the eaves and much sooner than courses of siding 198 ARCHITECTURAL RECORD enings. vel siding was y the Amana ; would serve llts the width xceed 8 time pine, ponderty weather to often has a ay with little . by red cedar, yellow pine cyfiress and -e fewer con? than other / as, red cedar ' ore the least it fastenings; eh, spruce, yellow pine told them in d ofweathered itable archidifficulty in -(instruction. tired for the ered lumber, n takes place utsofaBide eceive most e weathered courses of lecome fully ler than the tr the eaves ses of siding < _ X7 under a porch roof. Wide overhang at the eaves delays the weathering ofmore courses of siding than a narrow overhang does. Thus for a number of months, or even for a year or two, there is a mottled .appearance varying from nearly bright Humber to gray weathered wood. The unequal delay in attaining the "weathered appearance can be avoided by using rough sawed rather than the smoothly surfaced lumber to begin with and applying a gray oil stain. Such a stain can be made, for example, from raw umber in oil, white lead in oil, boiled linseed oil and mineral spirits or other paint thinner. The stain need be applied only once when the house is built; by the time the stain has worn out the wood will have developed its natural weathered gray color. Some houses recently have used bevel siding with the planed side out and have then been given the color without the roughness of weathered wood by applying a product known as bleaching oil or sometimes as redwood bleaching oil. A number of paint manufacturers supply such products. They may be described as natural finishes of the sealer type in which there are some pigments to give the gray color. When bleaching oil is used, the wood may be kept smooth indefinitely by renewing the finish as often as proves necessary, or the first application may be allowed to wear off and leave the,'Wood in its naturally weathered condition. Need for frvsf-fiestsfuaf Noils When exterior wood is to be allowed to weather naturally or is to receive a natural finish, it is particularly impor tant to see that all nails used to fasten it and all hardware that may he placed in contact with it are highly resistant to rusting. The heads of ordinary iron nails rust rapidly, and the iron rust promptly penetrates into the wood for some distance from the nail heads. In some woods such rust makes reddish brown stains, but in woods that contain tannins, such as cedar and redwood, the stains are bluish black and very un sightly. Corrosion-resistant nails, such as galvanised nails, cadmium-coated nnilB or aluminum nails avoid such difficulties. Although the weathered wood ap pearance may dispense with periodic renewal of paint or finish, it should not be used as an excuse for neglecting periodic inspection and careful main tenance of the building. Even when care is taken to provide firmer nailing than usual, some nails gradually become loosened and partly withdrawn by the operation of the forces of wood weather ing Everyfouror fiveyears suchloosened hails need to he driven in tightly again. Likewise, the same care about keeping joints tight, repairing gutters, and mak ing other minor repairs that would be taken with a painted house, is needed when the wood is allowed to weather. Exterior wood, then, may properly be allowed to weather naturally without protection by paint or other finish whenever it proves desirable to obtain an architectural effect in that way. For weathered wood it is wise to select the kind of wood carefully to obtain the intended result; and it is particularly wise to use lumber that is thick enough in proportion to its width, to-see that it is very firmly fastened with rust-resist ant nails, and to provide the' same care in maintenance that would be given to a painted building. Above.- Redwood Inn at Scotia, Calif-, with redwood sid ing and trim on first floor, redwood shingles on the second. It was 20 years old hers and had never been po/nfed. Below: the Old Fairbanks House, Dedham, Mass., built in 1636 and never painted. While pine siding was replaced in 1903. Window frame, facta wood may be the original NOVEMBER 1952 Z M 92063 F FLB 001162 - H The selection of durable exterior white paint is not difficult once a few basic paint principles are understood. The primary purpose of this article is (1 ) to outline the *' functions performed by the principal ingredients which make up modern ready-mixed exte rior white paint, and (2) to provide formulas which'may be used by the home owner or builder as a guide in selecting paint which will retain a good appearance and gradually weather away in such a manner as to make repainting less costly. Recommendations are based on a survey of trade-brand paints available on the market in 1950, and on extensive exposure tests and observations of houses made since 1922 at Forest Products Laboratory, Forest Service, United States Department of Agriculture, Madison, Wis. The article is written in as nontechnical language as the subject will permit. Addi tional recommendations for a successful paint job are given for the convenience of the layman. These include such items as preparation of surface, elimination of moisture beneath the paint, frequency of repainting, and proper application techniques. The survey of present-day exterior white house paints was sponsored by the Housing and Home Finance Agency as a part of Research Project No. Q-T-24 and was per formed under the direction of F. L. Browne, Chemist, Forest Products Laboratory, U. S. Department of Agriculture. This article was prepared by William A. Russell, Chief, Technical Standards Unit, HHFA's Division of Housing Research. I / Selection of Durable Exterior White House Paint *' Exterior painting, even when the most dur- paints upon which each manufacturer stakes his : able type of paint is used, is usually the largest reputation. First-line, trade-marked paints are | item of maintenance expense for the owner of more carefully formulated than other less ex ? the average house, particularly if the exterior pensive paints, often referred to as "competi covering.is wood siding. ' The cost of repainting tive" paints. The latter are often made up Ia house often amounts to several hundred especially for painting contractors in order to I dollars, of which the largest portion by far is meet competition. Mere presence of a formula I the cost of the labor to prepare the surface and on the label, however, does not insure that the apply the paint. The amount of paint re 1 quired to repaint the average small house is i seldom more than eight to ten gallons, so that paint is. of first quality because laws in many states require that all paint offered for sale to the public must have the formula on the con l the additional cost of procuring a good durable tainer label. ^ paint is very small in relation to the total cost A recent nation-wide survey of dwellings i of the repainting job, usually not more than a made by Forest Products Laboratory, Madison, dollar or two per gallon. On the other hand, Wisconsin, under the sponsorship of the Hous where care is not taken to select a durable ing and Home Finance Agency reveals that it paint, repainting is often required twice as is false economy for the home owner to Use frequently, which practically doubles the cost anything less than first-line, open-formula of paint maintenance to the owner. paints. The purpose of this article is to explain All reputable companies manufacture and the functions performed by the principal ingre recommend durable house paints. These paints dients of modern white paint and to provide are, in general, trade-brand paints which are guides which will permit any builder or home advertised to the public. They are first-line, owner to select or specify paint which will retain quality-controlled products which have been a good appearance for a reasonable number of developed by patient research and are com years. It is limited to selection of ready-mixed monly open-formula paints (i. e., the formula is white paints for application to wood which is printed on the container label). They are the exposed to the weather. Recommendations MARCH 1953 17 I N41698.65 herein contained ate based chiefly on a survey of 60 leading brands of white paint available on the market in 1950, together with informa tion derived from paint exposure tests during the past 30 years under the (.supervision of F. L. Browne, Chemist, Forest Products Labo ratory, Madison, Wis. NTot only paints of many different formulas have been tested, but studies have been made on all of the common woods and of the variables of application and maintenance, including actual 15-year weather ing tests of typical paints under various re painting schedules. The word "durable" as used herein refers to ability of the paint film to resist cracking, crazing, peeling, and excessive chalking, all of which have to do with the integrity of the paint film rather than the appearance of the paint. For example, a white paint on the exterior of a honse may change to a. gray color after pro longed weathering. The owner of the house may feel that the paint is not durable from the standpoint of appearance, although the integrity of the. film may be substantially unimpaired. Paints are less durable when exposed to bright sunlight, and, as would be expected, the same paint applied in a northern latitude such as Minnesota would retain its good appearance often for several years more than if applied in one of the dry southwestern States, such as Arizona, where sunlight is much more intense. Paint Composition The common ingredients of modern while paint, for application to exterior wood are rela tively few. Basically, exterior paints are a mixture of finely ground insoluble particles, called pigments, which are suspended in an oily liquid, called the vehicle. Pigments con sist of white lead, zinc oxide, titanium dioxide, and pigment extenders. Vehicles consist of raw or refined linseed oils, driers, bodied oils, and volatile thinners. By varying the amounts of these ingredients, an enormous number of paint formulas can be produced However, certain combinations of these ingredients have stood the test of time and are known to be durable. Of course, no paint can be expected to last forever and, consequently, repainting is re quired even with the most durable types of 18 paint. It is important, however, in order that the painted surface he suitable for repainting, that the paint film retain its. integrity and gradually weather or wear away by disintegra tion into fine dustlike particles (so-called "chalking") rather than by cracking, curling, or peeling. No amount of repainting wifi remedy a paint coating which has cracked. On the contrary, tests show that repainting actually aggravates the condition. Overpainting, the building up of thick coatings by many applications of paint, often produces less durability than too thin a paint coating. It is important, therefore, that paints he of the "chalking" type so as to per mit of periodic, repainting without building up too thick a coating. Otherwise the paint will have to be entirely removed at great expense if durability is to be achieved. odie Imild - no ( i ^-ii Ialso ft atej .. out \ i much iiinou v oatl I'ui i rliab und er fiickec it gaj ' usu - a-dly <i iriixt By The Pigments placed A pign To produce exterior white paints having de leeted sirable weathering characteristics, certain fun ..fungi damental relations between the ingredients mak . Idditic ing up the paint must be observed. One of the duced j most important of these is the amount of chem l.'( ted ] ically active pigments contained in the paint. The pigments in white exterior paint serve sev | i l-ydrog. -straighi eral purposes. Some, especially white lead and \ ILZ) ps zinc oxide, are chemically active; they neutral ize the acid produced by aging linseed oil which otherwise would seriously reduce the durability . 1 \ nn< e loi < ontam dicated of the paint. Others, especially titanium dioxide., have great covering power or opacity, whichis the li'ad wit paint fil ability to hide or conceal what is behind them. Others provide bulk and resistance to abrasion at low cost. They are often referred to as "ex tenders" since they reduce the amount of higherpriced lead, zinc, and titanium pigments needed. age and stead of makes r unless a These le During the past 50 yearn there has been a disappea great change in the pigments used in exterior By 19f white paint. In 1900 nearly all house painting begun tc was done with pure white-lead pigments in ran nmm dio linseed oil, White lead is still one of the most great wh . important pigments in good paint. It is prob time whi ably the most chemically active pigment ami Mioopaei by reacting chemically to neutralize the acid tliannec* decomposition products of linseed and other ''('cure op drying oils, it enables paint films exposed to the Was limit weather to retain their toughness and flexibility e\( enders for a longer period of time. White lead has *>il. Tita HOUSING RESEARCH MARCH mm er that tinting, ty and ntegrao-called curling, other desirable characteristics; it weathers by mild checking and chalking so as to facilitate normal maintenance repainting without the ne cessity for complete removal of old paint. It also makes the paint resistant to absorption of water. Tests indicate that paints made with a paint out white lead absorb up to several times as much water as those having a substantial mtrary, ;ravates amount of white lead, which tends to make them weather more rapidly. iing up >f paint, > thin a re, that to per iling up lint will expense Pure white lead paint remains one of the most reliable paints for maintaining its integrity even under rather adverse conditions but it is at tacked by hydrogen sulphide fumes, which turn it gray in contaminated industrial atmospheres, is usually more expensive, and becomes more easily soiled by dirt than most paints made with a mixture of lead, zinc, and titanium pigments. By 1920 many paint manufacturers had re placed a portion of white lead with zinc oxide. A pigment also chemically active, it is not af ving de- fected by hydrogen sulphide. Also it acts as ain fun- a fungicide to prevent the paint from mildewing. lts makle of the Addition of moderate amounts of zinc oxide pro duced a somewhat harder .paint film which col jf chemie paint. >rve sevlead and neptral- lected less dirt and grime, was less affected by hydrogen sulphide, and chalked less freely than straight white lead paints. These lead-zinc , (LZ) paints retained their dean white appear ance longer, particularly in residential areas un )il which orahility idioxide, Achisthe contaminated with industrial fumes. Tests in dicated that replacing too much of the white lead with zinc oxide results in a hard, nonelastic paint film which tends to become brittle with id them. abrasion o as"ex)f highers needed. age and weathers by cracking and curling in stead of by slight checking or chalking. This makes repainting difficult and often ineffective unless all of the old paint is first removed. These lead-zinc (LZ) paints have now almost s been a disappeared from the market. . exterior By 1930 a new pigment, titanium dioxide, had painting begun to appear in many white paints. Tita .ts in raw nium dioxide is a chemically inert pigment of the most j. great whiteness and opaqueness. Up until this t is prob- time white lead and zinc oxide provided all of nent and the opacity; they were used in larger proportions the acid than necessary for chemical activity in order to ,nd other secure opaqueness and the use of "extenders" jed to the was limited, since most of the commonly used flexibility extenders are virtually transparent in linseed lead has oil. Titanium dioxide, on the other extreme, is ESEARCH MARCH . 1953 so opaque that it may be diluted with two to three times its volume of transparent pigments and still be as opaque as the lead and zinc pig ments. The transparent pigments used for ex tenders are usually finely ground silica (sand) or some compound of silica, such as magnesium silicate (talc). They are chemically inert and are very low in cost. By substituting a mixture of titanium dioxide and these extenders for a portion of the higher-priced chemically active pigments, a considerable saving in cost of pig ments is effected and the more critical lead and zinc pigments are conserved without sacrificing opaqueness or covering power. Titanium dioxide and the silicates commonly used as extenders are chemically inert. Unlike the lead and zinc pigments they cannot be counted on to neutralize the acid products gen erated by the aging of linseed oil. When used in moderate amounts they improve the covering power of the paint and enable it to retain a clean white appearance without sacrificing du rability. It is extremely important that they be used in moderate amounts and always in com bination with sufficient amounts of chemically active pigments to neutralize the acid generated by the aging of linseed oil. Otherwise the paint will usually lack durability. By 1950 the great majority of paint manu facturers were producing titanium-lead-zinc paints for sale as their first-grade, trade-brand paints! A survey of over 60 well-known tradebrand paints in 1950 reveals that approximately 75 percent of the brands on the market were titanium-lead-zinc (TLZ) paints. Lead-zinc (LZ) paints, on the other hand, had practically disappeared from the market and accounted for only 3 percent of those surveyed. Straight white lead (L) paints accounted for approximately 6 percent of those on the market. The remaining 16 percent were the leadless, so-called fumeresistant paints, often recommended for use around industrial areas where hydrogen sul phide blackens lead pigments. This latter class contained titanium-zinc pigments (TZ). From the preceding it is apparent that while in the early part of this century lead or lead and zinc pigments furnished both chemical activity and opaqueness, in modem paints they are used for their chemical activity rather than for opac ity because opacity is obtainable much more 19 economically by using titanium dioxide and low-priced extenders. The Vehicle The vehicle for exterior house paint consists principally of drying oils; oils which oxidize and dry out to form tough elastic films when exposed to the atmosphere. The most im portant of these is linseed oil which is a veget able oil derived from flax. Other drying oils, such as sov bean oil and.tung oil, are used in varnishes but seldom in exterior house paint. Either raw linseed oil plus necessary driers or so-called boiled linseed oil, in which the driers have already been incorporated, may be used. Raw linseed oil without driers hardens too slowly. The name -`boiled" linseed oil is mis leading because the raw oil is not actually boiled but is only slightly heated in combination with driers, such as soluble compounds of lead, manganese,: and cobalt, until the driers dissolve in the warm oil to produce a slightly thickened oil which dries more rapidly. The better grades of raw linseed oil, which have been purified by treatment with acids or alkalies, are called "refined" .linseed oils. Paints having relatively large amounts of raw or boiled linseed oil are known to the paint trade as "oil rich." They are preferred for exterior paint applied to wood, since they produce a tough elastic film. When drying oils are heated to high temperature for a considerable period of time, they become thickened in consistency and are then called "bodied oils." In addition to the raw and boiled linseed oils, a portion of the vehicle may consist of bodied oils and resins. These are thick heat-treated oils or resins which require additional volatile thinners to provide workability. A moderate amount of bodied oils usually improves the application properties by making the paint flow out smoothly without leaving conspicuous brush marks. But too much bodied oil changes the paint into an enamel and makes it much more difficult to apply. When present in too great a proportion, bodied oils reduce the toughness and elasticity of the film to the point where it becomes brittle and is unable to expand and contract with the seasonal changes of the wood, so that cracking and curling of the paint result. Paints containing Jargc amounts of bodio<| oils and resins -are known as "oil-restricted'! paints and are often advertised as "enamelized,1! "quick-drying," or "resin-fortified" house paint These oil-restricted paints are midway betwee# oil-rich paints and enamels. Oil-restrictei| paints have some of the properties of enamel| and varnishes and, accordingly, would b| expected to have less durability, when expose| to the weather, than oil-rich paints. | Prior to World War II, there were only a fey brands of oil-restricted paint on the market! the best brands of paint contained only a sma| proportion of bodied oil. Oil-restricted paintf became general during the war due to a critics shortage of linseed oil. By 1948, when linsee| oil again began to be in good supply, most mail ufacturers of good paint began to increase the unbodied oil content of their first-line paints By 1950, some manufacturers had returned | oil-rich formulas, and most present-day, .firs! line paints show a trend back toward oil-riq formulas. | The balance of the vehicle is composed | thinners and driers. Volatile thinners are us<| in order to provide the proper consistency fy easy application and to reduce the thickness | film so as to increase the rate of drying. Tlf commonly used thinners are turpentine, whi| is distilled from the natural resin of pine trees and a petroleum distillate known as "miners spirits" which evaporates at about the sans rate as turpentine. Both turpentine and mi| eral spirits evaporate almost completely durii the drying period of the paint. While turpej tine was originally the favored thinner, miner spirits are entirely satisfactory and are le expensive. j To summarize, linseed oil is still the md important ingredient of the vehicle in first-graj exterior white paint. Bodied oils are usj sparingly and mineral spirits have, to a lafl extent, replaced turpentine as the volat; thinner. Research and experimentation in paint f| mulation continues, with now combinations! pigments being tried with new vehicles. Gt| methods of producing durable paints may! developed as our present knowledge is extend 20 HOUSING RESEAR* of bodied restricted" amelized," use paints. ,y between, -restricted >f enamels would be sn exposed only a few e market; lly a small ted paints a critical ten linseed most mancrease the ne paints, itumed to day, firstrd oil-rich nposed of s are used stency for lickness of ing. The. me, which ring trees, "mineral the same and min ify during le turpenr, mineral l arce less the most Srst-grade are used bo a large 5 volatile paint fornations of ss. Other s may be extended. Modern Paint Formulas There are no published industry standards which would assist the home owner and builder in selecting a durable paint, despite the fact that satisfactory paints are obtainable in most , paint stores. The home owner is usually con fused by advertising claims and the lack of information which would assist him to identify a good paint. Today's first-grade white house paints are the result of extensive and costly research on the part of the paint manufacturing industry in an endeavor to produce good paint at a reasonable cost which will perform satis factorily in a wide range of climatic conditions. In order to provide a satisfactory guide for identifying a good quality paint, 60 leading brands of open-formula, first-grade white painfc available on the market in 1950 were surveyed. As previously stated, 75 percent of these paints were titanium-lead-zinc paints. Some manu facturers offer a "fume-resistant" white paint, with titanium and zinc pigments but no lead, for use in industrial and other localities in which there may be hydrogen sulphide in the air. The formulas of the titanium-lead-zinc paints surveyed varied considerably. Formulas were averaged and the average formula is shown in table 1. Formulas of paints which have been under going actual weathering tests at Madison, Wis., for 15 years under various schedules of mainte nance repainting were compared with the aver age formula. A paint which conforms approx imately to the average industry formula for 1950 was found to be one of the more satisfac tory of those tested. The Federal Government has prepared spec ifications 1 for the procurement of white exterior paints which are known from actual experience to have good durability. One of these, Federal Specification TT-P102, contains a formula for white, exterior, ready-mixed, titanium-lead-zine paint. The formula for this paint is given in table 2, accord ing to Form A. 1 For sale by the Superintendent of Documents, XJ. Printing Office, Washington 25, D. C. Price 10 cents. Government Tablet Average TLZ paint of 1950 according to Form A Average TLZ paint of 1950 according to Form B (percent by weight) (percent by weight) Percent total paint Total pigments__ __ ___________ _______ ______62. 5 Percent pigments . White lead __ __________________ ___ ______26. 2 Zinc oxide __ .. ______ ____ __ __ _____ 2& 8 Titanium dioxide_____________ _ ______ 14. 7 Extenders________ ____ _____ 30. 3 Percent total paint Total vehicle. __ ______ _ . _____ 100. 0 __ ______37.5 Percent vehicle Baw linseed oil. _________ ___ __ _____ 52.0 Bodied linseed oil_ -------------- ______23.0 Thinner and drier ...._______ ________ _____ 25.0 100. 0 Percent total 'paint White lead_______________________ _________ Zinc oxide 18. 0 Titanium dioxide--_- 9.2 Extenders____-- --._____-- -- _____________ 16. 4 18. 9 Total pigments__________ ______________ ________ 62.5 Raw linseed oil__________ -,_________________ 19. 5 Bodied linseed oil--___ 8.7 Thinner and drier. 9. 3 Total Vehicle.__________________________________ ___ 37. 5 Paint formulas may be given in several different forms. Two' of the most common forms, which for purposes of identification are arbitrarily denoted as Form A and Form B, are given in table 1. In Form A the pigment and vehicle compositions are shown separately, while in Form B the percentages of combined pigment and vehicle (total paint) are shown for the same average first-grade titanium-lead-zine paint man ufactured in 1950. ESEARCH MARCH 1953 21 Table 2.--Federal Specification TT-P-102/ Class A Ex terior, White, Ready-Mixed, Titanium-Lead-Zinc Paint According to Form A Percent by weight Mini Maxi mum mum Percent total paint Total pigments___ _______ ____ 62 Percent pigments 31 Zinc oxide------------ ---------- - ....... 25 27 Titanium dioxide, anatase type------ 15 17 AH other pigments 1______________ 28 Matter soluble in water___________ 0.8 Percent total paint Total vehicle _ ___ __ _____ 38 Percent vehicle Bodied linseed oil -- ...----------Thinner and drier -- _ ------------- 60 16 20 20 i The other pigments shall be magnesium silicate, aluminum silicate, silica, or any mixture thereof. A comparison of the average formula of firstquality trade brand titanium-lead-zinc white paints as shown ini Forni A of table 1 with Fed eral Specification TT-P-102 as shown in table 2 reveals that they are quite similar in many respects. Pigment contents are 62 and 62.5 percent, respectively; chemically active lead and zinc pigments are 55 and 56 percent, respectively; and totals of raw plus bodied oils are 75 and 76 percent, respectively. Principal differences are in the ratio of lead to zinc and raw to bodied oils and in proportions of pigment extenders and thinTiers. These do not appear to be great enough to have much effect on satisfactory performance of the paints. It should be kept in mind that the formula shown in table 1 is the average for first-quality industry paints and that the first-quality paint of many producers is in even closer agreement with the Federal Specification cited. It may, accordingly, be safely concluded that exterior white paint having a formula that falls within the range of values between those in table 1 and those in table 2 would be expected to provide a durable paint which weathers by 22 chalking mildly so as to facilitate maintenance repainting without costly removal of the old paint. These paints are sometimes advertised as "self-cleaning" since the weather-stained outer particles chalk off and expose white unstained particles beneath, thereby maintain ing a clean appearance. Federal Specification TT--P-103 covers white, exterior, ready-mixed, titanium-zinc paint, a lead-free paint which is recommended for in dustrial and other areas where hydrogen sul phide would cause white lead to turn gray. The formula for this so-called fume-resistant paint is given in table 3, according to Form A- For industrial areas where it is customary to use a lead-free fume-resistant paint, a paint similar in formula to that shown in table 3 would be expected to give good service. Federal Specification TT-P-104 covers white, exterior, ready-mixed white lead paint, the formula for which is given in table 4. Where integrity of film rather than a clean white appearance is desirable, white lead paint similar in formula to that shown in table 4 Table 3.--Federal Specification TT-P-103; Exterior White, Fume-Resistant, Ready-Mixed, Titanium-Zinc Paint Ac cording to Form A Percent by weight Mini Maxi mum mum Percent total paint Total pigments-- _______________ 59 Percent pigments Titanium dioxide, anatase 38 19 9. 5 "'"as 43 Percent total paint 41 Percent vehicle Raw or refined linseed oil__ , 50 Bodied linseed oil _ ____ ______ 20 Thinner and drier ___ _____ 26 24 i Other pigments shall be magnesium silicate, aluminum silicate, silica, or any mixture thereof. Calcium sulphate in an amount (maxi mum 22 percent) corresponding to the extender portion of the rutile titanium calcium pigment used will be permitted. HOUSING RESEARCH Table 4.--Federal Specification TT-P-104, Exterior White, Ready-Mixed, White Lead and Oil Paint According to Form A Percent by weight Mini Maxi mum mum Percent total paint Total pigments------------------------------------- Percent pigment Basie carbonate white lead_____ . Matter soluble in water___________ Percent total paint Total vehicle -- __ - _ ----------- ------ Percent vehicle Linseed oil-------- -------------------Thinner and drier --- - ------------- 71 73 99 0. 8 27 29 70 75 25 30 TT~P-25a is shown in table 5. Similar primers are available at paint stores and are recom mended for specific use with trade-brand paints. Where fume-resistant titanium-zinc paint is to be applied, a lead-free primer is made by adding 1 pint of linseed oil to a gallon of the finish coat paint (table 3) and up to 1 pint of turpentine or mineral spirits to increase work ability and penetration into the wood surface. A primer for use with straight white lead paint is also made by adding 1 pint of linseed oil to a gallon of the finish coat paint. Table 5.--Federal Specification TT-P-25a,- Exterior Primer, Ready-Mixed, White Percent by weight Mini- Maxi mum mum would be expected to give good service, espe cially in clean residential atmospheres. Priming Paint A special priming paint is generally recom mended by manufacturers for the first coat on new wood or where; well-weathered old paint is to be repainted. 'It is important that the primer and the finish coats be compatible. A primer produced by one manufacturer should ordinarily not he used with the finish paint of a different manufacturer, since formulas may be different and the oils in the two paints may react adversely and cause poor adhesion of the finish coats to the primer. Zinc-free primers are usually preferred except for fume-resistant paint (table 3) because their adhesion to the wood is usually better. When it is impossible to get a recommended primer, a substitute primer can be made by adding 1 pint of linseed oil to 1 gallon of the finish coat paint in order to compensate for the oil which will be 'absorbed by the wood. It is also customary to slightly thin such a primer with not to exceed 1 pint of thinner per gallon to increase workability and penetration into the wood surface. Either turpentine or mineral spirits may be used for thinner. For guidance fn selecting a priming coat for titaniumJead-zinc paint, Federal Specification Percent total paint Total pigments-_____________________ 62 Percent pigments Total white lead____ - _______ 50 Basie carbonate white lead____ 25 Basic sulphate white lead ___ Titanium dioxide (nonchalking ru tile type)_______________ ____ 12 Extenders 1____________________ 38 Matter soluble in water_____ 0. 8 Percent total paint Total vehicle___ ________ _ ________ 38 Percent vehicle Raw linseed oil- _______________ Bodied linseed oil________ Resin (pale eoumarone or ester gum)._ __ _ _____ __________ Thinner and drier. - ______ ... __ 32 32 4 32 i Extenders shall be white siliceous mineral pigment types of mag nesium. silicate, aluminum silicate, and silica. Guides (or Selecting Good Paints Armed with this information, builders and home owners should be able to provide them selves with exterior white paints with good performance characteristics if they will take the following steps: 1. Buy or specify only paint that carries the formula printed on the container label. 2. When a titanium-]ead-izinc exterior white paint is desired, examine the formula on the label and he sure that : MARCH > 1953 237538--53--------i 23 (ct) Total chemically active, pigments (lead plus zinc) are not less than 55 percent of the pigments (34 percent of the total paint) by weight. (6) White lead is 25 to 35 percent of the pigment (16 to 22 percent of the total paint) by weight. _ (c) Zinc oxide is 25 to 30 percent of the pigment (16 to 19 percent of the total paint) by weight. .. id) Pigment extenders (silicates) are not rnore than three times the titanium dioxide, by weight. (e) Drying oils (bodied plus unbodied) are not less than 75 percent of the vehicle (28 percent of the total paint) by weight. if) Bodied oils are not more than 25 per- cent of the vehicle (10 percent of the total paint) by weight. 3. When a good fume-resistant exterior white paint is required, for use in industrial or other areas contaminated by hydrogen sulphide, ex- amine the formula and select one which is similar to that given in table 3. 4. When a straight white-lead exterior white paint, is desired, the formula should be similar to that shown in table 4. ,5. Select priming paint for titanium-leacl- zinc which the manufacturer recommends for use with his finish paint. The formula given in table 5 may be used as a guide. For titaniuru zone (fume-resistant) and straight white-lead paints, add linseed oil, in accordance with manufacturer's recommendations (usually 1 pint of linseed oil to 1 gallon of paint) to the finish paint to produce a primer, g. Owners or builders specifying paint in contracts should specify the formula. Specify- ing only the brand hame is not sufficient, since most paint manufacturers make various grades and types of paints. There should be no "or equal" provision in the specification, because that phrase is meaningless in view of the lack'of commercial standards for paints. Inspections Plate 1.--Durable Paint Will Not Correct Construction Defects Note wood siding badly rotted out around a window opening which was improper ly Flashed. A durable paint was applied to this house 4 years before: the picture was taken. The paint is still sound even on the boards which have totted. 24 HOUSING RESEARCH IS te ar idfor in rn- sad 1U- of ish in tfynce des "or use vof ons d*CH Plate II.--Blistering Caused by Condensation Water-filled blisters which form during the spring thaw are usually caused by condensation of moisture which originates as water vapor within the house and migrates in the form of vapor into the cold cavities between the studs, where it condenses on sheathing or siding. Usually more pronounced on north side of house. Seldom' found on unheated porch walls or garages. Photo shows blisters which formed in early March on the north wall of a test building, in Pennsylvania, which had been painted with three coats of titanium-lead-zinc paint. Blistering was caused by high humidity within the building plus an ineffective vapor barrier and was not the fault of the paint. should be made to see that the paint specified is actually used on the job. Other Precautions The mere selection of a durable type of paint, of course, will not insure a satisfactory or dur able paint job. Even the best paint will not be durable where precautions are not taken to keep water from getting behind it. Plate I shows wood badly rotted out around a window opening due to omission of flashing over the opening. A durable paint was applied to this house 4 years before the photograph was taken MARCH 1953 and is still sound even on the boards which have rotted. Siding on an improperly constructed house may also become soaked with water due to condensation2 of water vapor originating within the house, basement, or crawl space. This may cause blistering of the paint as shown in plate II. Conversely, improperly formulated paints would not be expected to be durable even when applied to a house which is properly constructed to keep the wood dry. 2 See HHFA Publications, Condensation Control in Dwelling Construc tion, August 1949, 20 cents; Technical Reprint No. 1, Crawl Spaces, February 1950,15 cents. For sale by the Superintendent of Documents, U. S. Government Printing Office, Washington 25, D. C. 25 FLB 0011 Plate III.--Effect of Condensation on Paint This photograph of attached dwelling units, in southern Illinois, illustrates the effect of severe condensation on exterior paint. Wall is pockmarked with bare spots where blisters have broken and paint has peeled off. The paint on the upper portion under the eave is stained by mildew. The wall had no vapor barrier. Even the best paint will not be durable unless excessive condensation is controlled; | f Causes of Nandurabifity When the home owner has had trouble with the previous paint he should examine it carefully before repainting, to determine whether it was caused by moisture behind the paint or whether the paint, itself, was at fault. If the paint developed water-filled blisters during the spring thawing season after a severe winter, the lack of durability may be due to condensation. Where such is the ease, no amount of repainting even with the most durable type of paint will remedy the situation. The cause of the mois ture should first be corrected by applying a continuous vapor barrier on the interior face of the exterior walls or by elimination of exces sive moisture in the basement or crawl space. Blistering due to condensation is usually most pronounced on the cold north wall of the house and leaves the wall pockmarked with bare spots which may be round, oval, or elongated in the direction of the grain as shown in plate ' III. Where blistering is due to condensation, it usually occurs only on the exterior walls of heated rooms, seldom on unheated garages or >: open porches. On the other handy cracking, scaling, and peeling, or excessive chalking of the paint with no evidence of blistering indicates that an improperly formulated nondurable paint has been used. It Is usually more pronounced on i the south side of the house where it is subjected to the direct rays of the sun and occurs equally ;, on unheated and heated portions of ilic liouvp, indicating that it, is not due to condensation. Plate IV illustrates cracking and peeling on both the heated wall and the unhealed porch ' gable approximately 18 months after the paint > was applied. Plate V shows a home on which paint is chalking badly on both the house and '; the unheated garage after a short service life. ' 26 HOUSING RESEARCH MARC 1 FLB 001172 Plate IV.--An Example of Nondurable Paint Note cracking and peeling on both the heated wall of the house and also on the unheated porch gable indicating that a short-lived nondurable paint was applied. The house was repainted approximately 18 months before the picture was taken. Complete removal of the old paint is recommended before repainting. ndensation , peeled off. . Even the shown in plats condensation, terior walls of ted garages or scaling, and the' paint with cates that an tble paint has pronounced on s it is subjected . occurs equally is of the house, ) condensation, and peeling on unhcated porch after the paint home on which 1 the house and Lort service life. NG RESEARCH Plate V.--An Example of Excessive Chalking Paint on this home has eroded by excessive chalking after a short service life. Note that the paint has chalked off the unheated garage as well as the heated walls of the house. This indicates that an improperly formulated; paint has been used. If the cause had been excessive condensation, the paint on the unheated garage would not have been affected. Complete removal of the old paint will be necessary to insure durability of future paint coats. MARCH 1953 27 FLB 0011 s Plate VI.--An Example of Over-Painting This 25-year-old house had been painted so frequently that an excessively thick coating had been built up, as evidenced by cross-grain cracking. When an additional coat of paint was applied, blisters formed. Wood was found to be dry. The cause of the blisters was found to be due to chemical attack by the new paint on one of the oldest layers of paint, not to condensation. The indications arc that improperly formulated paints have been used of the type known to the trade as competitive paints which are manufactured down to a price in order to meet competition rather than up to a durable standard of quality. It is, of course, sometimes difficult to deter-' mine whether lack of durability is due to improperly formulated paint, excessive con densation, or a combination of both. When the lack of durability has been identified as improperly formulated paint, it is necessary to completely remove the old paint and start over again, or the repaint job usually wall not be durable. Building up thick coatings of paint by frequent repainting usually only aggravates the cracking and peeling, even when good paint is used, and may result in blistering as shown in plate VI. Where early removal of a cracked and peeling paint job is too difficult, it is usually better practice to endure the unsightly appearance until its removal becomes easier. Repainting should not he necessary more frequently than 4 yeai-s in southern climates, or 6 or more years in northern climates . where sunlight is less intense. Plate VII shows clearly the effect of too frequent repainting. j'f j 11 Weather Conditions The surface of the wood should be dry. Finish lumber or siding should preferably be kiln dried. If the. lumber or finish has become wet, at least 1 week of dry sunny weather should precede the painting. It is best not to apply paint in cold, foggy, or damp weather. The surface should be free of dew or frost and painting should not be done when the temperature is turP ^rolT ^les below 50 . Summer or early fall, wb en the wood is thoroughly dry, is the preferable time to repaint. Preparation of New Wood Surface Pam used entii base All pitch should be scraped or burned fromi ^eve knots and these places should be scrubbed withl it to 28 HOUSING RESEARCH? MA FLB 00117 Plate VII.--Showing Results of Too Frequent Repainting Results after 15 years of maintenance painting. Both the 18- by 22-inch upper panels were originally given a priming coat and then painted with two additional coats of titanium-lead-zinc paint. The panel on the left was subsequently given two coats of the same paint every 2 years and photographed at the end of 15-year exposure. The panel at the right was given two coats of the same titanium-lead-zinc paint every 5 years and photographed at the end ofl 5-year exposure. Panels 98S and112Sare closeup views of portions of the panels directly above them 1% by 2% inches in size showing details of condition of the paint. The panels were con structed of southern yellow pine and Douglas fir and faced south at Madison, Wis. turpentine prior to painting. To prevent paint from peeling or being discolored over knots, these are often spot primed a day or two in advance of applying the first or priming coat of paint. Shellac and aluminum paints have been used for sealing knots but neither has proven entirely satisfactory. A new synthetic resin base knot sealer, known as formula WP578, was developed a fow years ago for sealing knots in Western pines and firs, and tests to date indicate it to be effective. Tho formula for this knot MARCH 1953 sealer is shown in table 6. It is produced and recommended by a number of paint manufac turers and is available at most paint stores. Knots should be scaled before the priming paint is applied. Table 6.--WP578 Knot Sealer Percent by weight Phenol-aldehyde resin spirit varnish- _ . . 33)4 Polyvinyl butyral resin. . .________________ _ _ 3}i Denatured alcohol (ethyl)_____ . _ . .... ......... 63)4 100 29 FLB 0011 Application of Priming Coat The first or priming coat of paint should be thoroughly brushed and cross-brushed so that cracks and nail holes receive enough paint to wet the surfaces. The prime coat should be allowed to dry for several days, following which nail holes and cracks should be puttied. Drying Time Between Coats In dear warm weather, 2 or 3 days is sufficient (hying time between coats. A longer time is required in cold or damp weather. Paint should not be applied over preceding coats which are not hard and dry. Drying time should not be unduly long between coats, however--seldom more than 2 weeks. Unduly long drying time between, coats can be as harmful as insufficient drying time. Repainting The procedure for repainting depends on the condition of the old paint. Where the paint is cracked and peeling, or where heavy coatings have been built up by previous repainting and have checked badly, it is recommended that ah the old paint be removed either by burning it off with a torch or by the Use of paint remover. The recommended procedure for repainting is then the same as that given above for new wood. Where the old paint has weathered by chalk ing off, ail loose paint should be removed by wire brushing or scraping. Following wire brushing and scraping the surface should be sanded with No. 1% or No. 2 garnet paper to further insure the removal of loosely adhering paint. Number of Coats For previously unpainted wood, or wood from which all the old paint has been removed, three coats are usually applied. The priming coat is spread to cover approximately 600 square feet. This is followed by a second coat which is usually thinned, in accordance with manufacturers' recommendations, with not more than 1 pint of thinner per gallon of paint and spread to cover approximately 800 square feet. The third and final coat is applied without ihinni ng at the rate of approximately 700 square feet per gallon. For.repaxnting, where the old paint was of a durable type which has become well-weathered by crumbling, flaking, or gradual chalking off, two coats are usually applied. The first coat may be either a regular priming paint, or a substitute primer made by adding 1 pint of lin seed oil to the finish paint to compensate for oil which will be absorbed by the old surface. The priming coat is applied in the same manner as for new wood, at a spreading rate of 450 square feet per gallon, and the finish coat is applied without thinning and spread to cover approximately 700 square feet per gallon. Where the old paint is in good condition and shows only fine checks or mild chalking, a onecoat repainting job is recommended in order to avoid building up a thick coating. The prime coat is omitted and a thicker film is applied without thinning at a rate of 600 square feet or less per gallon in order to achieve complete coverage with one coat. As previously stated, the building up of thick paint films by frequent repainting should he avoided, because thick films are prone to crack and curl and eventually will have to be completely removed at great expense in order to eliminate this trouble. Before repainting, the home owner should allow sufficient time, for a large portion of the paint to chalk off. Present day titanium-lead-zinc paints are de signed to maintain a clean white appearance in ordinary dean, residential atmosphere, even ..though the paint has weathered almost down to the wood. It is better to err on the side of too infrequent repainting than to overpaint, and it is much less costly. The original clean white appearance can often be restored by simply washing the paint to remove the sur face grime. Mere unsightliness which can be corrected by cleaning should rarely be con sidered sufficient reason for repainting Until the coating has become well worn. Conclusions The success of a painting job depends prin cipally on the following factors: 1. Selection of a durable type paint which weathers by chalking mildly. 2. Maintenance of dry wood beneath the paint by controlling condensation and prevent ing rainwater from getting behind the siding and trim. 3. Selection of favorable painting weather. 30 h o u s in g :r e s e a r c h tanner of 450 ;oat is cover 4. Proper preparation of the surface to receive quality described herein and should inspect the the paint. operations of the subcontractor to make sure 5. Proper application at not too frequent that the paint specified is actually used on the intervals. job. Competitive paints, which are formulated Authorities are in agreement that shopping down to a price instead of up to a minimum stand around for paint bargains, at the expense of ard of quality, should be avoided both by the quality, is false economy. Builders should re builder in the original paint job on the house | quire painting subcontractors to furnish open and by the homeowner when repainting is formula paints of at least the standard of necessary. on and a onerder to prime ipplied feet or mplete up of should rone to e to be n order ainting, at time alk off. are deiearance re, teven 3t down 3 side of rerpaint, lal clean ored by the sur0 cam be be conuntil the I\ j ,, "- 5 -f ? : \" ads prin- nt which .eath the prevent,he siding reather. ESEARCH MARCH * 1953 287088--53--------5 31 FLB 00117 PAGE 6, SECTION 2 .WISCONSIN STATF jniiPNAl. SUNDAY. MARCH 7 Repaint at Longer fnteFv^TxperfrAcfv/se Tests Prove The OrTEaf MAX CA^SS- ^RpqBUi ^ JOHN NBWHODSE 5 /i(*I'to'sitbaepennmd<i2sc"oovvoiet*reendibtahfac tnpaial;int A typical white lead paint, as (State Journal Staff Writer! has a "grain" which is deter determined by federal specifica Kepaint your house nore often mined hy the direction of the tion, calls for at least 71 per bent than once in every six years, last.stroke of the brush and which of the weight of the paint to be and you may be in for trouble. thus usually follows the grain in white lead pigment and 29 per hat's th word froir the For the wood.) cent vehiele. Of the vehicle, at est Products Laboratory, now But, with the paint, piling up least 70 per cent must be linseed that the results of a 15-year ex with repainting, the paint crack oil. periment are in. The too frequent repaintings they have found, result in too thick a coat of paint on your house. This thick coat of paint is subject to what they call ed across the grain, giving the .-ignal for removing rho paint and starting out all over again. Most satisfactory of the 12 The federal specifications gov erning titanium--lead-zinc paint calls for 62 per cent of pigment and 38 per cent vehicle.; Of the paints tested, in terms of long--P->gnient, there must be a mini* cross grain cracking. In cross grain cracking, range economy, was the standard mum of 31 per eent white lead, the white lead paint, said the labor- from 25 to 27 per cant zineoxide, cracks will rather- than the siding- run vertically to, horizontally with, latory. "Even When it appears, it Painting under the heaviest re- and '15 to 17 per cent titanium schedule -- two coats dioxide. The vehicle must contain means that whole pieces of the every two years -- it stood up paint are going to come off soon without cross-grain cracking for ---perhaps from the weight of 10 years," said Dr. Browne. the.next coat of paint alone. With two coats each six years. To be safe, there's nothing to it stood up the entire 15 years, 60 per cent of raw or refined lin seed oil: 16 to 20 per cent -of bodied linseed oil, and a 20 per cent maximum oE thinner and drier. do -but remove the paint--and Without trouble. And it'took a Paint in the Fall that is much more expensive and time consuming, than any single painting job--and stavt painting all over again. In their experiment, Drs. F. L. Browne and D. F. Laughnan, of the laboratory, tried out 12 paints over the 15 year period. And they found that--in terms Of long time economy--ujhite lead was the most satisfactory, though , not the cheapest nor coat every three years and two Late summer or early fall is every five without well." trouble a the best time for painting, says the laboratory, A time when the Paint `Dusts' What it means, said tory man, is that the paint crumbles away Off the labors-, white lead at a rate temperature is hovering in the 70's is best. At least a week should have passed since the last rain, and the old paint and wood which permits repainting at sixyear intervals--possibly foi' the entire life of the house--wilhou' having to remove the old paint. "Perhaps the most widely user should be thoroughly dry. First step is to clean off ail loose paint .with putty knife or scraper. Sandpaper rough edges. two,necessarily the best for bright ness or for hiding qualifies. Tempted to Repaint The temptation is to repaint when the first paint job loses its luster, and may even be crack ing and crumbling here and there, say Drs. Browne and Laughnan. The obvious answer to the problem is, of course, to re paint, at longer intervals. So, to determine what the interval should be, they set up a test fence and painted panels with first grade paints today," says; an article by Fred Strehge to a recent issue of Science and Me chanics magazine, "are formula tions of white lead, titanium di oxide, and zinc oxide. "The titanium-dioxide, lead' zinc paint tested did not resist cross grain cracking as- well as the white lead paint. In fact, even with the minimum of coats each six' years, it showed cross grain cracking by the time it was 15 years.old. "The best of the lead-zinc and prime the bare wood. If you're using a white lead paint, add linseed oil to it at the" rate of one pint to the gallon and its suitable for use as a primer,, too. Otherwise use the commercial primers for the type of paint you're using. The new paint should go on at the rate of 700 feet to the gallon. If you're a beginner, you'll prob ably get it on too thin. So mark off a space 10 feet square and, if it takes a little more titan;a pint the two 12 paints at intervals from coats every two years to two I paints tested took a coat I five years and two coats every every of paint, you're getting it on at the right thickness. coats every six years. Four of the paints used tell the story pretty well, as far as to day's most widely used paints are concerned: a typical white lead paint; a lead-zinc paint; a titanium - lead zinc paint, and a titanium zinc paint. jsix years without showing cross -grain cracking at the end of the IB years, but any heavier repaint ing schedule brought trouble within the test period, "The titanium-zinc rreemmaaiinneedrt free from cross grain cracking when repainted with two coats If you plan two coats, let a week elapse between coats. And then, says the' labor gto.r'' i| don't expect it to stay as bright as HI*t'lsoogkoetdtow.hw..e--ena-tty--hoeur -foiurfst t~apjoutt iutnotnil. it's wise to repaint. Since some woods hold paint better than others, four species each six years." . ,I Of wood were used on the fence Though white lead paint held I to represent siding -- Douglas the edge, the laboratory points : fir, southern yellow pine, eastern out that the other paints had ad white pine, and western cedar. vantages of their own, over the - Generally' speaking,- the white more expensive white lead, and cedar tend to hold paint "Ip general," said the labora ir because the annual growth tory, "these pigments dry to a imgs aic liano'cer and have lehsasirier- film than white lead and of the hard summeiwuod -- Hthieey lend to shed dirt more read -Jow-Eiowing, dark part of eaiclyh. Titanium dioxide has several nroivmg ring- horn which thtiemes as much hiding power as Odinl weal he: s la-ilci either white lead or, zinc oxide, \t fust tlit \dthcimg was and a, a luio is a brighter white about ivhdi coil'd expeit, witn than the white lead paint." the paint' medians dov it ei'her Be sure to watch the label by checking and r nimbi mg o'- by when you buy paints, the labora < rack nf md Hiking The ciotic- tory says. Most manufacturers winch go only part wav through 1 have first duality paints, hut llm film ot pirn and the n at to, I make us well competitive lines i N41698.66 FLB 0011 $WiM~WUi itb, j Clear Finishes For Exteriors Of Houses By F. L. Browne, Chemist, Forest Products Laboratory, U. S. Department Of Agriculture Madison, Wis. DURING the early colonial period in America the exteriors of wood the mountains, where precipitation is chiefly in the form of snow, the brown houses were neither painted nor fin color may persist indefinitely but at ished in any other way. The wood was lower elevations, where there is rain, simply allowed to weather naturally. all woods eventually become gray in Later on, when the materials were color. (2) Some woods take on a lus available and painting became socially trous, silvery gray but others turn to acceptable, most of the colonial houses a dull, darker gray. in towns and cities were painted. In Weathering soon roughens smooth New England at least two houses built wood surfaces. First the grain becomes as early as 1636 still stand and are raised; that is, the hard bands of sum- still unpainted, the Hartwell Farms merwood form ridges. Then minute house at Arlington and the Fairbanks checks or cracks begin to appear and House at Dedham, Mass.di Allowing steadily increase in number and size exterior wood to weather naturally until the surface becomes decidedly has been frequent practice ever since. rough and the fibrous structure of the Sometimes it is done for economy, as exposed wood is greatly loosened. i in the communally owned villages of Finally, the wood substance erodes the Amana Society in Iowa from 1858 away very slowly and the hoards be to 1932, and sometimes for an archi come thinner at a rate of approxi tectural effect that may be peculiarly mately Vi inch a century. appropriate in special cases, such as Another result of the weathering the Pilot -Butte Inn at Bend, Calif., and process is a tendency for boards to other buildings of much pretension. cup, warp, and pull at their fastenings. When smoothly surfaced wood is al Boards thin in proportion to their lowed to; weather naturally, it changes width are more seriously affected than materially in appearance for a few thicker and narrower boards. To stand months or years. Thereafter it stays weathering well, boards should be no nearly unaltered for a long time. Tlie more than eight times as wide as they color is affected very soon. Woods like are thick and they should be nailed in redwood and redeedar, which owe their place especially firmly with corrosion- strong color to substances soluble in resistant nails. water, may first become bleached. Although unprotected exterior wood Woods of lighter color, such as pine work is practicable, economical, and at and spruce, may first become brown tractive for a limited number of pur from the action of sunlight. High in poses, it has too many shortcomings to become a popular choice for build j The fourth in the series of lec tures at the Paint Technology ings 'of prideful occupancy. As a rule we are unwilling to part with the Course at the Illinois Institute of Technology, held last fall under smooth, flat surface, straight lines .1 the supervision of C. W. Selheimer, and snug, well-fitted joints of newly Professor, Department of Chemical Engineering.--Editor. erected woodwork, and we are not con- WHITED STATES DEPARTMENT OF AGRICULTURE N41698.67 FLB 001 tent to be confined to a gray color. fibers near the exposed surfaces. The Moreover, the transition from, initially moistened fibers try to swell but are bright wood to Ihe weathered gray restrained by the fibers more distant color takes place slowly during a num from the surface, which are still dry. ber of months and proceeds unevenly The moistened fibers, now under com over a house because the sheltered pressive stress, become distorted in areas change much more slowly than shape; the cavities within the fibers the fully exposed areas. are narrowed and the hoard becomes With increasing prosperity and re slightly thicker. When the rain passes, laxation of the rigorous social re the moistened fibers dry out again; but straints of the Puritans, painting grad by reason of the distortion they ex ually became customary in the colonies, perienced while plasticized by moisture, first among the wealthier merchants they now strive to shrink to something and crown officials and later among less than the width they had at the be the rest of the citizens. Since oil paint ginning. Thus, a surface layer of the remained an imported luxury until board is left in tension and sufficient after the Revolution, most of the early repetitions of the wetting and drying painting was probably done with white cycle may result in cupping, warping, wash and the closely related red iron or cracking. oxide water paint that is still widely These developments can be prevented used for farm buildings in Scandi by the action of a protective coating navian countries. Readers of Mark on the exposed surfaces in retarding Twain's "Tom Sawyer" are aware that the absorption of moisture by the wood whitewash was still popular for ex fibers near the surface sufficiently to terior wood in the middle of the last allow the moisture that gets through century. Water paints such as white to diffuse through the wood enough to wash, which are economical only when avoid any serious differences in mois labor is cheap, provided variety of color ture content within the hoard. When but did not prevent the other develop so protected, all of the wood in a board ments of wood weathering, surface remains nearly constant in moisture roughening, and tendency to cup and content if the cycles of wetting and warp. drying occur at short intervals of time The protective power against weath and, if the cycles occur over long inter ering of the oil paints, varnishes, and vals, all of the wood keeps nearly in 3r.-.. sealers comes from their ability to re step as the moisture content and di tard the rate at which moisture from mensions change slowly from minimum rain or high humidity can penetrate to maximum and back. In either case,- into wood and dry out again after the internal stresses are avoided and the] weather changes(3). None of .the pro phenomena of weathering do not set in. tective coatings is impermeable to No doubt the use of protective coat moisture; in fact, they all absorb water ings on wood became general in the and swell, many of them to a much Colonies on the hulls and spars of ships greater extent than wood does (4). But before it did on houses, because ships i water penetrates protective coatings were the life blood of the economy ol less rapidly than it does wood. -Thus, the times. We get the terms "spar'1 the wood is protected against great varnish and "naval stores" (for rosiij inequalities in moisture content and the and turpentine) from this period, internal stresses generated by unequal clear* coating suoh as varnish, rathe] moisture content. than paint, was required to permit con When wpod boards are exposed to stant inspection of the wood for firt the weather unprotected, each rain signs of failure under stress or onse storm quickly wets a thin layer of wood of decay, in order that replacemer FLB 001 Lbers near the exposed surfaces, The noistened fibers try to swell but are ; estrained by the fibers more distant rom the surface, which are still dry. The moistened fibers, now under comjressive stress, become distorted in ihape; the cavities within the fibers j ire narrowed and the board becomes slightly thicker. When the rain passes, f ,he moistened fibers dry out again; but yy reason of the distortion they ex perienced while plasticized by moisture, :hey now strive to shrink to something less than the width they had at the be ginning. Thus, a surface layer of the board is left in tension and sufficient repetitions of the wetting and drying cycle may result in cupping, warping, or cracking. These developments can be prevented by the action of a protective coating on the exposed surfaces in retarding the absorption of moisture by the. wood fibers near the surface sufficiently to allow the moisture that gets through to diffuse through the wood enough to epuld be made before thei'e was dis astrous failure in an emergency. More over, skips, which were economically productive and carried a supply of Jabor that was not fully occupied at *11 times, could bear the expense of frequent renewal "of varnish. Houses and farm buildings, which were other wise circumstanced, required much more lasting coatings, when protective coatings came into such use. House paints made with opaque pig ments in linseed oil had the necessary durability and were appropriate for smoothly surfaced woodwork such as newly erected siding and trim. Rough wood, such as the sawed surfaces of rough lumber and wood that has be come weathered, consume excessive amounts of paint and to many there is something incongruous about coating them with glossy house paint. Well pigmented oil stains, however, make appropriate and durable semi-opaque coatings for rough wood surfaces; such stains have long enjoyed wide use on jobs of general repainting may suffice. But in recent years a demand has arisen for clear finishes on major ex terior surfaces of houses, particularly siding, which are fully exposed to the weather unless the house is well shaded by trees<5). The demand comes in part from a desire to retain the attractive red color of some woods, such as red wood and redcedar, or the interesting patterns of knots in common grades of lumber or the so-called peeks of heart rot in some species; in part from the desire for radical departure from past Custom expressed in the popular ranch type house and other modernistic de signs; and perhaps in part from the desire to get away from the plague of abnormally early failures of house paints that has been troubling us for many years. At any rate the demand did not arise from any planned mer chandising on the part of the paint industry; on the contrary it caught the paint industry unprepared. avoid any serious differences in mois wood shingles and are therefore com Natural Finishes Less Durable ture content within the board. When monly called shingle stains. The most important point to remem so protected, all of the wood in a board remains nearly constant in moisture Clear Finishes Seldom Used content if the cycles of wetting and Until the last fifteen years or so, drying occur at short intervals Of time i varnish or other clear, unpigmented and, if the cycles occur over long inter- *prot--e--c--t-i-v-e fin-i-s--h- ---was seldom uiwseud won vals, all of the wood keeps nearly in major extenor wood surfaces of houses step as the moisture content and di- were fully exposed to the weather, mensions change slowly from minimum { ""t varnish finishes have long been to maximum and hack. In either case,; ased on minor exterior surfaces, such internal stresses are avoided and the - B's front doors, where they were phenomena of weathering do not set in. nearly always at least partly projected Ito doubt the use of protective coat- against sun and rain by a porch roof, ings on wood, became general in the a sheltering overhang of some kind Colonies on the hulls and spars of ships; over the door, by deep indentation of before it did on houses, because ships; the door in the wall, or by a protective were tmhee lmifee buliououdu o<jif. the_ 1 +s ecic-ouniioymju"yj o__f_fI__f_l'_y___s_' _c-re__e--n ^fo__r VsUu4m4Um.iieytr cauntdu OstboVrAmUl mdojyoi-r the. iti m___e__s. ,WT,e.. get the terms "sparr""!ffnoi'rMw/iTinltPteT*r. When sC!ut fFfPfiirctiiPeTnlttly sh-e.1l4t-ered varnish and "naval stores" (for rosin from sun and rain, clear finishes mav and turpentine) from this period. Algo as long before needing renewal as clear coating such as varnish, ratherstfte intervals between repaintinss of than paint, was required to permit con-;the house paint on the fullv exnoJ.,) stant inspection of the wood for first woodwork; or, if the natural fbfiS ber about natural finishes for house exteriors is that they are far less durable and require far more care in maintenance than good house paint or shingle stain. On the parts of houses fully exposed to sun and rain, renewal of natural finish twice a year for the first 2 or 3 years and annually there after may be necessary. If the prop erty is thoughtfully landscaped, enough shade may eventually be obtained from trees to prolong the life of a natural finish so that renewal every 2 years may suffice but it is unwise to promise intervals longer than 2 years. Thus a natural finish may be practicable for a house owner of average income who expects to apply the finish himself, but it may prove too expensive for one who expects to hire painters to do the work. Some of the characteristics often signs of failure under stress or onset are partly protected, one extra renewal of decay, in order that replacement^ these easily accessible areas between asked of natural finishes are quite be yond the possibility of realization in our present state of knowledge. For k- $| FLB 00118 3 example, some inquirers ask for a pro tective finish that will keep the appar ent color of the raw wood as it comes from the lumber yard entirely un changed and will not add any gloss or luster whatever to the originally gloss less surface. That cannot he done short' of some as yet totally unforeseen process for rendering lignin and cellu lose waterproof without altering the wood structure, depositing anything in the cell cavities, or extracting any sup plementary ingredients from the wood. For the initial color of raw wood is analagous to the color of a tinted house paint after it has faded; that is, it is a structural color that depends upon the existence of many air-solid inter faces With high reflective power for light limiting the average depth to which light penetrates the surface be fore it is reflected back to the eye. As soon as part or all of the air in the wood cavities near the surface is dis placed with a solid or liquid, which necessarily has a refractive index for light much higher than that of air, the optical system is changed, light penetrates deeper into the wood sur face before it is reflected back to the eye, more wood has a chance to absorb light selectively, and the color of the wood appears to be darker. Any protective finish necessarily dis places some of the air in the wood near the surface and therefore seems to darken the color of the wood even if the finishing material itself is entirely colorless. What actually happens is that the finish reveals more nearly the true color of the wood. At the same time replacement of some of the air near the wood surface is bound to raise the gloss level at least Slightly(6). Different clear finishes, quite apart from any inherent color of their own, vary greatly in the extent to which they bring out the true color of wood. Those finishes that penetrate deepest darken wood most. Thus raw linseed oil darkens wood more than does a varnish, even though the varnish itself is usually darker in color than the oil. A so-called penetrating wood sealer, the nonvolatile portion of which is cus tomarily more highly bodied than that of a spar varnish, may darken wood less than varnish does, and a fast-dry ing spirit varnish or a nitrocellulose lac quer may seem to darken it least of all. The extent to which the materials penetrate wood in the time that it takes for them to harden thoroughly stands in the same order as their abil ity to darken the apparent color of the wood. Changes In Color Take Place Besides the initial change in appar ent color brought about, by application of a clear finish, further changes in color take place over a period of time. One change comes from the action of light, especially of the ultraviolet light in sunshine, on colored substances in the wood itself. Most woods darken toward brown in color. A few, chiefly exotic species of especially strong color to begin with, turn lighter in color. The change in color goes on more rapidly the stronger the illumination and the higher the proportion of ultraviolet in the light. The change in color can be retarded by including in the clear finish, some patented ingredients that are opaque to ultraviolet but transparent to visible light, but the change will, ultimately take place anyway because it is brought about in the end by the visible as well as by the ultraviolet light. The other source of darkening in color that takes place as time passes comes from decomposition of the finishing material itself. Many materials, especially the drying oils and varnishes, form strongly colored decomposition prod ucts. The protective natural finishes, if adequately maintained, prevent devel opment of the gray color of weathered wood. But if the finish is allowed to go long enough to lose its protective power before it is renewed, the gray: | i FLB 00118 is usually darker in color than the oil. A so-called penetrating wood sealer, the nonvolatile portion of which is cus tomarily more highly bodied than that of a spar varnish, may darken wood less than varnish does, and a fast-dry ing spirit varnish or a nitrocellulose lac quer may seem to darken it least of all. The extent to winch the materials penetrate wood in the time that it takes for them to harden thoroughly stands in the same order as their abil ity to darken the apparent color of the wood. Changes In Color Take Place Besides the initial change in appar- , snt color brought about by application 1 color of weathered wood will appear. It develops first on the boards most fully exposed to sun and rain, usually the lowest courses of siding On the south side. Once the grayness develops, satisfactory renewal merely by apply ing fresh finish is impossible, for the gray color continues to show through the new finish. Restoration of the de sired color requires scraping or sand papering to remove the grayed wood before refinishing. Even then a close matching of color, cannot be obtained because the newly exposed wood may be lighter in color than the rest of the wood that has darkened from the action of light. sightly spotting of good house paints; with natural finishes such rust spots are even more conspicuous. Rust dis colors wood , of any kind hut the spots may be especially conspicuous on woods that contain much tannin, such as redwood, redcedar, oak, and chest nut, Soluble compounds of iron react with tannins to form blue-black com pounds related to some writing inks. Other extractives present in many woods may also form strongly colored compounds with iron. The discoloration at nails may spread an inch or so into the wood in the direction of the grain. Well galvanized iron, cadmium-plated iron, aluminum, zinc, and stainless steel do not discolor wood. ]f a clear finish, further changes in | Natural finishes More Exacting It is also important that the finishing :oior take place over a period of time. I Ine change comes from the action of ight, especially of the ultraviolet light n sunshine, on colored substances in he wood itself, Most woods darken oward brown in color. A few, chiefly xotic species of especially strong color o begin with, turn lighter in color. The hange in color goes on more rapidly he stronger the illumination and the igher the proportion of ultraviolet in le light. The change in color can be retarded y including in the clear finish, some itented ingredients that are opaque to traviolet but transparent to visible jlit, but the change will ultimately ,ke place anyway because it is 'ought about in the end by the visible ; well as by the ultraviolet light. The her source of darkening in color that i kes place as time passes comes from composition of the finishing material ielf. Many materials, especially the ying oils /and varnishes, form ' ongly colored decomposition prodts. The protective natural finishes, if j Thus, natural finishes are more ex acting than house paint or shingle stain in their requirements for good main tenance. Paint or stain can be neg lected for a time after renewal is in order without seriously complicating the renewal, but natural finishes must be renewed before they have broken down in protective power. As the cri terion of the proper time to renew a natural finish, some property other than graying of the wood must be used. Perhaps the best basis for judgment can be found by observing the behavior of drops of water sprinkled on the surface of the most exposed area of the house. Most satisfactory finishes have enough water repelleney at the outset to keep water from Wetting and spreading over the surface readily. As long as protection remains adequate the water rolls off readily in droplets; but as protection fails, the water spreads over and clings to the surface, and finally can be seen to penetrate and be retained for a time by the wood, When that happens, renewal of the material itself be free from soluble compounds of iron. Spirit varnishes that have come in contact with rusty iron, even the iron of the container in which they have sometimes been sold, may discolor wood from the reaction of iron with tannins or other wood extractives. Similarly the use of steel wool to smooth exterior wood before finishing usually leaves particles of steel in the wood to rust and cause discoloration. Natural finishes for exterior wood may be divided into four types: var nish, wood sealer, drying oil, and non drying oil finishes. Varnish finish. Paint technologists by tradition generally turn first to the varnish finish to supply the demand for an exterior natural finish. For doors, windows, and other readily ac cessible minor areas for which a mod erate degree of protection must be maintained without fail, the varnish finish is still advisable and is usually acceptable. But when major areas, such as siding, are to have natural finish, iquately maintained, prevent devel- | finish must not be delayed much longer. varnish seldom gives the desired ap nent of the gray color of weathered { Exterior woodwork that is to receive' pearance and proves too troublesome od. But if the finish -is allowed to f a natural finish should be fastened with to maintain. long enough to lose its protective { corrosion-resistant nails or screws. The varnish used for exterior sur ver before it is renewed, the gray | Rusting of iron nails often causes un faces is, of course, a spar or a marine spar varnish. On new wood at least three coats are advisable, the first of which may he thinned moderately with turpentine or other paint thinner. Shellac should not be used for the first coat on exterior surfaces even over knots. The varniSh- finish is highly glossy and resinous in appearance, qualities that are usually considered objectionable for large areas like sid ing, and it usually darkens seriously in strong sunlight. When it comes time to renew a var nish finish because protection is failing on the more exposed areas, the entire house, or at least an entire side of a house must usually be revarnished be cause freshly applied varnish will not match the older varnish either in color or in gloss. Since the coating wears away very little on the more protected areas, a few renewals make it too thick to continue to perform satisfac torily. Alligatoring or cracking and scaling in a very unsightly pattern may then set in according to the nature of the varnish. Iii either case complete removal of old finish by use of varnish remover becomes necessary before re finishing can be done satisfactorily. Such removal is expensive and laborious. Kind To Select When varnish is used for large areas, it is best to select a kind that disintegrates by a very fine crazing followed by, fine crumbling, as the old fossilresin varnishes used to do and some ester-gum varnishes still do. Syntheticresin varnishes often develop milky, opaque -patches where the coating has lost adhesion to the wood without breaking open. The opacity is a struc tural phenomenon at the air-solid inter faces of the air pocket between coating and wood. Although the synthetic-resin varnishes may remain free from- craz ing and maintain gloss relatively long, they eventually crack, curl, and scale badly and turn out to be less durable than a varnish in which fine crazing sets in relatively early. Varnish, in common with j natural finishes, is less resists! mildew than are house paints i with chemically active pigments. I ever there may be lingering danf to favor the growth of fungi, var| for exterior use should be made| a suitable content of preserve Alternatively, the wood-work ms treated with water-repellent preg$ tive before the varnish is applied the woodwork contains sapwood, is always susceptible to blue sta| the presence of dampness, applicl of preservative before varnishing i pecially desirable. :? Wood sealer finish. The wood si finish differs from the varnish f| more in the methods of applied, and maintenance than in the comp tion of the material used. As a i a wood sealer for exterior use i4 oleoresinous varnish, possibly of so| what higher degree of body thal spar varnish, but of relatively low <| tent of nonvolatile, say 30 to 40 perc| by weight. It is designed to | promptly and completely absorbed | the wood surface after application lj to penetrate the wood as little 'j possible after its initial absorption,j The wood sealer finish may be if scribed as a finish in, rather than | the wood surface: It should not led a continuous coating of appreciate thickness on the surface. For thj reason one application on new woe may suffice, though two are usual! recommended: For renewal, one app| cation is nearly always enough. Sind, wood varies greatly in absorptivenes| it is advisable to wipe off any mf absorbed sealer shortly before it ha* stood long enough to become tackjl If wood sealer is applied too gened ously without wiping off the excess it is converted to a varnish finish afte| a few renewals. , The wood sealer finish lacks the lustrous appearance and has mueh lessij gloss than the varnish finish. It alsdj darkens wood less both initially and '14 4- / FLB 00118 other mt to made Wheripness nishes i with /ative. lay be servajd. If which :ain in Lcation ; is es- sealer finish lcation xnposia rule, is an some;han a w conlercent to be bed by on but tie as ion. be de an on, t leave eciable r that ; Wood Usually i appli- Since veness, iy un lit has i tacky, genercxeess, h after tes the Ich less It also ly and after aging. For these reasons most users of natural finish on large areas, such as siding, prefer the sealer to the varnish finish. Moreover, the sealer finish offers important advantages over varnish in maintenance because it is practicable to renew Sealer on,the more exposed parts without going over the less exposed parts of a side wall where a longer time may well elapse before renewal. If care is always taken to wipe off unabsorbed sealer, there is no possibility of developing a coating thick enough to crack, curl, or scale and ; therefore no danger that removal of old finish wifi become necessary. The wood sealer finish is nearly as sensitive as varnish to the development of mildew in damp places. Incorpo ration of preservative in wood sealers is therefore customary. Alternatively the wood may be treated with waterrepellent preservative before the sealer is applied. Some commercial wood sealers con tain a very small proportion of colored pigment, usually to provide a color similar to that of the heartwood of redwood. Such pigmentation adds to the reliable service of the sealer, evens up the color if the wood contains some white sapwood along with red heartwood, and gives light-colored woods like pine more nearly the color of redwood or redeedar. Pigmentation has the further advantage of restoring the desired color if some of the wood has become slightly grayed before the finish is' renewed. Drying-oil finish. In climates like that of southern Arizona, where damp ness never lasts long, a practicable natural finish can be made with ordi nary linseed oil with or without addition of a small proportion of pigment. The nil may be raw linseed or other drying oil, with little or no thinner, or it may be moderately highly bodied oil with a generous proportion of thinner. The oil finish produces less gloss than a sealer finish but it darkens the wood both initially and .on aging more than varnish finish does. Drying oil, unless highly bodied, is less inclined than sealer to leave an excess on the surface to be wiped ofif. On the other hand, if overgenerous application forms a coat ing oyer the surface, the coating is unduly soft and holds dirt easily. Drying oils are particularly suscep tible to growth of mildew in damp places. For that reason the drying oil finish is impracticable in most of the more heavily populated parts of the country unless it is well fortified with an effective preservative. Non-drying oil finishes. Since oil finishes are drawn completely and rela tively deeply into the surface of wood. It is not necessary that they have dry ing properties. Some of the most satis factory natural finishes do not dry. They should, however, have the prop erty of making the wood repellent to water and, for most parts of the coun try, they may well contain preserva tives. The essential ingredient for water repellency in the non-drying oil finishes is a hydrocarbon wax such as paraffin. The typical water-repellent preserva tive may contain from 1% to 3 percent paraffin, S to 10 percent resin or resin and nonvolatile oil, and 5 per cent chlo rinated phenols (all by weight) in a mixture of mineral spirits and other volatile solvents. The content of non volatile in such products is somewhat too low for a natural finish but ad justment can be made by increasing the content of wax and perhaps that of nonvolatile oil. Some of the best of the non-drying oil finishes also contain small proportions of colored pigments. Changing from natural finish to paint. Since house owners often choose a natural finish without having been made aware of the frequent renewal necessary to maintain them, it often happens that they soon wish to change to more durable paint finish. Special problems may arise in that case. House paint becomes unreliable in performance if it is applied over varnish ,i~_. FLB 00118 or other unpigmented coating of appre ciable thickness. All varnish or wood sealer that has accumulated until' it forms a continuous coating should be taken off with varnish remover, the surfaces washed free from wax, and sandpapered lightly before paint Is applied. Such removal is most neces sary on the sheltered areas where the varnish remains in best condition. Even wood on which there is recently applied wood sealer or oil finish is not in suitable condition for reliable paint ing. At least a year should be al lowed to elapse before paint is applied and then all sheltered areas where any sheen remains should first be sand papered or scraped well. When wood has been finished with non-drying oil finishes high in wax, several years should elapse before any attempt is made to apply paint and even then it may be doubtful whether the paint will give its normal service on the more sheltered areas. It is safer to change from the natural finish to a shingle stain in such cases. Bibliography L Browne, F. L. Wbod siding left to weather naturally. Architectural Record. November, 1952, p. 197. 2. Frey-Wyssliiig, A. Die verfarbung ungsschutzten holzes dureh das wetter. Schweitzer Zeitschrift fttr Forstwesen 101:278 (1950). 3. Browne, P. L. Effectiveness of paints in retarding moisture absorption by wood. Industrial and Engineering Chemistry 25?835 (1333). Paints as protective coatings for wood. Industrial and Engineering Chem istry 28:798 (1936). 4. Browne, P. B. The absorption of water, swelling and solubility of free films of paint. To appear sometime in 1953 in the Journal of the Forest Products Research Society (re print available from Forest Products Daboratory). 5. Browne, F.: D. Natural finishes for ex terior wood. Architectural Record, Feb ruary, 1952, p. 196. 6. Browne, F. D. Wood properties that affect paint performance. Chapter 11 of ' Organic Protective Coatings," ' by William von Fischer and Edward G. Bobalek, pub lished by Reinhold Publishing Corp., 1953. : Reprinted From The American Paint Journal, May 24, 1954 Issue l e WOOD SIDMG N41698.68 FLB 00118 Ir Types of normal and abnormal paint behavior. Upper left, typical checking and crumbling of] white lead paint; upper, right, cracking, curling, and ..flaking typical of most zinc-containing ] paints. In both cases, it is time to repaint, tower left, cross-grain cracking, an abnormality j that results when paint film gets too thick; lower right; blistered paint, an abnormality usually ] caused by moisture behind the paint-film. Remove paint that has cross-grain cracking to the] bare wood before repainting. Where moisture has blistered paint, find and eliminate theif source of water and remove all blisters and loose paint before repainting. Washington, D. C For sale by the Superintendent of Documents, 0. S'. Government Printing Office Washington 25, D. C, - Price 10 cents FLB 001188 WOOD SIDING How To Install It, Paint It, Care For It M--107844 ;af checking ami crumbing of j epical of most zinc-containing jrain cracking, an abnormality paint, an abnormality usually as cross-grain cracking to the : paint, find and eliminate the lainting. | By the Forest Products Laboratory, Forest Service Wood siding is put on houses for many good reasons. For one, it will keep the bright `new; "face" of any home attractive, for many years to come. In fact, given reasonable care, wood siding will retain its beauty for centuries, as has been amply proved by houses that date back to early Colonial times....... . . There are sound design and struc tural reasons, too, for using "wood siding. Its great flexibility and variety in patterns, sizes, and colors range from the captivating sim plicity of; Colonial clapboard to the 5 equally dhujitmig board-'and-baften ' Siding, of modern ranch and vam- hler houses, : In between are many ; other varieties and combinations "tJuitprochi.ee distinctive and attrac- "'tlve- effects, ` . Then there are the hard-headed dollars-aifd-cents reasons, such as Wood's 1X \y initial cost and the ease and speed; with which' it can be sawed, fitted, and nailed' into place. Also, its fuel-saving Value, due to the millions of tiny hollow fibers that make it a good insulator, and its natural resistance to the ravages of weather make it desirable. There are other reasons, too, such as wood's ability to hold a wide va riety of finishes--clear ones that reveal and accentuate its natural beauty, stains that impart a rustic appearance,; and paints of every conceivable color.. Within limits, the color scheme can be changed periodically to give a home a. fresh ne'w appearance in keeping with changing tirries. So it's little won der that wood, siding has come to stand for Warmth, comfort,' Secu rity, beauty--all the things that spell "home." Kinds of Wood Siding There are many kinds of wood siding on the market today (fig. 1). All will give good service, provided they are used right. For houses, bevel siding is perhaps the most widely used. It consists of hoards sawed in half so that one edge is thicker than the other. Drop sid ing is also used, especially on houses without sheathing. To make it, boards are patterned along the up per edge and grooved or lapped on the lower. Bevel and drop siding October 1956 rnment Printing Office ts Figure 1.---Three types of wood siding, left to right, bevel siding, drop siding, vertical boardand-batten siding. 1 FLB 001 are applied horizontally and tend to be well and properly built to insure make a house appear lower and long-lasting service. :j longer. Houses are built differently todaj Vertical siding is increasingly add must serve under different con popular on' one-story houses; It ditions thaii -in grandfather's day. consists of square-edged or tongued- Insulation, weatherstripping, and and-grooved boards applied verti generally tighter construction have cally, usually with narrow strips cut down fuel bills and made for called battens nailed over the joints. - greater comfort, but have also cre Vertical; siding tends to make a ated some wintertime problems in -house appear taller.. our northern States, wherever The kind .of- siding chosen will proper precautions have not been depend on where the house is built, taken. ' > ` its price range, and the architec Part of the water Vapor former tural effect wanted. 'A range of within a house moves through the; qualities is available, from clear, inner surfaces of walls because of edge-grained lumber to fiat-grained differences in temperature betwi material with knots and other char acteristics that should he given spe the inside and outside! Under cer- tain temperature conditions, this water vapor condenses and collects cial finishing treatments, depending as liquid water or frost back of the; on the effects wanted (fig. 2): . siding. And much more water or : Paints last longer and give bet frost is likely to collect back of the ter service on softwoods of low den- ~ siding- of an insulated than an un shy" than on those of high density, insulated house, because the outer and on edge-grained than oil flat- skin of an insulated house is colder.; grained' boards, 'On woods with With the return of warm weather, broad summerwood bands,' a'spe - this moisture can--and often does-- cial primefi .(first coat) as heeded cause the exterior paint to blister. fori good - service, as described on . ' The problem has been further ac page 9. ; ' centuated by central heating plants and indoor plumbing, which have The House and its Siding created a great deal more water vapor in houses---vapor that has Wood siding is a part of the house, less .chance to escape to the cold, and therefore its performance is outdoors than is the ease in the vitally affected by the test of the older, less tightly constructed | structure. The whole house must houses. EDGE-GRAINED SIDING FLAT-GRAINED SIDING Figure 2.--Edge-grained (left!, flat-grained siding. ":ll ii m m nii insur- /today nt con 's day. y, and n have : de for so cre ams in i ierever t been j ,brined gh the use of it ween er cer- \ s, this ; ollects ! of the ; ter or of the in un- outer tolder. lather, loes-- iter. ier acola nts ; have water There are a number of things that can be done to help keep moisture out of walls. One of tire most ef fective is to put a good vapor bar rier (fig. 8) under the plaster of exterior walls in every insulated house built where the average Jan uary temperature is 35F. or lower. Asphalt-coated paper, aluminum foil, and polyethylene film make good vapor barriers. Bain and snow water must be kept out too. Roof gutters must be sloped and have enough down spouts or they may overflow during rainstorms and let water seep into walls through joints in the siding. Likewise, the eaves must be well flashed. This helps keep out snow melt when gutters become clogged with ice. Good roof overhangs help a lot and metal flashing is needed in roof valleys, along dormers, and around chimneys. Window and door frames also need adequate cap flash ing. Joints should be snug where siding boards butt together and against window and door trim. But siding that is fitted against roof shingles, as on dormers (fig. 4) and roofed entryways, should be about 1 inch short. Otherwise, water can soak into the end grain and cause the paint to fail, A comparatively new treatment for the siding itself helps keep moisture out of walls. Siding can be dipped in a water-repellent pre servative before it is installed, or the water repellent can be brushed on after the siding is installed and before it is painted. These pre servatives are sold by lumber deal ers and some paint stores. They contain waxes, resins, and oils that cause water to slide off, instead of wetting the backs of the siding boards by working through the butt joints or crawling up through the lap by capillary action. Installing Wood Siding Wood siding is simple to install. It is precision-manufactured to standard sizes and is easily cut and fitted and fixed in place with ordi nary tools. Courses of siding should be spaced so that a single board runs continuously above and below win dows and above doors without notching. Bevel siding 6 inches wide should have at least 1 inch of Figure 3.--How a vapor barrier prevents vapor from entering an insulated wall. 3 FLB 00119 flashing extends back of siding and under shingles. overlap between, courses. Siding 8 inches'or wider should overlap at Wood Finishes least 1% inches. -- The first finishing job on a house -Siding 'should be butted snugly is the- most important one.. It is and ;squarely against door andwin-i the foundation for gU subsequent dow casings, comer boards, and ad--, .finishing, and if all goes well it will iv joining board's. (Corner boards remain there for the life of the should lie flat against the sheath house. ing.) If metal corner covers are ' Selection of a finish must be made used, siding boards should'be care-1 from among, three broad classes: fully cut to avoid leaving a hollow . (1) natural finishes, (2) stains, and place under the corner cover where (3)' paints. The choice, of course, water could collect. Mitered cor will depend to a great extent on ners should be precisely fitted for personal - preference, considering the same reason. the advantages and disadvantages To fasten siding in place, zinc- of each class of finish. coated, alum inrun, or other noncor rosive nails are recommended. Natural Finishes Plain steel-wire nails, especially the large-headed ones designed-for flush driving, make unsightly rust spots on most paints. Even small-headed Statural finishes either penetrate the wood or form a film on its sur face: The penetrating finishes may be clear or pigmented; the film- plain steel nails, countorsunk and forming type is usually clear. puttied, are likely to spot the finish Natural finishes of the surface- with .rust. .. . i, coating type give a lustrous, even 4 FLB 00119 1 r. Metal a house f It is >seqiieixt 5 II it will f of the he made ; classes.: i tins, and j f course, : stent on isidering ! vantages I I penetrate 1 its surshes may the filmear. surfaceous, even s i ; I { glossy coating. These are chiefly spar varnishes. A really durable natural finish of this type has yet to be developed. The penetrating natural finishes leave little or no continuous coating on the surface. They include oil finishes, wood sealer finishes, and water-repellent finishes. The lat ter penetrate wood readily and completely, but the oil finishes and especially the sealer finishes may leave some excess on the surface. For best results, the excess should be wiped off from 5 to 10 minutes after application. All three types of penetrating finish look better and last longer if they contain some pigment. Before a natural finish is applied, it should be tried on samples of siding to be sure the effect is what is wanted. If there is likelihood that a paint finish may be wanted later, a wood sealer or an oil finish should be chosen. Although the pigmented water repellents are among the better natural finishes, they contain more wax than the water-repellent preservatives rec ommended for the treatment of sid ing. They are likely, therefore, to interfere with the drying and ad hesion of house paints, whereas the water-repellent preservatives do not. Natural finishes are not nearly so durable as paint. Therefore, they must be renewed more frequently than paint, usually every year or, at the most, every two years. Even with such attention and care, the surface-coating types may ulti mately need to be removed com pletely to restore a satisfactory fin ishing surface. In any case, they must be removed entirely before paint can safely be put on. Stains Good shingle stains are inexpen sive and much more durable than natural finishes,, therefore requiring much less maintenance. They come mostly in dark browns, greens, reds, and yellows. Stains penetrate and color wood, obscuring its grain but leaving little or no surface film. Bough-sawed or weathered wood surfaces are especially suitable for stains. Good stains should last at least 5 years, and may last as long as 9 or 10. Even on planed sur faces, they will last at least as long -.as paint before needing renewal. Since stains form little or no coat ing on the surface of the wood, they do not crack, curl, flake, or scale. Neither do they blister. Some stains, however, contain creosote, which may discolor light-colored paint applied over them later. House Paints House paint is the most widely used finish for wood siding and white house paint is the most pop ular. A good white house paint should last at least 4 or 5 years be fore it must be renewed; tinted paints, 5 or 6 years ; and dark-color paints, 6 to 8 years (fig. 5). House paint consists of two parts, a solid part (pigments) and a liq uid part (the vehicle). The pig ments include hiding (opaque) pigments and transparent (extend ing) pigments. The vehicle con sists essentially of a drying oil (usually linseed oil), a thinner, mineral spirits or turpentine, and a small amount of paint drier or japan drier, necessary to make the paint harden promptly after appli cation. The kind and quality of a paint are determined by the nature 386438--,56----2 5 FLB 00119 Men use it has good tint retei . olors-in-oil may be added to r iill iMI paints. In addition; si-(- staining by rusting i 1 *i ohably the most important ,i>o['rties, however, is its non. t i \ cnoss to water. Even whe |j<>c<l to water for a long tit *.v.elb only about as much as. Figure 5.--Expected service life of white, tinted, end colored paints. docs when wet. Consequent Lrto little tendency to blister. White lead paint also has of its pigment,'the proportion of desirable. In order to select, the disadvantages, some of which pigment in Che veh icle, and the kind type of paint that is likely to give led many houseowners to of vehicle. .... the most satisfactory service, the other types of house paint. Fo Ilonse paints m&y be classified homeowner should be familiar with it has lower opacity, or h simply according to the pigments the conditions to < which house power, than the other types of. ' used in them. Using this system, paints are subjected in his area. He paint. Also, it has an off-- there are six basic kinds or types of must also, know which types of color that does not. compare f house pain#: white lead, titanium- paint will stand up best under these ably with the intense, bri lead-zinc, titanium-zinc, titanium- conditions--which of the various white of most other paints. 0 lead, titanium, and dark-color.' paint properties are important to The more serious objections - Each type has some of the char him Under the circumstancesj and dirt retention. Despite the acteristics generally considered es which are relatively unimportant. -thatit wears away faster than sential in good house paint. These In terms of years of use, white paints, it Collects more dirt ax include durability sufficient to last leadjpamt isfhe^oldest. Jt has been tains it longer than most other 4 to 6 years before needing renewal, .used op. houses in this-eountry since rof paints. Another serious c a normal foran of wearing that in- , Colonial tinii# . arid ; it mi still pre itiqn is its-property of discolor! surds a good, repaint surface with ferred by gome painters and house contact with hydrogen sulfide a minimum of preparatory work, owners to the other types of house ssainc organic sulfide gases and a norHiaily fast rate of wear .paints. However,; it now accounts cause the formation of black from the surface... This last is to for only a very small fraction of the sulfide. Because of tbis proj -prevent; the accumulation of ah ex total volume of house paint used in white lead paint and other p cessively thick film, of paint when a reasonable maintenance schedule is followed (a single coat every 4 or 5 years or 2 coats every 6 years) . Paint should also have a clean, highly reflective color and ability to remain free from excessive dirt collection in service. It should be this country* ^containing lead pigment shoul White lead paint is a durable paint that normally fails by check ing and qrumblinfj; This pattern of failure leaves a good repainting sur ?bc used in areas where these cl `cals are likely to Be present i atmosphere. Finally, white face that requires little preparatory paint is slightly more expe work. It is also a comparatively than other types of house pain soft paint that wears away at a J Most paints are of the titan nonsensitive to moisture and should faster rate than most other paints. Tead-zinc type. The lead and -not be stained by metal corrosion. This permits a flexible maintenance Content of such paints ranges Nor should it be discolored by hy program with' little risk of building extremely high to very low, an drogen sulfide or organic sulfides. the paint film to excessive thickness. .proportions of lead and zinc No one typo of house paint on -White lead paint is available in vary widely. In general, pain the market has all of these char readv-to-use form and as a paste this type have a brilliant and lr acteristics. All have some desirable that can be mixed on the job with .reflective color, remain unifo features and some that are not so linseed oil, paint thinner, and drier; clean in service, and are dui FLB 001194 Because it has good tint retention, They are generally hard arid wear colors-in-oil may be added to make away slowly. tinted paints. In addition, it re Paints of this type, like most sists staining by rusting metal. paints that contain zinc oxide, nor Probably the most important of its mally fail by cracking, curling, and properties, however, is its nonsensi flaking. With paints that fail in tiveness to water. Even when ex- this manner, it is necessary to take j posed to water for a long time, it certain precautions to insure a good j swells only about as much as. wood repainting surface. The film of | does when wet. Consequently, it paint on the wood must not be per- has little tendency to blister. . mitted to become too thick and the White lead paint also has some failure must not be permitted to re disadvantages, some of which have advance too far before repainting is ?e led many houseowners to prefer done. le j other types of house paint. For one, Zinc-containing paints have been Sji i it has lower, opacity, or hiding se power, than the other types of. house le paint. Also, it has an off-white pf color that does not compare favor so ably with the intense, brilliant us white of most other paints. One of found to swell much more than wood when wet, and must therefore be classified as moisture-sensitive. They blister more readily on con tact with water than do the other types of paint. Under some condi fo the-more serious objections is. its tions, contact with water may not Id -dir-t-retention. Despite the fact cause zinc-containing paints to it. that it wears away faster than other blister but may simply induce pre te paintsyit collects more dirt and r.e- mature cracking, curling, and flak ;n tains ifelqnger than most other types ing. Precautions suggested on co ee- se ts ae in of paints. Another serious ohjec* ri<o.n is,its property of discoloring on contact with hydrogen sulfide and some organic sulfide gases that . cause the formation of black lead sulfide. Because of this property, | white lead paint and other paints page 16 will help reduce contact of this type of paint with water. Titanium-lead-zinc paints also are likely to become stained by nail rust and by the corrosion products . of iron and copper screens. The dead in them accounts for their dis j1 containing lead pigment should not le be used in areas where these chemi- k- j cals are likely to be present in the pf k- : atmosphere. Finally, white -lead fy paint is slightly more expensive coloration by hydrogen sulfide and certain organic sulfides. House paints of the titaniumzinc type are sold in large volume, second only to the titanium-lead- fy i than other types of house paints. - zinc paints. Their properties are ` a ) Most paints are of the titanium- very similar to those of the tita- ;s. dead-zinc type. The lead and zinc nium-lead-zinc paints. The most ce content of such paints ranges from important difference between them ig {extremely high to very low, and the is that the titanium-zinc paints do ss. {proportions of lead and zinc also not discolor on exposure to hydro in. {vary widely. In general, paints of gen sulfide or organic sulfide gases, to (this type have a brilliant and highly since they contain no lead or other jdi jreflective color, remain uniformly pigments that react to form metallic sr. clean in service, and are durable. sulfides of dark color. For this rea- 7 son they are .often referred to as "fume-proof" paints and are rec ommended for use where SitLfide digcoloration is a problem. Paints made with titanium and lead pigments, but without zinc oxide, hare appeared on the market in recent years. Most of these are sold as "breather-type" paints. They contain---in addition to tita nium and lead a high proportion of transparent (extemMng) pig ment to binder (the nonvolatile part of the vehicle). Paints of this type are characterized by their lack of gloss. A few paints pigmented with titanium and lead are sold as "titanized white lead." Some paints of this type, contain no ex tending pigments, but are made with a conventional ratio of pig ment to binder and therefore have as much gloss as the zinc-cont aining paints. - : Paints of the titanium-lead type are nonsensitive to moisture and therefore blister-resistant. They have high opacity and generally rate between white lead paint and the zinc-containing paints in color quality, resistance to soiling by dirt and staining by rusting metal, and the rate at which they wear away. They fail by checking and crum bling, and provide a surface that is easy to repaint. They are, however, discolored by sulfides. Paints made of titanium pigment alone, combined with:one of seyeral special vehicles, are now available on the market. One of the vehicles used is a long-oil alkyd resin j an other is referred to as a copolymer solution. Titanium paints are sold as "blister and stain resistant'' paints. Like the "breather type," they have little or no gloss- in opacity, color, and resistant to soiling by dirt and staining h rusting metal, titanium paints at like the titanium-lead paints. Th titanium paints differ in that the are enamellike in their cbaraetei i sties and resist sulfide discolors tion. These,paints normally fail b cracking, curling, and flaking, an-) indications are that they wear awai at a rate similar to that of the tit mium-lead paints. i :!D&rk-polor paints, sometimJI called trim paints or trim-an trellis paints, consist chiefly m dark-color pigments with little, i any, titanium dioxide, white lea< or zinc oxide. In most trim paint the major part of the vehicle varnish, usually an alkyd-resin va nish. .Iron oxide paints--the f; miliar red barn paintsj-may also 1 classified as dark-color paint Sometimes used on bouses, they a very durable if properly made; 1 general, good paints of dark colo: are more durable than any white .< light-colored paint and less sensith to Water than are white' or ligb colored paints made with zinc oxid Paint Primers Some paints can be used as sel primers, while others need a sped primer for the first coat on ne wood. Tbe proper choice of prim Can do much to insure a long-las ing, trouble-free paint job. In pa ticular, a primer should be free < zinc pigments, even if a zinc-co) tain ing paint is used for the finis coat. Most paint makers provh : special, zinc-free house-paint prill ers or undercoatefs for use wit their mixed-pigment paints col taining zinc. As a rule, it is wi to use primer and finish paint of tl same brand. 8 / FLB 001 jsistanc? New wood that is to be finish have a wide roof overhang to shield ining b; coated with white lead or titanized the walls ? Has it adequate gutters lints ar tvhite lead paint can be primed with and downspouts and are they prop its. Th' the finish-coat paint (called "self- erly installed? Is there a good hat the, priming") or with a zinc-free, vapor barrier along with the insula haractei prepared house-paint primer, tion ? If the answers are yes, a zinc- liscolora "-Breather-type" paints and tita- containing paint stands a fair ly fail h nium-alkyd resin paints are usually chance of success (but only over a king, an- used as self-primers, zinc-free primer). If there is rear awa, A. special primer is needed for doubt, one of tlie zinc-free paints is f the tit a flat-grained wood with wide sum- the wiser choice. merwood bands (fig. 6) and wood sometimes with knots. Alnminum.house paint, Lrun-aiu; sometimes called "aluminum paint chiefly .cf for wood," has been found best, Finishing Wood Siding and Trim , h little, i Paints applied over ordinary primvhite lent ers are likely to flake off the sumrim paints merwood rapidly, leaving unsightly vehicle if blemishes. Knot sealers, which 1-resin vai minimize "bleeding," may be used ts--the ft over knots in wood having narrow may also h summerwood bands, Questions that arise regarding the job of applying finish include: When to paint? Where to begin? How many coats? Finish can be applied witb a brush, spray, or roller. A brush is generally used and, for purposes of or . paint Selection of a particular type of ses, they ai. house paint requires careful y made. L thought, Where moisture troubles tlJU w? 01 are widespread, a zinc-free paint is my w lec ^ he preferred. The experience of ess sensi n 0j.jiers jn the neighborhood and city this publication, brush application is assumed. Finish is beat applied during warm, dry weather when several weeks of sunshine can be expected. This creates a problem with regard h zincoxxd 13 helpful in finding out what types to houses built during fall or winter, { of difficulties' with paints are com and often builders let them stand mon and which paints serve best. with a prime coat until spring'be Tlie construction of the house fore finishing the job; This proce used as sel should also be considered. Does it dure can result in trouble. The leed a sped coat on ne| fire of prinii e a long-las' , job. In pa f ild be free tf if a zinc-coi j for the finisi ikers provicf se-paint prinj for use wit; paints coi: ule, it is wifi di paint of tlFigure 6.--Applying aluminum house paint as the primer on flat-grained siding and wood with Irnnfc 9 FLB better practice in such eases is to morning, the east side late in t brush water-repellent preservative morning, the south side well ati \ on the siding, after which it can go noon, and the west side during I;, without finish iuxtil spring. afternoon. Because water-repellent preserv Morning dew or the water ol atives help keep rainwater out of brief shower should be wiped o house walls, the most effective time and after half au hour of wan.' to apply them is before any other weather sunshine painting cm 1 finish has been put on the siding. gin. After many hours of luu They are especially recommended rain, however, a day or two of <h for use under moisture-sensitive ing is needed. paints, natural finishes, or stains The beginning painter can lw>, that contain.no fungicide. to gage spreading rates by apph i> With natural finishes, 1, 2, or 3 a pint of paint evenly over a me.i applications may be required, de ured area. For example, at pending on the type of finish used. Spreading rate of 600 square feet The manufacturer's directions the gallon, a pint covers 75 s(|'u> should be followed. In general, feet, or an area of 5 by 15 feet; natural finishes are easy to apply. TOO square feet a gallon, a pint Stains, too, are easy, to apply. On ers 873/s> square feet, or an areal planed wood surfaces, one applica 5 by 17y2 feet. The average tion may be enough, but two appli ner tends to spread paint oni cations usually result in a more dur able job. Two applications are; For modern paints of avert! generally recommended oh rough- composition., a total t hickness of f sawed or weathered surfaces. tween 4% and S mils results wli ' The answer to the question, "How 1 coat of house-paint primer is many coats?" depends largely on plied at 600 square feet a gallon i , the kind of paint selected. As a 2 coats of finish paint at 700 sqita >' rule, a 3-coat job is recommended feet a gallon each. for new1 wood. Many builders ap In warm, dry weathereach < ply only 2: A first paint job should should dry a day or two before be 4% to 5 mils (thousandths of an next is applied. Cold or da inch) thiek, which is about the weather may make an extra day i thickness of a dollar bill. It is dif ficult, if not impossible, to apply that much by brush with 1 primer and 1 finish coat of today's average two advisable, but more thar weeks between coats should avoided. paints. In winter especially," 3 coats are needed. Exception ally Finish Maintenance heavy coats, where paint is applied Hot summer sun, wirid-driv at a rate of 450 to 500 square feet a rain and hail and dust, and wint gallon, are likely to result in wrin snow and ice gradually take a 1 kling, loss of gloss, and slow drying of even the best finish. How f during cold weather. queutly the finish should be ; With paint, an old craftsman's newed is governed by the rate rule is: "Follow the .'sun around the which it weathers away. Finis! house." , This means that the north vary considerably in this respe side khotdd be painted early in the The1 popular natural finishes ue 10 FLB 001 ite in t] ' renewal every year or two. Stains, well nfti |On the other hand, are very durable uring lat| and should not need to be renewed ' in less than 5 years. There is con ater el' siderable variation, among paints, piped oil also, but the types most commonly warniV used on house siding weather away g can be* at fairly uniform rates, so that def of har^ inite repainting schedules are prac o of drj tical. Penetrating natural finishes are ran lean, easy to renew. Fresh finish is sim- appLyiffi ply applied when the old finish ap- r a measS pears to need it. As with the first le, at 4 finishing job, any excess of sealer or re feet h| oil should be wiped off, so that for- '5 squarl mation of a surface coat- is pre' feet; a| Tented. pint cov Natural finishes that leave a sur- i area.o5 face film are more troublesome to 56 begin maintain than those, which pene- out toi^ trate the. wood. . Difficulties arise I mainly because the finish on certain average areas of a wall, such as those under >ssofbe, roof overhangs, remains in good Its whe: condition longer than that On ex- er is ap posed wall areas. It is reeom- llou ant" mended, therefore, that only the 0 squar more weather-beaten areas be. re- , newed. This is sometimes difficult, ich coa| because these finishes are not easily fore th blended over worn and unwOrn r dam| areas to give a uniform appearance. 1 day c If, on the other hand, the protected than ; areas are renewed as frequently as uld b the unprotected ones, excessively I . thick: coatings will be built up and * will require costly removal later. :e Stain finishes can be renewed' drive ^thout difficulty when their ap- wintt Rearance indicates the need for 3 a to; I'enewal. ' lW fj.e As already pointed out, a paint re maintenance program, is determined rate a. by the kind of paint used in the first inislffi job. The basic rule is, paint only espeef after most of the old paint film has s nee weathered away. Always remem ber that coating thickness can build up dangerously if paint is ap plied too frequently, with resulting abnormal behavior that spells trou ble and possibly costly removal of old paint by blowtorch or paint and varnish remover. Assume the first 3-coat paint job was 43/2 to 5 mils thick. As a rule, at least 4 years are required to wear away enough zinc-containing mixed-pigment paint to make room for I coat of new paint applied at 650 to 700 square feet per gallon, and 6 years for 2" coats applied at 700 to 750 square feet each. White lead paint wears away about half again as fast as the zinc-containing paints. The zinc-free, "mixed-pig ment paints are more like the other mixedi-pigment paints than pure white lead in wearing rate. Darkeolor paints, including iron oxide paints, wear away most slowly of all. . The wearing rate pretty well tells what to do: 1 coat not oftener than every 4 or 5 years, Or 2 coats not oftener than every 6 years, for white and tinted paints. One coat every 6 years is enough for dark-color paints. In repainting, good practice is to Use the same type of paint origi nally applied on the house, A change to a different type of paint may result in early failure through incompatibility. If, therefore, a paint has given satisfactory service, it should be used in repainting. If a paint has given trouble, a change to a different type may be advisable. Even then, it is best to wait at least 4 years after the last repaint job before making such a change. When color schemes are changed, a couple of simple rules should be followed. The best practice is al ways to use essentially the same I - 11 1' I| ' I FLB paint for repainting that was orig inally applied on the house. If white lead paint was used, a change from white to a tint mqy be made by adding colors-in-oil. Howeyer, colors-in-oil should never be added to white mixed-pigment paints. If such a paint has been Used and a tint is desired, purchase the tinting-base paint made by the same manufac turer for tins purpose, A change from a white or light-color paint to a dark-color paint may be made without too much risk of failure, but a white or light-color paint should never be applied over a darkcolor paint. Different paints, naturally, wear differently--and show wear differ ently. Paints that do not contain zinc oxide, such as white lead paint and the titanium-lead paints, nor mally begin to develop fine fissures, called checks, in a ; year or two. These slowly multiply and deepen, eventually reaching the wood, and the old paint crumbles away. More over, in a year or so some of these paints will soil quite noticeably. Later oh, as the paint chalks and begins to crumble, the dirt will dis appear; or, the surfaces can be washed with water and a cleansing agent sold by paint dealers. Paints containing zinc oxide wear quite differently. They begin to crack through to the wood in oc casional spots during the second or early in the tliird year, meantime having developed chalky surfaces that dull their luster, As time goes on, more cracks open, they widen and lengthen, and the paint around them curls back and flakes off. Such normal paint behavior is best taken in stride. If possible, a repaint schedule of 1 coat every 4 or 5 years or 2 coats every 6 should be maintained. However, this m,i* not always be practicable. If, id example, the original paint j<>: wears away in 3 years to the exl e, ^ that appreciable areas of siding ,n *| laid bare--as frequently happw.' with scanty 2-coat jobs--the ov m \ will understandably want to repa t at that time. This can be done wit, reasonable safety because the ori,, inal paint film was in all likelihood too thin to start with. All loopaint should be removed with scraper and wire brush, the b.u ^ areas should be spot primed, at then 1 qoat of topcoat paint app I ii overall. Thereafter, the more in tended repaint schedule should 1 , resumed. Finish Troubles Figure 7.--How Ice dams farm. r Paint troubles arise from variorj snow-d causes. Most common are vs | n troubles in tightly built, insula u bouses lacking vapor barriers; iai or other water that gets behind si ing; improper first priming of wo< with wide1 summerwood bands.; i painting too soon; or use of ! ferent type of paint in repaint jol ing all paint down to the bar and starting oyer. Before any repainting is dc probable cause of the trouble be ascertained. If it is < springtime blistering in the northern States, a better vapi Evidence of paint trouble u-mnl comes in the form of excessively l.i wearing away of the paint, as I ill tefing followed by peeling, or premature or excessive crackin' curling, and scaling. Once trouble has set in, the be- course is to go slow. Premature i- painting to cover up uniiirlit. paint failure in the long run on makes matters worse. The coatinij will be built to dangerous thi<-" nesses on places where paint dii In come off. Ultimately, the coal in will get too thick, and an abnoij -- nudity known as cross-grain crael| ing will set in. Once that happen| there is no recourse except remo Rqiire 8.---Treating lap, corner, and bu 12 / FLB 001200 -- untamed. However, this may ways be practicable. If, for >le, the original paint job away in 3 years to the extent ppreciable areas of siding are tare--as frequently happens canty 2-coat jobs--the owner lderstandably want to repaint ; time. This can be done with able safety because the orig lint film, was in all likelihood in to start with. All loose! should be removed with a r and wire brush, the bar? should be spot primed, and coat of topcoat paint applied :. Thereafter, the more ex| repaint schedule should b| d. ` I mirm smtVj Finish Troubles jj t troubles arise from variouf i Figure 7.--How ice dams form, Snow wafer from upper roof freezes on cold overhang or in snow-dogged gutters, builds up dam* rier is probably needed. This can r iproper first priming ofwooi gidetosuomsomoeiir;wooroudsebaonfdas;d4i s ;ype of paint in repaint job^ ce of paint trouble usuallf kfT a"5' reP""tinS fm. * dueJFboa"!,ea.llSe1f tbe double should springtime bbllisVtering m th'e colder northern States, a better vapor bar- be obtained by painting the indoor side of the exterior walls. Two coats of aluminum paint plus 2 coats of decorative paint are best for sand-finish plaster. On smooth plaster, a primer and sealer and 1 n the form of excessively fa| y a|yay of the paint; as bli| followed by peeling, or a| ure or excessive cracking , and scaling. j trouble has set in, the bee BUTT JOINT- s to go slow. Premature re! g to cover up unsightlj ailure in the long run onlj natters worse. The coatini built to dangerous thick n places where paint dicbif f. Ultimately, the coatin : too thick, and an abnoi mown as cross-grain era cl set in. Once that happen no recourse except remoi Figure 8.--Treating lap, comer, and butt joints before re^S.^9^ --votive 13 coat of decorative paint joake a good barrier. For gypsum board, 2 coats of rubber-base paint appear to be effective. Sliutting offhumid ifiers will also help. Where the trouble is due to water that gets inside the walls from the roof, leaks should be found and the gutters examined and rehnng lower if necessary, especially if the trou ble is due to ice damming (fig. 7). If the gutters overflow . during heavy rains, additional downspouts may be needed or the gutters may need to he pitched more. If water is getting through the joints of the siding, the lap and . butt joints should be treated with water-repel lent preservative (fig. 8) before j repainting; this type of solution is i highly penetrating and creeps well into the joints to seal them against future inroads of rainwater. Whatever the cause, it should be ; found and corrected before the house is repainted. Then the re paint job should markedly reduce future recurrences of abnormal paint behavior. u. S. GOVERNMENT PRIKTltfG OFFICE: 1956 ts of the t joints ev-vepeli before Hutton is *eps well i against ev. should be fore the [i the re ly reduce abnormal vD _ +< IS, 1960 i- vXtkSLnA'\ , \Jj Uu , k&UU <U1 141 Wood Siding Left To Weather Naturally By F. L. BROWNE Judging from inquiries received from time to time at the Forest Products Laboratory, some people are intrigued by the possibility of leaving exterior wood entirely un finished, to weather naturally. If suitable precautions are taken it is practicable to do so. But whether this is desirable is a question the architect and owner must decide. Paint or so-called "natural" finish, though, is likely to remain the cus tomary treatment for exterior sur faces of smoothly planed wood, and stain for rough wood. Nevertheless, the practicality of weathered wood is adequately demonstrated by much past experi ence. For the first century or so of the American Colonies, particu larly in New England, wood was the predominant building material and the exterior surfaces were left un painted to weather naturally. It was not merely that paint was an imported luxury. To the Puritan mind of the time, painting was an ungodly arrogance for anyone but a high crown official or a very wealthy merchant. There is record of the expulsion of a barber from the Mas sachusetts Bay Colony for aspiring beyond his station in life when he spent part of a small inheritance for painting his house. Many of the wood buldings of the early Colonial period still stand. Most of them, of course, were painted when it became socially ac ceptable to do so, and they have been kept painted since. But some, including two of the oldest houses that remain, have never been painted. New Englanders claim that they have the oldest wood house in the United States, now known as the Old Fairbanks House at Dedham, Mass. The first part of the house was built in 1636. Most of the clap board siding was replaced in 1903 but has now stood nearly 60 years (AlV. Browne is a Chemist with the Forest Products Laboratory, Forest Service, U. S. Department of Agriculture, Madison, Vis. without paint. The oldest portion of Hartwell Farms at Arlington, Mass., also built in 1636, is still covered with the remnants of the original clapboards. From 1858 to 1932 the Amana So ciety owned communally seven vil lages in Iowa County, Iowa. The houses were of wood and were left unpainted except for window sash and doors, which were painted. When I saw them for the first time in 1927 the houses were well main tained. The chief carpenter told me that the Vz- by 6-inch bevel siding lasted from 30 to 50 years before they found it advisable to begin making replacements. In 1946, fourteen years after the Part of a 25-year-old signboard made by stenciling letters on unpainted wood. Erosion of the unprotected wood by weathering left the letters embossed one-sixteenth inch. Such evidence as this is basis for the conclusion that wood weathers away about 14 inch in a century. residences passed into private ownership, I again visited two of the villages. To me by far the most attractive and neatly kept houses were those that remained loyal to the old custom, with the siding un painted but with comer boards, facia boards, and window and door cas ings, as well as sash and doors, deco rated with paint. The houses mentioned so far were all very modest dwellings, left un painted for economy or to conform to local custom of the time. But there are at least a few' examples in mod ern times of more pretentious build ings for which weathered wood was chosen strictly for its appearance. Two of those I know are hotels that must attract patrons to remain in business. Pilot Butte Inn at Bend, Ore., and the Redwood Inn at Scotia, Calif., are the leading hotels in their communities. Both were in opera tion for several decades without paint. The Process Of Wood Weathering Wood exposed outdoors, such as siding and trim on buildings, if with out protective painting or treatment changes materially in appearance for a few months or years, after which it stays nearly unaltered for a long time. The color of the wood is affected very soon. Ail woods change toward a brown color. Woods like redwood and red cedar, which owe their color largely to substances soluble in water, may first become bleached before the browning be comes observable. Still later all woods turn gray. The changes in color reveal chemi cal changes in wood during weather ing under the action of sunlight, air, and water. Only those parts of the wood close to the exposed surface are affected. The surface first dark- N41698.69 FLB 001203 142 ens to a brown color that penetrates 0.02 to 0.10 inch into the board. The brown layer retains the normal ar rangement of wood cells in orderly rows. The brown color comes chiefly from decomposition products of the wood lignin. Later, as rain leaches the brown decomposition products, a gray layer 0.003 to 0.01 inch thick, consisting of a disorderly arrangement of loosely matted fibers, develops over the brown layer1. The gray layer is composed chiefly of the most leach-resistant parts of the wood cellulose, rain having extracted from it nearly all of the lignin and much of the more sensitive parts of the cellulose. From the cellulose the xylan and arabinan are leached most extensively, the galactan and mannan somewhat less so, and the more resistant glucosan least extensively. As substance is lost from the sur face, the brown and gray layer s move more deeply into the board, but the process is so slow that only 14 inch of thickness is lost in a century. Where precipitation occurs as snow rather than rain, as in high moun tains, the lack of leaching keeps the gray layer from forming and the wood remains brown indefinitely. Weathering produces physical as well as chemical changes. Wood near the exposed surface of a board fluc tuates between wet and dry con ditions more rapidly than the in terior of the board. The swelling and shrinking stresses set up thereby soon begin to roughen the surface. First the grain becomes raised; that is, the hard bands of summerwood rise above the softer springwood be tween them. Then minute checks or cracks begin to appear in the surface and steadily increase in number until the surface becomes decidedly rough. The chemical changes in the gray layers add to the roughness and in addition make the surface of the board soft. Besides the many minute checks in the surface, most woods soon de velop some larger and deeper checks or cracks that are easily visible and may become conspicuous. As a rul$, the woods of moderate to low density acquire fewer of the conspicuous checks than do the woods of high density. Edge-grain boards check wx ySX Q q z {L +< +1 q less than flat-grain boards of the same variety of wood. As a result of the weathering process there is a tendency for boards to cup, warp, and pull at their fastenings. Firmer nailing may therefore he necessary when wood is left to weather than would be re quired if it were kept well painted. The cupping tendency varies with width and thickness of the boards. The greater the width in proportion to the thickness, the greater is the tendency to cup and pull at the fastenings. Although %- by 6-inch bevel sid ing was considered satisfactory by the Amana Society, 3A- by 6-inch siding would serve much better. For best results the width of the boards should not exceed eight times thenthickness. Cypress, hemlock, white pine, ponderosa pine, and spruce usually weather to a light-gray color that often has a silvery sheen. A darker gray with little or no sheen is de veloped by red cedar, Douglas-fir, fir, Southern yellow pine and red wood. Red cedar, cypress and red wood commonly acquire fewer con spicuous checks or cracks than other woods do. Similarly, cypress, red cedar and redwood generally have the least tendency to cup and pull at fastenings; whereas pine, fir, hem lock, spruce, Douglas-fir, and South ern yellow pine require firmer nail ing to hold them in position. Development Of Weathered Appearance Takes Time Although the appearance of weathered wood is attractive for suitable architectural effects, there is difficulty in making use of it for new construction, in that much time is required for the change from new to weathered lumber. Moreover, the change seldom takes place evenly over the different parts of a side wall. Those boards that receive most rain and sunshine become weathered first. Usually the lowest courses of siding on the south wall become fully grayed and roughened sooner than the top courses of siding under the eaves and much sooner than courses of siding under a porch roof. Wide overhang at the eaves delays the weathering of more courses of sid ing Lhan a narrow overhang does. Thus for a year or two, there is a mottled appearance, varying from nearly bright lumber to gray weathered wood. The unequal delay in attaining the weathered appearance can be avoided by using rough-sawed D _ rathe lumb a gra be n umbe linsee other be ap; is bui worn velopt color. On used given ness o a prod someti A nur supply descrit sealer pigmer When 1 may be renewi; proves cation and lea weathei -Need When allowed to recei ticulai-ly nails us< ware th. with it i ing. The rust ra John R. Ti bevel sidii, level. Sout istic gray i already giv establisht FLB 001204 |D _ +< 15, 1960 rather than the smoothly surfaced promptly penetrates into the wood lumber to begin with and applying for some distance from the nail a gray oil stain. Such a stain can heads. In some woods such rust be made, for example, from raw makes reddish brown stains, but in umber in oil, white lead in oil, boiled woods that contain tannins, such as linseed oil and mineral spirits or cedar and redwood, the stains are other paint thinner. The stain need bluish black and very unsightly. be applied only once when the house Corrosion-resistant nails, such as is built; by the time the stain has galvanized, cadmium-coated, or worn out the wood will have de aluminum nails, avoid such difficul veloped its natural weathered gray ties. color. Although the weather appearance On some houses bevel siding is may dispense with periodic renewal used with the planed side out and of paint or finish, it should not be given the color without the rough ness of weathered wood by applying a product known as bleaching oil or used as an excuse for neglecting periodic inspection and careful maintenance of the building. Even sometimes as redwood bleaching oil. when care is taken to provide firmer A nunjber of paint manufacturers supply such products. They may be nailing than usual, some nails gradually become loosened and part described as natural finishes of the ly withdrawn by the operation of sealer type in which there are some the forces of wood weathering. Every pigments to give the gray color. four or five years such loosened nails When bleaching oil is used, the wood need to be driven in tightly again. may be kept smooth indefinitely by Likewise, the same care about keep renewing the finish as often as ing joints tight, repairing gutters, proves necessary, or the first appli and making other minor repairs that cation may be allowed to wear off would be taken with a painted house and leave the wood in its naturally is needed when the wood is allowed :r :d re h dl ?' ah- a- weathered condition. Need For Rust-Resistant Nails When' exterior wood is to be allowed to weather naturally or is to receive a natural finish, it is par ticularly important to see that all nails used to fasten it and all hard ware that may be placed in contact with it are highLy resistant to rust to weather. Exterior wood, then, may properly be allowed to weather naturally without protection by paint or other finish whenever it proves desirable to obtain an architectural effect in that way. For weathered wood it is wise to select the kind of wood care fully to obtain the intended result; and it is particularly wise to use ing. The heads of ordinary iron nails f' 1 ' rust rapidly, and the iron rust for I lumber that is thick enough in pro portion to its width, to see that it is tere for 1 1 ;ime I new , the enly side most ibred 1 es of fully than sr the jurses Wide rs the. >f siddoes. iere is g from gray John R. Talbot residence in Madison, Wis., built in 1958 with unfinished redwood bevel siding on upper level and vertical tongued-and-grooved siding on lower level. South end of house shown was in advanced state of weathering to character ling the istic gray tone when photo was taken in September 1960. Weathered siding has m he |:. already given this ranch-style house an appearance of being long and comfortably i-sawed | established on its hilltop location--an effect enhanced by Wood-shake roof. t 143 very firmly fastened with rustresistant nails, and to provide the same care in maintenance that would be given to a painted building. Home Building Peak For 1961 New home starts should reach the second highest peak in U. S. history in 1961, say housing economists who claim to know. The figure given by most of these experts is 1,424,000 new home starts in the upcoming year, with an all time high cash investment of twenty billion dollars. Private industry will build 1,375,000 new homes in 1961, the men who profess to know claim, and 22,000 will be built on farms with smaller amounts allocated to various types of public housing. There will be plenty of money to borrow for home purchases. Family incomes are also up. But the big thing in home building next year will he competition, and this may well force builders to put more into their houses, and to create the most livable possible product. * Mistletoe A Pest Mistletoe may be a boon to lovers during the Christmas season, but it brings no joy to the guardians of California forests. John R. Parmeter, Jr., assistant professor of plant pathology at the University of California in Berkeley, reports that small, leafless dwarf mistletoe looms as the No. 1 disease menace to coniferous trees in the state. The plant is causing millions of dollars of damage annually to red and white fir, sugar and ponderosa pine, and Douglas fir. Paruieter explained that dwarf mistletoe is a parasite which at tacks tree trunks and branches, and that, although it reduces the growth rate and quality of older trees, it seldom destroys them. Ironically, heavily-infected young trees are usually rendered worthless as Christmas trees and eventually die. Parmeter is conducting a study of dwarf mistletoe with the aim of de veloping effective means of control ling it. FLB 001205 The Multiple Use Act it {$ By George S. James, Since 1905, the Forest Service Ifas managed National Forests under principles of multiple use and sus-x- tained yield. Yet, as recently as June 12, 1960, the President signed the Multiple Use-Sustained Yield Act (Public Law 86-517) which di rects that the National Forests be managed according to these princi ples. To appreciate fully the need for the Congress to reaffirm these principles, which have been fol lowed for more than 50 years, it is necessary to understand the histori cal development of the National For Mr. Janies is Assistant Regional Forester, Southern Region, U. S. Forest Service, Atlanta, Ga. esb-y. The creative Act of Congress, approved on. March 3,1891, gave/the President power to establish forest reserves from the public domain. During the next 14 years, 60 forest reserves were proclaimed^ totaling about 56 million acres. /The forest reserves at this time were under the administration pf the Department of Interior, \/ as a major milestone in the devel opment of the National Forest sys tem, in the East particularly. It authorized purchase, for National Forest purposes, of forest lands nec essary to protect the flow of naviga ble streams- Most of the present National Forests east of the Great Plains were established by purchase under this act, since there was little public domain left; At the present time the National Forest system in cludes more than 180 million acres of publicly-owned forest and water shed lands in 39 states. est program and the tremendous needs, now and in the future, for using the resources on these public forest and watershed lands. ' For. M. The Forest Development Of The National Forest Program The 1891 legislation authorizing Early History Of Forest Conservation On February 1, 1905,''the forest reserves were transferred toNthe De partment M Agriculture, anHx Gif the establishment of forest reserves made no provision for their admin istration or use. This was corrected In the first century of American ford Pin^hot became "the first Chief by the Organic Act of June 4, 1897, independence forest land was cheap of the/Forest Service. In the ne^t which authorized the hiring of em and plentiful. Forest owners usually two years, the establishment of new, ployees to protect and administer aimed at a quick return from cutting area/ by Presidential proclamation \ the reserves and thus make possi the timber and selling the cleared increased the size of the forest re ble their use. This basic act, with land to settlers. Some far-sighted serves to more than 100 million later amendments, was the one un- efforts were made to check the .acres. These lands were located al- del\which the National Forests were wasteful destruction of forests, and /most wholly in the public domain admihistered prior to the Multiple about 1850 several states initiated y* states west of the Great Plains. The Use-Sustained Yield Act of 1960. action to protect their forest re-/ name "Forest Reserves" was On February 1, 1905, the day the sources. A few passed laws encoui4 changed to "National Forests" in forest resei^ves were transferred aging tree planting. In 1873 /the 1907. from the Department of Interior, American Association for the/Ad- East of the Great Plains the Na Secretary of \Agriculture James vaneement of Science memorialized tional Forest system got under way Wilson wrote a\letter to Gifford the Congress and the states concern in 1907 with the proclamation by Pinchot, the fbst\Chief Forester, ing the importance of preserving President Theodore Roosevelt of the laying down the Basic principles the forests and the need for legisla Arkansas National Forest This was which the Forest Service has con tion to secure this objective. In soon followed by the establishment tinued to follow. This Wk(:oric letter 1876 the Congress/ appropriated of the Ozark National Forest also said, in part; "In the administration funds for a study .of the nation's in Arkansas, the Ocala and Choc-- of the forest reserves it musbclearly forest conditions./Three extensive tawhatchee National Forests in be borne in mind that all land'-ls to reports were sufeinitted to the Con Florida, and the Superior National be devoted to the most productive gress during the seven years which Forest in Minnesota. (The Choc- use for the permanent good of th followed. A small Division of For lawhatehee has since been taken whole people and not for the. tem estry was established in the Depart over by the Defense Department porary benefit of individuals or ment of Agriculture in 1881, and and is known as the Eglin Air Force companies. . . . You will see to it reports and bulletins were published Base.) that the water, wood, and forage of to increase public interest in for- The Weeks Act of March 1, 1911, the reserves are conserved and FLB 001206