Document 69152bLN94XdkLK1avk8Y4vE

DUP 000255 Making White Pigments HE first step in the making of paint T is the selection and preparation of the pigments. Upon the care and Romans called it "ceruse" and made it by exposing lead over sharp vinegar, which differs only slightly from the mod purity, and more efficient methods of handling. The metallic lead from which white lead skill with which this is carried out de ern practice. Progress has been chiefly m is made occurs in nature as an ore, which pends in large measure the excellence of the direction of greater fineness, higher must, of course, be mined and refined be the finished product. fore it can be made into a pig Paints are mixtures of solid ment. The ores of lead occur in particles or pigments and a liquid veins and pockets far under the or vehicle. Pigments are finely surface of the ground. They are ground metallic, earthy or animal associated with other minerals substances which give to paint which must first be removed. body, hiding and covering quali The lead is then cast into bars or ties, and color. The vehicle is a pigs and is ready to be made into ' liquid in which the pigment parti the white lead of commerce. cles are held in suspension, with The Dutch are credited with the object of producing a durable being the originators of the proc paint film, uniform in color and ess by which most white lead is consistency. made and which is called after In making a good paint many them--the Dutch Process. In different pigments are used, and it this process the lead is first melted is only by their most careful selec and cast into "buckles," so called tion and mixing that the best re because of their fancied resem sults can be obtained. One pig blance to the shoe buckles of ment may have good covering colonial times, but which look qualities but lack durability. much more like the round waffles Another may be much more dur of the present day. These buckles able but lack the necessary hiding are then placed in earthen' jaife qualities. Still a third may have over a small quantity of weak the property of neutralizing ele acetic acid--which is practically ments in the paint film that our domestic vinegar. The pdts, would otherwise impairits stability filled with buckles, are then piled or shorten its life. The very twenty or thirty feet high 1 in highest order of skill on the part huge sheds in what are known' as of the p&intmaker is required in "corroding stacks." Each corrpd- order to select and combine those ing stack, which is as big as a pigments best adapted for the house, is built up of alternate purpose. layers of corroding pots and sp^nt The oldest and most frequently tan bark, which is nothing mbre used pigment is white lead, which than oak bark that has been u ed was used as a paint material be in tanneries. - fore the Christian era. The A Modern CrmM Ucod for Renoriiii Corroded 1 -- d from Or Stocks In thecorrodingstacks, whichkre tnoido t Corroding Stock DUP 000256 16 closed nghr < \rcpf fur -mall un tunes for vonularion. tin- tm lurk bum* u> -lowly decompose and give oiT carbon dioxide gas, which is the <ame thing that our lungs give off when we breathe. In fermenting, the tan bark also generates heat, which warms the acetic acid until it forms vapor. The vapor rises up through the lead buckles and gradually turns them white, for acetic acid has the power of corroding load. It is the nature of lead to turn white when it corrodes just as iron turns red and cop* per green. The white substance is lead acetate. But that is only half the story. As fast as the lead is corroded the carbon dioxide which is constantly being given off by the fermenting tan bark attacks it. A chemi cal change takes place and converts the lead acetate into basic lead carbonate, or, as we call it, white lead. The complete process so briefly described takes from three to four months. The stacks are then torn down and the particles of white lead ground in linseed oil. The resulting product is the finished pigment--the white lead in oil of commerce. The Carter, or. as it is sometimes called, the quick process is also in common use for making white lead. Here the change from lead to white lead takes place in fif Du Pont Magazine teen day*, -o that there is a decided -uving in time over the Dutch process. In this proresv the lead, instead of being piled m Macks, is powdered from the molten con dition and placed in large closed wooden cylinders winch revolve slowlv. While they revolve, acetic and and carbon diox ide arc introduced into the cylinders and eorrode the lead, converting it into lead carbonate in much the same way as in the Dutch process. White lead, the most commonly used of all paint pigments, has the greatest cover ing power of any of the white pigments. That made by the Dutch process has unusual hiding power, while the quick process lead has better whiteness and spread. The best paints are, therefore, made by using for the white lead base a mixture of stack and cylinder process lead. Such paints have greater dura bility and combine the advantages of each. Unfortunately, white lead pro duces a rather soft surface in the com pleted paint film and it is turned black when it comes in contact with sulphur fumes in the air. It cannot, therefore, be used satisfactorily in paint without having another pigment present to count eract these tendencies. The pigment usually used in paint in April, 1918 conjunction wi'h iuul is /.inc -i\ide This pignimt has been m use far only about sixty vears. but its use has assumed tmportant proportions m the paint trad*' Like white lend, it is made by two pro cesses. In the indirect, or. as it is some, times called, the French process, the metallic zinc is subjected to extreme heat which converts it into vapor. The vapor or "smoke.'' as it is called, is conducted through largo chambers where the zinc oxide settles in the form of dust. In the direct, or American process, the zinc oxide is made direct from the zinc ore, which is mixed with fine anthracite coal and charged in furnaces. The gases are conducted into huge bags or filters which retain the zinc oxide dust but allowthe other gases to pass through. As a pigment, zinc oxide is very long wearing and has good covering power. It is second only to white lead in this respect. While lead when used alone produces a film that is too soft, zinc oxide, on the other hand, when used alone, has a ten dency to produce a paint film that is very hard and brittle. These two pigments are, therefore, nearly always used in com bination with each other so as to counter act the defects of each and produce a wellbalanced paint. Muff!* Burner Wti*r* Rock * Burned in Making Litkopoaa DUP 000257  `r' " Lithopoo* Filter pTtMM Sublimed white lead or lead sulphate, Watch the Details that are poisoned or diseased in such a as it is commonly known, is also made way as to make the crops unprofitable. directly from the raw ore in practically During this period, when unprecedented This should be avoided by careful rota the same manner as zinc oxide. It has a activities are demanding the fail tunc of tion. fine grain and produces a film a little oven* worker, many details are likely to Only the l>ost seeds should be selected, harder than white lead, but not quite so go without notice. In many cases this as faulty seeds cannot be expected to elastic. It dries very slowly, and, of may not have a bad effect, but in farm produce satisfactory crops. course, this is a good quality for it pro operations neglect of certain details can The little details of crop growing must longs the life of the paint film. A fourth class of white pigments are the leaded zincs, which are usually about result only in failure. This is especially true of orchard and garden pests. Many orchards appear to l>e healthy during the l*e as closely watched by the gardener as they are hy the extensive farmer if suc cess is to be expected. i half and half lead sulphate and zinc oxide and partake of the nature of both. They are made in the same way as sublimed white lead, by heating the ore and col lecting the dust in chambers. The leaded zinc pigments lack the covering power of white lead, but they are more durable and less likely to chalk. One of the newer pigments used in the paint industry is lithopone, or Beckton White, which has become exceedingly winterand spring months, but laterdevelop troubles of one kind or another that abso lutely ruin the fruit crop. The only guard against these troubles is constant spray ing. a detail which should never be neglected at any time. In the anxiety to produce the maximum amount of fo<xl crops, there is a likelihood of planting crops on lands to which they are not suited, or on lands that have already become sick of these crops, or Why Watte Time? "Why do you consider women to be superior to men in intelligence?" "A bald-headed man buys his restorer by the bottle, doesn't he?" " Er--yes." "Well, a woman doesn't waste time on a hair-restorer; she buys hair."--London Passing Show. popular in the last few years, particularly for interior painting. It is a mixture of ` the solutions of the salts of zinc and barium. These are mixed together in the proper proportions in a vat, and the litho pone precipitated in the form of a powder. This powder is then washed, baked, and ground very fine, and it is ready for use as a pigment. Many other pigments are used in the manufacture of paints. The more im portant of these will be discussed in a later article. Held Hi* Audience The Lecturer--There was one time in my life when I had no difficulty in hold ing an audience. The Sympathizer--When was that? The Lecturer--The night I proposed to my present wife.--.4 nailers Spraying tb Only 3*fcu*rd Aiainst Many Orchard Pc*t DUP 000258 32 Du Pont Magazine April, 1918 iJW311IIIIE a!DU PONT AMERICAN INDUSTRIES? laf For the convenience of buyert considering the purchase of any Du Pont product, and desiring specific information, this coupon is printed. Upon receipt, it will be forwarded immediately to the proper office for attention. Fill in, Cut Out and Mail This Coupon I Du P.r r. \pr. -IS) Sales Promotion Division Date E. I. du Pont de Nemours & Co. Wilmington, Delaware i--! M EXPLOSIVES 3 Farm Explosive* Blasting Supplies Industrial Dynamites Blasting Powder Q Permissible Explosives 3 Road Building Clay Mining Land Clearing Tree Planting Charcoal Wood Pulp Saltpetre Refined Nitrate of Soda PAINTS Town and Country Paint Colon in Oil Vitrolac Varnish Vitrolac Stain Finish 0 Flowkote Enamel Duliee for Mills Antoxide Iron Paint Shingle Stain Auto Finish Sanitary Wall Finish Q Bridgeport Standard Paint Wheeler's Wood Filler Bridgeport Wood Finishes Smokestack Paint Floor Varnishes Q Floor Paints Enamels Concrete Paint Marine Paints Industrial Paints 3 Railway Painta Ferro-Keep (Metal Paint) Bam Paint Wagon and Carriage Paint Auto Paints and Enamels O Decorative Stains Varnishes Wire Screen Paint Japans Shellac - Red Lead SPORTING POWDERS Hunting Trapshooting Q Black Sporting Powder Smokeless Powder a Hand Trap O Rifle Smokeless Powder Pistol Smokeless Powder Resort Shooting Shooting in Colleges Shooting on Boats O Carpolene (Wood Preservative) q Wood Oil Dead Oil Belt Cemenr Household Cement Blanc Fixe q Solvents Leather Substitute Solutions Split Leather Solutions a Patent Leather Solutions Coke Belt Cement CHEMICALS 3 Acids White Lead Alums Lithopone Litharge Rubber Makers White Dry Colors 3 Pulp Colors Salt Cake Barium Chloride Q Distilled Water Bronze Powder 3 Bronzing Liquids Wood Lacquer 3 Metal Lacquer 3 Waterproof Cement 3 Py-ra-lin Enamel Pontar Pontoklene 3 Pitch 3 Pegamoid Aluminum Paint 3 Mantle Dips Leather Renovators 3 Ether 3 Parlodion a Niue Cake Creosote G Shingle Oil' Pyroxylin Soluuons 3 Benzol Products Carpo (Metal Paint) PY-RA-LIN Py-ra-lin Toilet Goods Challenge Ocanable Collars Novelty Sheeting Transparent Sheeting Py-ra-lin Rodj and Tubes Py-ra-lin Pipe Bits O Py-ra-lin Specialties Brushes Q Mirrors Combs Toilet Sets 3 Manicure Sets Desk Sets Colored Sheeting COATED TEXTILES Fairfield Rubber Cloth Rayntite Top Material Motor Fabrikoid Craftsman Fabrikoid Truck Special Fabrikoid Marine Special (U. S. Standard) Shoe Soecial Book-Finish Fabrikoid Fabrikoid Sheering 3 Home Uses for Fabrikoid Fabrikoid for Baggage Fabrikoid for Upholstering Rug Anchor O Hat Sweat Material 3 Buggy Aprons Fabrikoid for Railway Cars Name...... Position Your Address (If Personal) ................. ............ Name of Concern (If Company) ........... .............. Address of Company ........................................... BUSINESS: I] Manufacturer; Z Producer; O Jobber; Dealer; Z Consumer. (Check which) What Du Pont products do von sell?............... ...................................................... If a user, for what purpose does the product checked, or that which you now use, interest you ? ................ Specific Questions Should Be Asked In An Accompanying Letter mi in | ?= p=4 ! P1 miiTrimnri"nminiTfriii rrrmTrrrmTir DUP 000259