Document qkRrXyZYQwx1mmO9G8Bk8dM1q

342-1002 Copies: 100-300-640-X REPORT t o vi Name of Co.: HE ROESSLER AND HASSLACHER CHEMICAL CO. Depaitaient : SYNTELLAO n /> ^' fi \ ' . > *-C NOTES ON CIRCULARS AND SCIENTIFIC! PAPERS, BUREAU OF STANDARDS. Author : A< L, PITMAN Date Fane 26, 1926. -0...T CIRCULAR 117 - U. S. Government Specifications for Interior Varnish.. A list of specifications for all such varnishes. The only test retuirel for which we have not apparatus is that of flash in a closed cup* The required value is so low, 30*0., that wo should pass it on alcohol solutions of Syntellao readily. It is required that the solution he clear, whioh would limit us to grade *F* H composition of Syntellao, to my knowledge, will stand the 18 hours water immersion repaired without whitening. A rubbing test is given on p. 6. Most artificial lacs are .un satisfao to ry for cabbing work. tive * There appears part missing, though the page numbers are consecu OIBOUT.aR t o . 69 - Paint and Varnish Issued in 1917 - 83 pp. little mention of shellao P. 27 for reference on shellac varnish analyses B. 59 Shellao for a liquid filler on closed grained wood. P. 80 and 81 a brief glossary of terms. A good brief review of paint and varnishes as a whole. CIROTOAR No. 471 - Methods of Measurement of Properties of Bleotrio In- ! 1 - gqiaxing~Ba teria1s ! ELECTRICAL PROPERTIES: Phase difference. This is a measure of the power loss. It Is the most important test for high frequency work, low power loss in radio work means sharper tuning. When this test is made, the dielectric con stant is readily figured, also. Sample apparently required is quite large about 12" x 12" x 1/4*,to Judge from picture. Surface Resistivity. A block of 10 x 10 x 1 cm is about the size used, 'inis value depends on the humidity. gMshfrover-Voltage at faaio frequency. A block 10 x 10 x 1 cm is used. Endurance Test. Break-down ?Qltags The apparatus is not specified precisely. A molded cup is specified for this by a .S. T. M. In Ellis, the electrical properties tabulated are:- Surface resistivity at 00$ relative humility (Otoe) Phase difference at radio frequencies (degrees) Dielectric constant (faradB) Dielectrio strength (volts per mm.) Mtt TSSTS1 fensity and Moisture. Use a 5 x 10 om sheet of thickness as for this. (b &.> This work was on laminated products). Express as gm. water absorbed per cm^surfaoe tension. She modulus of elasticity is difficult to get as the extens!oSisso small in two inches that a very delioate extensometer is required which is liable to be broken at the break of the piece, they had some trouble on the breaking strength, until they got jaws which permitted some self-alignment of the specimen. Impact Strength. The dimeneions of the specimen used are given. Ti is not stated whether these are for the standard Charpy specimen. These dimensions given are 7-1/2 x lxl om. It is probable that an instrument for this determination could easily be constructed. The principle employed is that of measuring the reduction in the energy of a pendulum which has broken the test piece. Permanent distortion. These tests are made on a 12 inch span. It is possible the transverse molded pleoe for the transverse teat would be suitable* MaohiniBg oualitlea So fer as I know, the iype of composition in which"we areinterested is not used for machining. Thermal, expansion. This was tested on a 30 cm. X 1 x 1 cm. piece in an electrically heats1"air oven and using travelling microscopes for thefimeasurement* (for pure iron X find the thermal expansion is 6*7 x 10- per J?. For shellac molding stuffs it is 12 to 23 x 10** per PF. According to Ellis, the compounds of low value give less trouble in complicated molds. A.S.T.M. Preprint 1926. - Report of Committee D-9 on Electrical Insul ating Materials. The follow irxs sms some of the suggestions which have been put forward. Those chosen here appear to be of direct interest to us. Compression test, a cylindrical block which is higher is re commended to replace tbs cube at present recommended. The dimensions are to be 1-1/4" high x 1.128" diameter. Accuracy of tests. Machines are to be good to 1$ at the lowest value usecH A" spheribaT bearing block is specified for the compression test. In the various tests, the machine running idle shall have a crosshead speed not to exceed 0*060 inches per minute. Impact test. Three machines of the Izod type have been made* Some progress was achieved:, bat the Committee is no ready to make recommendations, fl'ram Mr. I. D. Wiliams I find that in the lead type a notched speeimun is held vertical at one end. It is broken by the impact of a pendulum striking at a definite point above the notch and opposite to it. She loss in the pendulum's energy is reooraed) The flash-over Voltage lest is found not well suited to the pur pose intencfecL. 1 "" Surface and Volume Resistance have been found very difficult to separate, "^ CIBOPMR 2g& - IHSULATIHO PROPERTIBS OF SQIIP DIEL33 TRIGS: Descriptions are given of apparatus and calculations required in determining the volume and surface resistivities of materials. The effects of humidity ana temperature are disoussed. The surface festivity is shown to be due to a surface film, usually of water or of oil., on the insulator, This is generally the im portant factor^in determining the leakage between two conductors in sulated by a solid dielectric. Rosin has a higher surface resistance than orange shellac which is better than white shellac (P.389). Sealing warn containing both is nearer rosin. Shellac has as>hhfh'>a volume resistivity as the best bakelite furnished in 19U (.373) , Stokes compared with commercial resins are unique in two respects. (See P.388 and 392-393). 1 - The surface restivity of waxes is very high oompared to resins. 2 - The change with humidity is very little. OCaatBST; It would be'well for the foregoing to be borne in mind, for if some wax can be used, perhaps shellac wax may serve, there are three possible good effects -tfif. one possible bad one. The three good ones are:- 1 - Increased surface resistance, particularly when damp. 2 - less sticking (waxes aid here). 3 - Improved water resistance which is of importance in phone pieces subject to a misty spray.* A possible bad effect is that waxes, especially when in large amount, weaken. OIROHIiAR go 358 - Expansion of Insulating Materials. Bakelite type compositions range between 20 and 40 X 10" ex pansion per 0, Hard rubber is 80 x 10" per C (P.409)o Above 60C a shrinkage sets in which may be quite marked, so much so as to he de terminable by sp* gr. measurements. Other materials as porcelain are also considered. AB.TK* Preprint; b? A.B* Pfund. - feats for BjardneBa. Sloes Oolor and leveling of Varnishes* " (IT. B. A. H Pfund, Professor at Jobns-Hopkins, aid and directed the work recorded here for Du Pont.) Hardness* The scale la that of the force required to press a 2 saa. diameter "sphere into a f ilm to a-given depth. The indentations are measured when the pressure is still applied. Films prepared, by whirling dise method (walker and Thompson A.S.2.M. 22 IJ P.465 1922), gloss Gloss is defined as the ratidTBpeoularly reflected light to tratreflee ted hy a true plane of the same material at the same angle. (Elsewhere in paper testing, Ingalls has a "glarimeter" in which this is defined as polarized to the total reflected. Reflection is made at the polarizing angle). For "normal" gloss the image of two parallel sires 0.5 mm. diameter and*,;am apart, are viewed hy reflection from the surface. "Resolving" power is better, the mors slanting the reflection; determine the angle where the two wires are seen separate. Then measure intensity of speoularly reflected light at that AngLe* For "high" gloss another method is giTen. For oolor - Efund uses two comparator wedges. One is amber gLass, the otter is hollow for the varnish. leveling* This is concerned with obliteration of brush marks. A.S.T.M. Preprint Ho. 49 (1926). - A recording drying time meter for varnishes and similar materials J.McE. Sanderson.;____________________________ S. has developed a machine for measuring the drying time. This gives consistent results; show the time to the loss'of tackiness; the time to hard-dry. He uses as a measure of the first, the time period in which sand on the film cannot he brushed off later. For the time to harddry, he used the time during which the sand can just be tapped off. S. points out that in furniture manufacture, the finishing process earning at the end when schedule interruption is most serious, so that the drying time is an important factor. B. OF S, SCIENTIFIC PAPER NO.*278 - An Investigation of the laws of Plastic ------- *----------------------------- -- ------- FIowTHgene C .I'irigBam''(1916) '------- ;-- According to this paper, when the packing of solid equal-sized spheres in a liquid is at the cubical condition, the percent of solid is a maximum for normal plastic flow. This is at 50$ by volnae'of solids, nearly. When the solids percent is further increased to 74$, we have tetra hedral olose packing. Beyond this point there will be insufficient liquid to fill the pores. Below 60$ scalds by volume, plastic flow is possible. The lower limit below which the mixture behaves as a liquid does not con cern us here. Above 60$ solids, flow is accompanied by rupture and move ment on -the slip planes with slipping. Taking the formula used at the American Composition Oorp., I find that this gives a solid percent by volume value of olose to 50.