578 



THE INDIA RUBBER WORLD 



May 1, 1921 



IL&TEBIAL 



7. The material from wliich the bags and other rubber pieces 

 arc made shall contain 92 per cent by weight of new washed and 

 dried hard fine Para or the highest grade only of new Hevea 

 plantation rubber. 6 per cent by weight of sulphur and 2 per cent 

 by weight of magnesium oxide. . 



8. The rubber compound shall be properly vulcanized and 

 shall have all the characteristics of a compound of the above com- 

 position. , . . . , ,, , J 



9 The fabric strips and all other fabric pieces shall be made 

 of cotton duck weighing about ten (10) ounces to the square 

 yard. The count per square inch of the warp and filler shall be 

 approximatclv equal. . , „ . .,r • 



10. The fabric strips and all other fabric pieces shall be tric- 

 tioned" and "skim-coated" on both sides with the rubber com- 

 pound specified in paragraph 7, and must be properly vulcanized 

 to the bag to give a good adhesion. 



Lacing Cord 



11. The cord for lacing together the two portions of the bag 

 shall be a Venetian blind cord or equal, of such size as to enable 

 it to just pass through the holes of the eyelets. The ends of the 

 cord shall be dipped in waterproof stiffening material to facili- 

 tate lacing. 



Grass Mat 



12. The mat to be used between the rubber bag and the gaso- 

 line" tank shall be an unwoven grass mat, approved by the In- 

 strument Department, Production Engineering. 



MANUFACTURE 



13 The bag shall be smooth and free from pitting or other 

 imperfections. It shall have a uniform thickness of 1/16-inch, 

 and shall be plied on the calender into a solid body, free from air. 

 No minus variation in thickness will be allowed. 



14. All pieces of fabric or rubber shall be vulcanized to the 

 bag by heat at the same time the bag is vulcanized. 



15. Joints shall be thoroughly cleaned before being overlapped 



FACILITIES FOR TESTING 



16 The manufacturer shall provide the necessary testing 

 equipment, approved by the Inspection Department. He shall 

 provide the necessarv assistants for making the tests. 



17. Tests shall be made at the manufacturer's plant or at a 

 place designated bv the Inspection Department. 



18. The manufacturer shall bear the cost of all tests and shall 

 supply the material ready for testing without additional cost to 

 the purchaser. When bags are not tested at the manufacturer's 

 plant, the manufacturer shall pay all cost of transportation in 

 addition to the cost of the tests. 



Test Specimens 



19. The manufacturer shall, at his expense, furnish with each 

 "heat" of bags a sample of vulcanized rubber at least eight (8) 

 inches square and 1/16-inch thick. A fabric strip, one and three- 

 quarters (1J4) inches wide and eight (8) inches long, shall be 

 wholly vulcanized to the rubber along one edge. 



20. The manufacturer shall guarantee that the sample fur- 

 nished was vulcanized with and under the same conditions as the 

 bag which it represents. He shall also guarantee that the mate- 

 rials in the sample are the same as those used in the bags. 



Tensile Test Specimens 



21. Tensile test specimens of the ruliber shall be cut with a 

 die from the sample furnished by the manufacturer or from a 

 sample bag. 



22. .-\dditional test specimens of rubber shall be cut from the 

 sample bag in such manner as to include a joint in the rubber 

 between the component pieces of the bag. The sample must be 

 cut at right angles to the joint so as to include the joint in the 

 center of the constricted portion. 



23. The constricted portion of the specimens shall be one- 

 quarter (%) inch wide, and shall have smooth edges. 



Friction Test Specimens 



24. Friction test specimens shall be cut to a width of one (1) 

 inch from the sample furnished by the manufacturer or from a 

 sample bag. 



TESTS 

 Tensile Test 



25. The tensile strength of the specimens selected as specified 

 in paragraph 21, must be at least eighteen hundred (1800) pounds 

 per square inch. 



26. The elongation of a two-inch section at the breaking point 

 must be at least 700 per cent. 



-'7. The permanent elongation must not exceed 12V'2 per cent 

 when the specimen is stretched from two inches to fifteen inches, 

 held in the stretched position for ten minutes, and then released 

 for ten minutes. 



28. The specimens selected as specified in paragraph 22 must 

 not fail in the joint. 



Friction Test 



29. The "friction," or the adhesion of the fabric strips to the 

 rubber body, must be such that a load of 12 pounds shall not 

 cause a separation at a rate greater than one inch per minute. 



INSPECTION, EEJECTION AND REPLACEMENNT 



30. All finished bags, and all materials used in the construc- 

 tion thereof, shall be subject to inspection by the Inspection 

 Department of the Bureau of Aircraft Production under its 

 Manual of Inspection. 



31. Acceptance or approval of materials in process shall in 

 no case be construed as a guaranty of acceptance of the finished 

 articles. 



32. The inspector shall have full and free access to all parts of 

 the manufacturer's plant concerned in the manufacture of these 

 bags, and the manufacturer shall at all times afford him adequate 

 facilities for determining that the materials and the bags conform 

 to this specification. The inspector shall also be afforded oppor- 

 tunity to check and mark all materials in process or in stock. 



33. The manufacturer shall furnish adequate private office 

 space and office furniture for the use of the chief inspector and 

 assistants. 



34. All accepted bags shall be plainly stamped with the 

 official acceptance stamp of the Bureau of Aircraft Production. 



35. Rejected bags shall not be resubmitted after replacement 

 of defective material witlumt the express consent of the chief 

 inspector. 



36. The manufacturer's name or trade mark, the Bureau of 

 Aircraft Production order number, size of bag, and the date of 

 manufacture, shall be permanently impressed on the two sections 

 of the bag. 



37. The manufacturer shall pack with each bag the proper 

 length of cord for lacing together the two portions of the bag. 



38. The manufacturer shall also pack with each bag sufficient 

 grass matting to completely envelop the tank. 



39. The manufacturer shall furnish and pack with each bag 

 printed instructions, approved by the Bureau of Aircraft Pro- 

 duction, for its installation. A small envelope to contain these 

 instructions shall be supplied, printed as follows : 



IMrORT.AXT 



Do Not Throw This Envelope Aw.^y. It Contains In- 

 structions roR Inst.m-linc Rt'BEER B\GS ON Gasoline Tanks. 



40. The bags shall be packed for domestic or overseas ship- 

 ment as directed by the purchaser. 



RUBBER GASKETS FOR GASOLINE TANK FITTINGS 



Specification No. 16,008.,A, September 25, 1918 — Supersedes Specification 

 No. 16,008 



16,008 



GENERAL 



1. This specification covers the general requirements of the 



Bureau of Aircraft Production for rubber gaskets to be used on 



gasoline tank fittings. 



MATERIAL 



2. The material from which the gaskets are made shall contain 

 not less than 32 per cent of washed and dried fine Para or first 

 latex crepe, not more than 1 per cent of free sulphur, with the 

 remainder suitable dry inorganic mineral fillers. 



3. The rubber compound shall be properly vulcanized and 

 have all the characteristics of a compound of the above composi- 

 tion. 



MANUFACTURE 



4. Gaskets shall be cut on a lathe, molded or stamped from 

 the vulcanized rubber compound. 



5. Gaskets must have smooth faces. 



6. Dimensions. Gaskets shall conform to the dimensions 

 called for on the drawings or in the order. 



INSPECTION 



7. The inspector shall have free access to all parts of the plant 

 where the gaskets are being manufactured and shall be afforded 

 every reasonable facility to satisfy himself that they are in accord- 

 ance with this specification. 



Communications regarding all technical matters pertaining to 

 specifications should be addressed to the Specification .Section, 

 Bureau of Aircraft Production, U. S. Army, Dayton, Ohio. 



