300 



THE INDIA RUBBER WORLD 



(March 1, 1919. 



Other rubber pans used in the A. T. mask included a clarifying 

 tube, a Y-sliaped tube leading from the die casting and delivering 

 air from the canister through its two branches to the eye-pieces. 



The chin rest shown in Figure 13 was a molded rubber part 

 composed of a sponge rubber face and a soft rubber back slotted 

 for fastening to the die casting. The surface of the sponge rubber 

 was made smooth in the molding. The soft rubber and sponge 

 were molded separately and cemented together. Production of 

 these two parts was obtained in large quantities with little trouble. 

 Altogether, complete parts were furnished for 364,000 A. T. 

 masks up to the time of the armistice. 



THE K. T. TYPE RESPIRATOR. 



This mask was developed at the Gas Defense plant to meet 

 5he same requirements as outlined in describing the A. T. res- 

 pirator. It was made up by sewing and cementing stiff fabric 

 ■and rubberized stockinet to a frame similar to the frame in the 

 old-type masks. It contained many improvements in harness 

 and fit which led to comfort. Air was deflected upon the eye- 

 pieces by a molded rubber shield. Altogether, 338,000 of these 

 were manufactured in the plant up to the armistice, over half 

 of which were suitable for overseas use and the balance for 

 soldiers in the training camps. 



A stiff and gas-resisting 

 fabric was needed to give body 

 to the mask which would 

 otherwise collapse against the 

 face with each individual. Ex- 

 periments were made to de- 

 velop a stiff and impermeable 

 fabric which was demanded by 

 this type. Several construc- 

 tions were developed. One in- 

 volved the use of one ply of 

 enameling duck impregnated 

 with semi-hard rubber joined 

 by cement to a ply of the regu- 

 lar gas-mask fabric. Another 

 used a preliminary stiffening 

 treatment of the duck followed 

 by rubberizing and doubling 

 with the regular fabric. The 

 last named method produced 

 the most satisfactory fabric, 

 giving great elasticity, yet 

 sufficient stiffness for the purpose, for which it 

 HARD RUBBER ANGLE TUBES. 



The angle tube (see Figure 5) was ordinarily made of alumi- 

 num by the pressure-die-casting method. This process required 

 complicated dies and cores, and in the spring of 1918 it became 

 evident that the capacity available was not going to be sufficient 

 for the needs, and attention was directed to the possibility of 

 hard rubber as a material. 



The various hard rubber companies cooperated in the develop- 

 ment of this article and, working with the Rubber Committee, 

 developed specifications. The great question to be determined 

 was the degree of hardness desirable and whether or not the 

 threads would stand temperature changes. Tests were made in 

 great numbers in cold storage and in warm weather to decide 

 points in the specification. The merits of various methods of 

 manufacture were discussed in meetings. The consensus of 

 opinion of the Rubber Committee in conference with manu- 

 facturers and Gas Defense representatives was that hard rubber 

 as a material \vas satisfactory for use but not as satisfactory as 

 metal. The 700,000 deliveries of this product justified this con- 

 clusion, as much trouble was encountered due to variation in 

 hardness and in dimensions. Some were so soft as not to 

 permit assembly to masks. 



Fig. 18.— Rubber Workshois L(.,v(, I.-.l.\;mj L 

 Long Island City, New York. 



itended. 



Other materials furnished by the rubber industry included 

 zinc-oxide adhesive tape, rubberized felt for the bands of the 

 R. F. K. type mask, strapping for covering sewed seams on the 

 K. T. mask, rubberized stockinet for the K. T. mask, and 

 molded rubber air deflectors for the K. T. type mask. Several 

 thousand oxygen inhalers (Fig. 16), were shipped overseas for 

 use in treatment of gassed soldiers. The rubber parts involved 

 in this equipment included a face mask of metal filled with a 

 pneumatic rubber cushion, a flexible armored rubber hose, and a 

 rubberized fabric breathing bag to regulate pressure. 

 REGARDING SPECIFICATIONS. 

 The policy followed by the Gas Defense Division in harmony 

 with the advice of the Rubber Committee w-as to use only the 

 best materials throughout. Organic accelerators were barred 

 from general use for two reasons: (I) certain parts were in 

 contact with the mouth or face and (2) the use of these accel- 

 erators by the trade was new and not fully developed. In the 

 case of the A. T. mask and parts in contact with the face, lead 

 compounds were not permitted. This was due not to the knowl- 

 edge that lead poisoning could be trarrsmitted in this manner, 

 but to the knowledge that skin irritations were liable to develop in 

 some cases from heat and eon- 

 tact, and it was not considered 

 advisable to have a discussion 

 as to the effect of lead in such 

 cases. This requirement made 

 a difficult compounding prob- 

 lem for the manufacturer, es- 

 pecially since a non-blooming 

 product wa» desired. 



Reclaimed rubber was not 

 permitted in any product. This 

 was not because of failure to 

 realize that reclaims could be 

 used successfully, but because 

 it was considered difficult to 

 write specifications which would 

 amply protect the Government 

 on products which had to be 

 put into use immediately for a 

 vitally important purpose. That 

 the policy followed in writing 

 the specifications was justified, 

 is proved by the results shown 

 by the product. There are no reports which indicate that the 

 rubber goods furnished in our gas masks were unsatisfactory 

 at the start or after use. The writer personally inspected a 

 salvage dump of masks in France, and with one exception, found 

 no evidence of rubber failure from aging. Tliere was, in the 

 case of the flutter valve, wljich when mounted on the metal 

 fitting was stretched by the bead, a tendency to surface check, 

 but this serves merely to support a well-known fact that rubber, 

 when placed under continued tension, does not age well. 



SPECIAL RUBBER LABORATORIES. 



Laboratories were established at Akron and at each assembly 

 plant for the purpose of determining the fact of compliance 

 with specifications. In all these laboratories physical tests were 

 made on cured slabs and upon the articles themselves. The 

 Akron laboratory was in charge of an experienced rubber man 

 and cures were checked on all deliveries. The institution not 

 only was of value to the Government but often saved contractors 

 losses on off-cure articles which had not been caught by regular 

 inspection. 



At Long Island City a chemical laboratory was equipped to 

 perform chemical analysis of the rubber products. One sample of 

 each article from each manufacturer was analyzed every month. 

 It is gratifying to state that this check revealed no attempt on 



