. Rubber hand stamps and the manipulation of rubber; a practical treatise on the manufacture of India rubber hand stamps, small articles of India rubber, the hektograph, special inks, cements, and allied subjects . inch with temperatures corre-sponding to steam of such pressures: Lbs. per square inch. Temp. Fahr. Temp. Cent. 275° 135° 284° 140° 293° 145° ° 149° The illustration, p. 64, shows a vulcanizer of moderntype made for rubber stamp work. In some recentvulcanizers the water and steam are excluded fromthe vulcanizing chamber, being contained withindouble
. Rubber hand stamps and the manipulation of rubber; a practical treatise on the manufacture of India rubber hand stamps, small articles of India rubber, the hektograph, special inks, cements, and allied subjects . inch with temperatures corre-sponding to steam of such pressures: Lbs. per square inch. Temp. Fahr. Temp. Cent. 275° 135° 284° 140° 293° 145° ° 149° The illustration, p. 64, shows a vulcanizer of moderntype made for rubber stamp work. In some recentvulcanizers the water and steam are excluded fromthe vulcanizing chamber, being contained withindouble walls forming a steam jacket and maintain-ing a constant heat within the chamber. Theseillustrate a point that has been mnch misappre-hended, namely that curing is independent of pres-sure or atmosphere. Because vulcanizers havegenerally been filled witli steam at high pressuremany have supposed that the steam or pressure hadsomething to do with their action. The fact is that 66 RUBBER HAND STAMP MAKING it is only the heat due to the steam at such pressurethat is instrumental. Steam is a very powerfulradiator and absorber of so called radiant heat. Forthis reason an atmosphere of steam maintains all. Steam Jacket Vulcanizer. parts of the vulcanizer at an even temperature andis to that extent advantageous. Its presence andthe pressure it generates are not by any means re-quired for vulcanizing. Its pressure is entirelywithout effect. To use a steam vulcanizer, water is introduced. AND THt: MANIPULATION OF RUBBER. 67 the article m the press or mould is placed in it, andthe top is secured. Heat is then applied, best if onthe small scale, from a Bunsen gas burner gas,or oilstove. Either the pressure gauge or thermometermay be watched, and the flame turned up or downto keep it at the proper temperature. Moulding caimot be executed in the ordinaryclosed chambers. The press must first be heated tothe temperature of boiling water or thereabouts andthe moulding is then effected
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Keywords: ., bo, bookcentury1800, bookdecade1890, bookidrubberhandstamps01sloa
