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 use of rubber in surgery and dentistry, rubber tires, the hektograph, special inks, cements and allied subjects, also giving the sources of India rubber and its history .. . nerally it isrolled out or calendered into sheets of differentthickness from which articles are made in mouldsby curing. These sheets are of especial interest to the readeras they are the material from which most small arti-cles are made, including rubber stamps. This r
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 use of rubber in surgery and dentistry, rubber tires, the hektograph, special inks, cements and allied subjects, also giving the sources of India rubber and its history .. . nerally it isrolled out or calendered into sheets of differentthickness from which articles are made in mouldsby curing. These sheets are of especial interest to the readeras they are the material from which most small arti-cles are made, including rubber stamps. This rolling of the mixed india rubber into sheetsof definite thickness is done by special calenderingrolls. The product is termed mixed sheet. In the mixing rolls the incorporation of othermaterial is often brought about. Zinc white, leadsulphide, antimony sulphide, chalk, clay, talc,barium sulphate, plaster of paris, zinc sulphide,lead sulphate, white lead, oxides of lead, magnesia,silica, form a list of ordinary mixing lower the cost of the finished material and areoften serious adulterants. For some cases the addi-tion if not carried too far is not injurious, or even 44 RUBBER HAND STAMP MAKING may be beneficial. A proper admixture renders thegum more easily moulded and treated in the shap-ing Mixing Rolls. The next step in the vulcanizing process is theheating of the mass, which step is called to a temperature in the neighborhood of that ofboiling water the mixed rubber can be heated with-out change except as it is softened. But if the heatis increased it begins to get a little more elastic andless doughy, and eventually becomes i( cured orvulcanized. The temperature for vulcanization isabout 284° F. (140° C). The word about is usedadvisedly, for it is not only a question of heat but oftime of exposure. After vulcanizing, including thecuring, india rubber cannot be moulded to anygreat extent. In the manufacturing process, there-fore, it
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Keywords: ., bookcentury1900, bookdecade1910, bookidrubberhandst, bookyear1912
