Special Designed Machine for Cutting Rubber
Courtesy of the United States Rubber Co.
Tapping Hevea Rubber Tree on Ceylon Plantation
Courtesy of the United States Rubber Co.
Softening Vats
Courtesy of the B. F. Goodrich Co.
After the rubber is dry, and has been tested by the chemist, it goes to the grinding mills where it is refined on warm rolls and made ready for the compounding or mixing. It is impossible to make out of rubber alone, shoes or other products that will withstand extreme changes in temperature; certain amounts of sulphur, litharge and other ingredients are necessary in combination with the pure rubber to give a satisfactory material. The gum from the grinding mills is taken to the mixing mills, where, between the large rolls, the various materials are compounded into a homogeneous mass. The compounded rubber goes from the mixing mills to refining mills, to be prepared for the calenders.