Rubber powder recovered from old tires can be converted to materials with interesting, useful physical properties. Rubber powder is recognized as a valuable raw material which may be processed into several useful products. In the cure cycles described, using only rubber powder and vulcanizing agent without virgin parent-compound, rubber powder can be converted to a plastic or elastomeric material, according to the percentage vulcanizing agent. As in the case of classical rubber vulcanization, the physical properties of the vulcanizates from rubber powder are found to be largely dependent on the conditions of cure. The effect of vulcanizing parameters on the vulcanizate properties were particularly studied.