and stationary knives is too wide the uncured compound sheet will not be cut efficiently then the cut pieces of uncured compound will be too big and will tumble into the chopper potentially clogging the screen holes because of friction generated by the rotating knives one skilled in the art will recognize that the spacing between the various components and the rotational velocity of the non stationary blades may be adjusted for uncured polymer sheets of different compositions or thicknesses in one embodiment the particles range in size from about 6 mesh to about 24 mesh the cut particles may be sieved to remove fines and larger size particles particles of different colors can then be blended in pre set proportions to provide a desired design for the final product for example a mixture of different colored particles can be used to form a speckled design in the final product because the particles are uncured they may stick together during mixing if they are compressed a double cone blender or other blender with no internal moving parts can be employed to combine the particles about 0 1 to about 1 by weight of calcium carbonate a clay talc zinc stearate etc can be added to the blend to facilitate blending and avoidance of clogging a rotocure press may.