a method for producing composite , structural plastic prototype parts , having visual and structural characteristics equivalent to those of an actual part to be commercially produced using existing soft tools , including wax , plaster , plastic , spray - metal , and rubber molds ordinarily used for visualization model making , developed using the latest rapid prototyping techniques . short length fibers reinforcing low viscosity thermoset resins , and in particular resole phenolics , provides a pourable low bulk density polymer compound with minimal externally applied thermal requirements during molding and post cure when required .