Abstract: Prosthetic devices of utilitarian, yet natural and unprecedented life-like appearance, are formed of durable elastomers. A seamless flexible negative mold of a biological body member selected to form the basic model is made by painting on to it nylon mesh-reinforced silicone with direct monitoring and correction of the positioning of the parts. A positive wax model is cast in the mold and subsequently modified by sculpturing to the requirements of the individual for whom the prosthesis is being developed. From the master wax model a negative metal mold is made by electroplating. New and unique provisions for ventilation to effectively remove from the molds solvents of the elastomer dispersions greatly improve the quality and rapidity of production. Invented methods of creating ventilation ports without damage to the critical interior surface of the molds and of degassing the dispersions to eliminate bubble defects are employed.