An inexpensive and most frequently used method in the prototype process is casting urethane parts from silicone rubber molds. The urethanes today along with mold making techniques from previous years give prototyping the respectability it deserves. This paper describes the techniques used to cast quality urethane parts from a silicone rubber mold following the five step duplicating process: 1) creating the master pattern; 2) designing the mold; 3) making the mold; 4) casting the urethane parts; 5) finishing the urethane parts.
