|Molding: After a piece has been completed in clay, the molding process begins. Polyurethane, or synthetic rubber, in liquid form, is applied to the clay with a paintbrush. This sets quickly and forms a layer of soft rubber. This step is repeated several times until the desired thickness is reached. This soft rubber mold is the first, or inside, mold.
The soft mold, however, is not sturdy enough on its own for the casting stage. Therefore, it is necessary to make a second mold, known as the "mother mold", that surrounds the soft inner mold. It is made of a modified gypsum resin, a plaster-like material, and is applied by hand.
Once set, both the mother mold and the soft inner mold are lifted off the clay. Each mold is individually cleaned and prepared. The two molds are then joined back together again (but without the inside clay sculpture), secured to prevent leakage, and readied for casting. The entire molding process usually takes several days.