 Step 1. Unlike centrifugal casting, the method described here relies only on the force of gravity to fill the mold cavity. Due to the lack of casting pressure and the relatively low temperature of the metal being used, it may be necessary to cut additional gates in your mold to make it easier for the metal to fill the mold cavity. This is especially true when the items being cast contain thin areas and/or complex sections. The gates are usually cut as shown in the photo at right.
 Step 2. The most important step when casting white metal into a Cold Mold is powdering the mold. Mica Powder should be applied liberally to both mold halves and into all vents, then blown off the surface of the mold. The powder performs three functions during casting:
1. Speeds the flow of metal into the mold cavity.
2. Keeps the vents open for gasses to escape.
3. Protects the surface of the rubber from heat.
 Step 3. Place mold plates on both sides of the mold and secure with C-clamps or similar clamps. Avoid applying too much pressure with the clamps. They should be only tight enough to keep the two mold halves in contact with one another. Metal is then poured into the sprue at the top of the mold. Use gloves to avoid burns from molten metal. Once poured, the cast piece can be removed from the mold within minutes. |
