Step 1: Create the Pattern
Before you make your mold, you must create a pattern to determine the mold’s shape. The pattern can be a 3-dimensional model of your final cast. It may be shaped in wax, sand, plastic, or even wood. Some casters use molds made of plaster or silicone, which are materials that could not withstand a molten metal cast, but allow the caster to mass create wax multiples to use in expendable mold casting. When you are shaping your pattern, make sure you account for any anticipated shrinkage when the metal cools. Patterns may also be gated with sprues to allow the molten metal to flow into the mold.