Investment casting

Investment casting is a way of making metal parts. It's like making a mold from wax. First, a wax pattern of the part you want to make is made. Then you coat it in a special material called a 'investment'. The investment hardens and then it and the wax are heated. The wax melts away, leaving the investment in the shape of the part you want to make. Then molten metal is poured into the investment, and when it cools, the investment breaks away, leaving a metal part.