Casting is the process used to form metal for a custom piece of jewelry. After a wax model is created, it is attached to a rubber base then enclosed in a steel flask. Investment is then poured into the flask and air bubbles are removed from the investment with a vacuum pump. After the air bubbles have been removed the mold is placed in the kiln to burn the wax out. Once the wax has burned out, metal is melted, then poured or released into the flask using a resistance vacuum. After the metal has cooled the flask is submerged in cold water to remove the investment, leaving the cast ring to be polished.