Lost-Wax Casting
Definition
A manufacturing process where a wax model of a jewelry piece is encased in plaster (investment), burned out in a kiln, and replaced with molten metal to create the final piece.
Lost-wax casting (also called investment casting) is the primary manufacturing method for producing jewelry at scale. The process begins with creating a master model — traditionally hand-carved in wax, now often 3D-printed from a CAD design. The wax model is attached to a sprue (feed channel), placed in a flask, and surrounded by investment plaster. The flask is heated in a kiln to melt out the wax, leaving a negative cavity. Molten metal (gold, silver, platinum) is then forced into the cavity by centrifugal force or vacuum pressure. After cooling, the plaster is broken away to reveal a rough casting that is cleaned, polished, and finished. A rubber mold of the master allows mass production of identical wax copies for repeat casting.
Usage in the Trade
Lost-wax casting is used in the production of rings, pendants, earrings, brooches, and virtually all mass-produced fine jewelry. It is the bridge between design (CAD) and finished product in modern jewelry manufacturing.