Casting metal in a mold formed around a wax model, which is burned out to leave a cavity for the metal.
The piece begins as a model: carved by hand in wax, or printed in resin from a CAD file. The models are mounted on a wax column, the sprue, that will channel metal to them, and suspended in a plaster-like investment inside a flask. The flask is fired until the wax has burned out, leaving a cavity in the shape of the model, and molten metal is cast into it, poured or driven by centrifugal force. GIA lists the same steps: model, spruing and treeing, investing, burnout, casting.
The wax is lost in each casting, so each wax model gives one casting. To repeat a design, a mold, usually of silicone or gum rubber, is made around an original model, and wax is injected into it to make as many identical wax patterns as needed. From the casting, a bench jeweler takes the piece on to a finished, set and polished jewel.
In job listings
The term appears in foundry and production roles: foundry operators and assistants, casting coordinators, and prototypists who prepare carved or printed models. Chopard lists lost-wax carvers and casters among the artisans of its high jewelry workshops. These roles come before setting and polishing. See current foundry roles.
