Lost-wax process, also called cire-perdue, method of metal casting in which a molten metal is poured into a mold that has been created by means of a wax model. Once the mold is made, the wax model is melted and drained away. A hollow core can be effected by the introduction of a heat-proof core that prevents the molten metal from totally filling the mold. Common on every continent except Australia, the lost-wax method dates from the 3rd millennium BC and has sustained few changes since then.