Casting a brass head, Togo

The process of lost-wax casting, or cire perdue, has changed little since the 3rd millennium BC. Solid cast-metal objects can be heavy and expensive, but the lost-wax technique enables the production of hollow metal objects to be produced – especially duplicates from originals – through a series of steps.

First, a clay or plaster model (‘core’) of the object (pictured left) is covered in wax (centre). A second layer of clay is applied over the wax with ducts for drainage, then the piece is heated so that the wax melts away leaving a cavity that can be filled with molten metal. Once the metal has cooled and hardened, the clay is chipped away (right) to reveal the metal object. These objects were donated by Robert Sutherland Rattray in 1910.

Accession number: 1910.48.1–.3