Casing in Bronze
Bronzes (which are produced at a foundry) are made by the lost wax method. This method has been used to make bronzes for thousands of years. All bronzes are cast from some form of original or “master”, most usually constructed from clay, plasticine or wax. Chloe prefers to use wax.
First a mould is taken from the original. Today, this mould is usually made from silicon rubber, which is flexible and easy to use. Previously piece moulds were made from plaster. Molten wax is poured into the mould. The mould is moved and rotated to ensure the wax coats the whole of the inside of the mould evenly. This process is repeated until the required thickness of wax is achieved (this will be the final thickness of the bronze). The wax cast is now removed from the mould. The cast is hollow, as only a thinnish layer was built up in the mould. Wax rods (sprues) and a funnel- like cup are fitted onto the wax cast which will eventually take the poured bronze and allow for release of captured gasses. The sprue system and wax positive are then coated (inside and out) with a ceramic liquid.
The piece, now coated in a ceramic shell, is fired in a kiln. This bakes the shell and melts the wax, which runs out of the mould, leaving a cavity in its place. (Thus the term, “LOST WAX.”) The ceramic shell is removed from the kiln and molten bronze is poured into the mould. This is left to cool and the ceramic shell is cut and chipped away. The cooled bronze is a replica of the wax cast, including the sprues and funnel. These are removed by an artisan. Then by grinding, chasing, sanding and polishing, all areas are blended back to make the bronze look exactly like the artist’s original sculpture. The bronze is now treated with chemicals and heat to give it the chosen patination. The patina is sealed under a wax coating and becomes a permanent part of the sculpture.
Bronze is a wonderful material; strong, beautiful and durable. There are 5000 year old bronze sculptures that look as good today as the day they were cast!
If you would like to order a sculpture, enquire about availability, or commission something new, Chloe would love to hear from you! Please use the Contact form.