The Bronze Process

The Bronze Process Used By Sculptors Lee Leuning & Sherri Treeby

Once an idea for a bronze has been researched and formulated, our artists begin by welding a tubular steel support system together. This acts as a skeleton and sub-straight for the next layer of a light weight material such as foam which comprises the majority of the form. Special clay is then applied to the surface of the foam, then formed, fashioned, and detailed to what the eventual bronze sculpture will look like.

For large and intricate sculptures, the clay model may be cut down to smaller, more manageable pieces before the bronzing process begins. The clay model that is to be bronzed will usually have a two part molding system applied to it. The first mold layer or skin mold consists of either a latex or silicon rubber that is applied in a liquid state and left to solidify to a flexible material that captures all of the detail of the original clay surface. The next mold layer or mother mold is then applied directly onto the skin layer. The mother mold is usually made from plaster or fiberglass resin and is there to cradle the skin mold to keep its original form. Removing the molds from the clay sculpture destroys the original model.

The skin molds are cleaned, allowed to dry, and prepared for the next step of pouring liquid wax into them. The liquid wax is poured into the mold, allowed to cover all the surfaces inside and then poured out. This process is repeated as needed. The wax is separated from the molds and then prepared further by attaching a sprue system which will be the eventual channels molten bronze will flow through. The wax image and sprue system are final inspected and begin another coating system which will create an eventual non-refractory shell coat of material where molten bronze will be poured.

Once the final layers of shell coat have been applied and thoroughly dried, the wax is completely removed by very high heat. The remaining shell of material is ready for the molten bronze to be poured. Once the metal has cooled, the majority of the shell material is “shocked” off by hammer blows to the sprue system before it is cut off. Any remaining material can be scraped off manually and/or sandblasted.

These newly formed bronze pieces of the eventual sculpture are then welded together to make the finished form. Various techniques including chasing, sanding, and polishing are used to create the desired surface. Various types of acids are then applied and heated to give the bronze its color and also acts as a protection coat to prevent oxidation.

The bronze is then mounted to the desired base such as wood, marble, or stone.