The process begins with an idea which is translated into a rough, three-dimensional model. This rough model is refined until the shape is accurate and artistically perfect. The artist then completes the sculpture, usually in clay, wood, stone, wax, styrofoam, automotive body filler putty, or plaster.
The Rubber Mold
A Flexible mold is made from the artist's original using clay, rubber and fiberglass. These modern techniques and materials are able to capture every detail. The mold process can take up to eight days.
The Wax Casting
Hot molten was is painted and/or poured into the rubber mold, producing all detail of the sculpture. Cooler wax is then added in various layers, until proper thickness is achieved.
Wax Chasing
When the wax casting is removed from the mold, a trained artisan hand-finishes it to perfectly match the original.
Sprueing
Wax rods, generically called sprues, are fit, formed, and wax-welded on and around the detailed wax replica. These sprues have different names and functions. Risers and vents assist wax to escape during firing, and air to escape during casting. Gates allow molten bronze into the mold. Molten bronze is sometimes distributed to various parts of the mold by feeders and runners.
Investing
The wax casting is cleaned and coated with up to seven layers of a liquid refractory ceramic in a temperature and humidity controlled environment. The investing process can take up to seven days as each coat must dry before the next is applied.
Burn Out Firing
The ceramic mold is fired in a kiln, which melts out the wax and bakes the ceramic, leaving a cavity in its place. (Thus the term, Lost Wax).
Casting
The ceramic mold is preheated, then filled with molten bronze at a temperature of 2100 degrees Fahrenheit. (Bronze is an alloy, primarily copper - up to 96%)
Knockout
After the bronze has cooled, the ceramic mold is carefully hammered and chiseled, broken away, revealing the sculpture within. The bronze is sandblasted and the gates are power cutoff.
Chasing
The raw casting is then turned over to another artisan who grinds away the gates and sprues, blending these areas into the casting. Then comes the balance of the chasing process: Leveling, grinding core pins, weld, sand, file, die grind, bead blast, rough buff, and quality control.
Patination
The chased bronze is now treated with chemicals and heat to give it the chosen color. This patina is now a permanent part of the sculpture. These wondrous colors are controlled corrosion. The process is proprietary, but involves undercoats, varied chemical sequences, different temperature ranges, and multiple processes. After the color is applied, hot wax is used to seal the metal's pores. Then the sculpture is buffed bright where required, and re-rubbed and re-waxed 3 times by hand.
Basing
The base finishes the bronze and makes it ready to be shipped to a collector's office or home.