Limited Edition Bronze Sculptures
Upshaw uses the lost wax process which is an ancient method of casting dating back more than 5,000 years.
It begins with an original piece of sculpture, made from any medium (wood, clay, metal, etc.). A mold is made of the original artwork. The modern mold making material is usually silicon rubber. A mother mold is then made on top of the rubber mold to hold the rubber in place after it is removed from the original artwork. The mother mold can be made from plaster, fiberglass, or a similar product.
After the mold is removed from the artwork, it is reassembled. Then the mold is filled with wax to a thickness of about l/4 of an inch. The mold is then removed from the wax resulting in an exact wax replica of the artwork. It is refined to remove any imperfections.
The wax sculpture now receives sprues and vents which are wax tubes that will eventually provide paths for molten casting material to flow and air to escape. Next a ceramic shell mold is created around the wax sculpture with the sprues and vents attached.
The ceramic shell mold is thoroughly dried. It is then placed in a kiln so that the wax melts and burns completely out. While the ceramic shell is still hot, molten metal is poured into the mold. After cooling, the shell is broken away from the metal sculpture. The sprues and vents are then removed.
The sculpture is cleaned up and ready to receive the patina or color. A variety of colors can be attained with the use of heat and chemicals.
Although the process is complicated, the resulting sculpture is beautiful, enduring and permanent. It can withstand the elements of nature, and will last for thousands of years. Currently, Upshaw works with the Valley Bronze of Oregon foundry in Joseph, Oregon and Art Work Foundry in Berkeley, California.