What is a bronze sculpture? How is a bronze sculpture made?
- First, a clay sculpture is created. Inside the clay sculpture is a skeleton made of wire, called an armature. This holds up the clay. Many times the clay that is used is an oil-base clay. It will never dry like water-base clay does. This clay cannot be fired, it would melt; it is good only for making a mold.
- A blue rubber mold is made. At the foundry, a blue rubber liquid is brushed on the sculpture; many layers of this rubber are added making it thicker and thicker. When this dries, it is opened (like the shell around an egg) and then the clay sculpture is discarded. On many sculptures, the mold is made in pieces, which will be put together again later.
- A wax copy is created. After putting the empty blue rubber mold back together, the foundry pours wax into it. The wax hardens into the exact image of the original sculpture. The blue rubber mold is removed, and can be used again and again.
- A ceramic mold is made. The wax sculpture is dipped into liquid ceramic clay, called slurry. It dries between each dipping. It is dipped many times until it is thick and chunky and looks like a wasp’s nest. When the ceramic mold is dry, it is fired in a kiln. Because the wax melts, it runs out, which is where the name “lost wax method” came from. The ceramic mold is baked hard.
- Pour the bronze. The ceramic mold is the only thing that can withstand the heat of molten metal. Hot liquid bronze metal is poured into the ceramic mold and allowed to cool.
- Reassemble the bronze sculpture. The ceramic mold is chipped off and is destroyed in the process. The bronze pieces of the sculpture are now reassembled, welded together and the seams are finished.
- Patina. The bronze sculpture is now treated using a variety of chemicals and heat that will give the color that the artist chooses; this is called “patina.” Patinas come in every color. After the patina, the piece is sealed with a coat of wax.
- Enjoy! The finished bronze is mounted on a base and delivered to the artist. This piece of art is eternal! It will be enjoyed by your great-great-grandchildren, and last forever!