CREATING A BRONZE SCULPTURE

with the "Lost Wax" process

STEP 1: Every bronze sculpture begins as a concept expressed in an original sculpture created by the artist. This original sculpture, or "prototype", can be created from wax, clay, plaster, or other materials favored by the artist.

STEP 2: A mold is made of the prototype. Usually a rubber flexible mold is made with a rigid outer mold called the "mother mold". A good mold will reproduce an exact copy of the artist's original.

STEP 3: Molten wax is poured, or "slushed" into the mold to produce a wax copy of the original. This wax will serve as a form for the bronze copy. The wax "cast" is removed from the mold and is "chased" to a final finish approved by the artist. Each wax casting is treated as if it were an original and only then, if approved, is signed by the artist.

STEP 4: Wax rods, called "gating", are attached to the wax in a way which allows the molten bronze to flow through the shell while allowing air and gas to escape. A pouring "cup" is placed onto the wax where the molten bronze will be poured.

STEP 5: The wax is then coated with a ceramic material called "investment". At least seven to eight layers are applied over as many days which creates a strong, heat resistant mold into which the molten bronze will be poured.

STEP 6: The wax, now coated in a ceramic shell, is fired in a "burn-out" kiln to a temperature of approximately 1800 degrees F. This causes the wax to melt out of the shell leaving a negative mold in its place. This process is how the term "LOST WAX" got its name.

STEP 7: The ceramic shell is again preheated to 1800 degrees F. At the same time, bronze is being heated to a temperature of 2100 degrees F. When all the conditions are right the molten bronze is poured into the shell.

STEP 8: The ceramic shell, when cooled, is broken away, the piece is sandblasted and the gates and sprues cut away. The bronze (just as the wax prototype) must be chased, sanded and polished. Sometimes, (often), welding is required to make the bronze look exactly like the artist's original sculpture.

STEP 9: The "chased" bonze is then treated with chemicals and heat to force the "oxidation" of the bronze that produce the colors desired by the artist. The "patina" can be left in its natural state or sealed with wax or lacquer to prevent further oxidation.