The underlying structure of the sculpture is created in metal (the armature). The armature is where the initial line of the sculpture - the basis for all that will come after - is created.
The Wax Pouring Process
The mold is now ready to receive
the wax. The mold is separated and the first coat of wax is painted into
the mold in order to capture the fine details of
the original artwork. Next, the mold is reassembled and wax is poured in.
The mold is rotated until an even thin coat of wax is obtained. After the wax has
completely cooled the back up shell and mold are removed and the wax
casting is revealed.
Wax Chasing and Spruing (Gating)
The wax is cleaned; seam lines and any slight air bubbles that may have
occured in the wax pouring process are removed. Wax gates and sprue bars
are attached to the sculpture along with a pour cup. This creates a plumbing system that allows the wax out and the bronze in.
The Ceramic Shell
The prepared wax casting is dipped into a liquid slurry and covered with a fine sand. Once it has dried, the process is
repeated. This process is repeated until the shell is strong enough to withstand the molten bronze. This ceramic shell goes
both inside and outside the wax thereby allowing the bronze
sculpture to be cast hollow.
The Casting Process
The ceramic shell is placed in a kiln where the shell is baked and the wax is "lost" as it melts, flowing out of the shell as it is heated. Once the shell is de-waxed it is cooled and inspected for cracking or defects.
The Completion Process
(Welding, Metal Chasing and Patination)
If the wax pattern was sectioned for the molding process, it is now
reassembled and welded together. The sculpture is then chased to
remove any sign of welding. Several different sanding and detailing tools are used to give the most accurate surface possible.
Careful manipulation of the sculpture is often a part of this stage (and sometimes the sculpture bites back).
The patina is the finishing color. A variety of
chemicals are used in order to achieve the specific coloring desired for the piece. After the patina is applied the sculpture is sealed with a wax coat to protect the finish.