We are using the “Lost Wax Casting” method for making our master sculptures. A single sculpture masterpice will normally take two/three weeks for completion using this method. The quick summary of our labor intensive process is give below:
Creation of the mold
The initial step in creating a mold from the original work of art is by far the most critical and imporatant. All the details which appear on the original sculpture must be carefully captured in this mold. The mold are made from hard plaster/resin. The mold (depending on the size of the sculpture)is cut into sections for casting.
Making the Wax Cast
Molten wax is poured into the mold to form layers of wax. This wax model is an exact duplicate of the original casting.
Chasing the Wax
The wax model is pulled from the mold and hand chased (re-detailed) by a skilled artisan. Wax rods (gates) and pouring cup are attached to the wax casting in just the right positions. This gate will assure a full pour.
In this step a ceramic mold is casted. The wax casting is dipped into the investment liquid several times in a temperature controlled environment (at about 72 Fahrenheit) to create the ceramic mold. The investment liquid is basically liquid clay. The next step involves dipping the ceramic mold into coarse ceramic sand. The ceramic sand is applied several times, each time the coarseness of the sand is increased. Between each application, the ceramic layer must be dry before another layer can be applied.
The ceramic shell is placed into a kiln and fired. The shell is baked and hardened while wax model is melted and drained away from the shell. Here the wax is lost (Hence the name lost wax process) and a hollow ceramic/sand mold is created. The molten wax is then collected and recycled for future use.
The molten bronze is poured into the ceramic sand shell immediately after the shell is removed from the kiln. The molten bronze is at abt 2050° Fahrenheit at the time of the pouring.
After the bronze has a chance to cool down (usually several hours) the shell is carefully broke away leaving the unfinished bronze.
The sculpture is carefully inspected at this point. Any ceramic shell fragments are removed by sand blasting.
All the pieces of the sculpture is welded together by skillful craftsman.
The weld marks are re-detailed by skillful craftsman.
This process is similar to the sandblasting, however the glass beads are extremely fine and ensure a smooth bronze finish.
The now smoothed bronze sculpture is further polished by hand in preparation for the patina.
The sculpture is first washed in acid bath then heated under high temperature. The patina chemical is then hand applied and baked into the sculpture to create long lasting luster. Many different colors of patina can be created by a skillful craftsman.
Wax is hand applied with heating to the sculpture to ensure a beautiful patina.
* The above mentioned casting process is only the guideline for manufacturing sculptures using lost wax casting .The actual process may differ a little as per the requirements