The lost wax process in a long and labor intensive process in which the original wax sculpture and the mold made from it for pouring the bronze are lost in the process of producing the final bronze sculpture.
Sometimes an artist prefers to sculpt with a different material than wax, as was done with the turtle. It was originally sculpted out of ceramic clay. The sculpture was then cut up and a plaster molds were made of each of the pieces. (see photo)
The plaster mold was then used to make wax parts. (see photo) These were further refined and fit together to make a finished wax sculpture. (see photo) Besides allowing choices of modeling materials other than wax, having a mold is advantageous if an accident occurs later in the process. One can produce new wax parts from the molds instead of starting again from nothing.
The finished wax figure must next have a wax pouring cup, sprues, and vents attached to allow the bronze to pour in and reach all parts of the sculpture while allowing air to escape and not block the flow of the bronze.
Next the piece is dipped many times in a ceramic material and sand, which must be dried between each applied layer. This process usually takes several days. This produces the ceramic mold. (see photo) The ceramic mold is fired in a kiln to melt out all of the wax (thus the name lost wax). Cuts made to avoid cracking by expansion of the wax, and any cracks that developed in the process are patched and fired with a blow torch. (see photo)
The ceramic mold is then supported in a bed of sand and molten bronze is poured into the mold. (see photo)
Most of the ceramic mold is then broken off of the bronze with a hammer and remaining ceramic material is sand blasted off. The sprues and vents must be cut off and grinding, polishing, and welding as required are used to finish the piece and to reshape areas where sprues or vents were attached and to repair any imperfections.
A patina is applied to give it the finished desired color, or it may be allowed to patina naturally with age and weathering. A brown and golden patina was applied to the turtle, followed by a light coat of wax to help protect its surface. (see photo)
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