Bronze Casting Process
I begin my sculpture in clay, plastercine or wax.
To cast in bronze using the lost wax casting process, there must be a wax copy of the original. At times, I may sculpt directly in wax or will make a silicone mold off my original.
The wax then proceeds to mounting where the wax system is attached to the original sculpture. This is where the bronze will eventually flow thru this system once the wax is lost.
When the mounting system is completed, the original wax sculpture is dipped in a slurry of sand and silica and binder. The first coat is very fine sand and thin slurry to coat the wax and mounting system. The coats of slurry are built up from fine sand and slurry to coarse sand and a thicker slurry. This will become the mold encasing the wax.
Once cured, the piece is dewaxed so that in fact, all the wax is lost. Hence the name lost wax casting. The wax can be recycled and used again by the foundry.
The wax original and mounting system is now hollow and fired in a large furnace, ready for casting.
The Bronze Pour
Each sculpture is heated to a different degree depending on the complexity.
An average temperature would be around 2000 degrees Fahrenheit. The molten bronze is poured into the hollow system and then cools.
Once cool, the mold of hardened sand and slurry that encased the wax is chipped away. What was hollow is now filled with bronze, system and all.
The bronze mounting system is cut away from the sculpture and the sculpture is finished and ready for patina.
Mounting to a base is generally required unless it is free standing. The patina are chemicals that are put on the sculpture in a hot or cold process. Preparation of the bronze is very important to decide finish, preference and colour. The final sculpture is completed with hot or cold wax depending on the patina colour and desired effect.
The entire process usually takes 4-6 weeks from start to finish. Bronze is a precious metal but it takes many man hours and special skills to produce one sculpture. For this reason, metal sculpture is unique, one of a kind and worth its weight in bronze.