Project Detail: Cast Bronze Sculpture via the Lost Wax Method
Step 1. Clay
The Lost Wax method was invented a few millennia ago, and it's still in use today. To begin, the sculptor initially sculpts their design out of clay. In my case, I used plasticine.
Step 2. Molds
Once the initial clay sculpture is complete, a mold must be constructed to create a negative of the sculpture's form, I used a two layer mold, with a flexible rubber inner section being supported by a hard shell of plaster and gauze.
Part 3. Wax
Once the molds are complete, molten wax is poured inside to create a wax copy of the sculpture.
Part 4. Thermal Shell
After a wax copy is properly chased, touched up, and ready for final replication, one must form what is essentially a highly heat resistant mold onto the wax copy. In Sculpture II, we used a ceramic shell, built up from layers of mineral slurry and silica sand.
Part 4. Pouring
Once the ceramic shell is finished, it's placed in a furnace to burn out moisture, wax, and any other material inside the shell. The now empty shells are then buried in a sand pit, and a forge team works together to pour the molten metal from the crucible into the shell.
Part 5. Chasing
After the metal has cooled, the shell is broken off to reveal the cast sculpture inside, often with many imperfections. At this stage, excess metal from the cup and vents must be trimmed off, and the surface of the sculpture is chased to fix any cosmetic defects.
Part 6. Surfacing
Finally, once all major defects are corrected, the sculptor surfaces the sculpture to their liking in regards to texture and color. I used a variety of patinas to add color, as well as an antique quality, to my sculptures.
