BRONZE IS AN ALLOY OF 95% COPPER, 4% SILICON, .02% TIN, .02%LEAD, .06% ZINC
1) CREATE - wax sculpture, large sculptures are cast into numerous sections.
2) SPRUE - attach wax gates, vents & pouring cup - which act like plumbing to the work.
3) INVEST - dip in a liquid ceramic slurry to build up numerous layers of a hard refractory mold.
4) BURN-OUT - an autoclave and hot kiln melt the wax out of the hard mold - "lost wax method."
5) POUR - molten bronze is poured in the empty mold at 2100' Fahrenheit.
6) BREAKOUT - once cool the ceramic shell mold is broken away to reveal the bronze sculpture.
7) SANDBLAST - remove the last traces of the ceramic shell mold that adheres to the bronze.
8) FINISH & CHASE - bronze feeder gates & sprues are cut off and various pneumatic tools.
grind, sand, & polish until the bronze sculpture looks exactly like the original wax sculpture.
9) WELD - numerous sections are welded together and polished smooth.
10) PATINA - various chemicals are applied to the surface both cold & hot to age the metal into various colors. Paste wax is applied to hold the patina color and add a protective polish or shine.
11) BASE - some works are attached to wood or marble bases unless they were designed with bronze bases.
FOR EDITION COPIES:
1) RUBBER MOLD - a flexible rubber is coated over the original piece and a rigid plaster mother mold holds it in place. This is a time-consuming & difficult process which can be costly.
Note: the original sculpture can be made of any material: wax, metal, stone, wood, clay, etc.
2) WAX COPY - hot wax is poured into the rubber mold and allowed to cool solid.
3) CLEAN WAX - the wax is removed from the mold and carefully cleaned to remove all seam lines, air bubbles or flaws.
4) REPEAT PROCESS ABOVE - repeat each step above for each edition copy.