BRONZE IS AN ALLOY OF 95% COPPER, 4% SILICON, .02% TIN, .02%LEAD, .06% ZINC


STEPS:  

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.


Teaching Bronze Casting Process at Merced College

Seen here pouring molten bronze metal into student molds.


For 35 years I taught bronze casting in my SCULPTURE: 3D Foundations class at Merced College, where I would produce a variety of sculptures each semester for demonstration and lecture purposes with my students.  I recently retired in 2017.




ARTWORKS FOUNDRY

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Various Sculpting Methods 

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