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Bronze Sculpture Ceramic Sculpture
 
 

The Process of
Lost Wax Casting

 

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   The creation of great bronze masterpieces is a time honored craft, dating from classical antiquity  through the Renaissance in the 15th century . Modern technology has contributed some refinements to ensure a more uniform quality, and greater possibilities.

   The first and most important step, is of course creating the original work of art. This is where talent and training of the artist come together to turn that magical spark of inspiration into a  tangible  object. This step for me can take from a month to a year, depending on the project. Upon completion, the sculpture is taken to an art foundry where the following steps are followed.

1. When a bronze sculpture is cast using the lost wax method, a flexible rubber mold is made from the original model.

2. For each casting, a positive hollow wax model is produced by pouring hot wax into the  mold.

3. This wax model is re-detailed, an often long and careful process, then

4. Dipped in a liquid clay and silica, in successive layers to produce a ceramic shell of sufficient strength to withstand the  weight of the molten bronze. The inside of the piece molded this way, to keep the final sculpture hollow.

5. The wax is melted out of the ceramic shell (hence the name, the Lost Wax process) leaving a hollow vessel shaped exactly like the original clay model. Then the shell is preheated to 1900 degrees and

6. the molten bronze is poured in and left to cool.

7. When the shell is chipped away, the raw casting is revealed.

8. It is then sandblasted and hand "chased", or finished, to its ultimate perfection , by the skilled craftsmen of the foundry, in my case, Artworks in Berkeley.

9. Finally,  the chased bronze is treated with chemicals and heat to give it the patina colors that can bring the piece to life. This patina is now a permanent part of the sculpture, These wondrous colors are controlled corrosion. The process involves undercoats, varied chemical sequences, and multiple processes. The last step is sealing the work with hot wax, at which moment the piece  takes it's final appearance.

 
 
© 2008 Claudia Cohen. All rights reserved.