Friday, March 5, 2010

Bronze Sculptures: Part Two


 
Robert Graham "Gabriela" 105/250...For more information on this sculpture, please contact us


The most popular and commonly used casting method for fine art bronze sculptures is lost wax casting, cire perdue, which is an ancient process that dates back thousands of years. This type of casting was first used in ancient Mesopotamia, and around 550 BCE, it is believed that the Greeks further mastered the technique, as they were the first to scale their figures up to life size.  The construction of life sized bronze statues involved many complications and required special techniques; the trick was casting hollow sculptures, which were lighter weight for transportation and required less metal to produce.  Many sculptures were initially made from welded metal sheets, which led to the lost wax casting method.

Lost Wax bronze casting, also called “Lost Mould” when materials other than wax are used, is a casting process that involves creating a bronze object from a sculptural model and can vary with each foundry.  Traditionally, a form is modeled from a soft-bodied material like wax or clay, then is covered with a softer inner mold and a rigid outer mold.  Inner molds may consist or latex or silicone rubber, where as outer molds are typically made of plaster or fiberglass. 

After the mold is made, the original model is removed, and the inside of the mold is poured and coated with molten wax until a desired thickness is reached.  This new wax shape is an exact replica of the original model, but is hollow (in some cases solid – for smaller sculptures).  It is pulled from the mold and may be re-detailed by the artist or artisan, after which, wax rods and a pouring cup are attached to form a tree-like structure (a process called spruing).  This provides channels for metal to flow in and air to escape during the casting.  The sprued wax form is then dipped in a ceramic-like shell mold material and is placed in a kiln, which hardens the shell mold and melts out the wax inside.

The shell mold then cools and is tested for leaks and durability, then is heated back up and poured with bronze.  The shell and metal are cooled, then the metal is broken out of the shell and is assembled (in the case of larger objects cast in sections) sandblasted, polished, and waxed until a desired decoration is achieved.


 
"Bronco Buster" by Frederic Remington. Remington began to employ the lost-wax casting process in 1898 with Roman Bronze Works in New York. His bronze sculptures are very desirable and highly reproduced by foundries using the same casting methodFor more information on this sculpture reproduction, please contact us


After a final polishing, corrosive materials may be applied to form a patina effect or the bronze may be gilded (coated with gold) to produce a matte gold luster.  Some artists may choose to embellish their sculptures with additional paint, metals, jewels, glass for eyes, or ivory.




"Eternal Story" by Dimitri Chiparus.  Chiparus was known for his charming Art Deco Chryselephantine (bronze and ivory) figural sculptures.  Our Chiparus reproductions, beautifully handcrafted at a Los Angeles-baed foundry, are decorated with paints, patina and mammoth ivory.  For more information on this sculpture, please contact us





1 comment:

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