19th & 20th Century Bronze Sculptures

Lost Wax Casting

The lost wax method of producing bronze sculpture dates back over 4000 years.  This form of casting bronze has been used by every ancient culture. It reached its peak of technical proficiency with the ancient Greeks.  The Roman civilization carried on with this method of producing bronzes by casting sculptures of their gods and leaders using the lost wax method. The common foundry term Roman Joint is still used today when describing how pieces of a bronze sculpture are fitted together. In the lost wax process of bronze casting, the artist's model is used to make a multi segmented mold of either plaster or gelatin. The mold is a perfect negative of the original work and this mold making process usually damages the original model, sometimes destroying it entirely.  Melted wax is poured into the mold and swirled around making a thin impression of the sculpture.  The mold is then separated leaving a positive wax model of the sculpture. The artist touches up this wax blank, adding additional detail or even changing the model. Spues and vents of wax are attached to the wax model to allow for the smooth flow of the molten bronze and for gases to escape.  This unique wax is covered with slurry, which is a mixture of plaster and fire retardant materials and a core of slurry is inserted so that very little bronze is required. The slurry covered wax is then heated and the wax is evaporated or poured out, thus the term lost wax as the wax is now gone leaving only a void that will be replaced by the bronze. Molten bronze is poured and when cooled the slurry and core are broken and the spues and vents are cut off.  The roughness is hand finished to remove the traces of the casting process leaving an exact copy of the wax model.