Bronze is an alloy of tin and copper which has been used to make sculpture since antiquity. The ‘indirect’ method of lost wax casting dates back some 6,000 years. The skill of the foundry’s craftspeople gradually transforms the sculptor’s original from the first stage of making a rubber mould using the wax model through a number of stages to the lengthy and patient chasing of the metal prior to patination, the chemical application of colour using oxidising agents. The mould allows a number of casts, or editions, to be made whereas the ‘direct’ method of lost wax casting uses the original wax model which is consequently destroyed. Sand casting is a more recent, simpler technique using moulds of fine blocks of sand.
For further, detailed information about bronze casting read ‘The Alchemy of Sculpture’ by Tony Birks, published by Pangolin Editions and Marston House.