The lost wax process
The lost wax process was invented by the ancient Greeks some 2500 years ago and they would recognise it today.
A mould is made from the original sculpture and that is lined with green wax, to which the sculptor can make adjustments before the wax model is coated in fine silicone granules. This is then fired in a kiln, both hardeneing the silicone and allowing the liquid green wax to run out. The silicone vessel can now be filled with molten metal, usually bronze (or silver). Once the raw bronze has cooled it is chased to remove imperfections and then treated with chemicals which stain or patinate the metal. This is then heated again to fix the patina and finally a layer of protective wax added before it is fixed to its mount.