Bronze Casting Process
1. The original work is created in clay, plasticine or any other material from which a mould can be made.
2. Step one of the rubber mould is to create a wall out of plasticine around the artwork.
3. The sculpture is covered in liquid rubber and left to set.
4. The set rubber is covered in plaster (a mother mould). Then the clay is removed.
5. Next, the mould is filled with hot wax and left to cool. When opened, the mould reveals a positive copy of the original in wax.
6. The wax positive is then touched up to remove any seams or bubbles.
7. The wax positive is coated in a heat resistant ceramic shell.
8. The shell is heated in an oven until all of the wax is emptied out. The recovered wax is saved and can be used again.
9. When the oven has cooled sufficiently, the empty shell is removed.
10. The cooled shell is planted in a sand pit to await the molten bronze.
11. Bronze ingots are melted in a crucible at 2000 degrees.
12. The liquid bronze is held with metal clamps and poured, by people braver than myself, into the upturned shells.
13. The bronze is left to cool in the shells for an hour or two.
14. When the bronze appears black, it’s cooled.
15. The ceramic shell is smashed away with a hammer.
16. The bronze sculpture is eventually revealed.
17. After sand blasting, the bronze has a shiny, gold appearance.
18. Finally, the 'patina' is created by applying a solution to the heated metal resulting in a chemical reaction.