3: Wax Casting
OVERVIEW | MODELING | MOLD MAKING | WAX CASTING | WAX CHASING | CERAMIC SHELL | POURING BRONZE | CHASING | PATINA
|Bronze sculptures are usually cast hollow if they are over any size
1" in diameter. This is for three reasons; the cost of the metal, the
weight of the metal, and most importantly the properties of the metal. Bronze
experiences heat deformation as it cools and the thicker the casting the more severe the
deformation, for this reason most pieces are cast hollow.
The rubber mold, with the plaster mother mold supporting it, are used to create the wax positive. The goal of the wax casting is to create a hollow wax copy of the sculpture that will later be used to create a heat-resistant shell that encapsulates it. This hollow wax casting could be pictured much like a hollow "chocolate Easter bunny" where it looks solid from the outside but is in fact a hollow object. The wax casting will then be melted out and bronze will be poured into its place. Incredible detail can be captured in this way and it is important that the wax is an accurate copy of the original model.
This process allows the sculptor to create a limited edition of their work. On each bronze sculpture one should find the sculptors name, date, copyright symbol and the casting/edition number. 1/12 for example means it is the 1st casting in an edition of 12. After the 12th casting the original rubber and plaster mold is destroyed.
Pouring Wax into Mold