Once the casting is approved by the artist the sculpture is sandblasted. Next the surface texture is prepared by different techniques that can include abrasion, polishing and sanding.
Timing is crucial as the oxidation process starts as soon as the sandblasted sculpture is exposed to the atmosphere.
The hot patinas are so named because the metal surface of the sculpture is heated to open its pores. Hot patinas offer a great amount of control in colour variation.
When the base coat is sprayed onto the hot bronze surface, the colour changes from yellow, to purple, to white and then to gray.