At this stage, the bear has been sandblasted and I am inspecting the welds, seamlines, and chasing before patina.
Fit-up, welding, armature, chasing, and the final sandblasting have been completed. The patina is a permanent color that is applied to the bronze. The surface of the sculpture is heated and treated
with chemicals which react with the copper in the bronze. Various colors can be obtained by using different chemicals; for instance, ferric nitrate gives golds, rusts, and reddish tinges, while liver of sulfur produces browns and blacks.
In the above image, a foundry technician applies liver of sulfur to the sculpture;
one of the few chemicals that does not require heat during application.
This image shows a wash-down after liver of sulfur and scotch-brite scrubbing.
After liver of sulfur is applied, the sculpture is scrubbed back with scotch-brite pads to reveal high points and enhance the patina. The scrubbed areas accepts the ferric nitrate as heat is applied. Note, one technician is blasting with propane heat and the other is spraying ferric nitrate.
After the sculpture cools, seal is applied to protect the sculpture surface.
After the seal cures the sculpture is waxed, and after the wax hardens the sculpture is buffed imparting a time-honored luster.
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