Wednesday, 12 September 2012

#310 In the foundry: "Moose Flats" con't . . .

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, cupric nitrate creates blues and greens, ferric nitrate gives golds, rusts, and reddish 
tinges, while liver of sulfur produces browns and blacks.

To learn more about this project, start with Post #274.

A foundry technician applies liver of sulfur to the sculpture;
 one of the few chemicals that does not require heat during application.

Next, the bronze is heated and cupric nitrate is applied.

Below, the cupric nitrate application has been completed.

Next, the sculpture is "scrubbed back" with a scotch-brite pad.

Finally, ferric nitrate is applied with heat.

After the monument has cooled, a coat of paste wax is applied.

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