Monday, February 21, 2011

Copper Prep #3

After polishing with the Never Dull and cleaning several times with the alcohol, I then use ca.400 grit wet/dry sand paper to take off the red curprous oxide (CU2O) formed by reaction between surface of copper and oxygen in the air. You can see the fine powder that's on the sand paper and the difference between the cleaned side/dirty side.

This abrading, done in small circles with dry sand paper and quite abit of pressure, is what allow the paint to bond with the copper. I think an ion is exchanged between oil paint and the metal, but don't know the science exactly - only that it works!

Then I clean off any red dust that is left behind, again with the alcohol. Now it's ready to accept the ground of thinned flake white.

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