A red patina can be developed on copper with a torch and any number of fluxes. The heat is applied to the copper from below. When the copper glows red hot sprinkle on the flux for a speckled look. Alternately, apply the flux first, then apply heat, for a smoother color. (Generally, both techniques happen at the same time because the salt bounces around.)
A client wants me to do a Waterfall Weaving for him, but before he orders he wants a sample of the green copper patina with various light copper browns. He actually sent me a piece of couch fabric to match! Unfortunately, it’s winter in SW Michigan and the shop is on the cool side. Normally I can get a great green on copper patina using Sculpt Nouveau’s Tiffany Green. When it’s 90 degrees, I actually get the beautiful grayish green, the traditional verdigris (‘green of the Greeks’), my favorite. 60-80 degrees and I’m getting fairly neutral greens. Any temperature below 60 and I’m getting bluish greens. This gentleman does not want any bluish-greens. So I’ve been running tests to nail down a reliable (?) patina I can reproduce in the cooler months.
Prep the Copper
- Cut the copper – this is best on copper at least .015″ thick
- if you are planning on having it water jet cut later, add at least 1.5″ to your sizes
- Sand the front with a 3M coarse grinder pads. This will hide the scratches that copper inevitably gets and create a nice pattern in the metal.
- Alternately, use an orbital sander, 50 grit. This is an attractive pattern.
- If you are planning on brazing decorative lines – e.g. ovals, circles, zig zags – on the copper, now is the time to do that