The color comes from the reaction products with an acid.
My dad knows a metal artist and she just uses weak dilutions of acids.
She sprays on weak dilute acid for green use muriatic/hydrochloric acid it will form copper chloride a green stain. Sulfuric acid makes copper sulfate, that will appear bluish.
test coupons, various dilutions, and various temperatures are prescribed for you to determine best method you seek.
I would also consider an alkaline "stop bath," not just a rinse. Baking soda perhaps?
milo
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CR4 - Thread: copper patinationcopper patination. 11/19/2008 4:54 PM. Anyone have a good recipe for copper patinization that shows dark blues and greens. also how will relative humidity ...
cr4.globalspec.com/thread/29520/copper-patination - 7 hours ago
by A Whyte
Patina - Wikipedia, the free encyclopedia The green patina that forms naturally on copper and bronze is known as verdigris and ...shows the copper beneath a layer of copper carbonate patination. ...
en.wikipedia.org/wiki/Patina - 32k -
Copper.org: Corrosion Protection & Resistance: Green Patina Finishes The much admired natural protective coating of a blue-green patina characterizes older copper roofs, including ancient cathedrals as well as bronze statues ...
www.copper.org/resources/properties/protection/green.html - 81k
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Take it easy, bb. >"HEAR & you FORGET<>SEE & you REMEMBER<>DO & you UNDERSTAND"<=$=|O|=$=>"Common Sense is Genius dressed in its Working Clothes"<>[Ralph Waldo Emerson]
You will get different colours depending on how the Formula is applied, IE: brush, sponge or cloth. Hope this helps. This side is really amazing.
These are some Formulas
Apple Green Patina (Pink Label)
Powder Blue (Yellow Label)
Light Blue-Green (Green Label)
13.178g of Cupric Chloride
3.013g of Cupric Chloride
24.8g of Ammonium Chloride
3.074g of Ammonium Chloride
13.008g of Ammonium Chloride
23.3g of Sodium Chloride
100ml of Water
100ml of Water
100 ml of Vinegar
1.6 ml of Liquid Ammonia
Observations
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Take it easy, bb. >"HEAR & you FORGET<>SEE & you REMEMBER<>DO & you UNDERSTAND"<=$=|O|=$=>"Common Sense is Genius dressed in its Working Clothes"<>[Ralph Waldo Emerson]
While babybear seems to have given a detailed answer, with several good links to multiple resources regarding patina, I may have stumbled across a simple home-brew solution earlier today...
Coincidentally, I was just reading the November issue of This Old House (TOH)magazine on the train ride into work this A.M., where Tom Silva (The TOH show's G.C.) mixed up a solution of 2 cups of vinegar mixed with a tablespoon of salt, and applied the solution via a sprayer.
I can't say that I have any experience with this, but I think that I'll give it a try...
the solution you list is what I use to clean my copper-bottomed pans. They come up like new. Can you let me know it say a vinegar solution works. Not sure is a 'salt and vinegar would as it cleans. But it may do. As I said with different methods of application it also gives different results.
I like the explanation of
Milo, who tells what acids make what colours. And although your suggested solution cleans my pans. applied and left to grow crystals over a few days or weeks instead of rinsing off as I do, it will be interesting to see what happens?
Good luck..............
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Take it easy, bb. >"HEAR & you FORGET<>SEE & you REMEMBER<>DO & you UNDERSTAND"<=$=|O|=$=>"Common Sense is Genius dressed in its Working Clothes"<>[Ralph Waldo Emerson]
Thanks for all the info guys its way more than i've found on the subject. I've found some artist supply houses but their pretty much against letting out wat their formulas are, as their in the business of making money and I'm not against that I just don't have the patience to buy 4 or 5 formulas to get the colors Iwant. Thanks again everyone.
Whether the patina/temper color is durable and lasting is unknown.
you make an interesting point. Friend have copper jewelry which has not changed or worn off. I can't recall now if the crystals need to be 'fixed'? My guess is they may do.
Take care...........
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Take it easy, bb. >"HEAR & you FORGET<>SEE & you REMEMBER<>DO & you UNDERSTAND"<=$=|O|=$=>"Common Sense is Genius dressed in its Working Clothes"<>[Ralph Waldo Emerson]