Chemically Produced Copper Patinas
A discussion started in 2003 but continuing through 2018(2003)
Q. I am seeking information for creating various colored patinas on copper through the application of heat and various chemicals. I'm trying to produce yellows, greens, black, reds, oranges, blues or any other colors which may be possible. I'm hopeful that someone can advise me which chemicals, with or without heat, will produce what colors. I am a retired architect and active metal sculptor. Any help would be very much appreciated.
Thank you,William W. Wood, Jr.
- Las Vegas, Nevada, U.S.A.
A. Try to get a copy of the book "Contemporary Patination" by Ronald D. Young =>
It's a great book with many formulations for a variety of colors produced on many metals. It would be a good first step to answer your question.
- Sandusky, Ohio, USA
A. These are a few of the tried and true patinas I've used in some of my sculpture, I suggest using a clear lacquer over the finished piece if it is going to be handled or exposed to elements. Most of the chemicals listed can be found at school laboratory supply companies. Anyway, onto a few recipes.
Before doing any of these patinas use scouring powder to get the metal surface TOTALLY clean, polish if you can but be sure that you leave no residue on the metal.
1 Tbsp ammonium chloride 1 Tbsp salt
1 oz. ammonia
1 qt. bottled water
Mix well and coat at least four times for a good patina.
Blue Patina (easy to do)
Wet the surface of the metal lightly with water (I'd suggest a spray bottle). Sprinkle salt on the metal (I'm wondering if you just do a supersaturated solution of saltwater, would you get a better effect? If you try it let me know), and enclose it with a dish of ammonia.
Brown Patina (easy to do)
Apply a few drops of oil to your hands and rub the piece, then apply a light flame until the piece starts to smoke a bit. Play with what type of flame you use for.
Red (pain to do)
5 gm copper sulfate
1 liter water
3 gm copper acetate
1 gm sodium hydroxide 1gm calcium carbonate (better known as chalk)
Add the last three ingredients in the quantities listed, 3 parts copper acetate, 1 part sodium hydroxide, and 1 part calcium carbonate. Mix the three ingredients well and let it sit for a week to "set up." After a week has past (or seven days, which ever comes first), pour off the top liquid for use, this stuff is a substitute for a traditional Japanese patina called Rokusho, I haven't been able to find a supplier for it stateside. You boil the copper in this stuff until you get the color you want, you might want to try this in addition to the blue, could be very striking.
Keep doing the green patina over and over again.
- Elizabeth City, North Carolina
Q. I would like to suggest an armadillo coiled up in self defense around the sides of a large copper tank. I imagine a Myan like piece with irregular and unconnected spots. Before doing the above sequence to darken the background areas how should I protect the shiny areas? I also wish to have a shiny margin at the top and bottom of the work. Is the best way to protect the shiny metal different when straight lines are required?James Nagy
- Beaver, Pennsylvania, USA
A. To the person making the armadillo ... actually, to get a black I would use a liver of sulfur. when you purchase it it comes in little rocks, like rock salt, one rock to about 2 cups of water kept warm, BUT NOT BOILING! Dip piece of paint on liquid with a brush. run under cold water to set the color. Then take it back a bit with steel wool [linked by editor to product info at Rockler] or very fine sandpaper. Repeat process 3-4 times. This will give you a deep purple-y black on copper or sterling. then to give raised areas intense copper shine use a brass brush and take it across the surface. Sometimes I use a thin layer of paste wax and then rub it with an old t-shirt. I used this same process on a form fold box, it looks great, almost like fabric or skin.Erin Ibey
- Denton, Texas
Ed. note: Liver of Sulphur [linked by editor to product info at Amazon] is also available inexpensively as a premixed liquid from the underlined link if preferred.
I have a question for Marc Banks. When you do the patina for blue, what do you mean by enclosing in a dish of ammonia? If it's putting it in a a dish of ammonia how do you keep the salt from washing of the copper? Does it Change it completely blue or just speckles? Is the ammonia that you can buy in a supermarket okay?
- North Miami Beach, Florida, U.S.A.
November 2, 2011
Wow...when I went looking for chemicals I found what appears to be a very comprehensive list of formulas.
- Cumming, Iowa
February 12, 2018
Q. Hi, I have bought a copper sheet that I want to patronize. I was going to use ammonia and water / salt and maybe do some torching too. It is for a fireplace surround. There is a stove instead of an open fire. On reading the previous threads I was thinking of going for car spray to seal the colour in. Does anyone know if this Would this work for an interior. I'm a total novice so any advice is greatly appreciated. Thank you, Kate from Ireland.Kate McGowan
DIYer - Firhouse, Dublin, Ireland
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