How to stain copper?

November 13, 2008 8:52 AM

I need to stain copper with a variety of different colors. How do I do this?

Ok, so I suppose I'm mainly looking for a product that will stain copper. It actually has to stain the metal such that it doesn't change it dimensionally. That is, it can't be an applied product that creates a film or layer such as paint or lacquer. I need something available in a variety of vibrant colors.

Lastly, it has to be easy to use. It would be ideal if the product allowed me to submerge the copper to take the stain - like with easter eggs.

posted by whatisish to Media & Arts (3 answers total)

Best answer: What you are asking about is patina (naturally, copper gets a green patina when exposed to the weather, but it can be done chemically as well). The key is to make sure the copper is really clean before applying any of the following solutions:

Green Patina:
1 tsp. ammonium chloride
1 tsp. sodium chloride (table salt)
1 oz. ammonia
1 qt. distilled water

Blue Patina:
Spray copper with water, sprinkle on sodium chloride, and enclose with a dish of ammonia.

Brown Patina:
Potassium Sulfide (also know as 'liver of sulfur' or 'sulfurated potash') - be careful though as this is toxic

Red Patina:
Mix 3 parts copper acetate, 1 part sodium hydroxide (be careful, this is a strong base - it will burn you), and 1 part calcium carbonate (chalk), then boil with 5 parts copper sulfate (toxic) in 1L distilled water until you get the color you want (please don't use anything that will come in contact with food though (such as pots) and make sure you do this with excellent ventilation.
posted by stevechemist at 9:16 AM on November 13, 2008 [4 favorites]

Best answer: stevechemist has it if you're comfortable mixing your own. If you prefer to not deal with the chemicals directly, check with a jewelry supply for premixed oxidizers. (you don't have to use Santa Fe Jewelers Supply, I just happened to have this link on hand)
posted by 1f2frfbf at 9:29 AM on November 13, 2008 [1 favorite]

Response by poster: Thanks to you both. Your answers led me to to various recipes, which is exactly what I was looking for.
posted by whatisish at 12:21 PM on November 13, 2008