Getting copper pipe to turn green

A. Try this site it gives a whole load of information on patinas.
https://www.sciencecompany.com/Patina-Formulas-for-Brass-Bronze-and-Copper.aspx

A. I used rhododendron fertilizer and it worked great.

A. I made some wind chimes from 28 mm (1") copper pipe, carefully cut and tuned to give eleven different notes all in harmony. I then wanted to artificially age them. I obtained a pleasing bluish green quickly by using a thin paste made from soldering flux, salt and a little vinegar. This "paint" was applied daily for about a week, some areas receiving extra if the colour was not developing as well as I wanted. It is a bit variable and patchy but I never cleaned the pipes before treating as I did not want a uniform finish. The patina has worn off where the pipes are struck by the wooden strikers but the rest has been extremely durable and has only improved over the last seven years or so since I made them. The colour fades a little towards brown oxidised copper when wet but returns as the chimes dry.

We use Liver of Sulfur. Has anyone tried this? Clean copper turns a beautiful blue-green color.

A. Hello Patrick,

Here's a patina formula I found online that will give copper that bluish-green antique look you desire: Take 8 ounces of salt and 8 ounces of ammonium chloride and mix them with a quart of vinegar. Mix in a half ounce of ammonia when you are ready to put it on the copper. Spread it on with a soft brush and let it sit for 24 hours. If you want it darker, repeat the formula and let it sit another 24 hours. When it's done and has sat for a full day, wash it down and protect it with wax or lacquer.

Good luck,

A. In the summertime, spray it with a spritz bottle with a mixture of salt, vinegar and water every morning and night. Green in about 2 weeks. When you get the green you like, rinse it with a hot water spray twice a day for a week. Then polish it with felt or canvas and wax it.

A. To turn copper green spray with 1/2 strength muriatic acid ⇦this on eBay or Amazon [affil links] . Sprinkle with kosher salt. Place in sun. With in 24 hours it will look like 100 years old.

A. Hello Esta. It's a public forum where anyone is welcome to respond. The question has already been "sorta" answered with three different solutions; but the exact response that you and Bryan request would require you to supply a detailed list of exactly what comprises "better" for you (how important is safety to pets, compared to cost, compared to speed of results, compared to labor hours, compared to exact shade, etc.) so let's turn our noses up at the other two of the three good Samaritans who helped :-)

... But we can list some advantages/disadvantages by saying that muriatic acid is very dangerous stuff that must be treated with great respect, so it has that downside. And commercial patinas have the great advantage that they are formulated for the exact purpose, after a good deal of research and experiment, so they ought to be "best" in functionality -- but they are probably quite expensive compared to household chemicals. Best of luck!

Thanks Ted, I did see and appreciate the helpful answers of the "Samaritans" who did respond. But like Bruce H of Laurel, N.J., I was hoping to hear from someone who had tried at least a couple and found one better than the others. Guess, I'll have to try them all myself!

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Ed. note: Sorry to put you to the work of testing more than one, but if you do, please come back and tell us your results, Esta. Thanks.

A. May sound crazy, but I used Miracle-Gro diluted w/ water on my copper bays and it worked. It's much safer, easier and better for the environment than muriatic acid.

Q. I'm trying to patina some copper and am not having very much luck - I even tried urine! It produced a peacock blue color but it washed away. I've read in two places that Miracle-Gro works.
but was curious if Miracid would work better? Isn't acid the thing you need to do the job? Thanks! Good column!

A. Miracle-Gro for African Violets in a liquid form is GREAT!.
I brushed (like I was painting) on the copper and it turned a lovely green the sunny day after I finished the job!
Thank you for the tip, Steve.

A. Now, Winona. Your ex gave you a very attractive answer, and it sounds like, instead of simply climbing a ladder at night and doing it, you're working hard to find some trivial objection just to pique him :-)

Seriously, people have related some success stories with salt + ammonium chloride + vinegar, and salt+vinegar, and muriatic acid + kosher salt, and Miracle-Gro. If you have time to search the site you'll find dozens more threads on patinating copper, with still more approaches like ammonia. There is unfortunately no way to say which approach is "best" or most "surefire". The ease of different approaches will vary, and the speed, the safety, the exact color, the smoothness; the pattern will vary with some people preferring perfect uniformity and others wanting variegation. the durability will vary -- and it will remain a matter of opinion whether these approaches, or commercial patina solutions, or urination is "best" :-)

But are you positive that you have real copper, not copper colored aluminum? Sadly, sure-fire is impossible unless you can tell us exactly what copper alloy was used on your windows, what heat treatment sequence was performed, what mechanical preparation and sanding/buffing the manufacturer used, what type and brand of brass lacquer, epoxy, polyurethane or other clear coat they applied, and a dozen other questions we consumers are not privy to.

The closest we can come to step-by-step is to say that you must first remove whatever clearcoat is protecting the copper. Try lacquer thinner ⇦this on eBay or Amazon [affil links] Warning! highly flammable! first. If that doesn't work, you will have to use Aircraft Stripper, which is terribly toxic and noxious stuff requiring goggles ⇦this on eBay or Amazon [affil links] , rubber glovesrubber gloves ⇦this on eBay or Amazon [affil links] , and outstanding ventilation. After you have bare copper, please pick whichever approach sounds most authoritative or promising to you, and odds are it will work just fine. Very best of luck!

Regards,

You are right. Cannot answer all these questions. I do however know this is REAL copper. Saw it being installed, and know from the bank I needed to rob to pay for it, that it is the real thing. I am still pondering these various options. Muriatic acid is not on my list...too toxic, but all the others will be tried and I will keep you posted. winona

A. I am an artist and use small bits of copper sheet and wire. I don't have a standard recipe but have found that hot sauce works well. I had several bottles of old Tabasco in the kitchen and that seems to work well. Experiment. Have fun!

Thanks, Paul, that's very interesting! Can you possibly provide a reference?

Regards,

A. Hi Gary. Part of the coloration on copper, like the verdigris, is actual pigment. But part of the color, especially the iridescent appearance, is diffraction effects where part of the light bounces off the topmost tarnish or oil, and part of the light penetrates it and bounces off the substrate, causing interference colors. Think of the rainbow effect of a drop of oil in a puddle -- which is the same effect (oil isn't rainbow colored, it's interference coloration).

When you put any additional clear material on top, whether water or wax or lacquer, it can cancel those colors because the topmost reflective surface is now greater than a wavelength away from the substrate reflective surface.

Regards,

A. So instead of Miracle-gro I just used Copper sulphate (I get it in the gardening section with the other fertilizers, etc.). I am fairly sure it's the active ingredient in Miracle gro as I have substituted it many times in Jewellery work like electroforming, e. and looks the same. My copper jewellery goes very blue with just plain copper sulphate :)
Good luck!

A. Your brown color is the surface of your copper that probably now is one form of copper oxide which can vary from an off red to brown to black.
To have gotten it to a green, you might have had success with daily misting with a salt solution.
The brown oxide will not dissolve in water. To remove it, you might try ammonia. I suspect that it will take several applications.
Other things that might remove it are normally dangerous.

A. About using MiracleGro for green copper patina, yes, it works!
Paint it on thick -- make it a paint-like substance with a little water ... needs nice bright sunshine to dry -- a nice patina of green always looks different while it is raining, but it will come back to green patina when sun comes out. Give it a try.