copper

[gert]

How do you make copper turn green?

[Thad Van Gilder]

spray it with bleach.

-Thad

[RGM]

I believe you can get the effect that you are looking for by wiping it down with sulfuric acid (diluted). Excellent chance that I'm wrong on that one. Hell, maybe vinegar (acetic acid) would work? Call up your local leaded glass/stained glass shop and ask them what they might have that would work. They generally have a few different chemical solutions they use to put different "patinas" on copper foil and the lead that is used in their line of work. Good luck.

[Mike Field]

.
Wait.
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[Jack Heinlen]

Acids, at least in my limited experience with copper bottomed pots and vinegar, remove verdegris. Salt solution? Or the above suggestion of talking with a decorative copper worker sounds good.

Why?

[jhl]

:D The amount it turns green is inversely proportional to the degree with which you want it to shine!

[gert]

we don't want it to shine at all, it's a Han dynasty (reproduction) flying horse.

[Bruce Hooke]

I recall hearing that a famous bronze sculptor encouraged his sons to pee on his sculptures to get them to develop the right patina!

On a more serious note, this website has one solution: http://www.diynet.com/diy/ww_chairs_stools_benches/article/0,2049,DIY_14439_2276538,00.html
Make sure you check the links under "also in this episode" at the bottom of the page.

This website has more detailed options depending on the exact color you want: http://www.secure.sciencecompany.com/thesciencecompany/patina.cfm?SID=1&

Realize that these recipes largely use nasty chemicals and frequently require you to heat the chemicals and the metals. Another option is to send the object out to have it done by a pro. One place I came across in browsing the web that can apparently do this is: http://www.aurorastudios.com

[Venchka]

I'm not sure which liquids to apply, but the process is greatly aided by the application of heat. I watched a friend literally "paint" color on bronze with a propane torch and various solutions.

[gunsmith]

You may not believe this but it is the truth. The answer to your question is mares piss (the horse kind). Not a dangerous chemical at all. When I was younger and serving as an apprentice carpenter I re-timbered clock and church towers. When finished the sheet metal men came in and covered the tower roof with standing seam copper. While this was going on I would be sent up to a farm that had mares that saved the urine for the pharmasutical industry which made birth control pills from it. I would get a couple of 5 gallon buckets and bring it too the men on the roof. As soon as the copper was finished they would mop it with the urine. Within a day or less it started to turn that beautiful green. Within a week you would never know it was ever copper. So now go get yourself a bucket and------ smile.gif

[Jamie Hascall]

A friend worked for a pipe organ company and when it was time to patina the pipes, the boss would go buy a keg of beer and tell the guys to have at it.

That said, lemon juice and salt is one combo that can get a nice blue-green color, and there are a lot of commercial preparations that do an extremely nice job. Copper is fairly easy to patina, but brass can be much trickier to get a good green as the copper is locked up more tightly in the alloy. Bronze I just like to drop in the salt water and let nature take its course.

Jamie

[Mrleft8]

Salt and vinegar. But really pee does a better job. The salt and vinegar mix leaves a kind of powdery residue that flakes off fairly easy.

[gert]

thx all