How can I oxidize copper without the use of a patina?
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Hi,
I'm a high school student. For a Design and Technology project I have to design and build a light. I want to use copper rods for my main shaft, which I will try to entwine around each other. But to suit the style of my design, it would be more aesthetic if the copper where rustic, i.e. green. So I would like to know if there were a quick way to oxidize the copper, and create an authentic layer of copper oxide around it, without using any patinas? I have already tried heating small samples of copper, which did turn the copper green for a while, but the oxide ions didn't stick to the copper and so dissipated away again. And on further heating it just created a layer of black carbon (or was it black copper oxide?). Anyway, I then tried bleach, which is working VERY slowly, and also it would not be practical to oxidize 180 cm copper rods in bleach.
So please does anyone have an answer? It would be a great help to know how to turn copper green without the use of a patina, because I will get extra marks for the oxidizing process.
Thanks a lot!
Sienna M.student - London, Great Britain
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One way is to set it outside and spray it every morning and every night with a mist or acidified salt solution. Time, from 1-2 weeks. A guess would be a couple tablespoons of common table salt, 1 liter of water and acidify with a couple teaspoons of muriatic acid. Check with your facilities folks. Another source would be the chem lab, only here it will be labeled hydrochloric acid. Use a little less of this as it is about 20% stronger. You could also try straight vinegar. This will form a copper acetate film. This also needs to set outside for the duration. The temperature changes with the humidity and dew seems to accelerate the process. PS, this solution is relatively safe, but it will slightly etch concrete and it will promote rust on virtually any bare steel within several feet. James Watts- Navarre, Florida +++ Sienna, there is a nice article in the Metal Finishing Guidebook and Directory on ANTIQUING OF BRASS, COPPER, AND BRONZE by Mark Ruhland of Birchwood Casey. I suspect it would be in a local library, and I'd suggest you start there.
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The easiest,fastest, simplest way to oxidize copper is to either spray, dip or brush the copper with
Sno Bol Toilet Bowl Cleaner
.
The completed results are within a few hours.
- North Port, Florida
February 24, 2008
I just bought a Copper Top Table with some scratches... got a reduced price and was confident I could remove them. Found that when a lightly sanded with 600 grit wet/dry paper, I left fine scratches and removed some of the red oxide. Thus removed everything using
lacquer thinner and
0000 steel wool [linked by editor to product info at Rockler]. At the stage of oxidizing and want only red not the green patina. Any suggestion on How to Do?
hobbyist - California.
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February 25, 2008
You might consider flame coloring, Sienna. If so, please see letter 2662 for a discussion and examples.
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Basic Copper Smithing and Flame Painting on Copper |
January 12, 2009
The best way to change the copper to green is to use
muriatic acid. You normally use it to clean the grout between tiles. Do not dilute it and apply with a brush where you want it to turn green. It will do it over night. To prevent further tarnishing you can varnish your project.
Good Luck
Bocas del Toro Botanical Gardens - Bocas de Toro Republic de Panama
April 19, 2009
I have done a few coppers and have found the best two ways to change the colour is to use battery acid for green and muriatic acid for blue.You can get both with out a problem. Muriatic acid is used to clean tiles and concrete. Clean off the copper with either of the acids and then wash with non-chlorinated water, dry and then paint on the acid of your choice. It will change over night . If you want the color permanently lightly brush off the access patina and leave for a couple of days. Then varnish with a satin polyurethane or varnish.
Hope this helps
david
Bocas del Toro Botanical Gardens - Bocas de Toro Republic de Panama
July 19, 2009
Will this work on items that have been copper plated? or chromed and then rubbed down to the copper base? I am building a motorcycle, and wanted to do some of the parts copper and then need the patina look (green) .
keith price- puyallup Washington
January 29, 2010
It has been my experience the easiest way to achieve the patina you are looking is to use
Liver of Sulphur
[linked by editor to product info at Mister Art]
. It is available in easy to use gel form on line or at a metal art supply store..
metal art - Livingston, Texas
December 20, 2011
PEE ON IT!
CARLOS JUENKE- Frederickburg, Texas
