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How to tarnish / darken brass

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Q. Hello, I am an artist and I incorporate found objects into my art work. Some of which are brass fittings, keys, etc. . I do not like the finish of the brass. Can anyone direct me to a product that I can apply to these pieces that will tarnish the brass. I asked today and found all products on how to clean. How can I tarnish brass. Thank you. Lisa Grant

Lisa Grant
- Dripping Springs, Texas


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A. Black for brass:
200 gm cooper carbonate
1 lit ammonia /
25%/ Cold immersion!

Brown for brass:
5 gm cooper sulphate
50 gm potassium permanganate
1 lit water Hot immersion(90 C)!2-5 min.

Yellowish-brown to orange-red for brass
100 gm copper sulphate
50 gm sodium chlorate
1 lit water Hot immersion (90 C)!

Goran Budija
- Zagreb ,Croatia

Patina Basics


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A. Use Liver Of Sulphur [linked by editor to product info at Mister Art] , can get it at art supplies stores.

Simon Dupay
- Roseville, Minnesota


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A. Brass Darkening Solution [linked by editor to product info at Rockler].

Paul
Civil War Relic Preservation - West Virginia


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I was to tarnish brass on my fireplace, which cannot be immersed. Any ideas?

Debbie Cohen
- Montclair, New Jersey


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Q. I wish to darken my brass frogs (about 2 feet high). They were dark when purchased but the lawn people sprayed them with fertilizer which pitted them. In trying to save them from this I covered them with tomato paste which then removed the darkness (exposing bright brass) in a spotty way. I would like to preserve them and get them back to the way they were. Wish to do this myself in the safest manner possible. I am a senior citizen.

Toba Saskor
- Pinehurst, North Carolina


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A. Hello, Toba. If you want to patina brass you can wait for the elements, or else use a chemical that is powerful enough to do what you want done in the time you want to allow.

The reaction colors vary greatly depending on what reagents you use; you may be able to get some sort of green with vinegar and salt, or with ammonia, but if you want brown-black you'll probably have to use the homebrew recipes offered by Mr. Budija, or the brass darkening solution that was suggested. Best of luck.

pic of Ted Mooney Teds signature
Ted Mooney, P.E. RET
finishing.com
Brick, New Jersey

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Q. I have a pair of solid brass dog tags with an engraved logo. The logo engraved is black, and I got my name engraved, but I don't know how to make the engraved part look black like the rest of it.

I want to tags to look tarnished, but now that they do, you can't read my name because it is the same shade as the tarnish rather than black. Anyone know how to fix that? I really appreciate any help you can give.

Thanks,

Tracy Powell
- Tallahassee, Florida


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A. It may be more than you want to tackle, Tracy, but the usual way it is done is to blacken the whole item and then "relieve" the body of the tag, leaving just the engraved area black. Relieving involves buffing/polishing away the patina from the raised areas.

But you could try applying a darkening chemical just to the engraved area with an artist's brush. The best chemical for that is selenium dioxide; I believe the commercial "brass black" for guns contains selenium dioxide. Good luck.

pic of Ted Mooney Teds signature
Ted Mooney, P.E. RET
finishing.com
Brick, New Jersey

Brass Black Metal Finish


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Need selenious acid or other chemical to darken brass, in larger quantities than the 2 oz. bottles.

Steve Adeleted
- Dry Ridge, Kentucky, USA
outdated


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I have a set of Polished brass lamps that I would like to darken. Is there a necessary treatment to remove any coating on them? They have never tarnished after lots of handling in the last 20 years. There are little balls on the pull chains that HAVE tarnished. Also can any of the previously mentioned treatments by brushed on to avoid immersion? After the darkening process, is it necessary to coat with anything else? Has anyone simply tried painting brass? I know, but I don't claim to be a purist, I just want to darken the shine for decorating purposes.

Elaine Cook
hobbyist - Grand Rapids, Michigan


 

Hi, Elaine.

If they never tarnished there is certainly a clear coat of some sort on them. If it's brass lacquer, you can remove it with lacquer thinner or acetone. If that doesn't get it off, it's not just lacquer, and you'll need to use aircraft stripper -- which is really noxious stuff to be used only outdoors with good ventilation and wearing gloves and goggles.

You can lacquer them after the darkening, but I don't think you really need to. Brass is difficult to paint. You must start with a self-etching primer. Good luck.

Regards,

pic of Ted Mooney Teds signature
Ted Mooney, P.E. RET
finishing.com
Brick, New Jersey


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I own an antique chandelier that has areas of polished brass and some of oxidized brass. The dark areas are actually black. I need to blacken an area to match what was previously blackened. My question is this. Will liver of sulphur darken or blacken brass? I have never worked with it, but notice the cautions for proper ventilation warnings.

Carole S. Roberson
antiques dealer - East Berlin, Pennsylvania


March 29, 2011

Hi,
I am trying to blacken real brass plate purchased from a metal supply store. I soaked the tiny sample piece in acetone to clean it and then soaked it in a small glass jar of liver of sulphur. I bought the rock form of LOS and dissolved it in hot water. After waiting about 2 hours I noticed it turned very very slightly darker but it didn't turn black at all. The effect seemed to stop.

I also tried the vinegar and salt solution, followed by the bake in an oven at 350 trick and again.....no luck.

What gives?

Thanks,

Kris Kundra
hobbyist - Yardley, Pennsylvania

 

Hi, Carole; hi, Kris.

Jewelry artists use Liver of Sulphur for silver rather than for brass. While some people report some success with it on brass, it's probably not the best first choice. You might try Goran's home-brew recipe, the Rockler brass darkening solution or the Birchwood-Casey "brass black". Good luck.

Regards,

pic of Ted Mooney Teds signature
Ted Mooney, P.E. RET
finishing.com
Brick, New Jersey

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