How to Darken Copper, Brass or Bronze
Q. I am trying to figure out how I can darken metals of copper, brass or bronze in a relatively safe manner. I know that this can be done using selenious acid, but would like to find a way to do it with more "user friendly" chemicals, do you have any suggestions?
- San Leandro, California
Falls Township, Pennsylvania
I HAVE RECENTLY DEVELOPED A VERY SIMPLE PIECE OF CHEMISTRY TO BLACKEN COPPER. JUST TAKE THE ZINC PURIFIER USED IN A CYANIDE ZINC PROCESS, AND MAKE IT UP A 1% - ROOM TEMPERATURE. THIS HAS REPLACED OUR EBONOL SYSTEM WHICH RUNS HOT.
ALSO, THERE ARE OXIDE CHEMISTRIES USED IN THE PRINTED CIRCUIT BOARD INDUSTRY FOR MULTILAYER BONDING. THESE WORK ALSO, BUT YOU NEED TO WIPE THE PARTS TO GET A SOMEWHAT "SHINY" LOOK. WITH THE PURIFIER SYSTEM, THERE IS NO NEED TO WIPE.
- Cambridge, Ontario
A. Use liver of sulphur
Liver Of Sulphur
[linked by editor to product info at Mister Art]
. It will turn copper or silver from brown to black . You can order it from
Gessein^Gesswein. This is an excellent product and works great. Although it does smell like rotten eggs.
A. Selenium dioxide is a fantastic chemical for blackening copper and brass. In fact, it is the chemical trophy engravers use on a laminated brass plaque to make the lettering black (the lettering cuts through the lacquer). It's totally jet black and very hard. The product they use is called Gravoxide or oxidizer.
It's more readily available in Birchwood-Casey Gun Blue Gun Bluing. It's advertised as a blue/black oxide finish for steel but it is very effective on brass/copper. Brasso polish does not readily remove this finish.
I'd recommend an acid pickle to remove existing oxide or whatever method you have to get the metal very, very clean first.Danny Miller
June 25, 2009
A. To darken brass, you must first strip any varnish on it.
- Avondale, Arizona
July 3, 2009
Hi, Hong. My Palmolive Dishwashing Liquid does not list its contents at all except to say that it is phosphate-free and do not use with chlorine bleach.
Palmolive actually worked. Can't believe it. Few minutes and it looked like it aged months - and a nice brown. Thanks for the great tip!Jeff Mucci
- Pittsburgh, Pennsylvania
Liver of Sulphur
February 9, 2010
Q. Regarding Hong Lim's suggestion to darken brass with Palmolive Dishwashing Liquid, what would I use first to strip the varnish from a brass chandelier?ELLEN DRESSEL
- Grand Rapids, Michigan
A. Hi, Ellen. If the coating is brass lacquer, you can remove it with with Acetone or lacquer thinner. If it's a more durable coating, you can probably remove it with Aircraft stripper; it will not hurt metal, but is really noxious stuff absolutely demanding goggles, protective gloves, and truly excellent ventilation.
Ted Mooney, P.E. RET
Brick, New Jersey
Q. Can anyone give me the location/phone number of where I can get in touch with the supplier
referenced in one of the responses above?
- Azle, Texas
A. The spelling is incorrect on your inquiry, it should be "Gesswein" polishing tools and accessories.Gary Garcia
- Modesto, California
Q. We are lasering brass with a YAG laser and then using Gravoxide to turn the lettering black. It looks fine for a few days but then gets fuzzy looking (spider webs out from the text) because the Gravoxide isn't neutralized (maybe?) and keeps working. Does anyone have any ideas about another chemical to use or how to stop the Gravoxide from staying active?Joe Midkiff
awards industry - Statesville, North Carolina
Q. I am etching brass washers to make jewelry and would like to know of a relatively safe and economical way to do this. I have some directions that call for brass darkeners (Brass oxidizer) ...it comes in a pint size container...I don't need anywhere near this amount.Kathryn Adams
teacher - Easley, South Carolina
Ed. note: Brass Darkening Solution [linked by editor to product info at Rockler] is available in 2 oz. bottles as well as 8 oz. and 32 oz. You are wise to not buy far more than you need. Good luck.
Q. Can someone tell me a simple kitchen formula for turning copper or bronze to green? I have heard something like vinegar and ammonia plus a third ingredient, but have no idea of the proportions. I want to know because I want to stain my concrete floor. I used silver, gold and copper powder from Daniel Smith on wet concrete and got a beautiful green and black coloration, with a little brown. Now I am working with dry concrete and I want to try the copper powder again, and spray on a solution that will oxidize it. Then I will apply a clear concrete finish. Thank you.Jane Seymour
hobbyist/artist - Freeland, Washington
A. Well, more of a bathroom formula than a kitchen formula for turning copper to green: urine. Conservators of old paintings often use this method to create verdigris for mixing paint.Lee Boychuk
- Saanichton, British Columbia, Canada
June 16, 2010
A. For the person asking about a green finish:
Green Patina Formula:
2 parts white vinegar
1 1/2 parts non-detergent ammonia
1/2 part non-iodized salt
Clean fixture with Windex-type cleaner.
Premix patina solution in Windex-type spray bottle
Spray Windex cleaner on fixture to break surface tension, leaving it on when you apply patina solution.
Apply patina solution by spraying onto fixture, preferably in the early evening on a high humidity night.
Allow to set for 1 hour, then reapply solution observing where you missed applying on the first coat. If there seems to be oil that is repelling the patina solution, clean it off with the Windex cleaner.
Allow to sit overnight. In low humidity desert areas, use a plastic bag to create a tent over fixture (without making contact with it) to help keep the humidity high during curing. If there is low moisture in the air, the solution will dry out without creating the patina effect.
The result will be a bright green powdery patina. Do not rub off. In time (and re-applications) this finish will become permanent. The brightness will fade with time. To reduce green, cut back on the salt content. Color and effect is greatly affected by application ambient temperature and humidity.
- Keymar, Maryland, USA
Q. I have a house built in 1963 and all of the kitchen cabinets and drawers have hammered copper pulls that are no longer bright and shiny. I would love for them to be black, but I don't want to just spray paint them a flat black. Is there anything I can do to make them oxidized to a black finish? I hope that this makes sense because I have never had any experience with metals.
consumer - Toccoa, Georgia
A. Hi, Lauren. If they are real copper (check with a magnet first to make sure they're not steel), and there is no lacquer or clear coat on them, what you have read on this page should work. Good luck
Ted Mooney, P.E. RET
Brick, New Jersey
Q. My daughter is moving into a new house. Her fixtures all have the appearance of oil rubbed bronze. I have a lovely chandelier that is perfect for her dining room, except it has a shiny brass finish. Is there any way to paint or otherwise refinish it to give it a darker, duller look?Terry Foster
crafty mom - Columbia, Missouri
April 18, 2008
Q. I have a lovely chandelier that has a shiny brass finish. I would love to tone down that shininess. Actually I would love to find a way to refinish it with out taking it down and taking it apart? I know that is a lot to ask. But, that would really be a pain.
Is there a way to do this?
hobbyist - Rancho Santa Margarita, California
A. Hi, Terry; Hi, Laura
If you know the chandelier to be real brass, you can try to remove the lacquer from it with Acetone or lacquer thinner. Then you can darken it as above. But easier and safer, if not as permanent, might be a wax rub [linked by editor to Rub 'n' Buff product info at MisterArt]. Good luck.
Ted Mooney, P.E. RET
Brick, New Jersey
September 8, 2008
A. I would try to coat the surface of the chandelier with a dark glaze. The result would be a delicate finish, but a Chandelier doesn't get much handling and would look great for a long time to come. You could purchase some water based glaze and add extremely dark water based paint (found in craft stores) until it is the color you like and paint it on the brass with a small brush. This will make it look "antiqued". You can do several coats depending on how dark you want it to look. It will also tone down the shine.
I have also painted brass chandeliers white or off-white, or even a color! They look gorgeous! Just make sure you have cleaned it well and spray it with white paint.
- Chester, New Jersey
June 20, 2009
Q. We own several lamps and lights that are Brass Plated. Can you please tell me how to tarnish the plating so that it appears darker? Is there a simply product that can be purchased to accomplish this? If so, can you please tell me where to buy such product? Thanks!Tim Edwards
home owner, hobbyist - Clarkston, Michigan
September 3, 2009
Q. I am working on a "shadow box" for someone who is retiring from the Navy. The shadow box holds a flag and all of the member's medals. Inside the shadow box is a brass plate with all of the tours of duty. Unfortunately it is very hard to read the etching, is there any way to darken the plate so the etching is easier to read?Shannon Van Meter
Buyer - Ridgecrest California
September 30, 2009
Q. I want to match a new panel I am making with a hammered copper sink already in the room. How can I get the new copper to darken and what kind of wax is best for the finish? I called one company and the process they use on the sinks is "secret".Lois Campbell
hobbyist - Oswego, New York
August 17, 2010
Q. Hi there, I have a lot of jewelry brass backings and would like to turn them black, but use a safe product so it can be worn against the skin and clothing,
Thanks so much for your help.
jewelry maker - New Zealand
September 28, 2010
Q. Hello, I need to darken brass for my work (lamps), but I don't have easy access to the darken-it like products.
Even Palmolive washing liquid is not available here (Indonesia) and they never write the components on detergents.
I tried eggs with very little success and I am looking for some simple way to reach.
Please help me!
product designer - Bali, Indonesia
January 23, 2011
Q. Hello ,
Does a blackened brass with Rockler's Darkening solution hold up in a outside weather environment? Thanks!
- newton, Pennsylvania USA
January 24, 2011|
A. Hi, Ike
January 29, 2011
Q. Thank you for the info! A follow up question, is there anything that will darken brass and survive outdoors? Thanks IkeIke Sin
- newton, Pennsylvania USA
A. I'm not sure that we understood each other, Ike. If you blacken it and then lacquer it, it will hold up outdoors for a couple or a few years. The lacquer is easily stripped and replaced.
There are dark "Lifetime Finishes", which you may have seen on door hardware. But these require very expensive PVD (physical vapor deposition) machines, and are applied by OEMs not by consumers.
Ted Mooney, P.E. RET
Brick, New Jersey
March 18, 2011
Q. I have a chandelier made of steel and tubular steel and painted in a pewter color (cold grey/blue tones) with a highly lacquered finish. I'd like to change the finish to bronze (warmer tones) and I have some professionals telling me that it cannot be done over the high lacquer. Do you have any suggestions? Would auto paint cover? It is a detailed fixture and cannot be sandblasted b/c of the wiring.
I appreciate any suggestions.
homeowner - Orange, Connecticut
March 21, 2011|
A. Hi, Lisa.
Simplest, easiest, cheapest would be the Wax Rub if it works, so I'd try that first. If not, you can try removing the lacquer with lacquer thinner. If that doesn't work you can remove it with the far more powerful Aircraft Stripper, but only outside with good ventilation, not in place. Then you can use one of the fancy paints like American Accents.
Rust-Oleum Oil Rubbed Bronze
December 14, 2011
Q. Hi ! I am remodeling and bought wonderful doors at a salvage place. The handles were gold plated. I had the plating and underlying zinc removed leaving very bright brass. I would like to make the brass appear darker with a rosy tone to compliment a chandelier in the room. Is this asking too much ? I would appreciate any advice. Thanks !Diane Valine
- Rancho Palos Verdes, California, USA
December 18, 2011|
A. Hi, Diane.
A wax rub is probably the fastest and easiest route to the color you want while maintaining a real metallic look =>
Rub 'n Buff Sampler
April 30, 2012
Q. I have a couple of reproduction ancient bronze rings, and would like to put a dark brown patina on them similar to if they were dug up. I have tried liver of sulfur, the liquid form but after wearing them a day or two the patina starts to wear off. Did I not use it correctly, or is there another method to oxidize them?
- Griffin, Georgia, USA
May 16, 2012
Q. Hello everyone I read the thread before asking my question. And it was really informative & helpful. My question is how to create a shading effect on Gold Jewelry. One particular one I remember seeing it was a gold flower necklace & the petals had this shading effect from bright gold to dark brown. Any kind of help will be appreciated. Thank YouViral Soni
- Mumbai, Maharashtra, India
July 10, 2012
Q. Hello everyone,
I have a brass brass plate with lots of holes drilled into it that I would like to get really black. Some of the beams in the plate are as thin as 0.1 mm. We already tried to leave the plate in a solution of 250 g Copper-Hydroxycarbonate and 1 liter of ammonia for 3 hours and overnight. 3 hours wasn't sufficiently dark and the overnight treatment ate away a lot of the fine beams. Could you point me to other treatments or variations which are milder than this but also lead to a strong black? A black deposit on the plate would also work, but I do not know of a process to do this right now.
Any help would be appreciated.
Thanks a lot and best regards,
- Karlsruhe, Germany
December 27, 2012 -- this entry appended to this thread by editor in lieu of spawning a duplicative thread
Q. How to get the black color on brass using chemicals?Reza Karimkhan
- Tallahassee, Florida
February 18, 2013
Q. I have a copper weathervane (of a Labrador Retriever) what has turned nearly black, from being outdoors over 4 years. I would like to lighten it and preserve the lighter finish. The surface is 18" x 12", so copper cleaner is taking too long. The natural color is not shiny copper, but somewhat antiqued. What do you recommend? Should I just leave it dark brown?Jim Carlisle
- Colleyville, Texas, USA
A. Easy method for darkening brass:
I wanted to darken my antique brass hardware that had a finish on it. I needed to get the finish off first which I did with fine steel wool after sand blasting. I guess you could use acetone or some kind of paint or finish remover. I tried Palmolive but it didn't work. I ended up using ammonia and it was really simple. I put all my hardware face up on a cookie sheet inside a plastic trash bag. Lay the trash bag on the counter and slide the cookie sheet in. Fill a glass bowl with a couple cups of ammonia. Place the bowl of ammonia in the center of the cookie sheet. I also place a heavy drinking glass upside down in the center of the ammonia bowl to keep the bag up and away from the hardware. This way the fumes from the ammonia was able to circulate. I then tied up the bag and left it over night. In the morning the hardware was perfectly aged. It looks A bit dry so I am going to rub a little polish on it to just liven it up a bit. This method was simple and quick.Nancy Lucier
- Holland, Massachusetts
April 22, 2013
Q. Dear Sirs / Madams
As a very nearly retired signmaker, I have been making bronze plaques for over 50 years but have now hit a problem; the toning powder I used is no longer available.
This used to come for a company called Walsh and the label said "Contains Antimony Sulfide". I would mix the powder with Ammonia and brush it onto a bronze casting, let it dry and brush it off. The result was about "Pantone 497".
Can anyone help me with a formula to make an equivalent powder?
Thank you so much, in advance.
- Bristol, Avon, England
July 12, 2013
Q. Hi Mr Jacobs
We are a signmaker facing the same problem sourcing for the bronze powder used to tarnish brass.
May we know have you found another supplier other than Walsh?
Would appreciate it if you can share.
- Singapore, Singapore
October 9, 2013
A. I am currently using ammonia to darken a brass piano leg caster and it appears to be working. I've only had it outside in a sealed bag for about 24 hours. It hasn't reached the desired darkness yet but seems to be getting there. The first thing I had to do was remove the lacquer finish. I bought some finger nail polish remover as it contains acetone but it did not remove the lacquer, only seemed to etch it slightly. Having used it however, did make it easier removing the lacquer with sand paper. Once that was done, I put some ammonia in a disposable plastic storage bowl, used the lid to hold the caster and placed both into a small plastic garbage bag which I tied shut. Don't expect immediate results for a dark color using this method.Carolina Whitten
- Columbia, South Carolina, USA
Darkening a Brass Chandelier that has heavy Green PatinaFebruary 1, 2014
Q. I just purchased an old chandelier which appears to be brass. It has a heavy patina on it and I would prefer a darker color.
Is there any way I can achieve this other than spray painting it?Selena Norris
- Atlanta, Georgia
^- Privately contact this inquirer -^
A. Hi Selena. I find that to be quite an attractive chandelier and hate to see you mess with it. But the first thing to find out is whether it's actually brass. If it's magnetic, it's not brass, and is at best brass plated -- which probably will not stand up to the darkening chemistry. If it's not magnetic, it could of course be aluminum or zinc; but you may be able to sense whether it's aluminum just from the light weight. If you're pretty sure it's brass, then this thread has worthwhile ideas for you. Good luck.
Ted Mooney, P.E. RET
Brick, New Jersey