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Safely darken Copper, Brass or Bronze

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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?

Thanks-
Paul

Paul D [last name deleted for privacy by Editor]
- San Leandro, California

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A. You can try Jim Watts' favorite sulfide from egg formula (see letter 1178 or 12714)

Tom Pullizzi Falls Township, Pennsylvania

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A. PAUL,

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.

REGARDS,
RAY

RAY DELOREY
- Cambridge, Ontario

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A. Use liver of sulphur Liver of Sulphur [linked by editor to product info at Dick Blick]. 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.

Ed Kassery

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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 [linked by editor to product info at Amazon] Gun Bluing. It's advertised as a blue/black oxide finish for steel but it is very effective on brass/copper. Brasso [linked by editor to product info at Amazon] 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
Austin, Texas

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June 25, 2009 A. To darken brass, you must first strip any varnish on it. Surprising, one of the most commonly available household chemical you can use to darken brass is Palmolive Dishwashing liquid. Look at the label and see if it contains sodium bisulphite and other sulphur derivatives. These are very similar to the chemicals in Liver of Sulphur. Apply the dishwashing liquid with very little water to the bare brass and keep rubbing till you get the colour you want. This will take only a few minutes. When you get the colour you want, wash off the dish washing liquid. Hong Lim - 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. Regards, Ted Mooney, P.E. RET finishing.com Brick, New Jersey 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 (Click graphic for Maid o' Metal brand from Dick Blick)

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February 9, 2010

Q. Regarding Hong Lim's suggestion (6/25/09) 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

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February 15, 2010

A. Hi, Ellen. If the coating is brass lacquer, you can remove it with with acetone [linked by editor to product info at Rockler] or lacquer thinner [linked by editor to product info at Amazon]. If it's a more durable coating, you can probably remove it with aircraft stripper [linked by editor to product info at Amazon]; it will not hurt metal, but is really noxious stuff absolutely demanding goggles [linked by editor to product info at Amazon], protective gloves [linked by editor to product info at Amazon], and truly excellent ventilation.

Regards,

Ted Mooney, P.E. RET finishing.com Brick, New Jersey

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Q. Can anyone give me the location/phone number of where I can get in touch with the supplier Gessein^^Gesswein referenced in one of the responses above?

Kim M [last name deleted for privacy by Editor]
- Azle, Texas

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A. The spelling is incorrect on your inquiry, it should be "Gesswein" polishing tools and accessories.

Gary Garcia
- Modesto, California

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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

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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

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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.

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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

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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

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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

Application:
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.

Scott at Redstone Manor
- Keymar, Maryland, USA

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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.

Thanks-

Lauren White
consumer - Toccoa, Georgia

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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

Regards,

Ted Mooney, P.E. RET finishing.com Brick, New Jersey

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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

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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? Thanks, Laura Laura Nygaard 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 [linked by editor to product info at Rockler] or lacquer thinner [linked by editor to product info at Amazon]. 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. Regards, Ted Mooney, P.E. RET finishing.com 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. Angela Burns - Chester, New Jersey

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June 20, 2009 -- this entry appended to this thread by editor in lieu of spawning a duplicative thread

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

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September 3, 2009 -- this entry appended to this thread by editor in lieu of spawning a duplicative thread

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

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September 30, 2009

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

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August 17, 2010

Hi there, I have alot 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

Debbie Brown
jewelry maker - New Zealand

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September 28, 2010

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!

FX Hoffman
product designer - Bali, Indonesia

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January 23, 2011

Hello ,
Does a blackened brass with Rockler's Darkening solution hold up in a outside weather environment? Thanks!

Ike Sin
- newton, Pennsylvania USA

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January 24, 2011 Hi, Ike No, it will probably not hold up outdoors. But you can apply brass lacquer after the darkening, and then it should be okay. Regards, Ted Mooney, P.E. RET finishing.com Brick, New Jersey

Brass Lacquer

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January 29, 2011

Thank you for the info! A follow up question, is there anything that will darken brass and survive outdoors? Thanks Ike

Ike Sin
- newton, Pennsylvania USA

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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.

Regards,

Ted Mooney, P.E. RET finishing.com Brick, New Jersey

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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.

Lisa

Lisa Gold
homeowner - Orange, Connecticut

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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. Regards, Ted Mooney, P.E. RET finishing.com Brick, New Jersey

Rust-Oleum Oil Rubbed Bronze

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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

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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 => but the durability of that approach is questionable depending on exactly what you mean by "handles". Good luck. Regards, Ted Mooney, P.E. RET finishing.com Brick, New Jersey

Rub 'n Buff Sampler

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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?

William Summe
- Griffin, Georgia, USA