Making aluminum look like copper, gold, or brass

A. Hi Susan. Although a passable job can be done with paint if you're speaking of a roof or gutter, and you can buy that painted aluminum sheet metal, for closer-up stuff you'll probably want a real copper patina. That is done by "painting on" a coating of copper and its reaction products.

Further down the page you'll see responses to Jasper L where commercial products are linked. But read their instructions on-line before buying or starting the project because sometimes it's a two or three step process with a ground coat, then a main coat, then a reactive coat that patinates the main coat, etc.

Please tell us what it is (and how many) you want to patinate because this site serves hobbyists who want to make one, and manufacturers who want to make millions, and answers will be different for different needs. Luck & Regards,


Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

A. Hi again. For that application I see you're looking for a copper or "oil rubbed bronze" look, not a green-blue verdigris.
Luck & Regards,


Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

A. Aluminium can be copper plated by simple immersion : copper tartarate 50 gms /water 1 lit, pH of solution must be 3,5 (correct it with tartaric acid ⇦this on eBay or Amazon [affil links] !). 100 °C temperature of solution. Hope it helps and good luck!

A. We always appreciate Goran's helpful and knowledgable answers, but do warn you to try it on a piece of scrap before entrusting your whole soon-to-be-built surround to it. Just because it's theoretically possible doesn't mean the look will please you :-)

Luck & Regards,


Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

A. Hi again. Ig you use the Modern Masters, or other copper-bearing patina solution it should make little difference whether its applied to aluminum vs. steel.

Luck & Regards,


Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

A. Steel can be immersion coppered too (20 gms copper sulphate, 50 gms ammonia ⇦this on eBay or Amazon [affil links] 25 %, 1 lit water, add tartaric acid ⇦this on eBay or Amazon [affil links] until pH is 3,5). Hope it helps and good luck!

A. Rub it with olive or boiled linseed oil ⇦this on eBay or Amazon [affil links] (very sparingly),then heat it to max. 400 °C! Good luck!

A. Hi Andre. Aluminum can be anodized, dyed, and sealed. It should exhibit extraordinary outdoor resistance as entire skyscrapers are built with anodized aluminum.

But whether this offers you the option for the art you envision is a question I can't answer.

Good luck.

A. You can colour aluminum directly, without anodizing!

Black for aluminum:
10 gm potassium permanganate ⇦this on eBay or Amazon [affil links]
25 gm copper nitrate ⇦this on eBay or Amazon [affil links]
4 cc nitric acid
1 lit water

Hot immersion / 80-100 °C)
5 min. = brown
15 min. = dark brown
30 min. = black

A. Hi Pete. Goran is not asking you to use it full strength, but at a 251:1 dilution, 4 cc/lit. But since he is using liquid volume (cc) rather than weight (gm), he is referring to an available concentration, and standard nitric acid concentration is 69%-71%.

Luck & Regards,

A. Hi, David.

I have seen a roofing and gutter materials with such paints applied by roller coating but I don't know who makes them and whether that striated look can be applied in a single coat or if it needs multiple coats.

Good luck.

A. Most expensive is solid real copper. Less expensive, but looking exactly like real copper (because that's exactly what the surface is) would be copper plating. Depending on how close it needs to look, anodized aluminum with an "oxidized copper" colored dye or paint/powder will do it. You can post an RFQ what what you are seeking at www.finishing.com/letters/.

A. Try old burnt oil process-simply oil it very sparingly with some edible oil or fat(olive oil is best),then heat it slowly to max 400 °C. Repeat if needs. Hot air gun is best tool for that task, or kiln if you have it. Good luck and hope it helps!

"Zipper: An Exploration in Novelty"
by Robert D. Friedel

on AbeBooks

or eBay or

Amazon

(affil links)

A. Hi Mitesh.

You can coil anodize & dye it to achieve the effect. But I don't think you'll find any method of getting a consistent color without completely unreeling it and doing continuous web processing.

Please be careful about making aluminum look like copper or brass because it sure doesn't function like it :-(

I bought a replacement convertible top for my car which came with an aluminum zipper colored to look like a brass one. The white salty growth, corrosion pits, and general galling made it impossible to zip after just a weeks despite WD-40 ⇦this on eBay or Amazon [affil links] running over the window in a vain attempt to keep it functional; at the same time the brass zippers on my salt water boat were working fine ... If I were GM of the Universe it might be a shooting offense to color aluminum zippers to try to fool people that they are copper or brass :-)

A. You can plate copper to aluminum by simple immersion process!
Solution1.-1lit water ,150 ml hydrochloric acid,32 ccm sulfuric acid,15 gm copper sulphate.
Solution 2.-1lit water,100 gm copper sulphate,1gm potassium chloride.You must immerse object to solution 1,then rinse it and immerse in solution 2. Slightly acid boiling copper tartrate solution can be used too.
Hope it helps and good luck!

A. Simple and effective solution-oil it very very slightly with any edible oil(according to old books olive oil is best),then heat it to 300-400 °C (use hot air gun). Instead of oil you can use 2-20% shellac solution too. Yellowish-brown or black finish. Hope it helps and good luck!

A. Brooks,

Here is an old school way of coloring aluminum man. Try this, just make sure your wearing neoprene rubber gloves ⇦this on eBay or Amazon [affil links] .

solution a: sodium hydroxide and zinc oxide ⇦this on eBay or Amazon [affil links]

reaction to aluminum: turns the aluminum gray.

solution b: copper sulphate

reaction: turn the gray stuff to black and a little bit of red shade. Depends on how you apply the stuff.

hint: make the copper sulphate ⇦this on eBay or Amazon [affil links] is very diluted.

Old school but works!

A. Hi Claire. Aluminum can be clearcoated; lots of people polish their aluminum car wheels then clearcoat them. Also, the right alloys of aluminum can be anodized without losing substantial shine -- most dentists' lights and outdoor lighting reflectors, and many telescope mirrors are anodized aluminum.

Regards,

A. Wattyl has a product called Aluclear.

A. Hi, Jasper.

In a way, it is the copper itself that is responsible for the color, not the chemicals it was treated with. Aluminum doesn't form those colors; it can't.

But you can probably "paint" on a cupric solution. Commercial copper metallic surfacer [affil links] solutions are available. You can leave these as is, or go on to use a green patina [affil links] or blue patina [affil links] solution on the new "copper" surface. I would expect, though, that metal surfacing an aluminum table and patinating it to an attractive artistic look is a job for someone with some arts and crafts aptitude rather than just home handyman experience -- which leaves me out :-)

Regards,

A. Hi Pete. When acids are specified by volume instead of weight, the writer usually means at the strength one would typically find that ingredient in a chem lab for general purposes rather than any particular molar concentration for titration ... this is often the highest practical concentration, so I would guess 68% concentration.

Please introduce yourself and your situation so you can get better targeted responses: For example, Goran is one of our most helpful readers but he is a metals conservator and some of his responses in this one-room schoolhouse of an internet public forum are not targeted at nor appropriate for consumers. Thanks. Aluminum Black may be more appropriate for consumers, and Insta-blak from EPI / Electrochemical Products Inc. [a finishing.com supporting advertiser] more appropriate for industrial users. Good luck

Regards,

A. Hi JP. The conventional and "right" way that aluminum is colored is by anodizing it, which creates a microscopic honeycomb style surface on it, then dyeing it so the dye is absorbed into the pores in the honeycomb, then 'sealing' it (exposing it to very hot water and/or chemicals that cause the top of those pores to swell over and close.

Some people do this as a hobby but, if that is too involved for your purposes, then your choices would be to paint it with a gold/brass look paint, or to use gold/brass colored magic markers. But even starting with a uniform & very clean aluminum surface, I'm not sure whether you would consider the indelible marker coloration a "nice gold/brass look".

Luck & Regards,