Sound technical content, curated with aloha by
Ted Mooney, P.E. RET
Pine Beach, NJ
The authoritative public forum
for Metal Finishing since 1989
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Coating to keep copper from tarnishing outdoors
RFQ: Hello,
I have two copper awnings over my windows each 15 feet wide that are 25 years old. They have turned brown over the years but now something is dripping on them and the copper color is peaking though. So I obviously need to make them all brown again or preferably golden copper again. Do you know of any companies in or near Chicago that do that? Thank you.
- Glenview
July 22, 2021
Ed. note: Sorry, this RFQ is old & outdated, so contact info is no longer available. However, if you feel that something technical should be said in reply, please post it; no public commercial suggestions please ( huh? why?)
A. Kimberly,
Any mild acid (e.g. citric, acetic) should be able to take the tarnish off, though it won't prevent it from returning! Typically a clear lacquer coating is used for that.
As for creating the tarnish quickly, this is generally known as "aging" or "antiquing" which should narrow down a web search for you, including results on this very site: https://www.finishing.com/07/90.shtml
Ray Kremer
Stellar Solutions, Inc.
McHenry, Illinois
July 26, 2021
Multiple threads merged: please forgive chronology errors :-)
Q. I'm building a deck. I've researched railing and have not really been happy with anything I've come across. I was enamored with the coated aluminum balusters which lead me to my situation. I picked up a copper corner post cap and was really happy with the look of the copper against the wood. I would like to use 3/4" copper tubing for my balusters. I did a small section as a test - I cut a 10 foot section of tubing into 5 pieces, polished them up and spray coated them with a gloss water-based polyurethane. After a day in the sun the balusters are already showing signs of tarnish. My next thought was to dip the whole tube in a solvent based UV protective polyurethane. Am I barking up the wrong tree? The finished product is definitely worth the extra work, but only if there is a way to keep the copper from tarnishing.
Robert NiedzwieckiBob's Cabinets - Collinsville, Illinois, USA
2003
A. Just keep them cleaned and polished.
Simon Dupay- Roseville, Minnesota
2003
A. Your advice may be correct for navy sailors, Simon, but I can't even fathom the level of cleaning and polishing that would be needed to keep copper from tarnishing. I'm sure the copper needs to be lacquered or clear-coated.
Brass lacquer is probably better than polyurethane, Robert.
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2003
Q. Recently we purchased an expensive big copper weathervane while vacationing in Maine. We brought it home in our van and finally got it up on the front peak of the garage. So far, it hasn't tarnished and it's been about 3 weeks that it's been up. The saleslady told us it should take about 10 years for it to become fully tarnished. Too bad there isn't a spray-on product for the bigger outdoor copper items. I do know of a Hospital in the St. Louis Mo. area that has a huge copper roof. It's St. Louis University Hospital on Grand Ave. I'll bet it would really be a beautiful sight if a crew could get up there and clean it. at least if they fell off the roof, they'd be in a good hospital already.
What can I use to keep our beautiful copper weather vane, designed as a lake heron about 3 feet long with a wing spread of about 4 feet, clean and shining like the day it was bought?
- Pontoon Beach, Illinois, USA
2003
A. Hi Rose.
All metals with the exception of gold and other precious metals corrode. That's why you'll find gold nuggets in nature but not copper nuggets.
Brass lacquer can go a long way towards preventing that corrosion, but must be regularly renewed, especially outdoors, especially in the full sun that a weathervane sees. Good luck.
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
Q. Copper weathervane was clear coated with lacquer 8 years ago and has now oxidized. How do I restore the bright copper finish, and how do I reseal it.
Steven GulinoHome owner - Milford, Massachusetts
2006
A. Hi Steven.
The old lacquer can be removed with lacquer thinner ⇦this on eBay or Amazon [affil links] Warning! highly flammable! , the copper buffed back to a shine, and brass lacquer reapplied.
If the lacquer doesn't come off that way, it's not lacquer but some more exotic clearcoat. In that case, aircraft stripper.
will probably remove the coating without harming the metal, but it's toxic, noxious, dangerous stuff. Use only outdoors, preferably standing up-wind. Wear goggles
⇦this on
eBay or
Amazon [affil links] and rubber gloves
⇦this on
eBay or
Amazon [affil links] as a minimum. Good luck.
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
June 1, 2012
! I make copper wind chimes and have been looking for a product to keep them from tarnishing. I have found Everbrite [a finishing.com supporting advertiser] and Protectaclear from Everbrite [a finishing.com supporting advertiser] on the internet. All the reviews I have read are great. Am ordering me some. I wanted something that will not change the tone as I make some that are tuned to the pentatonic scale (black keys on the piano).
Mickey Willard- Corapeake, North Carolina
June 1, 2012
A. Hi Mickey. Sounds like a good coating for that situation, but remember that coatings don't last forever.
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
June 1, 2012
Q. Greetings,
We are currently landscaping and would like to put a perforated copper wall outside and up-light it. How can we prevent oxidization? Your help is greatly appreciated.
Vikki
- Santa Monica, California USA
September 10, 2016
A. Hi Vikki. We added your question to a previous thread on the subject. Brass lacquer has the advantage over most clear coatings of being easily removable ... in case you change your mind and go for natural aging at some point. Good luck.
Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
September 2016
Q. Thanks for your help.
If I were to use a metal outdoors, which one would you recommend?
- Santa Monica, California USA
September 12, 2016
A. Hi again. There is nothing wrong with copper -- it just depends on what you want. Stainless steel may involve somewhat less maintenance. Galvanized is good, but you might not like the look. Nothing wrong with painted or powder coated metal either is you like that look.
Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
September 2016
November 12, 2021
A. Titanium is the ideal outdoor metal. Can be anodized in many colors and hardly oxidizes, stays shiny, strong as the bonds of friendship. Unfortunately we still aren't producing enough of it to make it accessible, like ... so much so that this is a really unhelpful answer that I just typed, but it's too late now. Aluminum for similar reasons but less so.
Second place is bronze, it will develop a patina but that patina will be so extremely thin that bronze takes years to corrode.
Zinc, another largely unhelpful answer, but so far the cheapest, this is used to coat most steel that needs to be exposed to the elements
Brass. Brass is probably what you want. they make doorknobs and outdoor fixtures. Antimicrobial.
Oh, also stainless steel or anything with enough chromium in it.
Oh and in a certain sense, Gallium. because if it is warm outside it will melt into a shiny puddle and resolidify at room temp which is objectively awesome.
....sorry, you probably wanted more practical answers but they sent me and I am a year late. Have you considered thorium?
support dps - van nuys, California
Q. In one of your answers you say "Brass lacquer can go a long way towards preventing that corrosion, but must be regularly renewed, especially outdoors..." Is regularly weekly, or monthly, yearly?
Thanks for your help,
Kate
- Maple Valley, Washington
March 9, 2018
A. Hi Kate. Although people probably won't be able to tell you exactly how long brass lacquer will last, I think a year outside is a good guess, maybe two.
Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
March 2018
A. As a plumber for over 35 yrs you can always use a course grit cloth for getting back the original sheen; this is required for soldering old pipe but the patina is easily removed if you want to keep it shiny on a regular basis
Bryan Slack- Calgary Alberta Canada
A. For those looking to keep brass or copper polished and shiny, I have found a very good high quality Auto Wax works well. A good auto wax with high 60-80% Carnauba content (not liquid wax or cheap box store waxes) will last a long time. Car wax ⇦this on eBay or Amazon [affil links] is designed to last through sun UV and a host of environmental conditions as well as protect high quality auto finishes. The wax will eventually wear off, however it should easily last a year or more depending on where the copper or brass is located and what it is exposed to, not all auto wax is equal. I use a good quality "Zymol" wax on my vehicles and also on copper and brass articles as well as a collection of copper bullets with brass casings, it lasts months with handling them occasionally and is easily re-applied.
Tom Little- St Thomas Ontario
September 17, 2020
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Ed. note -- Gentle readers: Please try to avoid suggesting brands or sources ( huh? why?)
"Clearcoats/Lacquers for Brass from G.J. Nikolas"
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