Since 1989: Education, Aloha, & the
most fun you can have in finishing
Problem? Solution? Chime right in! (one of the world's very few 'no registration' sites)
"Coating to keep copper from tarnishing outdoors"
July 22, 2021
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.
Ed. note: As always, gentle readers, technical replies in public and commercial replies in private please ( huh? why?)
July 26, 2021
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
To minimize search efforts and to offer multiple viewpoints, we combined previously separate threads onto this page. Please forgive any resultant repetition, failures of chronological order, or what may look like readers disrespecting previous responses -- those other responses may not have been on the page at the time :-)
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 Niedzwiecki Bob's Cabinets - Collinsville, Illinois, USA ^
A. Just keep them cleaned and polished.
Simon Dupay - Roseville, Minnesota ^
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.
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?
Rose Young-Stewart - Pontoon Beach, Illinois, USA ^
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 Gulino Home owner - Milford, Massachusetts ^
June 1, 2012
A. Hi Steven.
The old lacquer can be removed with Acetone [affil. link to info/product on Amazon] or lacquer thinner [affil. link to info/product on Amazon]
, 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 [affil. link to info/product on Amazon] and
Rubber Gloves [affil. link to info/product on Amazon] as a minimum. Good luck.
! 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.
September 10, 2016 -- this entry appended to this thread by editor in lieu of spawning a duplicative thread
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 Smyth - Santa Monica, California USA ^
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.
Q. Thanks for your help.
If I were to use a metal outdoors, which one would you recommend?
Vikki Smyth - Santa Monica, California USA ^
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.
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 ^
September 17, 2020
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 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 ^
"Clearcoats/Lacquers for Brass from G.J. Nikolas"
Disclaimer: It's not possible to fully diagnose a finishing problem or the hazards of an operation via these pages. All information presented is for general reference and does not represent a professional opinion nor the policy of an author's employer. The internet is largely anonymous & unvetted; some names may be fictitious and some recommendations might be harmful.
If you are seeking a product or service related to metal finishing, please check these Directories: