Painting Copper

Patfromny

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Dec 2, 2012
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Hi all, I know this isn't a boat topic but I can't seem to find any info online that satisfied my question. I have a customer with two copper roofs over her bay windows. They are aged and they are staining the white siding around the windows black. She has asked me to paint them to prevent this from happening. Should I treat this the same as aluminium? Vineger, SE primer, prime, then paint? I know there are some pretty slick people here that might have dealt with painting copper in the past any suggestions would be appreciated. If copper simply will not hold paint I would like to hear that too. This isn't something I want to be going back to fix. Very difficult customer over the years. If copper isn't a good substrate for paint I will push for cleaning and waxing a bit harder than I have been so far. Thanks in advance guys.
 

Woodonglass

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Dec 29, 2009
Messages
25,924
Back in the 80's I did a bit of Roofing. Ran into some copper gutters occasionally. Had an old guy working for me and he clued me into this technique. Sand with 220, then wipe down with DeNatured Alcohol. THEN clean with Garlic Juice to Etch the copper. Weird I know but it works!!! Prime with rustoleum clean metal primer and paint with Rustoleum. Now that I've learned about the hardener, I'd suggest that if you really want it to last put some of it in it too!!! You WON'T have to do a GO BACK on it!!!
 
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harleyman1975

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May 12, 2003
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959
I was going to suggest a similar approach but use phosphoric acid instead of garlic juice and then an epoxy primer instead of a self etch, copper spray paint and then a clearcoat over that. I would be charging her about $1500.00 and telling her to expect a ten year life cycle.
 

Patfromny

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Dec 2, 2012
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Thanks guys. Those two replies are more info than I could find on the internet. Lol. I think she wants them black but I haven't gotten that far in the conversation with her yet. I have been doing her whole house inside in an off white with black doors. Real nice look. The only problem she has is she thinks the doors are open when she walks by. Lol. Wood, I have been having a tough time finding that hardener. Nearest tractor supply is in Connecticut about 2 hrs. Away. Was thinking of calling a few auto body supply shops but don't know if they would carry a hardener for oil paint. I guess I will find out since I need it anyway for my side panels if it ever warms up here on Long Island.
 
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Patfromny

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Dec 2, 2012
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My advanced carried the quarts...4 of them to be exact. Lol Oriellys is also in Connecticut. I can probably call around to some other advanced locations or just order it online. Thanks for the link. Have to order it this week so I can paint those panels. While I have your ear, what do you think of mixing rusto aluminium and royal blue to try to achieve a metal flake like finish? I don't want to use what is left of my boat paint but want to make the panels look similar. Wasn't sure if the aluminium rusto actually had flake in it.
 

Patfromny

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Dec 2, 2012
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How much paint will that treat? Is it 8 oz. To a quart? Need to know how many to order. It seems none of the advance stores in my area stock the hardener.
 
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PTChief

Seaman Apprentice
Joined
May 1, 2016
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36
You might check out Ace hardware as well. They make an aluminum/galvanized metal primer that might work for you. Being non-ferrous, copper should take any NF primer prior to top coating. My dad was a metal worker and he used to "etch" copper sheeting with vinegar and lemon juice before he painted. I never knew the theory behind it all but it worked and the shop always smelled good!
 

mxcobra

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Jun 27, 2011
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probably be easier, and cheaper to replace that copper with black pro panel. then scrap the copper for some extra cash....
 

Patfromny

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Dec 2, 2012
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Thanks PT and MX, I appreciate the ideas. I think i will just clean, prime and paint. In and out. Don't want to open a can of worms taking off the copper. God knows what is underneath. Sort of like probing for rot in a transom and stringers. I am too busy to have this turn into a framing job. Maybe in February that would be fine. Lol
 

fhhuber

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Jun 19, 2014
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1,365
Essentially...

You have to clean the copper BRIGHT AND SHINY, then de-grease then use a self-etching primer or some etching product.

Can''t wait a day between cleaning and painting... And its more touchy about this than aluminum.
 

Patfromny

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Dec 2, 2012
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1,197
Thanks fhhuber, I might just do one a day. I have to paint her doors and trim in the front too so I can fill the first day at least with work. If I have spare time I will start the cleaning process on the second roof and wait to chemically neutralize the copper till day two.
 

Woodonglass

Supreme Mariner
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Dec 29, 2009
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25,924
While I have your ear, what do you think of mixing rusto aluminium and royal blue to try to achieve a metal flake like finish? I don't want to use what is left of my boat paint but want to make the panels look similar. Wasn't sure if the aluminium rusto actually had flake in it.
UHMMM,NO, NO, NO!!! Aluminum Paint is a Different Kettle of Fish. Do NOT mix it with anything!!!! NO!!! Solly Cholly!!! Mix ratio on the Hardener is 2oz per quart. I like to mix it 2 cups at a time and use 1oz per 2 cups. Mix every 10 minutes for 30 minutes to let it "Cook" then shoot it!!! They Make "Baby Flake" metal flake you can add to your paint and shoot it with a standard Harbor Freight Spray gun. It's kinda Pricey though. About $20 bucks for 2oz!!!!:eek:
 

Patfromny

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Dec 2, 2012
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Thanks Wog. I did buy the same rusto type. One royal blue, one aluminium. Same white can. Aluminium is the color. I think i would rather use the metal flake anyway. 20 bucks is an ok price for the flake compared to me using my 200 a gallon or whatever it was blue "gold". I have a little blue left after the re-spray (neighbor hit me) and want to save it in case he hasn't learned to tie his boat close to the dock this year. Lol. Thanks for the mix rate and cook tip.
 

Patfromny

Lieutenant Junior Grade
Joined
Dec 2, 2012
Messages
1,197
Thanks Wog. I did buy the same rusto type. One royal blue, one aluminium. Same white can. Aluminium is the color. I think i would rather use the metal flake anyway. 20 bucks is an ok price for the flake compared to me using my 200 a gallon or whatever it was single stage blue "gold". I have a little blue left after the re-spray (neighbor hit me) and want to save it in case he hasn't learned to tie his boat close to the dock this year. Lol. Thanks for the mix rate and cook tip.
 
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