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Aluminum boat with copper paint problems
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I have recently purchased a used 16 foot aluminum boat. It had previously had the bottom painted with a copper based paint. Now, under the barnacles, there is oxidation and corrosion. The hull does not leak and the rivets appear solid. What must I do to ensure longevity and integrity with this bottom?
Tom Andersonteacher - Burlington, Washington
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The first thing you need to do is get the copper off there because it causes galvanic corrosion. Copper-based bottom paint is used as a biocide to deter marine build-up, it is not a corrosion inhibitor. It is only appropriate for use on plastic. It is probably impractical to test the hull integrity of a small boat like this, but a marine surveyor could look at it to make you more comfortable.
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 Ted Mooney, P.E. finishing.com Brick, New Jersey |
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What do you suggest I use to remove the copper paint on my aluminum boat. There are no real signs of corrosion yet. I also want to remove the paint over anodized on the sides of the boat. It is a classic FeatherCraft I have begun to restore.
Roger Heidt- Belleville, ON, Canada
Hi. When you folks speak of "copper paint", I'm assuming you mean ablative bottom paint that has copper in it, rather than copper colored paint. I imagine that it can be removed either with aircraft stripper [linked by editor to product info at Amazon] or by abrasive blasting. But as far as I know, bottom paint is a hazardous material, so the blasting service may need to do something about containment. Good luck.
Regards,
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 Ted Mooney, P.E. finishing.com Brick, New Jersey |
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I am currently restoring an aluminum hull boat I have DA sanded it completely with 80 grit paper and a stainless steel wire wheel. I am applying PPG DP-40 zinc chromate primer over all. I am then applying epoxy sandable surfacer,then a 3 stage urethane topcoat. I have used it over the years on all bare metal surfaces. It comes in several colors and has never failed me.
Shaun Ramirez- Clackamas, Oregon
March 30, 2009
Where can I buy PPG-DP-40. Shaun, tell me where I can buy everything that I need to paint my boat? Thank you.
Russ
- Belvidere Illinois
November 19, 2009
Hi, Russ. I don't know about the PPG brand, but
AwlGrip [link is
AwlGrip products at BoatersWorld] offers zinc chromate primer. Zinc chromate is labeled "For Professional Use" because of the toxicity of chromates.
Regards,
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Ted Mooney, P.E. finishing.com Brick, New Jersey |