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Old 02-02-2020, 06:34   #1
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Primer for bottom paint on aluminum RIB?

We have always painted our RIB with antifouling and would like to do so with the new to us aluminum RIB. It is powder coated.

I plan to do a light sand of the powder coating.

Do I need to prime after and if so with what product?
Thanks.
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Old 02-02-2020, 06:44   #2
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Re: Primer for bottom paint on aluminum RIB?

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Originally Posted by Calypso52 View Post
We have always painted our RIB with antifouling and would like to do so with the new to us aluminum RIB. It is powder coated.

I plan to do a light sand of the powder coating.

Do I need to prime after and if so with what product?
Thanks.
You know you need an antifouling without copper, right? I would recommend you use an epoxy primer to create as much isolation between the aluminum and the paint as possible. Interprotect2000 is a good choice but be sure to add the first layer of antifoul before the primer fully cures (fingerprint test, see application instructions)
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Old 09-02-2020, 19:01   #3
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Re: Primer for bottom paint on aluminum RIB?

As Jedi said, but if you have any exposed/raw aluminum, don't forget to (at least) spot prime with chromate.
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Old 12-02-2020, 16:29   #4
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Re: Primer for bottom paint on aluminum RIB?

Quote:
Originally Posted by Calypso52 View Post
We have always painted our RIB with antifouling and would like to do so with the new to us aluminum RIB. It is powder coated.

I plan to do a light sand of the powder coating.

Do I need to prime after and if so with what product?
Thanks.
Because aircraft are mostly aluminum and corrosion is very bad the aerospace industry has lots of choices for aluminum primers. a clean and etched surface will make for much better adhesion. Most primers for aluminum are chromate based. Zinc chromate was the most common. I am attaching a link to a marine formulated aluminum primer. Etching can be adequately performed with citric acid and ammonia and you won't have to resort to dangerous solutions. Test a small patch to see how aggressive your etchant is. You should get a bit of bubbling. Rinse it off with plenty of fresh water and dry it. Then prime


https://www.jamestowndistributors.co...RoCtf0QAvD_BwE
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Old 12-02-2020, 16:54   #5
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Re: Primer for bottom paint on aluminum RIB?

As I understand t he OP, he is planning to paint over powder coat, and thus etching the alloy has already been done!

I'm no expert on powder coatings, and there may be many different plastics used in them. I'd contact the dinghy's manufacturer and ask what they are using, and for advice on painting. I suspect that sanding off any gloss and then a coat of Vinygaurd or other vinyl primer, followed by antifouling will work just fine.

All the advice about how to coat bare alloy is interesting, but not applicable here.

Jim
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Old 12-02-2020, 17:17   #6
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Re: Primer for bottom paint on aluminum RIB?

Now that we got past the idea of no etching is needed and Jim has suggested a very good primer, I'll go the next step and throw in a good bottom paint that can be used w/aluminum.

Vivid by Pettit. A hybrid of ablative and hard paint that maintains its antifouling after you repeatedly haul/launch.
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