Painting Aluminum Hull Bottom

billyboy · 17 January 2015, 22:33

Hello all. New member here, and new owner of a 2000 10' Zodiac RIB with aluminum hull and 9.9HP outboard.

The hull bottom is in good shape except for a few small scrapes on the keel exposing the aluminum.

The hull bottom is mostly the factory white painted finish, but it looks like the previous owner did some touch-up along the keel. Not sure what he used, but possibly engine paint.

This will stay in the water in the marina (Lake Erie Islands) for the season. We use it to get around the marina and for short day trips into the bay.

I'm trying to decide whether to repaint the bottom with antifouling or the same paint that is on there (which I can't seem to find).

Any advice welcome!

beamishken · 18 January 2015, 00:17

im not sure what to use but be careful with antifoul as some types can increase corrosion on aluminium so make sure its a one suited t aluminium

billyboy · 18 January 2015, 00:29

I happened across a video of a guy painting a Merc outdrive with black Valspar Tractor and Implement enamel with hardener added. It comes in white, and the paint that's on the hull does look like an enamel.

Tractor and Implement Enamel

I'd have to prime the bare aluminum. What do you think?

beamishken · 18 January 2015, 01:17

You will need to etch prime any bare aluminium under whatever top coat you use but if your not using antifoul just make sure the paint is fully cured as it continues to cure for quite some time after its gone hard

Robert Bradley · 18 January 2015, 06:56

Billy boy i created an account to save you the agony of painting your hull with the wrong antifouling paint. I have a 24 ft pontoon boat and live near the ocean. I decided to paint the hull last year and after much research discovered that you MUST first apply a coat of E2000 epoxy paint to the aluminum BEFORE applying the antifouling paint. Additionally it is highly recommended that you use a product such as petite vivit antifouling paint. Cost is about 240 a gallon for the petite and around 100 for the two part epoxy paint. Just as beamishken stated you must me careful with the antifouling paint as the combination of copper based paint on aluminum submerged in salt or partially salty water can have a battery effect. The petite vivit is specially designed for aluminum boats and the directions on the back of the gallon call for a prior coat of the e2000. I hope that this information is helpful

billyboy · 18 January 2015, 16:51

Thanks! Yes, I'm familiar with this procedure. I removed all bottom paint and applied an epoxy barrier coat on my Bayliner the first year I owned it. I kept the bottom paint away from the outdrive. Even the stainless props reacted with the aluminum outdrive cases on the Bravo 3 drives in freshwater.

I'm wondering if applying bottom paint to a 10' RIB will create far more maintenance issues in the long run. The tubes cannot be painted with bottom paint and they will be sitting in the water, too.