Q&A: What Should I Paint On My New Aluminum Boat?

Question: You say you would not paint aluminum. Ok, it is hideously expensive (I have been quoted £10,000 just for materials), it is difficult to key, and we have been advised to sand blast and paint the same day (tricky!). So, if you were to start all over again with a newly built boat, what parts would you paint?

Answer: You are right, painting an aluminum boat is incredibly expensive and if you get someone else to do it the materials price you were quoted will be less than half of the final cost.

Yes, you must key the aluminum, but there is much more to it than that. You also need to acid wash and get a good zinc chromate primer on that day (this goes under the normal high build primer). Don’t believe anyone who tells you that acid etching and metal primers are not necessary. Even some professional painters will try and tell you this because they don’t want to deal with these nasty chemicals. If you don’t etch and prime properly, all your expensive paint will start bubbling in a couple of years. By the way, the same applies to painting aluminum spars.

The only part of a new aluminum boat I would paint is the bottom. Starting with a primer as discussed above, followed by a good barrier coat (we use InterProtect from Interlux) and topped off with an aluminum-friendly anti-fouling (we use E-Paint ZO).

Definitely do not paint the bilge. You will never get the paint to stick properly and you will then have to live with loose paint chips in the bilge with the potential to block bilge pumps, block limber holes and gather in wet clumps with any dirt. This will actually promote corrosion rather than prevent it.

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pete

We have a friend here in Morlaix that bought a small alu yacht that was well tatty. We sprayed a special etching primer for alu then 2 coats of undercoat and then 8 coats of polyurethene gloss single pack. It has kept well and can be repaired with a little rubbing of wet and dry and a touchup of the original paint

Taras

Hello John!
I have an old aluminum mast (on aluminum boat) that was painted couple of times but now the paint is coming off.
What do you think about stripping off the paint from the mast and leaving it unpainted? Are there any drawbacks to this? (I don’t care about the look)
Thank you!

Robert McArthur

When you say “don’t paint the bilge”, what would you do then in the engine room/bay? We’d like to see any leaks (or dropped coins!), yet the bare alu is, and will continue to be, covered by the barrier that forms on alu; let alone the small pits et al. that have formed over the last 20 years. We were thinking of sanding/grinding/prepping/painting the engine room bilge, but your comment has me questioning…

Robert McArthur

Ok – I hear :).
Any ideas on how to clean out the bilge around/under the engine so we can see problems/leaks more easily given shes oxidised and pitted a bit? Is it the usual grind and sand?
Also, have you or anyone tried using Cerakote over alu?

Thanks

P D Squire

Anyone got experience of vinyl wrap for aluminium boats?

Frederik Rebel

Hi John, I ama new member with a Dutch built aluminium boat (Koopmans 46 cutter pilothouse shallow draft). Instead of spending lots of timeand money I am thinking of taking the topside hull paint off as after some 20 years some bubbles appear. And some scratches 🙂 . I have heard of icepellet blasting and the like. Any thoughts on that? Regards, Frederik