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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Meet the Author


John was born and brought up in Bermuda and started sailing as a child, racing locally and offshore before turning to cruising. He has sailed over 100,000 miles, most of it on his McCurdy & Rhodes 56, Morgan's Cloud, including eight ocean races to Bermuda, culminating in winning his class twice in the Newport Bermuda Race. He has skippered a series of voyages in the North Atlantic, the majority of which have been to the high latitudes. John has been helping others go voyaging by sharing his experience for twenty years, first in yachting magazines and, for the last 12 years, as co-editor/publisher of AAC.

3 comments… add one
  • pete Oct 11, 2010, 5:04 pm

    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 Jan 25, 2016, 5:39 am

    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!

    • John Jan 25, 2016, 7:49 am

      Hi Taras,

      I think that would probably work fine. I know someone who did exactly that some years ago, and as far as I know all is good.

      Some will tell you that this course of action will be a problem because either there won’t be any anodizing on the mast, or if there was, it will have been compromised by the painting process; however, I don’t think that’s right. After all, unpainted aluminium boats are not anodized.

      One challenge will be how to get the the paint off. If you use chemicals you need to make sure they won’t attack to aluminium. Also, using steel tools to scrape is probably not a good idea, although stainless steel is probably alright. You might want to look into soda blasting.

      I’m guessing that you will need to remove all of the fittings to do this, so now would be a good time to make sure they are all properly isolated with plastic spacers and the fastenings liberally coated with either Duralac or Tefgel. Here’s a chapter from Colin that will help.

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