It’s Painting Time Again

It’s hard work keeping a boat looking good

As the old saying goes, you pay for your pleasures, and that’s certainly true when it comes round to the annual re-fit. The many little jobs that were just too awkward afloat, added to the big ones like antifouling, can all back up and lead to a formidable worklist. And to top it all, there’s the curse of aluminium boats – the paintwork.

There seem to be two schools of thought with aluminium boats and paintwork. The first is to touch up as you go along, then sand and paint on an annual basis when time and conditions allow. The second is to pretty much leave it alone and then blitz the job every five years or so. We tend to the former, as we think that there’s less chance of corrosion getting a hold under blistering paint, and in any case, some of the ‘let it go’ boats we’ve seen looked pretty terrible to us.

Tackling The Problem

We’ve been meaning to get to grips with the one area that is badly affected on Pèlerin, our OVNI 435—the topsides around the rubbing strake. We had a welded strake fitted from new, and have suffered considerable amounts of blistering along the line between the unpainted strake and the topsides. As we’re out in the yard at the moment and have staging alongside to get at this area comfortably, we’ve tackled this head on, and have got the affected paint off to the point where we can start to prepare the surface for painting.

But what a job it has been. It’s now obvious that moisture was able to get under the paint along the unpainted edge, and also under a fillet of polyester filler that was used to fair up the weld before painting. All of the areas of damaged filler have had to be removed, and we now face the choice of how to best make the paint surface look good, preferably without recourse to filler. Our plan so far is to fair it up by hand, then get a couple of coats of epoxy primer on and see how it looks. Minimal amounts of filler could then be used (if necessary) to achieve a good cosmetic appearance, before two further coats of epoxy primer, then undercoat and topcoat. We also plan to paint the strake, so that there will be no ‘edge’ for moisture to creep under in the future. Whatever route we choose, it’s going to be a lot of work.

The good news is that there is no corrosion, but that’s about it! It has been a long and painful business, largely due to a bad cosmetic decision in the first place. And it’s a pity, because this is about the only area on the whole boat that has been affected. Areas of high wear and tear, and where paint has been chipped, have of course suffered, but on the whole it’s more than manageable.

A Changed System

We’ve always used an International Paints system, and had always used their Etch Primer as a base coat, as all of the factsheets insisted that this was vital to achieve an effective tie with the epoxy primer. Now it seems that Etch Primer has been withdrawn from the market, it’s now straight on with the epoxy primer, so we’re hoping that this will work OK. I’m always a little suspicious when things that were once so essential before are no longer necessary today. No doubt there are good reasons why Etch Primer is no longer available, but it would be good to know just what those are, and gain some reassurance that the new system will work just as effectively in the future.

Because I know one thing—we don’t want to be doing this job again next year!

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Meet the Author

Colin Speedie

Colin, European Correspondent here at AAC, is a deeply experienced offshore sailor who holds a Yachtmaster licence, and a gifted photographer and talented writer who has added a whole new dimension to Attainable Adventure Cruising. In addition, since Colin and Louise are from England and had their OVNI 435, Pèlerin built in France, they bring a European perspective to our site. You can read more about Colin and Louise and their business at their website.

54 comments… add one
  • Chris May 1, 2011, 12:08 pm

    Colin, as to etching primer, it may be that International has dropped it because they couldn’t compete on price. It is still actively used in the automotive and aircraft painting businesses where people still swear by it. (Some at it as well I’m sure.)

    It’s available for ~$100 a gallon +/-. Is it possible you are in a location that prohibits it?

    • Colin Speedie May 2, 2011, 1:50 pm

      Hi Chris

      I’ve no idea, but I’ve tried on two occasions here in Portugal, and the yard just can’t get it.

      Etch Primer also seems to have been taken off International’s website, and I did try one or two of the bigger chandlers.

      Thanks for the link, though, and if I find out any more, I’ll post the details.

      • John May 2, 2011, 3:59 pm

        Hi Colin,

        OK, now I’m really confused. I think Interlux and International Paint are the same company. But now I find that Interlux is part of AkzoNobel which also owns Awlgrip, which I thought was US Paint.

        Anyway, no matter. The etch primer that I used with such success in the engine room of MC (see comment below) seems to be still available, or at least listed, here.

        • Colin Speedie May 3, 2011, 8:49 am

          Hi John

          Interlux and International are indeed the same company, part of the Akzo Nobel Group.

          The primer in your link is very different from the one that we have used in the past, and is well worth looking at for us in the future, although it doesn’t appear in the International listing in the UK. The Etch Primer we have traditionally used we called the yellow peril, and seems to have been removed from sale – a pity.

          Best wishes


  • John May 1, 2011, 12:08 pm

    I’m very disappointed to hear about the discontinuation of the acid etch primer. Like you, we have used that International Paint product with great success in the past and are great believers in acid etching generally.

    When we painted our old aluminum mast some years ago we were told that we could just use the gray standard primer. The paint failed in two years.

    When we did the boom some years later, we insisted on etching with a two part acid system from WEST, followed by acid etch primer from Awlgrip and then epoxy primer. The paint is still sticking to that boom 15 years later.

    This is now our standard system for all paint repairs on MC, and when done this way we pretty much never have an adhesion failure.

  • RDE May 1, 2011, 12:50 pm

    About 15 years ago I hired on as PM with a company that had two aluminum megayachts under construction. A week later a million dollar paint/fairing failure emerged on one of them. So I’ve had an intensive education in some of the things that can go wrong with painted aluminum boats.

    As you are aware, the transition edge between paint and bare aluminum is always problematic. Your choice to paint the rub rail is the best option— just sand and temp patch areas that become damaged on its face.

    Polyester fillers have no place on aluminum and should be ground off to bare aluminum and replaced with more moisture resistant epoxy.

    International Paint always recommended their 545 primer as the first coat on bare aluminum, a practice I don’t favor. The adhesion of the first coating to the bare metal is the most critical operation in the painting process. There are two procedures that I have found to work.
    1- Create a rough profile to promote mechanical adhesion, a 36 grit grinder works best.
    2- Thoroughly clean any grinding residue.
    3- Within a few hours, before any oxidation can take place, coat with an unfilled epoxy like WEST or MAS. If it is a high load area like a winch base, don’t hesitate to wet sand the raw epoxy into the aluminum surface. Let it cure to a green cure state and apply filler, or lightly sand being careful to not break through to the raw aluminum.
    4- If fairing is necessary, use raw epoxy filled with microballoons or one of the commercial pre-mixed epoxy fillers. If you have any Sterling fairing compound throw it in the garbage can.
    5- Lightly scuff sand before applying primers.
    6- If you fall through into bare metal the bare spot must be treated exactly as if starting from scratch.

    1- grind as above.
    2- Acid wash and alodine as per aircraft practice. Prepared surface is now protected and doesn’t require immediate attention.
    3- Pre-coat with epoxy.
    4- fair and prime as per above.

    Whenever anything is bolted to aluminum, whether aluminum, wood, or stainless, it should have a 4-6mil layer of plastic or mylar tape under it as an isolation barrier. All threaded bolts and screws need teflon anti-sieze compound or something similar.

    Fair winds

    • John May 1, 2011, 3:41 pm

      Hi RDE,

      I would certainly agree with everything you say above. We often use West System resin as the bonding coat on the aluminum and sand it in with wet or dry 80 grit paper.

      The only difference is that we have got even better results by using the West two part acid treatment first. This has worked much better for us than alodine.

      Having said that, some years ago when I painted the engine room on our boat, I scuffed things up and cleaned them as well as I could, but you know engine rooms—lots of nooks and frames that are hard to get to. So I used the Interlux acid primer and had great results even though I did not acid wash first. The great thing with the Interlux product was that you could paint it on with a brush, whereas the Awlgrip product must be sprayed.

      • Colin Speedie May 2, 2011, 1:59 pm

        Hi John and RDE

        Thanks for the useful comments, which we’ll certainly bear in mind for next time – we’ve gone ahead and painted over the rubbing strake, and we should be back in the water in a couple of days.

        We’ll see how the paint stands up to the next year, and if it works, great, and if not, we’ll look at alternative suppliers, and do a really thorough job. The simple fact is that we currently haven’t the time to start again, as we badly want to get back on the water!

        All our fittings are isolated as you suggest RDE, and I wish I’d bought shares in Tefgel, at the rate we use it. Alloy machine screws are used wherever possible for smaller fittings and below the waterline (such as the plates that cover our rudder hydraulics).

        But, like John, I liked the versatility of the International system, especially for touching up.

        Best wishes


    • Bryce Aug 10, 2016, 1:45 am

      Hi Richard,

      Just clarifying your quote: “Whenever anything is bolted to aluminum, whether aluminum, wood, or stainless, it should have a 4-6mil layer of plastic or mylar tape under it as an isolation barrier. ”

      Are you referring to the US “mil” (i.e. 1000th of an inch), or mm?

      Also, for the isolation layer, is any type of plastic best (eg. HDPE/nylon/etc), or are all of them equally effective?



  • Martin May 6, 2011, 10:00 pm

    “We often use West System resin as the bonding coat on the aluminum and sand it in with wet or dry 80 grit paper. ”

    Just requesting a clarification – it seems you’re not talking two-pack epoxy primer, but a thin layer of “normal” epoxy resin?
    And do you brush on a very thin (?) layer of this epoxy resin, and then sand through this painted layer, leaving the sanding grit to harden in this layer?
    I’ve been sanding the substrate, then I wipe off the sanding grit, and then quickly, within one or two minutes, get the paint down, hoping the aluminum does not oxidize in that one or two minutes. Sounds like I should change my method.

    • John May 8, 2011, 9:35 am

      Hi Martin,

      Yes, I’m talking about using standard WEST system two part epoxy resin with no filler as the first coat when we are going to use a filler to fair things out. When I say “sand in” I mean that you can get an even better bond by using a piece of 80 grade sand paper to key the wet resin into the aluminum, not sand said resin after it is dry. Once the resin goes tacky, but before it dries completely, we then put on a layer of filler made from WEST resin and their 410 sanding filler. When that is dry, we sand for the first time being very careful not to go through to the bare metal.

  • Gianca May 7, 2011, 7:44 am

    My choice is for no paint at all above the water line, but I remember Mr Garcia, owner of the French yard, suggesting to use a tape to cover the junction paint-bare aluminium.

  • Phillip Carr Jan 23, 2012, 9:29 am

    My boat is 13m aluminium, twinscrew motor boat built as a one off to Lloyds Class in Southampton UK in 1973. In 2009 the ultrasonics revealed hull thicknesses as new. I re-painted with International Interlux in dark blue. Adhesion is good but paint has dulled and appears to be still soft. I suspect low temp and high humidity during application. Anyway time to repaint and thinking of Awlgrip in white. Do I go back to bare aluminium and begin again or prime over the International and then apply Awlgrip? Would welcome comments.

    • John Jan 23, 2012, 6:33 pm

      Hi Phillip,

      If the adhesion is good, I can see no good reason to strip the paint back to bare Aluminum. We painted over dark blue Awlgrip with white, without any problems. Check with the Awlgrip rep though.

  • Richard William Lord Sep 28, 2013, 9:45 am

    My little aluminum boat and I are close to the bottom of the food chain compared to you ocean going heavy weights.. But for what it’s worth, when I “decommisioned” my 14′ 1980 MirroCraft last fall, I sanded her down to bare metal.. Then used a “poor man’s acid etch”—–vinegar and water.. Rinsed well, dried and hit her with 3 spray can coats (light, wet sanding between) of Rust-Oleum’s “Self Etching Primer”.. I finished up with 3 coats of Behr’s oil based semi-gloss paint, rolled out with a Harbor Freight foam roller..

    Almost a year later now and no blistering, peeling, chipping or cracking.. Granted, my “semi-gloss is now kinda-gloss” but, the main thing is— the paint’s still stuck..!!

  • Todd Huss Jan 19, 2014, 4:52 pm

    Colin, I’m curious to hear how the paint job has held up?

    • Colin Speedie Jan 23, 2014, 3:48 pm

      Hi Todd

      Like the curates egg – good in parts!

      Three years on, and most of the patches we repaired are OK, but some have done badly, mostly where they’re in areas that get abrasion or chipping. And then there are a whole new crop of blisters. At the moment I’m sanding and just leaving those areas until we’re at rest and able to finish them properly and start the painting process in perfect weather in one go.

      Best wishes


      • Todd Huss Jan 23, 2014, 5:42 pm

        Hi Colin,

        Will you continue to go straight on with epoxy primer or will you try and find etch primer next time? Just curious about your opinion on the necessity or lack thereof of an etch primer.


        • Colin Speedie Jan 23, 2014, 7:08 pm

          Hi Todd

          It depends on where we are, I think. If we’re in a yard where there’s a lot of painting being done then I think it will be available. Where we were last year at Peake’s in Trinidad I reckon they would have some, for example.

          However, I’d have to say that I haven’t noticed much difference in the long term condition of the touched up areas where we used the etch primer compared with those where we went straight on with epoxy. Preparation seems to be the key, as others have mentioned in the above comments.

          What we have to do is get the last bits of polyester filler off, and get right back to the bare metal – what a pain!

          Once we know what we’re doing, and get going on it I’ll post again. And next time we’ll do some trial areas, to see what works best.

          Kind regards


  • Norm May 19, 2014, 3:33 am

    Dumb question……how do you securely store partial cans of paint on a cruising boat? We have paint that we’d like to carry for touch ups, but I’d hate to the mess it could make of the interior if it got loose in a real storm….

    • John May 19, 2014, 12:00 pm

      Hi Norm,

      Not a dumb question at all, in fact a very sensible one.

      What we have done on Morgan’s Cloud is to fit an old plastic kitchen garbage can into a deep locker to hold paint cans. We cut it down so that it only just fits and the locker lid, which has securing barrel bolts, fits snugly down onto the top of the garbage can. The result is that any paint that leaks will be confined to the garbage can and can be easily cleaned out by removing the whole works from the locker and dealing with it on deck, or better still, on someone else’s deck! 🙂

      We have had at least two cans leak over the years and were very glad of this set up on both occasions.

  • David Oct 6, 2014, 11:23 pm

    Hi Colin, can only commiserate at the fun of painting aluminium. We bought an Ovni 435 last year and are currently fixing up similar blistering problems. We’ve been using a Gerni high pressure washer with a simple sand blasting attachment that sucks garnet from a bucket, and produces a really nice profile. A wash and a meths rinse to dry the area, and hopefully the Interprotect primer will be long lasting. One challenge is the built in water tanks, which are impractical to sand blast, and suffer from a pox of white alu oxide spots and pitting. Have you had similar issues, and any suggestions as to how to treat? Cheers David ‘Mirabooka’ (ex Calypso Music’)

    • Colin Speedie Oct 7, 2014, 8:39 pm

      Hi David

      Interesting way to deal with the paint stripping issue – presumably you run the device at fairly low pressure? One thing I’d look at is the use of meths as a degreaser, as it’s not the best in my experience – I use acetone liberally on a cloth, until the cloth comes up clean, and got good results.

      The unpainted tanks are indeed an issue, probably to do with the water quality/acidity wherever you are. I always favoured epoxy painted tanks, but after talking to a number of people who have had problems with that system I’m no longer so sure. Monitor them is all that I do, and so far nothing major to report..

      On thing that we do is clean the tanks twice a year, with a product called ‘Hydroconazole’ which a water purifying compound that is suitable for use with aluminium. This seems to work well, although it’s hard to come by outside France.

      Kind regards


  • David Oct 13, 2014, 6:46 am

    Hi Colin, thanks for the tips, the sandblasting is done with the normal water pressure from the Gerni, ie about 2000 psi, and is pretty effective, but we find it quicker to sand first. We are using a water based 2 pot epoxy paint in the water tanks, so will see how it goes…let you know in a few years! Interesting that it sounds like yours are bare metal, as ours were painted by alubat. We have taken to using a filter to get rid of the chlorine when we fill them, as I suspect you are right about the problems being caused by the water quality. Cheers David

  • Colin Palmer May 31, 2015, 11:30 am

    In response to questions in the Let’s think smart thread, this is what I have used on my Ovni (a 1996 Ovni 32).

    Bottom paint. I ground the bottom back to the aluminium with sanding discs on an angle grinder. Then International Etch Primer (which is no longer available) and several (three from memory) coats of Interprotect. That was 3 years ago and still in good condition.
    This year I repainted the white band on the topsides. The original paint was chipped and degraded. So a lot filling and of sanding with an orbital sander. I had to take it back to the aluminium in quite a few places. On the recommendation of a friend who builds aluminium workboats, I used SeaJet 017 epoxy bonding primer on the bare metal, first cleaning the abraded surface with ScotchBrite pads. Then three coats of Hempel Light Primer, which was high build and very easy to rub down between coats to give a very smooth surface, to which I applied two coats of International Perfection undercoat (which also flatted back well with the orbital sander) and two coats of Perfection top coat. Phew! The experts in the yard told me about the paint roller and tipping off method for the topcoat, which worked a treat. Just one small run and a finish that looks almost as good as if it had been sprayed. Now I just have to find out if it sticks. So far so good, but we are only a coupe of months into the season.

    • Frank Mulholland Jun 1, 2015, 12:37 pm

      Thanks for that and hope we haven’t upset John too much by miss-posting:-)
      Not sure I understood the “paint roller & tipping off method” though and did you do all of the intermediate coats with a roller?
      I have purchased quite a lot of the West 105 Epoxy & 206 Slow Hardener so I will probably continue to use these for the touch-up, base coat but I will probably use the Hempel Primer on top of this, as you suggest, when I get started on the larger areas. It would be really good to see how they last. Perhaps we could do an annual comparison update?

  • Colin Palmer Jun 1, 2015, 1:10 pm

    Yes, it was not an auspicious start to my posting on AAC, so like you I hope that John will forgive me.
    I used rollers throughout (except top coats – see below) and sanded each coat back to completely flat, which is much easier with the fine stipple of a roller finish than the brush marks and runs I get with brushes.
    For the final two top coats, I applied with a roller, rolling it well out and then stroking the surface vertically with a fine, high quality dry paint brush. This got rid of all the bubbles. The difficult bit was to keep a wet edge so I only did a small area at a time and kept moving. It is certainly a job that would benefit from having two people do it, and good to pick a day when the paint does not dry too quickly. I was lucky in that the boat was north south so I was able to work in the shade or with only very angled sun. The links below provide more information on this technique, and if you google it you will get lots more.

    Yes, lets compare notes from time to time.


  • Neil McCubbin Sep 19, 2015, 10:40 am

    First rule on painting aluminum boats and masts is “Leave it bare” because after 5-10 years the paint will start to blister off. Unpainted aluminium cannot blister
    It is of course essential to have antifouling paint below the waterline and a few inches above it
    On deck, it is best to paint only the places you would normally glue on Treadmaster or other covering. When it blisters, it is easy to grind clean and repaint
    If the toe-rail, chain plates and other places with complex surfaces and/or interior corners are painted, cleaning them for repainting is a h!@@ish job.

    It takes only a couple of days to paint inside the bilges. However it takes several years to carry all the bilge paint our in little pieces. We find it very hard to get paint to stick in the bilges, and regret having painted them.
    On the other hand, we just opened a water tanks after 11 years service, and found only a tiny area of blistering paint. We used a deVoe paint intended for insides of municipal aluminium water tanks. Good stuff. We have observed that unpainted aluminium water tanks form white pustules of oxide. We were finding this in our water filter, so opened the tanks. It all comes form the aluminium dip-tube that withdraws the water. I am replacing it with plastic.
    We had to repaint a few square feet of bottom after some welding, 3 years ago. We simply used 3 coats of International Interprotrect (5 minutes after grinding with 40 grit paper) and 2 coats antifouling. Primitive, but is has held up for 3 seasons, with only a quick coat of antifouling each year. No blisters

    • John Sep 20, 2015, 9:27 am

      Hi Neil,

      I would agree with all of your observations on painting aluminium, particularly your point about not painting the bilge. We are still scraping and vacuuming lose paint some 30 years after the bilges were painted!

  • Frank Sep 20, 2015, 6:40 pm

    Hi. We also have aluminium water tanks (Ovni 435) and had the same issue with white hydroxide deposits in the tanks clogging the water filter. We eventually traced it to Clorine in the fresh water (with help from this site and a comment from Colin Speedie, if I remember correctly). It was cured by filtering the water supply on every fill-up, with a good quality carbon filter, which removes chlorine, and gets changed twice a year. Although it seems worse around the dip pipe I don’t think this is the source and replacing it with plastic might be a waste of time. We cured it by cleaning the tanks thoroughly, then flushing them with filtered water to remove any remaining suspended hydroxide before filling again and then changing the demand side water filter. Not had a problem since.

  • Neil McCubbin Sep 20, 2015, 6:46 pm

    Good comment Frank.
    I can well believe chlorine is a bad actor.
    Our painted tanks are in great shape, but lots of pustules on the 1/2″ dia by 18″ long bare aluminium dip pipes.
    We have been using water form Norway and Scotland for the last several years, where chlorination is not practiced much. We never taste chlorine in the water.
    What kind of filter do you use that can remove chlorine at a reasonable flow. I would like to by one and do same

  • Frank Sep 21, 2015, 6:18 am

    We have been using the “Jabsco Aqua Filta” which is widely available in UK chandlers. They are expensive though and another Ovni user has reported success with “Fileder Spectrum ECB 5 micron cartridge in a Pentair housing” at 1/3 of the cost. I’m going to try one next season. Their UK website has lots of info and you may be able to find an equivalent wherever you are.

    • John Sep 21, 2015, 8:11 am

      Hi Frank,

      One trick that may help on the expense: Our first filter element clogged up very quickly. I talked to General Ecology about it and apparently the problem is that bacteria in the water collects on the outside of the filter and then multiplies while the filter is stored between uses.

      The answer is to rinse the filter in a mild solution of bleach and water after each use. With this treatment a filter element lasts years.

      • Frank Sep 21, 2015, 1:26 pm

        Excellent tip thanks. We use General Ecology on our demand side and I’ve always been impressed by the quality of their filters and housings.

  • Nick Kats Sep 21, 2015, 10:46 am

    My water tanks are SS, so the following question isn’t an issue for me. But aluminum water tanks, with aluminum rusting off as fine powder? Is it absolutely crystal clear that there are zero long term effects from drinking from unpainted Al tanks? Al is common in soil & rock but it is tightly bound as part of a complex of other elements & requires a great deal of energy to separate & extract in pure form. Pure Al does not naturally exist, and there are suspicions of pure Al ingestion (kettles, cooking pots etc) being associated with dementia.

    • John Sep 21, 2015, 12:44 pm

      Hi Nick,

      An interesting question. This has come up from time to time in connection with aluminium boats. The answers are not clear, but in our case we have always had a very fine filter on our drinking water tap, just to be safe, or at least, safer.

      On the bright side, most aluminium tanks are coated and further the white powder referred to is not pure aluminium, rather it’s a combination of aluminium salts.

      • Nick Kats Sep 22, 2015, 5:00 am

        I don’t know about the aluminum salts, John. To be safe I would group these with pure Al. The thread here discusses the recurrent problem of paint or epoxy coating quickly peeling off Al surfaces, so coating Al water tanks seems to be a poor solution.
        In the interests of health, the question, are Al water tanks safe, has not been clearly answered. Anyone else know? Alubat, OVNI, any input on this?
        My feeling, if there is no clear answer, is to play it safe and use an alternative to Al for water tanks.

        • John Sep 22, 2015, 7:37 am

          Hi Nick,

          You may be right. The point being that I think there are very few totally clear answers about the effects of environmental contaminates on us humans.

          On the other hand, the coating on our tanks is still in good shape after 29 years, so that’s a comfort.

  • Neil McCubbin Sep 23, 2015, 6:57 pm

    Safety of aluminium water tanks ???
    In answer to Nick, there is never any absolute proof that any substance is safe to eat, drink or have in contact with food.
    I have been working with such issues for 25+ years, and can find “suspicions” about anything.
    I do not worry about aluminium in water tanks. Many municipalities have them, many using same paint as we do.
    Drink cans are usually aluminium. IF aluminium is bad for me, I get in anyway from multiple sources. We all do.

    • John Sep 24, 2015, 10:04 am

      Hi Neil,

      That’s interesting about municipalities, I didn’t know that.

  • Taras Nov 24, 2016, 7:06 am

    Hi John!
    On my 30 years 39 feet old aluminum sailboat the bottom paint is still the original.
    The survey showed few places where the paint is not sticking anymore to the hull.
    I was asking around the boatyards (Netherlands) for professional bottom sanding and re-painting, and got quite high estimates (10-15k Euro). I’m in process of refitting the boat and have more important things on my list: engine repair, pumbing, new thru-holes, electrics, etc.
    My question is:
    – how bad is to have few spots on the bottom where the paint is not sticking good?
    – when is the good time to do the full bottom re-paint?
    – can I touch-paint the affected spots and wait for better time to do the whole bottom or should I bight the bullet and do it now?
    Thank you!

    • John Nov 24, 2016, 10:30 am

      Hi Taras,

      I really can’t give you an opinion without seeing the boat. That said, if the paint has not been stripped for 30 years, it’s time to do it.

  • Terence Thatcher Dec 12, 2019, 6:15 pm

    I know this conversation has been long closed. Thanks to Phyllis for reopening it for me and thanks to John and Phyllis for this invaluable and entertaining site. Now–on painting or protecting aluminum. I will never own an aluminum boat; too old and cheap to change boats now. But, like most of us, my sloop has an aluminum mast. In my boat, it sits in a space above the bilge and slips over a mast step, also made out of aluminum. So, the mast is the female part and the step is a male part. (Sorry for the old-fashioned references.) The mast step does not sit constantly in bilge water, but it does get wet as rain comes down the mast and as water from the forward part of the boat and the chain locker runs past to the bilge sump. Anyway, many years ago I discovered that the mast and step were corroding and sort of gluing themselves together. So I had the step cleaned and anodized. And I think my boatyard coated the step with epoxy, but did not coat the inside of the mast. Now, after over a decade of sailing without pulling the mast, the two parts corroded together again. In addition, I found some light corrosion under my Spartite at the partners. (While the Spartite is supposed to adhere tightly to the mast, obviously mine allowed some water to leak in between the Spartite and the mast.) So, I have cleaned it all up again, using stainless brushes on a Dremel tool. I don’t really want to use muriatic acid on the mast, but I will acid wash the mating surfaces with vinegar. Now, I seek advice on this question: what is the best way to create a thin barrier between the mast step and the mast and between the mast and the Spartite. The tolerances are too fine to put sheet rubber between the mast and step and at the partners that would defeat the purpose of the Spartite. My current plan is to coat the inside of the mast with West System Epoxy and recoat the step with the same. I also will coat the mast with epoxy at the partners. Or is there a paint I should use? I have been scared way from Zinc Chromate, even if I could find it. It sounds as if folks do use epoxy on aluminum as a base coat for paint, so perhaps it would keep the aluminum from corroding again. Thanks, as always, for any advice from the AAC community.

  • Terence Thatcher Dec 15, 2019, 12:01 am

    Thanks, as always.

  • Michael DiRusso Mar 4, 2020, 7:52 pm

    I’m new here, so apologize if it is addressed elsewhere. Unpainted wherever possible is appealing to me, but I recognize it is not to everyone’s taste and worry about resale after I pass. There is a YouTube channel “sailing chloe” where they used that new wrap on the hull above the waterline on a new Garcia. Any experience with that approach either new or after years unpainted?

    • John Mar 5, 2020, 11:09 am

      Hi Michael,

      Sorry I don’t have any experience, other than having seen a couple of boats (not aluminium) that have been wrapped. It certainly looks nice when new, but I wonder how it will hold up over time. And then the big question for me is what do you do when it gets really ratty and needs replacing?

  • Kevin Dreese Jul 14, 2020, 6:23 pm

    Kind of an old post but I am looking into aluminum boats (Ovni, Atlantic and Alliage) and wondering about the painted aluminum. Why not just sandblast it all back to bare aluminum and just leave it that way (other than the bottom paint below the waterline)? I like the look of the bare aluminum boats, but not sure how it would look on a boat not built to have it that way from the factory. Especially with Atlantic and Alliage, I don’t understand why they would paint the hulls. They look nice at first but the maintenance must be hard. Also, even Morgan’s Cloud was re-painted, so not sure what I am missing with leaving it bare.

    • John Jul 15, 2020, 8:04 am

      Hi Kevin,

      Yes, that’s certainly an option, but, as you say, probably better on a boat that was built to be unpainted from the go. Also, I think it depends on the type of boat as to how it looks. For example it works on Steve Dashew’s motor boats because they look kind of industrial anyway, but to do the same to Morgan’s Cloud with her classic good looks would be kind of a tragedy.

      You also need to think about non skid on deck and how much the plate will heat up in warm climates.

  • Leigh Merchant Nov 29, 2020, 8:05 pm

    Greetings all and thank you for this interesting and informative website.
    Glad to see this post continuing; much like the need to repaint aluminum boats continually. I am researching the best methods for that step in the process between the end of sand blasting and the first coat on decks and this forum has been very helpful in that regard. I last had the decks and topsides repainted in 2013 in Nova Scotia. The topsides are, for the most part still good but the decks have suffered and are in sore need of a redo. Lots of blistering that I have been scraping off as it occurs but of course that leaves bare aluminum which, although it looks patchy is not deteriorating any further. The last paint job was done with Awlgrip, the one that looks great but cannot be touched up. This time I am thinking of trying a paint that can be repaired as needed. Anyone have any experience with the combination of Alexseal and Softsand for non skid areas? The boat is a 15m flush deck aluminum centreboard built in Montreal in 2000 and designed by Gilbert Caroff. She is currently in Greece where I am glad to have a painted hull and decks

    • John Nov 30, 2020, 8:24 am

      Hi Leigh,

      For the non skid areas I would use Kiwigrip:

      I would also paint the rest with Awlgrip again and not change systems. Awlgrip can be patched, we have done it a bunch. Yes, the patch will not be perfect but my thinking is that if we want perfect paint jobs don’t own an aluminium boat.

      Also make sure that the bare areas are first coated with yellow acid edge primer, sprayed, not brushed. A lot of painters will tell you to use the grey primer on the aluminium because they don’t like messing with the acid etch, but that is simply lazyness and wrong and will result in coating failure within a short time. They will also tell you that they can brush the yellow primer, but thats BS too, because you don’t get a thick enough coating. An air brush works well for this on small areas.

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