Latest News: Forums Technical Pros and cons of painting hull

  • This topic is empty.
Viewing 7 posts - 1 through 7 (of 7 total)
  • AUTHOR
    POSTS
  • #4215
    mhardman
    Member

    Hi,

    I have a 1971 Mk 1, with a white hull and green deck. The hull is in the original gelcoat which is starting to look grubby and has a patch that has been epoxied, not to mention several bits along the centre chine that need epoxying where the gelcoat has broken off.

    So I’m thinking of painting the hull in white, after epoxying and sanding wherever it’s needed. I’d welcome people’s thoughts on the pros and cons of painting the hull (NOT the deck, right now)

    There’s an Interlux (US version of international, I think) paint called VC Performance Epoxy, it’s a 2-part epoxy without anti-foul. It looks ideal for the job – any thoughts on this too?

    Thanks in advance,

    Mark

    #9493
    admin
    Member

    Hi Mark,

    A good book I have recommends abrading the surface with fine wet and dry. It may be that the grubby surface is skin deep and with a bit of rubbing and a bit of buffing you will be able to restore the colour and gloss, but it won’t do anything for the patch, and if it is epoxy, that really needs protecting from UV light. You will no doubt want to repair and strengthen the hull where impacts have knocked off the gelcoat and produced a star crack, white Gel-coat repair from Plastic Padding is ideal but quite a bright white.

    If you do decide to to paint the hull, bear in mind that accidents happen and you will need to touch up your handywork at the end of each season. I am not familiar with Interlux but any two pack paint (like Perfection from International) has to be more difficult to patch-repair than a one pack. I am deck and hull painting a Mk2 at present and probably being too much of a perfectionist myself, but I know that my hard work will be scatched and dinged in normal use so I am using Brightside from International (now discontinued, grrrr). On a previous job I did on an Enterprise hull I used Toplac from International and four or five years on it still looks very good. Like yours that was white on white, a sensible decision. My current project (the Wayfarer) changes a white hull to dark blue. It looks great but I just know it is going to get damaged and when it does the white showing through will be very very obvious so I will want to be able to repaint it with minimum hassle.

    I also agree that if you can avoid it, don’t paint the deck. It is a very complicated shape, has textured areas that are difficult to paint and even more so than the hull, will need patch repairs in the future. I have no hair left after the frustrations of trying to get a perfect finish, the final straw came when the neigbour’s cat decided to wander about on the still soft paint overnight.

    Mike

    #9495
    mhardman
    Member

    Hi Mike,

    Thanks for the reply. Interlux is just what they call International in the US. They sell Brightside here, which I’ve used and agree is an excellent paint. However, where I used it in the bilge it has wrinkled and come away. It doesn’t seem to be able to stand long-term immersion. Maybe it’ll be OK on the outside of the hull where the boat dries quickly. The problem with the bilge is that in winter the boat cover leaks a little and it never really dries out properly down there.

    I wasn’t sure if the one-pack paints would be OK on the outside of the hull because of that experience. They do claim that the two-pack versions are more waterproof. Sounds like you’ve found the one-pack ones are fine.

    #9497
    Swiebertje
    Participant

    You can add pigment to your gel coat repair. For my boat I asked Mike Porter what pigment was used. Then I found the exact same pigment on Ebay in an amateur quantity (1/4 liter) and more important, for a friendly price.

    When painting your hull choose a colour similar to the existing hull colour. Then when you scartch it it won’t be as obvious as with a contrasting colour.

    Having had some experience with gel coat repair and pigments I wander if it is possible to paint a hull using (pigmented) gel coat? Or is it the same as two pot marine paint? Maybe some polyester specialist out there can shed some light on this?

    #9502
    admin
    Member

    Whoops, if you are leaving the boat on the water for extended periods then your choice of paints significantly narrows and I would suggest a conversation with International’s helpline. It may well be that single pack paint is not up to the job under those circumstances, sorry I didn’t consider that aspect in my previous response

    The paint inside the hull should be Danboline, which is designed for the job, but as has been said before on this forum, why bother painting the bilges?

    #9504
    mhardman
    Member

    My understanding is that the one-pack and two-pack paints are both polyurethane. The difference is the drying mechanism – one pack uses atmospheric moisture to catalyse, whereas the two-pack uses a reaction between the two parts. The one-part is theoretically less moisture-resistant as it tends to have small voids in it, caused by bubbles. Gel coat is polyester or epoxy.

    I don’t intend to leave the boat in the water. But I was a little worried (unduly) that one-pack wasn’t waterproof enough even for a few days immersion.

    #9511
    admin
    Member

    I had a look at the International website (well one of many), where both Perfection and Toplac are described as being for “above the waterline”.

    Perfection is a linear polyurethane that is chemically catalsyed using isocyanates, ok to apply by roller or brush but literally lethal if sprayed on without wearing positive pressure breathing gear. Toplac is a urethane modified alkyd, termed an enamel paint.

    Like you I was concerned that a cruise could mean leaving the hull immersed for a few days. The man at the International Paint Help-desk was not bothered with periods of up to 6 days but would not go beyond saying that extended periods of immersion risk the paint lifting. I guess he was covering himself and it is probably good for longer, but I cannot imagine needing to keep the boat afloat for more than a week or so.

    What ever you use do not be afraid of thinning the paint and apply lots of light coats with a roller and tip-off with a foam jenny-brush. A friend in the car repair business recommends using Scotchbrite to dull the surface between coats, it seems to take less paint off than fine wet and dry.

    I recommend a book by Don Casey called Sailboat Refinishing ISBN 0-07-013225-9. He is an American so some of the terms he uses are a bit different, but an excellent book about repairs and paints.

Viewing 7 posts - 1 through 7 (of 7 total)
  • You must be logged in to reply to this topic.