what are these spots in my gelcoat?

Discussion in 'Fiberglass and Composite Boat Building' started by naturewaterboy, Aug 9, 2009.

  1. duktig102
    Joined: Jan 2010
    Posts: 3
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: east sussex

    duktig102 New Member

    itself the best answer is just add salt water, I am confusing Gelcoat the car filler 1:4, to fill these shortages, I invite you to http://laminat-repair.co.uk/
  2. tunnels

    tunnels Previous Member

    Warning !!!! warning !! its happeing again !!

    Re: WARNING!!! Polyestermites

    Posted By: Sam McFadden
    Date: Friday, 11 August 2000, at 11:52 a.m.

    In Response To: Re: WARNING!!! Polyestermites (James Cameron)

    Sail magazine did an excellent expose of polyestermites back in the late 70's. Unfortunately, I think the polyester lobby in Washington has worked to suppress knowledge of this insidious infestation. Alarmingly, there is recent evidence of a mutation that allows common polyestermites to digest epoxy...

    : Several times you have indicated that you would be using polyester resin as a
    : finish coat. I thought someone would have warned you about polyestermites
    : by now, but it hasn't happened, so I thought I had better do it. I know
    : they are really bad in Florida.

    : It's not really surprising that there has been no warning, as polyestermites
    : are a really sneaky little critter, and most people have never seen one
    : and don't know anything about them. They look just like the polyester they
    : are eating, so unless you have some way to detect them, you could be
    : looking at what appears to be a really nice finish and it would be
    : polyestermites busy munching away.

    : The problem is, when they run out of polyester to eat, they leave, taking
    : your beautiful finish with them. That's why you don't see polyester suits
    : much any more. Some guy would be walking down the street in a well
    : tailored polyester suit and the polyestermites would eat the last of the
    : polyester, then leave, and the guy is standing there in his skivies,
    : unless he was wearing polyester skivies....well, you get the picture. It
    : was embarrasing, and there were a lot of complaints, but no solution to
    : the problem was ever found, so polyester suits just kind of died out.

    : Fortunately for you, you have used epoxy to build your boat. If you had used
    : polyester throughout, you could go out one day and pick up your boat to go
    : paddling and end up with an arm load of disconnected strips.
    : Polyestermites don't eat epoxy. It gives them really bad gas and tends to
    : give them away.

    : Detecting them can be a really vexing problem. If I were you, and going to
    : use a clear finish, I would mix a couple of small batches with some bright
    : colored dye in them, maybe dayglo yellow and dayglo orange. Then I would
    : sprinkle little spots of these colors all over the boat. That way, when
    : you check your boat, if the colored spots are moving, then you know you
    : have polyestermites and you can get the exterminator in to get rid of
    : them. You also might check with your local surf board place to see how
    : they handle the problem.

    : I thought you ought to be warned. Hope this helps. Good paddling

    : James :p
    1 person likes this.
  3. Itchy&Scratchy
    Joined: Jul 2008
    Posts: 140
    Likes: 3, Points: 0, Legacy Rep: 117
    Location: Oxford & South Africa

    Itchy&Scratchy Senior Member

    Judging by the blue streaks around those bubbles in the surrounding gel in those photos , it looks like the gel has been sanded too thin or applied too thinly when being moulded.
    If it is the sanding then the gel has been sanded away too much resulting in opening up of the the bubbles in the laminate.

  4. Herman
    Joined: Oct 2004
    Posts: 1,618
    Likes: 89, Points: 48, Legacy Rep: 1240
    Location: The Netherlands

    Herman Senior Member

    Oh yes, polyester mites. I have bad memory about them.

    The point is, your polyester gets eaten. OK, I can live with that. I have a garden full of plants, and they get eaten as well (only they grow back). But don't stop reading, it gets interesting.

    I once heard to get rid of the mites, you could scare them away by wiping with a mixture of acetone and styrene. And so I did. And I wished I never did that. What happens is that indeed polyester mites do not like the mixture, but no-one told me that wiping the boat with this mixture makes the mites very upset, and make them crawl up into my face and on top of my head, eating my hair! They got up about halfway, when I got the luck that my wife came by, and warned me. So hastily I dipped my head into a bucket full of acetone / styrene. Which luckily stopped the mites.

    so there I am, front head bold, sides and rear still with hair....

    And I will tell you: If you see all the guys in Washington, they are mostly bold or with little hair. They were all boat people, and did the same as I did, but all of them were so ashamed, they conspired together, and organised this huge cover-up. Thay is why no-one knows about it! Conspiracy!

    Now I also understand why I have seen boats transported to Area 51...
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