Fluid leaking from blisters on hull

Discussion in 'Fiberglass and Composite Boat Building' started by d. right, Feb 17, 2019.

  1. d. right
    Joined: Jan 2018
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    Location: kuranda,australia

    d. right Junior Member

    Im restoring an 18 ft swiftcraft dominator (aussie hull). I have sanded the topsides but have not touched the sides. The hull has been undercover for the last 18 months and is completely dry. There are quite a few blisters on the sides which are exuding a slightly tacky tar like substance and lots of pinholes on the topsides with the same problem.
    The boat was stored outside ( in north Queensland ) for many years without being used. Im concerned about repainting the boat without addressing this issue.
     

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  2. Mr Efficiency
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    Mr Efficiency Senior Member

    The main spots appear to be where the old registration stickers were ? I can't imagine what else could be going on, give the whole area a wipe over with a strong solvent like acetone, and see what remains.
     
  3. kapnD
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    kapnD Senior Member

    Sure looks like blisters, grinder time!
    Looks like the stickers held in moisture under them, blisters more commonly occur below the waterline.
     
  4. d. right
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    d. right Junior Member

    Thanks Mr E and kapnd. These blisters are on the bottom and sides. I can wipe the tar off with my finger. Maybe a quick spot grind and seal with epoxy?. Probably 2 or 300 of these little spots all over.
    Cheers D
     
  5. d. right
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    d. right Junior Member

    Some spots show on the inside and outside as well.
    D
     
  6. Mr Efficiency
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    Mr Efficiency Senior Member

    Don't grind anything, just yet, it will look like it had measles, forever after. Is the gelcoat raised, like a blister ?
     
  7. Mr Efficiency
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    Mr Efficiency Senior Member

    Has it been near trees ? Amazing the gum and gunk that some trees can create.
     
  8. kapnD
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    kapnD Senior Member

    Do a google search on blister repair, there’s tons of info out in cyberspace.
    I’m afraid a quick repair is probably not an option, they need to be bled and washed out, sometimes that can take months.
    Blisters can penetrate deep into the laminate, and must be ground out to solid substrate, dried, then filled back in.
     
    fallguy and d. right like this.
  9. d. right
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    d. right Junior Member

    Just checked, the black stuff is water soluble
    D
     
  10. d. right
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    d. right Junior Member

    How the $#@ does water get into the laminate like the hull sides. Vertical surface gelcoated both sides.
    D
     
  11. Mr Efficiency
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    Mr Efficiency Senior Member

    Might be mildewed tree resin.
     
  12. d. right
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    d. right Junior Member

    Some are, most seem to be coming from pinholes in the gelcoat
     
  13. d. right
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    d. right Junior Member

    In the open, cow bay near daintree, Tropics!
     
  14. d. right
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    d. right Junior Member

    After 18 months undercover with western sun in the arvos i thought it would have dried out by now.
    D
     

  15. Mr Efficiency
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    Mr Efficiency Senior Member

    Yeah, well, the rainfall has been colossal, I would leave it be, till the wet is over around Easter.
     
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