Unwetted cloth problem... Please help!

Discussion in 'Fiberglass and Composite Boat Building' started by WilliamPrince, Nov 18, 2013.

  1. WilliamPrince
    Joined: Oct 2013
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    Location: Mexico

    WilliamPrince Junior Member

    Hey all, I have had a small problem with the application of a fiberglass cloth to my hull. I started late in the day and by the tome I was finished it was dark. Much of the glass did not absorb as much epoxy is it wanted, like the attached pic. It is all cured now, it has been 15 hours. What can I do to this glass to make it better? Can I sand and apply another coat? Will the cloth even absorb that next coat?

    All advice appreciated, thank you!
     

    Attached Files:

  2. upchurchmr
    Joined: Feb 2011
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    upchurchmr Senior Member

    Grind off the cloth.
    Nothing will help you at this point.

    Replace the cloth, making sure the surface is smooth with no sharp kinks in shape.
     
  3. WilliamPrince
    Joined: Oct 2013
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    Location: Mexico

    WilliamPrince Junior Member

    Grind off the entire cloth and start over? Or grind off the parts where it is unwetted and patch it?
     
  4. TeddyDiver
    Joined: Dec 2007
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    TeddyDiver Gollywobbler

    If it's structural do the first, if merely barrier batching is fine.
     
  5. WilliamPrince
    Joined: Oct 2013
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    WilliamPrince Junior Member

    It is structural. How bad would it be to leave them? I have poured more epoxy on them and it has taken SOMEWHAT... Not entirely but better than before. The boat only needs to last for 1 month, will it really be a big problem?
     
  6. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    I'm not sure what portion of the hull this is, but the photo shows 70% - 80% poor contact with the substrate, so it's useless, except as an abrasion resistant sheathing (a poor one at that).

    Usually, even in structural applications, you can just cut or grind out the bad spots and lay some more material, but with this much blistering, you're better off just grind it away and doing it again.

    If the boat only needs to last a month, then don't bother doing anything.
     
  7. WilliamPrince
    Joined: Oct 2013
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    WilliamPrince Junior Member

    That picture is of the worst affected area, but you are right, it is not good. I am also taping the chines inside and out, so that will give me some structural integrity. It's not a great job, of course, but I don't need it to last a long time. I have no experience in this matter, so it is hard for me to visualize the consequences of this. If you think my boat will be structuraly alright, at least for the month I need it for, I am inclined to leave it.
     
  8. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Well it still depends on where this is (what structural element). From the looks of it, you didn't have enough radius on the wood, for the fabric to lay down neatly.
     
  9. WilliamPrince
    Joined: Oct 2013
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    Location: Mexico

    WilliamPrince Junior Member

    This is over the outside of the entire hull, a 18 ft long canoe. It's only really bad in that one area, and there is a good piece of tape on either side of that chine.
     

  10. SukiSolo
    Joined: Dec 2012
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    SukiSolo Senior Member

    Hard to tell from the picture if a sealing coat of epoxy was put on before the glass was laid on. If it was not, then that is the problem, the wood has absorbed some of the epoxy and it has left some of the glass dry. It is something I come across frequently with epoxy and polyester.

    Get a proper orbtal sander and some 60 and 80 grit and take it back to the wood or wood/epoxy saturated surface and redo the coat. Use a gloss paint roller (mini) to really work the epoxy in. It is harder to work epoxy through a woven cloth compared to a woven roving. If it is still a problem use a woven roving as this will saturate better.
     
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