help with fiberglass

Discussion in 'Boat Design' started by SD spero, Sep 28, 2007.

  1. SD spero
    Joined: Sep 2007
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    SD spero New Member

    Just picked up a used hull. it has a spot at the bottom of the bow were its worn through the gelcoat and a layer of glass (i would guess from nosing up on the sand) do any of you have a suggestion for a process to fix it. I have some skill with glass work.
     
  2. KnottyBuoyz
    Joined: Jul 2006
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    KnottyBuoyz Provocateur & Raconteur

    There's some good video's on Youtube.com just search on "fiberglass repair" also the west system site has lots of info http://www.westsystem.com/ just look under the projects tab on their web site.
     
  3. SamSam
    Joined: Feb 2005
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    Location: Coastal Georgia

    SamSam Senior Member

    There are also bow protecters that glue on or stick on somehow. Google "keelguards" and go from there. Maybe you won't have to repair anything.
     
  4. SD spero
    Joined: Sep 2007
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    Location: San Diego USA

    SD spero New Member

    thanks , I have seen the videos and have done a fair amount of glass work. the problem is the damage is right on the cutting edge of the bow. do you think a low density filler will hold up?
     
  5. Geoh
    Joined: Jan 2007
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    Location: Arizona

    Geoh Junior Member

    Same prob only my hull 13' Galaxie jet boat has the scraped problem the whole length of the keel...thinking maybe a 6" wide fbr gls the whole length....no fbrgls skills here but got the hull for nothing and want to learn on it...
    not a jet guy...but might be fun to run up and dn on the colorado river between laughlin and havasu

    George
     
  6. alan white
    Joined: Mar 2007
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    alan white Senior Member

    Prep by cleaning with acetone and then sanding to roughen. Mask off areas surrounding.

    Best to fill the damage with a bit of epoxy mixed with filler. West 105 resin with 206 hardener and microballoons as filler. Mix til it will fluff like cake frosting without sagging.

    Epoxy is applied to the area. A thick clear polyethelene patch can be used to assist shaping by being laid over the wet epoxy and then manipulated with a wide putty knife. This allows the epoxy to be shaped into a near perfect replica of the ground-off material. All excess epoxy is drawn out the sides of the plastic patch and cleaned away. After curing, the plastic and the masking is removed. Match with gelcoat or paint, but do cover to keep the epoxy from UV degradation.

    Alan
     
  7. FranklinRatliff

    FranklinRatliff Previous Member

    Repair

    Do what Alan says.
     
  8. Geoh
    Joined: Jan 2007
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    Geoh Junior Member

    Thanks Alan
    I was afraid i needed the fabric strip. Saves me a lot of unnecessary work.
    George
     
  9. marshmat
    Joined: Apr 2005
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    marshmat Senior Member

    I agree with Alan, for the most part. Thickened epoxy is the way to go. You want it at about a peanut-butter consistency by the time you're done adding the filler powder.
    What to use for the filler powder is another question. Microballoons have been suggested. This option is probably the easiest to work with. But do you intend to be running the boat up on the beach, as the previous owner did? If so, you might want to consider a stronger filler, like a colloidal silica, since the microballoon/epoxy mix will wear down fairly quickly (it's designed to be an easy-to-sand mix, after all).
    Wax paper works quite well as a covering, too, to get a smooth finish if you don't have the thick, clear polyethylene Alan mentions. Believe me, the extra work to do a really good job with the smooth clear covering sheet is worth it, because the epoxy's awfully strong if you have to sand it smooth afterwards.
     

  10. alan white
    Joined: Mar 2007
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    alan white Senior Member

    I want to add that covering and smoothing with plastic sheeting is not a viable method with surfaces that are rounded a lot on two axes (strong compound curvature). Such might be the case here, judging by the stated cause of the damage, likely the knuckle, or transition between stem and keel.
    in such a case, one solution is to layer glass mat over the prepared surface, until it's sure the layering is above the finished surface desired. Mat is good for resisting gouging next time. It will have to be dressed and recoated (I suggest a coarse "flap disc" (radial over-lapping flaps on the FACE, not the edge) that you can get at Home Depot, though any normal sanding disc would also work.
    After careful shaping, add epoxy/microballoons as a sandable fairing compound (this time not like icing but more peanut-buttery for strength). This coating is mostly epoxy, and thin enough to be more cosmetic than anything else. The real beef is in the mat underneath. Sand, wet sand, paint or gelcoat.

    A.
     
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