Fiberglass help needed for bad damage

Discussion in 'Materials' started by 83trekker, Nov 4, 2014.

  1. 83trekker
    Joined: Nov 2014
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    83trekker New Member

    I know this Is a boat forum but I need some help with fiberglass and thought you boat guys would really be able to help me!

    So I have an 83 Toyota trekker 4x4 the whole rear is fiberglass, I have beaten this truck so back bad in my prime :) now I want to fix up the fiberglass, the rear main section is bad!!! But the rest is really nice shape.

    So I have drilled holes in all or almost all the little cracks everywhere (will finish the drilling soon). I have grinded out all the cracks and will be refiberglassing the inside of all the bad cracks with bondo fiberglass resin.

    My question is see attached pics how do I fill in the huge gaps and cracks on the front side will out using a filler to do it so it has some strength?



  2. priyeshsaxena
    Joined: Nov 2010
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    priyeshsaxena Junior Member

    Hi 83trekker,

    Not a tough job, but would require a lot of time to rebuild the surface and match everything.

    I believe the best would be to put back up plywood where ever there are big holes, grind the holes/damage surface to get nice taper surface, build up the surface with CSM300/450+GP Resin.

    After the built up laminate has cured, use orbital sander with 60/80 grits to get an even surface all over. Then use filler like poly putty to fill in the small gaps. Sand again to get a Primer ready surface, coat with primer, use Poly putty if required, sand again to satisfaction, Coat with Top coat, then use Polish papers to get good gloss finish.

  3. SukiSolo
    Joined: Dec 2012
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    SukiSolo Senior Member

    Build up the holes with resin, either epoxy or polyester and glass, woven roving and very fine CSM. Flush down and then use a mite of body filler (Bondo in the US) to fill pin holes prior to painting. If you use epoxy there are many other filler options but getting some new glass, scarfed across the gaps is the best long term solution.
  4. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    Welcome to the forum.

    The trick with these types of repairs is to make long transitions, from the ground down old work to the new. A 12:1 slope is the usual recommendation, which simply means every exposed edge, that will need to have something bonded in to replace damage, will be ground to a 12:1 taper, so the new stuff has enough surface area on the old, to offer enough bond surface.
  5. Steve W
    Joined: Jul 2004
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    Steve W Senior Member

    What Par said. Also, i would stay away from epoxy. Once you go down that path you can no longer use the multitude of excellent body fillers available that allow you to get the job done in a reasonable amount of time. Unless of course the original laminate used epoxy but that is highly unlikely.


  6. dinoa
    Joined: Oct 2007
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    dinoa Senior Member

    PE filler is usually adequate, for filling purposes, even if it's over epoxy. PE gelcoat over epoxy is the most common method of refinishing sailplanes. Epoxy fillers with PU topcoats are slowly displacing this method.

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