using epoxy and poly resin to do repair

Discussion in 'Fiberglass and Composite Boat Building' started by 61sg, Aug 11, 2009.

  1. LMB
    Joined: Nov 2008
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    Location: North Carolina

    LMB Junior Member

    PAR gave good advice. I usually tap the epoxy once it has gone through an initial cure but is still somewhat soft. This works well for smaller tapping screws but engine lugs might be too big. If you can work with studs cast in as PAR described that would be best bet. In this situation I probably wouldn't do the wax trick as it might mess with your bond (unless you are really comfortable with what you are doing). If you ever had to remove the studs they could be cut/drilled out and re-epoxied for repair.
     
  2. 61sg
    Joined: Aug 2009
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    Location: australia

    61sg Junior Member

    The mounts aren't rotten unlike the stringers, however they are stripped out hence why i was replacing them.

    So it sounds like perhaps i can leave the original mounts and just repair with epoxy?

    is this better than replacing the wood or a patch up?
     
  3. LMB
    Joined: Nov 2008
    Posts: 52
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    Location: North Carolina

    LMB Junior Member

    If the surrounding wood core is sound and only the holes are stripped repairing the holes only would be fine. Wood must be dry however. If its damp it will need to be dryed or alternatively use an epoxy that will cure in presence of moisture. This process of making epoxy filled "beds" for fastners is common even in brand new construction. Many foam core materials for instance just don't have the density to retain screws. There are a number of other advantages as well. If you don't have the west system user manual I would suggest getting it. It covers this process and a number of others. I think its free or maybe just a couple of bucks.
     
  4. missinginaction
    Joined: Aug 2007
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    Location: New York

    missinginaction Senior Member

    I'm just following along here. I'm wondering about trying the same type of technique on my flybridge. On my 73 Silverton restoration I'll need to reattach the flybridge once the cabin top is in place. By the time we hoist the one piece fiberglass bridge up there the cabin top will be completely finished and painted. I figured on putting an old carpet section down to protect the finish while I position the bridge.

    So....the bridge was attached to a 1" thick cabin top using lag bolts. These had a course thread and are not very long (obviously). I'm wondering what some of you think about drilling into the cabin top (very carefully, it's only 1" thick) using, say, a 3/4" or 7/8" Forstener bit. I'd get a flat bottom hole which I could fill with epoxy (use silica?) and then tap a machine screw into. This would give me better holding power I'd think and better protection of the cabin roof from water infiltration. I'd then install the original stainless bracket which would cover the hole.

    Any alternatives or suggestions?

    Thanks! Missinginaction
     
  5. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Use a "T" nut or "blind" nut, bonded into the roof. The epoxy bonded trick would work, but I like the idea of metal holding the threads if I want to remove things or really crank down on them.
     

  6. missinginaction
    Joined: Aug 2007
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    Location: New York

    missinginaction Senior Member

    Gotcha PAR. I've used tiny blind nuts over the years on radio controlled model airplanes. Thanks again for the tip, I'll file it away.

    MIA
     
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