Hull bottom repair prior to barrier coat

Discussion in 'Fiberglass and Composite Boat Building' started by ian_upton, Jul 26, 2017.

  1. ian_upton
    Joined: Apr 2006
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    Location: Grand Blanc, Michigan

    ian_upton Junior Member

    What is the recommended product to repair the gouges, chips on strakes, etc on the hull bottom prior to the barrier coat?

    Looking for something easy to use/mix and relatively tough (trailer bunks, trailer rollers).

    Is it as simple as:

    [​IMG]

    Ian.
     
  2. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    I'd recommend Progressive Polymers "Wet Dry 700" as the product to use. It's a Kevlar reinforced epoxy and tough stuff according to my tests. It can be applied in wet and underwater applications and doesn't need anything added to it to work well. It's pretty thick out of the can, but still can be putty knife or troweled into place.

    The 3M product you have there is a vinylester product with reinforcing 'glass fibers and a pretty standard stock to employ, though not as tough as Kevlar, still pretty good. It's a little easier to spread around, but both products I've listed will need some "fairing" to smooth them out afterward.
     
  3. Mr Efficiency
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    Mr Efficiency Senior Member

    How well does the Kevlar/Epoxy bog sand ?
     
  4. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    It sands as you'd expect a dense, thickened epoxy mix would. If it was me, I'd use this stuff to fill the bulk of the damaged areas, but leave it just a wee bit shy of fair. Then I'd come back and top it off with a fairing filler to making sanding chores easier and much smoother. The "Wet Dry 700" I mentioned is sold by another forum member who's been formulating goo for a few decades and knows his stuff.
     
  5. Mr Efficiency
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    Mr Efficiency Senior Member

    I thought maybe the Kevlar made it harder to sand.
     
  6. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    I've sanded it and it's no more difficult than a milled fiber and heavily silica mix. It does sand rougher than a silica/milled fiber mix, but both pretty much suck in this regard, which is why I always leave it a bit shy of fair and topcoat with putty.
     
  7. pauloman
    Joined: Jun 2010
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    pauloman Epoxy Vendor

    the wet dry 700 is my product and I use it all the time. Currently to rebuild badly rotted wooden window boxes. To shape it I use a 4 inch grinder with a 40 grit sanding wheel. You just touch the epoxy and it is gone!
     

  8. ian_upton
    Joined: Apr 2006
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    Location: Grand Blanc, Michigan

    ian_upton Junior Member

    Thanks PAR I will take a look.
     
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