Newbie Question on delamination

Discussion in 'Fiberglass and Composite Boat Building' started by marlin_angler, Apr 17, 2009.

  1. marlin_angler
    Joined: Apr 2009
    Posts: 1
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Masschusetts

    marlin_angler New Member

    Hello,

    I am new at boat repair, specifically the hull. For the first time, I am taking over the maintenance of repair, paint, etc...

    I noticed that on small parts of the keel, where the boat rest on the wood blocks used for support, the fiberglass has been cracked, and at some points a "leaf" has separated about a 1/4 of an inch.

    I would like to fix this, and my first thought was to "glue it back together", since it was a small part, then bondo, sand and paint.

    As you can possibly have already figured out, I have not a clue on this type of repair; but I am definitely willing to learn.

    Anyone has any suggestions??? :?: :?:
     
  2. blaze_125
    Joined: Mar 2009
    Posts: 87
    Likes: 1, Points: 0, Legacy Rep: 14
    Location: Canada

    blaze_125 I see the light!

    I haven't been around long enough to point you in the right direction, but I can tell you bondo is a no no. Bondo will soak water.
    PAR will most likely get in here and tell you the magic mix, that guy is just unbeleivable :)

    If I'm not mistaken, you'll want to replace bondo with a mixture of epoxy and various fillers.
     
  3. marshmat
    Joined: Apr 2005
    Posts: 4,127
    Likes: 149, Points: 63, Legacy Rep: 2043
    Location: Ontario

    marshmat Senior Member

    Hi marlinangler,

    I suspect what you're encountering is bits of gelcoat flaking off, not bits of fibreglass. It is quite common for gelcoat to crack at high-stress points. The stuff is just a shiny, brittle outer film of resin- it carries the colour pigment, and in theory keeps water out of the fibreglass laminate itself, but has no structural value.

    The actual fibreglass structure will be visible where the gelcoat has flaked off. It might be greenish, brownish or yellowish, slightly translucent, and will probably have a bit of the random texture of chopped-strand mat.

    If the cracking does not propogate into the fibreglass itself, the damage is superficial and the repair is easy. It's just a matter of chipping the damaged gelcoat off, and patching it- possibly with fresh gelcoat, but more likely with a heavily thickened epoxy filler. NO BONDO, EVER or you will be doing this again in two months.

    If the fibreglass is damaged, the cracks will extend into the laminate, where they will appear whiter and more opaque than the intact fibreglass, and may contain water. If you suspect the laminate itself is damaged, the repair could be much more extensive and time-consuming.
     

  4. PAR
    Joined: Nov 2003
    Posts: 19,133
    Likes: 487, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Log onto www.westsystem.com and down load their "user's guide" and other manuals about repair techniques.
     
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