Advice needed on deck repair

Discussion in 'Boatbuilding' started by skullhooker, Feb 8, 2008.

  1. skullhooker
    Joined: Sep 2007
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    Location: Indialantic, FL

    skullhooker Junior Member

    Found another problem on my boat.

    The deck is soft where a cooler seat was installed, see enclosed photo. The molded liner skin is made from about 1/4 inch thick FRP, with a 3/4 plywood core, and about two layers of mat underneath.

    I know the best way to fix a rotted core is to cut it out, but the top skin is the only strong part of the deck. Would drilling holes, letting it dry out and filling with epoxy give enough strength to support a couple of big guys on a leaning post?

    Thanks,

    Rob
     

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  2. rwatson
    Joined: Aug 2007
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    Location: Tasmania,Australia

    rwatson Senior Member

  3. Gypsie
    Joined: Apr 2005
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    Location: Lombok Indonesia

    Gypsie Randall Future by Design

    Bite the bullet mate and do it properly, replace the ply
     
  4. Landlubber
    Joined: Jun 2007
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    Location: Brisbane

    Landlubber Senior Member

    I'll second that Gypsie.

    Do it once and do it right, or don't do it at all!
     
  5. rwatson
    Joined: Aug 2007
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    Location: Tasmania,Australia

    rwatson Senior Member

    Hmm, conservatism is often the safest course - but I've read some pretty impressive examples of this stuff. It gets used in industry a lot too.
    Since its not a critical area of the boat, might be worth costing it out before going the big chop.
    Let's know what your thoughts are after you check it out.
     
  6. skullhooker
    Joined: Sep 2007
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    Location: Indialantic, FL

    skullhooker Junior Member

    I really don't want to go for the big chop. I don't care about patching holes, but I don't want to have to peel the skin, glue it back or new layup, and scarf / layup the edges. I have an idea:

    drill some hole saw holes, maybe 1" dia. or more, try the bent nail in drill method to chew away the core, and gradually use longer rods to say, chew away core areas 6" in diameter. Then I can drill a pattern of 6" o.c holes, and bit by bit, fill them back up with epoxy microballoon filler paste. The areas where the plywood is in ok condition but maybe delaminated, I could drill small holes and inject penetrating resin.

    What do you think of this idea? I know I'll have to use a lot of resin and it will be heavier, but I think I can do it quicker and the intact liner skin won't be dimensionally distorted.
     
  7. rwatson
    Joined: Aug 2007
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    Location: Tasmania,Australia

    rwatson Senior Member

    I can sympathise with your preference to not have to do a refinish job, especially if you havn't done a lot of this stuff before.
    Even so, I dont think you are saving much effort and expense with the bit by bit approach. The mucking around would be total hell, and produce a really messy result
    Also, I wouldnt expect microballoon filler paste to have a lot of strength, as it has no fibre running through it, and will just crack and break with use.
    Keeping the underneath floor intact is a good idea, as that would be a real ******* to finish (looks like really tight access from the picture).
    I would start out by marking a nice neat shape on the top that is larger than the suspect bit, and use a router with a thin cutting tool to cut deep enough to just get through the top glass layer,
    You should be able to lift the top level of the deck off in one big section with a bit of luck, and be able to see the damage underneath.
    (If you have the slightest doubt, stick some supports underneath to support all the shenanigans.)
    If the plywood is too far gone to resurrect with "magic goo" of some kind, get the router out again and cut some neat channels about 3 inches wide and deep enough to remove the plywood, without going through the bottom layer of glass. Make them run into the sound ply on either side.
    You can then build up layers of fibreglass/epoxy to create solid beams about a foot apart. hell, maybe do some 'cross beams' as well.
    When it cures ( and you have dried the bad plywood out between the "beams") cover the whole thing with a layer of epoxy, and lay the old deck over it.
    Gelcoat the strips around the edges, and voila - as good looking as new.
    The solid beams will support the weight, the epoxy will stop deck moisture getting into the old "filler" ply. If some rotten ply falls out, just polyester and matt into the holes. Just so long as you have a nice uniform surface to epoxy the original deck.
    Gee - sounds so easy, I might just drop in and do it all for you. - The again ...
     

  8. skullhooker
    Joined: Sep 2007
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    Location: Indialantic, FL

    skullhooker Junior Member

    rwatson, please do stop by, we live in Melbourne. Melbourne, Florida, USA that is. So we're brothers on the other side of the globe, they sell Fosters here too (if you all really drink it there).

    I am going to do as you said, route out the deck. Question, whats the best way to bond the old deck skin back to the repaired core? Epoxy putty spread with a grooved trowel? Thanks.
     
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