Strip foam boat building

Discussion in 'Boatbuilding' started by svfrolic, Jan 14, 2013.

  1. upchurchmr
    Joined: Feb 2011
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    upchurchmr Senior Member

    Whatever Kvsgkvng said ...... be very skeptical.

    No polystyrene - polyurethane has been used in the manner you suggest quite a few times.
    You don't really have to glue the strips together along the length. If you need to hold a strip together then just use a little thick superglue. It's the same thing done by Nick Schade for some parts of his kayaks.
    The epoxy from laying in the skins will penetrate the joints and make a more than adequate joint.
    There is a guy in Sweden (?Norway?) who does the same thing with wood strips for kayaks.
    Works great and is very quick, if you are going to paint. I did a test piece and it went very quickly (this was with wood strips).
  2. KeithO
    Joined: Jul 2019
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    Location: Michigan

    KeithO Senior Member

    To the OP: if you want to save some time, how about a stitch and glue project instead of a strip plank project? There are plans sold for plywood stitch and glue kayaks and you can substitute foam for the plywood if you add more reinforcement to make up for the difference in strength of the foam vs the plywood.

    I am planning to do this exact thing to make a replacement kayak for my wife. We bought her a kayak that was made from a stitch and glue kit from Chesapeak light craft. Its way too heavy for her to carry by herself or load on a car rack, its also 18' long and shes only 100lb so she could do with a shorter oal anyway.

    I plan on using 1/4" cross linked pvc core, cutting the foam as per the plans for plywood, then glassing 1 side on a long flat table with a mylar surface. By having 1 surface glassed the foam will be stiffened up but will be able to twist and the glass will provide strength for the wire which is used to wire it together. Foam alone would be too weak to be manipulated in this way. My thought is to put the glassed surface on the inside, where it can be bonded with tapes when putting the top and bottom hull halves together. Then join top and bottom together and fair the outer surface before applying the external laminate. I was going to do 2 layers of uni at 90'degrees to each other followed by a layer of bid.

    Compared to a strip build, one does not have to painstakingly fit the individual strips, which in the case of cedar strip boats are fitted to thousandths of an inch.... many craftsmen will work and entire winter on 1 strip kayak. If you use foam strips you do not have to be as precise since you can fair the core before doing the outer laminate and you will be painting the thing as opposed to varnishing the thing like a piece of furniture...

    If you are set on the kind of shapes you can get using strips, watch this video to see how the process is used on a sailboat hull. Take note how the width of the strips can be wider in areas of little curvature and narrower in areas of tight curvature.
  3. kerosene
    Joined: Jul 2006
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    kerosene Senior Member

    I did a bit of sin in resurrecting this old thread. Just thought the link was interesting (laminate uni directional glass to pvc core for strips).

    Op is surely ling gone and any idea of using styrene foam (xps let alone eps) for hull should be taken with a block of salt.

  4. upchurchmr
    Joined: Feb 2011
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    upchurchmr Senior Member

    You sure baited me.
    Next time I'll look a little more.:rolleyes:

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