Confused over fiberglass cloth

Discussion in 'Wooden Boat Building and Restoration' started by bobbrown, Dec 18, 2021.

  1. bobbrown
    Joined: Jul 2021
    Posts: 31
    Likes: 2, Points: 8
    Location: SE Georgia

    bobbrown Junior Member

    1/4” ply on frame…recommended 2 layers 6 oz cloth. Pretty straightforward.
    6 oz plain weave = .0093
    8.5 oz 2x2 twill = .0096
    8.5 oz 8 harness satin = .0090
    The questions are.. is the heavier fabric stronger than the lighted fabric and where does the 2,5 oz come from. If the thinner fabric uses less epoxy wouldn’t you gain strength by using a thicker fabric for not much more weight gain.
    Thanks
     
  2. Kayakmarathon
    Joined: Sep 2014
    Posts: 116
    Likes: 48, Points: 28, Legacy Rep: 10
    Location: NewEngland

    Kayakmarathon Senior Member

    Heavier fabric is stronger than lighter fabric of the same material and weave. There is no measurable difference between plain and twill weaves given the same material and weight. Lighter fabrics are used as surface finishes while heavier fabrics are used for structural applications. Fibreglast.com has good information about resin and fabric basics.
     
  3. fallguy
    Joined: Dec 2016
    Posts: 6,767
    Likes: 1,382, Points: 123, Legacy Rep: 10
    Location: usa

    fallguy Senior Member

    epoxy use for hand lamination is about equal to the glass weight, so generally, no to your last question and yes to the first, but with penalties of 5 oz per yard with resin

    the strands of the 8.5 oz are probably heavier is all

    twills are more noticeable from a distance if you are varnishing the final finishes

    stick to the plan..
     
  4. bobbrown
    Joined: Jul 2021
    Posts: 31
    Likes: 2, Points: 8
    Location: SE Georgia

    bobbrown Junior Member

    Got it…thanks
     

  5. Rod Tait
    Joined: Apr 2005
    Posts: 49
    Likes: 3, Points: 8, Legacy Rep: 10
    Location: Vancouver, Canada

    Rod Tait Junior Member

    I suppose it depends on intended use as well. If clear coating, then multiple layers of lighter glass is easier to clear out. If painting then one can use heavier cloth, use fairing compounds to smooth out and paint. Heavy strands and the way they are oriented will be harder to wet out clear. I always figure that two layers of 6 oz. with fibers running in different directions is stronger than one layer of 12 oz. Whatcha buildin?
     
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