Polyester resin contraction

Discussion in 'Fiberglass and Composite Boat Building' started by ed2, Apr 15, 2014.

  1. ed2
    Joined: May 2013
    Posts: 22
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    Location: mar del plata

    ed2 Junior Member

    hi all colleagues

    I have a question, I'm designing a small sailboat class, where the margins of tolerance in the measurement of the hull are very short, I build the molds for the hull, pergunta is whether I should take into account the contraction and make molds taking story index of contraction polyester resin (2%)

    thank you very much to all greetings
     
  2. rwatson
    Joined: Aug 2007
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    Location: Tasmania,Australia

    rwatson Senior Member

    I think your info isnt accurate - the contraction is a lot more than 2%


    One notable feature of fiberglass is that the resins used are subject to contraction during the curing process. For polyester this contraction is often of the order of 5-6%, and for epoxy it can be much lower, about 2%
    http://en.wikipedia.org/wiki/Fiberglass
     

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  3. Steve W
    Joined: Jul 2004
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    Location: Duluth, Minnesota

    Steve W Senior Member

    I would think that as long as the same resin is used for all the boats it wouldn't matter, shrinkage is typically not the same in all directions, you would usually get more shrinkage in the long dimensions.

    steve.
     
  4. ed2
    Joined: May 2013
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    Location: mar del plata

    ed2 Junior Member

    thank you very much steve I will consider
     

  5. johnhazel
    Joined: Jun 2008
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    Location: Michigan

    johnhazel Senior Member

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