Masonite (hardboard) as base for Fiberglass

Discussion in 'Boat Design' started by 500Lonepine, Jan 20, 2015.

  1. 500Lonepine
    Joined: Sep 2013
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    Location: Lake Leelanau Mi

    500Lonepine Junior Member


    I am designing benches for a sailboat and am thinking about using masonite as a base form for fiberglass. in other words the benches would be made from Masonite then covered with fiber glass.

    Is masonite a suitable base structure for Fiberglass in a marine environment?

  2. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Masonite will not hold up in the marine environment, but you can use it as a form, knowing full well it'll break down with moisture exposure. If the laminate is heavy enough, the masonite is simply a mold over which the wet fabric is applied, when it's dry, the masonite is just along for the ride.
  3. waikikin
    Joined: Jan 2006
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    Location: Australia

    waikikin Senior Member

    Quite some time ago we used to use masonite as a contact tooling surface for fiberglass molding, the dense smooth side was coated with shellac, waxed then pva Then molded off, now melamine faced sheet or polyesterboard-coated ply is easier.
    Seen quite a bit in lockers & also perforated masonite used as a lining panel form 50-60-s boats typically cruisers..
    Given the choice I wouldn't use as a form to leave in.

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