Fibrglassing question

Discussion in 'Fiberglass and Composite Boat Building' started by alyne, Dec 15, 2006.

  1. alyne
    Joined: Aug 2003
    Posts: 55
    Likes: 1, Points: 0, Legacy Rep: 38
    Location: Somerset UK

    alyne Junior Member

    Hi

    I have a plastic rotomoulded kayak (Scupper Pro). I want to take a fibreglass mould of part of the boat in order to make a mast step.

    My question is, what do I need to do before laying up so I can release the mould from the plastic surface, leaving no damage to the boat? The surface of the plastic is quite course, so I can't just use a release agent. Also as this is a small one off project I am hoping there is a low cost solution?

    Thanks in advance
    Andy
     
  2. marshmat
    Joined: Apr 2005
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    Location: Ontario

    marshmat Senior Member

    Are you taking the mould from the outside or inside of the hull?
    I know it sounds crude, but might I suggest plain old paraffin wax? Melt it, spread it on, smooth it with a plastic spreader before it cures. If it's lumpy you can point a hair dryer at it and it gets soft and workable again. $4.99 a kilogram at any grocery store, and it does the job....
     
  3. alyne
    Joined: Aug 2003
    Posts: 55
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    Location: Somerset UK

    alyne Junior Member

    Hi Matt

    I'm taking the mould from outside the hull so its easily accessible.

    Thanks for the suggestion. I knew there had to be a simple solution but couldn't think what to use!

    All the best
    Andy
     
  4. fiberglass jack
    Joined: Dec 2005
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    Location: toronto

    fiberglass jack Senior Member

    got to love that cheap floor wax works great, the only thing i would be worried about is if the resin will eat the plastic , as u are going to pull a mould from the outside i would cover the hull with wax paper cut several pieces and tape them down with scotch tape, after u gelcoat skin the part with a single layer of glass and let dry, what u will want to be carefull is exotherm heat if u lay up the mould in one shot the heat may distort the plastic , so do it is a few shots
     
  5. Frosty

    Frosty Previous Member

    Will fibreglass stick to Acrylic? Can epoxy be used as an acrylic glue.
     
  6. marshmat
    Joined: Apr 2005
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    Location: Ontario

    marshmat Senior Member

    There ain't much epoxy won't stick to, lol!
    I've glued acrylic with epoxy in the physics lab, it worked fine so long as the surface was roughened up a bit. It's not as good as an actual 2-part acrylic adhesive but those are really pricey and finicky. I have no idea how the epoxy-acrylic performs in the field as I've only ever done this to build relatively low-stress lab equipment.
     

  7. yokebutt
    Joined: Aug 2004
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    Location: alameda CA

    yokebutt Boatbuilder

    Andy, most rotomolded products are polyethylene, (often referred to by ungainly acronyms like HDPE and UHMWPE) wich is a great non-stick surface for most resins and glues.
     
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