Need advice on building my jig/mold

Discussion in 'Materials' started by noobiedork, Oct 16, 2014.

  1. noobiedork
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    noobiedork New Member

    Ok Im building a 1 off boat for now. I know how to build the jig etc, But I don't know the right laminate to place over jig to get a smooth easy to release finish. Should I use luan? or get a pvc material.? or something completely diff?
    I plan to destroy the boat after test sails to make a mold out of it. The jig will most likely be just for the one off. I need cheap, quick, and easy.... all relative of coarse. ;)

    20 ft sailboat . quick ,easy shape, out of glass, and not sure on epoxy or vinylester.
     
  2. redreuben
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    redreuben redreuben

    If it's a chine hull glossy melamine covered mdf works well male or female.
     
  3. SukiSolo
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    SukiSolo Senior Member

    Yes / \ is good although even cheaper, but not as stiff is the melamine faced hardboard. A coat of release wax on it and it will pop off.

    Although I've not tried this possible method myself - might be worth looking at shrink wrapping in polythene - if it will go down without a crease!. Could work on a smooth faired stiffish foam EPS? former.
     
  4. rwatson
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    rwatson Senior Member


    uh - you are going to build a hull from expensive materials to destriy it ? Whats wrong with good old Polyester for a test hull ??


    not in a milliion years
     
  5. Alik
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    Alik Senior Member

  6. rwatson
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    rwatson Senior Member

    Fascinating stuff Alik

    Whats the best surfacing for these kinds of moulds ?
     
  7. Alik
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    Alik Senior Member

    There are options. Most common - laminated MDF, it is smooth.
    This one on photo will sprayed/painted.

    Of course, some filler is needed after demuolding, in some areas.
     

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  8. rwatson
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    rwatson Senior Member


    yeah "sprayed/painted." - that's what I meant. Wouldn't you have to epoxy it for stability then bog it - then what would be the best top coat ?
     
  9. Alik
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    Alik Senior Member

    Actually there is one builder I know who sprays it. Will check what they use.

    Others just use laminated MDF.
     
  10. rwatson
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    rwatson Senior Member

    Its just that the pictures show plain MDF- that would make a useless surface to layup on. Even white mdf is tricky enough, especially if you have to seal between joins.
     
  11. Alik
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    Alik Senior Member

    You cant lay on plain MDF; the surface on photos will be painted. On the white stuff one can lay the laminate; the joints are treated by filler.

    It much depends what kind of craft is being built. If it is a commercial boat the requirements to finish are not as high as to yacht, especially in underwater area. For yacht, some filler should be used.

    We use this method for years, as with vacuum bagging of core and with infusion.
     
  12. SukiSolo
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    SukiSolo Senior Member

  13. rwatson
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    rwatson Senior Member


    Yeah - thats what I said ...

    "plain MDF- that would make a useless surface to layup on"

    Its what you coat the plain mdf with before layup that I am asking about.
     
  14. Alik
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    Alik Senior Member

    Use release wax, that's it.
     

  15. rwatson
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    rwatson Senior Member

    Your sure ?

    Just wax on plain mdf ?

    Even on the smooth side, that sounds like a good way to destroy the mould in one layup.

    I will do a few test bits, but i have reservations.
     
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