core mat

Discussion in 'Boatbuilding' started by mark775, May 1, 2010.

  1. mark775

    mark775 Guest

    Hi I am looking to manufacture quick, light and simple 2' x 1.5' x 1/4" compound curve panels that will be exposed to weather. I was thinking coremat with light glass on each side but am concerned about exposure of the coremat to weather. It's production of roughly 100 panels, so I would like it as simple as possible. One side good (both would be better but will accept one side good for ease of manufacture. Ideas? Two piece mold? Vacuum bag? How do I seal the edges quickly and cheaply?
  2. waikikin
    Joined: Jan 2006
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    Location: Australia

    waikikin Senior Member

    Mark775, Coremat is a terrific product, I've had window cut outs & offcuts etc kicking around the yard for years as bogboards & even laying in the dirt with only a bit of a mouldy look on the "endgrain", so long as the coremat is wet out correctly a quick flowcoat on the edges should be fine.
    Do some samples & weigh them & soak them etc to check uptake but most issues with coremat are resin starvation from its dry application to the underlying laminate- it must be "back wet" before install.
    Maybe an infusion process with a bulker mat could be the go but I have never done it so cant recomend, a two peice mold would be great too on that number & might look after your edge treatment- would depend on the fat in the job.
    All the best from Jeff.
  3. mark775

    mark775 Guest

    Do you think that if I make a two-piece mold strong enuf out of glass, I can "squish out" to proper (minimal) resin content without starved spots? Only need 100 parts and can't justify having metal molds made, I don't think.
  4. waikikin
    Joined: Jan 2006
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    Location: Australia

    waikikin Senior Member

    Seeing as the parts are only 24" x 18" yeah I recon you could easily make a glass matched mould for that but with coremat there's nothing minmal about resin content, also as a result of resin content be careful of the part cooking up.

  5. Herman
    Joined: Oct 2004
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    Location: The Netherlands

    Herman Senior Member

    If you need 100 panels, there would be 2 ways I would recommend:

    Make female mould.
    Use CSM as outer skin, Soric (infusion style coremat) as a core, and CSM as inner skin.
    Use vacuum film (depending on curvature use a flexible one, to avoid wrinkles) and sealant tape to the edges. (After doing a couple you lose minimal time closing the bag).
    Pull a vacuum, do a drop test, and infuse with polyester resin. (non thixotropic, low shrink version).
    One could optionally use peelply on the inner or even outer skin, over the whole panel, or just the edges.

    Make female mould.
    Apply thickness-calibrated cork or wax sheet into the mould
    Make semi-flexible top mould (with rigid edges). Check for details).
    Use same laminate as before.
    Toss in laminate, and infuse. One could infuse from a bucket of resin, or use a mixing machine, which sets you back a considerable amount of money. Is very fast, and resin waste is less than 100 grams per product.

    Advantages system 1:
    -lower in weight
    -less overhead costs
    -slower process
    -consumables and waste

    Advantages system 2:
    -fast preparations
    -fast infusion
    -low resin waste
    -no consumables
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