Flexible Moldmaking Sheet Material??

Discussion in 'Fiberglass and Composite Boat Building' started by Capt. Chris, Aug 18, 2007.

  1. Capt. Chris
    Joined: Feb 2005
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    Capt. Chris Junior Member

    Hey All,

    I'm looking for some sort of sheet material, similar to formica, but more flexible. I have to line a mold with 2" radius inside corners. Not too complex, tackle center halves. I'll mold these "U"s then cut to size, glass them together , fair and alwgrip. The form I have now is basically ribs about 6" apart ,all squared and ready for the inside "U" to be covered. Any suggestions??:?:
     
  2. Landlubber
    Joined: Jun 2007
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    Landlubber Senior Member

    Flexible Mould Lining

    I would suggest that you just lay up a very thin sheet of fibreglass on a plate of glass. Tissue or thin csm will bend around a 2" curve and you can then use one sheet for the whole interior liner. Cut the joints and fit nicely and the joint will be almost invisible. You can sand and fair the joint after fitting the liner anyhow and it will then be completely invisible, just make it in the centre of one of the flat pieces for ease of sanding and polishing. If you want to rib it, do so after fitting the liner, small moulded wood pieces are ideal, and can be waxed directly.
     
  3. Capt. Chris
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    Capt. Chris Junior Member

    I'm not too clear on the lay-up to keep the glass that flexible. I use 3/4 oz mat and 1708 biax, what would tissue be equivilent to in ounces of fiberglass?. I spent most of my time trying to get things rigid!
     
  4. Landlubber
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    Landlubber Senior Member

    Tissue would be about 1/2 oz. It really is very fine, similar to tissue paper, hence its name. Yeah we do not generally make something to flex this much do we. I am sure that you will be able to get some from your local laminator, it is used against gelcoat in normal construction using a mould, followed by 1 or 1 1/2oz cloth to assist prevent print through of the heavier layers that will be following. The rolls are about 36" wide, but you will be able to buy it by the yard. It will flex that much when it is so thin, and using flat glass will give you a perfect finish without any more work to be done, although I see you are going to awlgrip it anyhow. Have fun.
     
  5. Pericles
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    Pericles Senior Member

  6. dberr
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    dberr Junior Member

    A friend who built his own 45' catamaran used the same technique to make a shower enclosure for his boat. First time I saw it I asked how long it took to make the molds for the shower. He smiled and showed me some of the offcuts he had laying around. In his case, he gelcoated his mold (a sheet of formica) and applied two layers of 0.75 oz CSM. I was amazed at how flexible the cure sheet was. As I looked elsewhere on his boat I began to notice how much he had used this technique on his interior. I wouldn't be surprised if a layer of tissue (surface veil or veil here in N. America) laid up on a flat mold will bend to a 2" radius and allow you to make your parts.
     

  7. Capt. Chris
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    Capt. Chris Junior Member

    Thanks All,
    I think I'll give this method a try on a small scale since I have some formica in the shop. Always have plenty of mat kicking around. It seems to me that this method is alot like when we mold parts, just without the build up after the gel/mat starter. I just never had any reason to jerk with it until the whole part was laid up, especially with the price of materials these days. Thanks for the input!
     
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