Biased glass weave

Discussion in 'Boat Design' started by Fanie, Aug 18, 2012.

  1. Fanie
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    Fanie Fanie

    Hi everyone,

    This is the right forum, for a design I need a specific weave of glass.

    Does any one know where I can find biased weave, that is reels of 45 x 45 deg woven glass with a thread both sides and possibly a stitch in the length to maintain integrity during handling ? The ideal width should be 300mm.

    I saw lots of people asking for this but not one weaver refered to.

    I designed a machine that can do it but don't have the space for it :(

    Thanks...
     
  2. Red Dwarf
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    Red Dwarf Senior Member

  3. Fanie
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    Fanie Fanie

    Thanks Red, but that won't work... looking for a few hundred kg of the stuff in ie 20kg reels.
     
  4. PAR
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    PAR Yacht Designer/Builder

    How many linear meters do you need? 300 mm widths can be cut from 1.3 meter bolts or you can also get it "slit" from a 1 meter bolt or you can just cut it yourself as you need it.

    I don't see and issue here as most suppliers carry 45/45 biax in a few different weights and bolt widths. Now getting a 300 mm roll of tape (a different animal), with seized edges will be a hard thing, but not imposable if you need enough.
     
  5. Fanie
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    Fanie Fanie

    The glass is for making a hull, so tape won't work. The weight should be around 450g/m^2.

    The reson for wanting biased glass is it can form readily to any shape that goes taper etc.
     
  6. PAR
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    PAR Yacht Designer/Builder

    450 gm biax is what we call 12 ounce and one of the two commonly available weights. Why do you want such a narrow roll of fabric and why can't you cut a 1.3 m bolt down?
     
  7. Fanie
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    Fanie Fanie

    The glass needs to be fed through rollers in a continuous process and the side threads wrap around the rollers in std glass if they are loose.

    With biased weave the side thread/stitching is there to prevent elongation when handling the glass or it can go long and thin...

    Cutting std matt at 45 deg is an option if you want to work yourself to death... :D

    If I remember right the biax does not shape well.
     
  8. philSweet
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    philSweet Senior Member

    I'm a little confused. You want a factory 12" tape of +/-45, correct? So 9 oz, or 1708. What's the issue?

    You can slit wider stuff and dope the edges if you need to control them. Are the rollers being used to wet out the tapes?

    You can use a cheap masking tape banjo before you slit. The tape will fall off after wet out. Hopefully that is after the rollers. Are you making pipes or tanks with a winder?

    Much of this stuff is designed for tabbing and has limited drape. There are special twill and satin weaves for better drape. But I haven't worked with that stuff. Most of the satin weave is S-glass. Shoot Tunnels a PM. He'd know.
     
  9. Fanie
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    Fanie Fanie

    Have you ever sat and slit a reel of glass up ? It's too much work and tape. I did it before and swore never again (and I'm very lazy).

    The rollers are to wet the glass out. It is not really possible to wet out short pieces because of handling problems, it is desirable to have the glass in reels so the glassing process is a continuous one. The problem is the 0/90 glass does not conform to shape well, which can be cured if the biased weave is available in reels.

    Iow, if one slit the standard mat up at 45 degrees and stitch the sides and add them start to end then that is what I'm looking for. The problem is the cost when all these extra work gets done. If it gets woven like that in one process then it becomes a lot less expensive.

    The alternative is to have the standard 0/90 glass lenth required fed out, then cut and it gets placed by hand, still a massive job compared to if it gets wound automatic. To make a weaver that makes 0/90 deg glass at 12" (300mm) wide is relative easy.

    The "tape" you get is for finishing edges etc, it is low strenth, tested some here, you can actually rip it off and it tears too easy. It feels strong when on the reel, but once glassed and cured it doesn't make it.


    I want to add that it seems the biased tapes are not a true bias either, zig zagging the stitch is not desirable because if you want strength the fibers must be long streight pieces.
     
  10. Jeremy Harris
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    Jeremy Harris Senior Member

    I have a part roll of 450g/m² 45/45 biax, it is standard stock item from West. I think I bought the roll I have from the West distributor here, Wessex Resins several years ago.

    I've just checked their website and they still stock the same biax cloth in 1265 mm wide rolls (West cloth type 736) and also biax tape in 125mm wide rolls. The stuff is just two layers of fibres, stitched together. It's not woven in any way and drapes fairly easily to conform to complex shapes
     
  11. Fanie
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    Fanie Fanie

    Jeremy, biax has a 0 degree with added bias, right ? Biax is a biased with axial hence biax - I just rechecked the glass you get and none of them are a biased alone glass.

    I did consider just using threads from reels, but lots of other problems there...
     
  12. Jeremy Harris
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    Jeremy Harris Senior Member

    The stuff I have has one set of fibres running straight at 45 degrees to the edge and the other set running at 90 degrees to this, and is described as +/- 45 degree cloth. They also do a version with a thin layer of CSM bonded to it, presumably to aid getting a better surface finish. The stuff I have doesn't have the CSM layer.

    Here's an image of the stuff:

    [​IMG]

    West now seem to call this 737 on their US site, but the 450g/m² stuff is described as 736 by the UK distributor, not sure what's going on there.
     
  13. Fanie
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    Fanie Fanie

    Ok the piece in the foreground has chopped strand on the back.
    The piece behind it is not biased weave but biax, note the strands in the length of the material.
    The roll looks similar to the tape I have.

    If you look at standard woven roving the strands goes 0 and 90 degrees. If you turn it 45 degrees, then that is what I'm looking for. If you pull on this it elongates and become very thin, iow not 45 x 45 any more, that is why a stitch or thread on the sides has to be added, to maintain integrity.

    I had samples of just about all the standard stuff, it doesn't conform well and makes bubbles between the layers. As I said, if you hand-lay short pieces to compensate for the changing shape it works, but it's a beeeg job.
     
  14. philSweet
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    philSweet Senior Member

    So don't pull on it. Roll it up onto a cardboard tube as you wet it out. Drop it in bag. Drop bag in freezer. Do a few hundred pounds. Clean up. Then go to freezer and start the layup. Or just order prepregs.
     

  15. Jeremy Harris
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    Jeremy Harris Senior Member

    I'm with you. In the past I've cut biased woven roving out of wide cloth by cutting it at a 45 degree angle to the roll, using masking tape to hold the weave together. Works OK for small pieces, but I can see how this would be a problem for a big layup.

    The 450g/m² biax I have doesn't have the thin layer of GSM, just the stitching holding it together. The fibres are long, the whole width of the cloth as far as I've been able to tell, but the stuff does move around and distort when you pull it, just as you say.

    I've not had a problem laying it up, other than the fact that it doesn't much like being turned through a sharp radius near the edge - it tends to lift unless you bag it. For me it lays up almost as well as a more expensive, but lighter, twill weave cloth, but with a heavier build up per layer. It's certainly good in terms of getting a reasonable resin/glass ratio with a hand layup, mainly because being non-woven there's no inter-weave gaps to fill with resin. The twill weave does always seem to want to lay down more smoothly and easily though, which is useful if you've got a complex shape to lay up.
     
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