Diolen vs. Xynole

Discussion in 'Materials' started by Dan Seiple, Aug 30, 2018.

  1. Dan Seiple
    Joined: Feb 2018
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    Location: Berlin, Germany

    Dan Seiple Junior Member

    Diolen seems to be the European equivalent to Xynole – or at least similar. I'm building a 27' motorboat in Germany that calls for 2-layers of Xynole on the bottom. Xynole is 4oz. a square yard. I've found Diolen that is nearly 8oz. a square yard. So! Could I just use one layer of Diolen instead of 2-layers of Xynole – provided that the materials are similar?
     
  2. JamesG123
    Joined: Mar 2015
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    Location: Columbus, GA

    JamesG123 Senior Member

    While 8oz fibers are twice the diameter/weight of 4oz, its still only one ply so your matrix is only going to be one layer thick and any failure is going not have any backup, its just going to tear and peel right along the fail axis. I would follow the builder's specifications.

    If this is Diolen 855T, its discontinued, so might be (who knows how) old stock.
     
  3. Dan Seiple
    Joined: Feb 2018
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    Location: Berlin, Germany

    Dan Seiple Junior Member

    Thanks James. That would make sense. I've received a lot more responses on forum.woodenboat... the consensus there is that Dionel appears to be a stronger material than Xynole. However, it is hard to argue with your argument.
     
  4. JamesG123
    Joined: Mar 2015
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    Location: Columbus, GA

    JamesG123 Senior Member

    There would be nothing wrong with using two layers of the 8 oz. Diolen for a negligible increase in weight. You would use a bunch more resin though...
     
  5. Dan Seiple
    Joined: Feb 2018
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    Location: Berlin, Germany

    Dan Seiple Junior Member

    Actually, it's a pretty substantial increase. I'm building a 9-meter motorboat.

    I shared your argument with some others and they had different opinions. For the sake of conversation here's what they say:

    "The chemical bond between plies is going to be orders of magnitude greater in strength than the mechanical bond between resin and ply substrate, so any peeling will separate at the fabric/wood boundary, not interlaminarly between fabric plies. Ergo, no 'backup' by having two plies instead of one."

    "The individual fibers in the yarn should be the same regardless of fabric weight. In the heavier cloth, the yarn would have more fibers in each strand. You might be overthinking the failure modes. More total fiber weight will increase the overall properties, and whether it is multiple layers or not shouldn't make much difference when you are just looking a wear surface on plywood."
     

  6. JamesG123
    Joined: Mar 2015
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    Location: Columbus, GA

    JamesG123 Senior Member

    Ah the internet...

    Two plies provides more protection against penetration and a stronger laminate to prevent such peeling. You can cut one without completely compromising it.

    I'm not sure about the second statement, its seems to either be agreeing with me or contradicting itself. The strength from a laminate comes from the fibers, 2 plies spreads the loading better and at different angles, esp. if they are bias to each other.

    Only people who build wood boats that just happen to have glass to keep the water out use one ply. If you are building a composite boat that just happens to have a wood core, use 2 ply minimum. Or if nothing else; Follow the designer's specifications.
     
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