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Cutting dyneema

Discussion in 'Knives and Cutting Tools' started by Subcooled, Jun 2, 2016.

  1. Subcooled

    Subcooled Assistant Instructor

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    Can you recommend me a tool that cuts through 12mm / 0.45" of dyneema rope under water?
     
  2. tbone1004

    tbone1004 Technical Instructor ScubaBoard Supporter

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    no... I'm a textile engineer, dyneema is not designed to be cut. Smaller sections can be gone through with something like a trilobyte or a benchmade Z knife, but 12mm rope is too thick for that. You'd be sawing through it at best. Why would you need to cut rope that thick? Very difficult to get caught up in...
     
  3. Subcooled

    Subcooled Assistant Instructor

    # of Dives: 200 - 499
    Location: Finland
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    That, indeed, became apparent. Hard physical labour and the result wasn't much more than a little blunter knife. I finally managed to rip the rope apart with wire cutters. It wasn't elegant.

    Some talented sailors however, manage to get it into the prop.
     
    2airishuman likes this.
  4. lowviz

    lowviz Solo Diver ScubaBoard Supporter

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    My best guess would be to try this: McMaster-Carr

    Get the cheap black one at the top of the page, very thin and very sharp blade. We abused a bunch of them at work for all sorts of things. Amazing little tool...
     
  5. tbone1004

    tbone1004 Technical Instructor ScubaBoard Supporter

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    ahh. yeah for stuff like that sharp trauma shears are your friend. I thought you meant for a personal cutting tool. Dyneema is specifically used in applications where cut resistance is required. Takes some experimentation, but you can also usually cut it with an exacto type knife, but both will be dull beyond use afterwards. The hose cutters above won't work because the dyneema fibers will just find up in there. Sawing motion combined with scissor motion is required to cut this stuff
     
  6. lowviz

    lowviz Solo Diver ScubaBoard Supporter

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    Understood. Try tensioning the line and spinning the tool around it like we did.
     
  7. Subcooled

    Subcooled Assistant Instructor

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    Spinning the tool so that the blade cuts in,
    or spinning the tool like a lever around the prop axis?
     
  8. lowviz

    lowviz Solo Diver ScubaBoard Supporter

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    We would cut all sorts of annoying stuff including heavy gauge fine copper braid conductor covered by teflon. You have to tension the line then rotate the tool 90 degrees to the line (as it has to be) while your ever more educated grip increases the pressure as you rotate the tool around the line. It is quite natural, best if you just try it. You get both a scissors action (your grip) and sawing (the rotation). Worth a shot, cheap enough...
     
  9. runsongas

    runsongas Great White

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    a small pipe cutter might be worth a look
     
  10. JohnnyC

    JohnnyC PADI Pro

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    Sharp trauma shears, or a sharp razor blade type knife if you can hold the line against something like a table. Dyneema, and really any UHMWPE or LCP type fiber is specifically designed for its abrasion resistance. The most annoying part of splicing a core-dependent rope out of something like dyneema or vectran is tapering the tail since it's such a bitch to cut....
     

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