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Stuff you wouldn't think would dull a blade

Discussion in 'General Knife Discussion' started by Groove, Feb 6, 2013.

  1. Groove


    May 3, 2011
    Today I'm splitting and sizing soft foam pipe insulation (much like neoprene) for a project at work. First up was my Kershaw Skyline FB, it sliced like a laser beam for about five or six (6ft long) slices, then started to grab and tear the foam. I grabbed my Spyderco Tenacious out of my bag and continued with about the same amount of slicing before the edge was grabbing and hard to work with. Has anyone else here worked with this type of foam insulation?

    This got me to wondering. What other seemingly innocent materials will kill an edge so quickly?

  2. JDunn709


    Jan 7, 2009
    Fiberglass insulation is a monster, dish sponges with a 'scrubbing' side are as well.
  3. 9blades


    Dec 29, 2012
    ^^they eat up edges^^

    I was cuting some straps I thought the where plastic they turned out to steel...........
  4. red05


    Aug 19, 2010
    I did the same thing last weekend. I insulated some pipes with the foam insulation and it dulled my knife bad. I was using an old tradtional Craftsman linerlock since I thought the thin blade would be just the thing. I would have never thought it would dull the carbon steel that bad.
  5. Groove


    May 3, 2011
    This stuff is making me wish I had my GEC Bullnose in O1, just to see how long it holds out.
  6. Dorito Monk

    Dorito Monk

    Nov 17, 2008
    Old, shaggy, left-outdoors-too-long rope. It looks like normal rope, but it gets full of sand and grit that's really tough on your knives.
  7. theizzardking


    Dec 29, 2012
    the sheath itself.....glass filled polymers in the cheaper knife sheaths
  8. Czechmate


    Feb 24, 2011

    They are murder on knife edges... ;)
  9. theizzardking


    Dec 29, 2012
    haha funny how they just jump up and bite the blade when your cutting something normal...
  10. Dorito Monk

    Dorito Monk

    Nov 17, 2008
    Man, I wouldn't have expected that. :confused:

    Good thing you warned me - I was about to go cut some rocks in my backyard when I read that. :thumbup:
  11. T. Erdelyi

    T. Erdelyi Gold Member Gold Member

    Feb 3, 2001
    Carpet, I've seen carpet dull a circular sawblade usually you're lucky if ya a couple of slices in before it cuts like a buyer knife.
  12. Czechmate


    Feb 24, 2011
    You're welcome Dorito Monk. I like to help out folks wherever I go... :D

    On topic though, I've found cutting sandpaper quite damaging to knife edges; I was suprised at how quickly it can dull a sharp knife, especially coarser grit stuff.
    Last edited: Feb 6, 2013
  13. FortyTwoBlades

    FortyTwoBlades Baryonyx walkeri Dealer / Materials Provider

    Mar 8, 2008
    If find it helpful to cut from the backside of the paper. Seems to slightly minimize wear on the edge.
  14. theizzardking


    Dec 29, 2012
  15. Czechmate


    Feb 24, 2011
    I do cut that way and have found the same to be true. :thumbup: Last stuff I cut was coarse grip tape; after that the knife edge looked like it had been thrown onto rocks, all chippy and rolly and such. Not pretty but easy to fix.

    Yeh, practical as all get out but those are no fun to use... :D
  16. cncpro11


    May 28, 2012
    I dropped a knife in the dirt from about 3 feet and the cutting edge hit a small pebble.
    I could not believe how badly it damaged the blade.
  17. FortyTwoBlades

    FortyTwoBlades Baryonyx walkeri Dealer / Materials Provider

    Mar 8, 2008
    I love those things! :D
  18. HoosierQ


    Feb 9, 2010
    I suspect one of two things is happening with that pipe foam. Either there is something in that that's actually abrasive or could it be that the material is adhereing to the edge of the knife? I haven't dealt with it so I cannot say.

    Cutting rubber is very hard on the edge. Not only is the stuff tough but there are abrasive inclusions in the rubber. Same deal with cardboard. It's very unclean paper with soil (which is mostly extremely fine rock) and clay and other contaminates it there.
  19. CDKJudoka


    Jan 11, 2013
    Tomatoes!!! I have to sharpen my kitchen knives after cutting two of them. It doesn't help that I got cheesy steel in my kitchen that is probably made by cutting a tin can and shaping it like a knife.
  20. neffarious

    neffarious Basic Member Basic Member

    Jun 23, 2012
    Carpet, though it's not unexpected, its still rough. It's nothing like human flesh which you can cut through for hours before it dulls a knife.

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