weird german foil wire cup

Discussion in 'Armory - Q&A' started by Privateer, Feb 4, 2018.

  1. Privateer

    Privateer Podium

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    i was having trouble with a weapon using a screwless tip and i couldn't figure out the problem so I decided to rewire, even tho the wire job was only a couple months old, if that.

    upon removing the intact wire, I found this:

    [​IMG]

    [​IMG]

    sorry about the picture quality, I was taking pictures with my phone through a magnifying headset thing.

    anyone seen this before? did i get a defective one? I'll be honest, I put this weapon together and I don't remember the cup looking like that (the holes in the side), but that doesn't mean it wasn't that way on assemlby. More I'm curious about the little protrusion on the exit, and how the cup is conical like the inside of the barrel
     
  2. Emfuser

    Emfuser DE Bracket

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    I'm curious what some of our old hands here in this forum have to say about this thing.
     
  3. neevel

    neevel Armorer

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    Do you know what brand the point and wire are?
     
  4. Privateer

    Privateer Podium

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    I don't unfortunately, it's just a wire I had in my tool kit, but it probably came from Fencing Post or AF since that's really the other stores I order from.
     
  5. neevel

    neevel Armorer

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    What do you use to clean your points? I've encountered some wires in the past (including a few Leon Paul wires) which had contact cups that were degraded by 'plastic-safe' contact cleaner.
     
  6. Privateer

    Privateer Podium

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    hm, usually q-tip applied isopropyl alcohol, maybe acetone administered the same way.
     
  7. ktinoue3

    ktinoue3 DE Bracket

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    Never use Acetone. That is most likely the cause of the plastic cup melting.
    Isopropyl or Goo be gone are what I would recommend.
     
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  8. neevel

    neevel Armorer

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    That's the answer to your issue. Acetone is a solvent that attacks many plastics.
     
  9. Mac A. Bee

    Mac A. Bee is a Verified Fencing ExpertMac A. Bee Podium

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    When a cup is stuck in a barrel, I drop the barrel into a small glass tightly-capped jar of acetone. A little while later I use a cotton swap to swip it out.
     
  10. Privateer

    Privateer Podium

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    ok, i'll agree the acetone may have put the weird holes in the cup. probably isn't the first time I've used acetone on a barrel and never seen a cup get eaten like that.

    not sure if it matters, and this cup was not stuck, came out easily.

    but what about the conical shape of the bottom and the .. nub.. where the wire exits?
     
  11. neevel

    neevel Armorer

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    How aggressively a plastic is attacked by acetone depends on the particular plastic in question. There are a bunch of manufacturers making "German" wires, so this one would have come from someone using a plastic that happened to be more vulnerable to acetone than other manufacturers' cups (I'm pretty sure nobody is considering acetone resistance when selecting the plastic used for contact cups).
    The drooping at the bottom seems a pretty logical result of the cup being attacked and melted by acetone.
     
  12. dcchew

    dcchew Podium

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    In a pinch you could use acetone to clean out a barrel. However, you should do everything possible to rinse out any residue of the acetone from the inside of the barrel. That can be very difficult to do.

    I always recommend isopropyl alcohol (IPA) for cleaning tips. The higher the purity level, the better. I'm fortunate to be living in Silicon Valley and can get 99.99% pure electronic grade IPA.
     
  13. brtech

    brtech Podium

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    I find the fascination with the purity of the alcohol amusing. The part that isn't alcohol is water. 1%, 10%, or even 20% water isn't going to make any significant difference in cleaning, residue or material compatibility.
     
  14. jkormann

    jkormann Podium

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    But 100% pure IPA (from dcchew's post) will make a difference!

    Edit: huh -- IPA also means Isopropyl Alcohol.
     
  15. Privateer

    Privateer Podium

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  16. Privateer

    Privateer Podium

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    it'll be interesting to disassemble the other with the same setup and see what the cup looks like. distinct possibility I used acetone on it as well, but it is not as finnicky, if at all.
     
  17. InFerrumVeritas

    InFerrumVeritas DE Bracket

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    It has to do with evaporation rate. For some electronics this is important. For fencing equipment, it's really not.
     

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