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'Scientific' question

Discussion in 'CycleChat Cafe' started by Aperitif, 27 Jan 2008.

  1. OK - here's one for you science buffs out there.
    Just now, I was doing a bit of routine maintenance on my helmet (Cue fnarr et al)
    I cut off some of the excess strap last week and by the end of a week's commuting it had frayed a bit. Not fancying a bushy pom pom under my chin, I decided to glue the strands with super glue. Applying the glue to the strands in a sort of wiping fashion, I saw 'smoke' - real fumes coming from the glued area of the strap.

    What's all that about?
     
  2. freakhatz

    freakhatz New Member

    Why didn't you cut the straps with a nearly red hot knife? That would do both jobs at once and you'd still get plenty of smoke as well.
     
  3. Because I was thoughtless.
    Now answer the question :biggrin:
     
  4. yenrod

    yenrod Guest

    Burn the strands together...

    Well, thats what I'd do !
     
  5. Maz

    Maz Guru

    I'd do that, too.
     
  6. Yes - me too!

    Still no science. Holy helmet straps Batman!:biggrin:

    What I would like to know is; why does the application of super glue to nylon? (polyprop etc)filaments cause smoking to occur on contact?:sad: :biggrin:
     
  7. Cycling Naturalist

    Cycling Naturalist Legendary Member

    Location:
    Llangollen

    Because you've created an exothermic reaction with inflammable materials.
     
  8. Abitrary

    Abitrary New Member

    Hmmm, this might be falling for the old no smoke without fire story.

    There might be fumes, but unless there was extreme heat and possible flames, it could have been an endothermic reaction.
     
  9. Thanks Patrick and Abitrary

    This could also be the seedling of an explanation as to why yenrod's pants caught fire after he placed them in the oven last week...

    ...and innuendothermic reaction perhaps...or worse?:biggrin:
     
  10. redshift

    redshift Senior Member

    Polymerization of cyanoacrylates is exothermic. Also, cyanoacrylates and cotton don't mix.

    The strap presumably isn't cotton, more probably a polyester, but it's probably been impregnated with some skin acids (also cause exothermic reactions) and the resisdual water is what causes the glue to cure in the first place. It may just have been water vapour if the reaction's vigorous enough, combined with the usual fumes and by-products.*


    *I'm winging it. It's over 20 years since I considered myself a 'chemist!' :biggrin:
     
  11. Excellent redshift - sounds plausible to me...the resultant fumes were acrid enough...not that I was sniffing hard you understand...:idea:
     
  12. twentysix by twentyfive

    twentysix by twentyfive Clinging on tightly

    Location:
    Over the Hill
    If not sniffing hard why make the fumes in the first place? :idea:

    <Homer Mode> Hmmmmmmm Cyanoacrylates..... <Homer Mode>
     
  13. longers

    longers Veteran

    We use quite a bit of Superglue at work and have activator sprays to get it to go off instantly. It's so much more convenient for sticking your fingers together with.
     
  14. Keith Oates

    Keith Oates Janner

    I think I would stay with lightly burning the strand ends with a match, wouldn't know where to buy one of these Polymerization things!!!!!!!!!!!!!!!!!!!!!!
     
  15. domtyler

    domtyler Über Member

    I know the answer and could probably explain it in plain English, but the sad fact remains that there are so few people on this forum with the mental nouse to comprehend the complexity of my answer that I may as well not bother. So I won't. ;)