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3-May-2012 12:08:48 PM
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Thanks for the feedback. Will have to go looking for acid in my car I guess. I'd rather not name the rope maker for fear of tarnishing someone else's good name with my own stupidity.
No luck with the photos sorry, a bit technically challenged.
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3-May-2012 2:18:10 PM
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good on left, slight discoloration of failed rope on right.
No smell or taste difference.
I will break a section of 'good' rope and compare the broken ends under a microscope..
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3-May-2012 2:20:01 PM
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wish I had a car full of acid
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3-May-2012 2:52:59 PM
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Taste difference? You are a dedicated scientist indeed Mikl, you won't find me licking any ropes anytime soon :)
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3-May-2012 6:00:47 PM
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Faded rope appears thinner in your photo's Mikl. Also reading the Black diamond report into sulphuric acid damaged rope they indicated that the rope could have come into contact with battery acid in a car park. Is it known if this rope ever sat on the ground where a car had been parked - long bow, but possible.
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3-May-2012 7:07:07 PM
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On 3/05/2012 mikllaw wrote:
.
>No smell or taste difference.
But shortly after sampling the one to the right, a giant beetle wearing a KISS t-shirt explained nuclear fusion and drank the last beer from the fridge.
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3-May-2012 7:22:11 PM
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On 3/05/2012 stonetroll wrote:
>But shortly after sampling the one to the right, a giant beetle wearing
>a KISS t-shirt explained nuclear fusion and drank the last beer from the
>fridge.
What a jerk!
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4-May-2012 7:22:00 AM
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A long shot but had the rope ever been washed ? Many washing products contain sulphonates. An undissolved lump may have had an effect.
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4-May-2012 9:25:01 AM
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I can't see any real difference in thickness BUT about 5 minutes after I posted that there was no taste differnce, they was a slight acid taste in the back of my mouth
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4-May-2012 4:37:06 PM
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Probably should have spat the rope out and taken a few deep breaths. That lactic acidosis is dangerous!
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6-May-2012 9:30:49 PM
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I realise this situation is very different from the one being discussed here, but i thought i'd just pop it in to re-iterate the safety factor for those who might not be aware of what damage a burred caribiner can do to a rope.
http://dmmclimbing.com/knowledge/carabiners-and-potential-rope-damage/
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7-May-2012 8:18:13 AM
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Here's a report on an accident where the first draw on a route cutting through a rope: http://www.rockandice.com/articles/how-to-climb/article/1092-rope-chopped-by-carabiner
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7-May-2012 5:08:51 PM
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Okay, I did a few investigations. I broke one section of undamaged rope at 10.7 kN, away from knots, the first pass resulted in so much rope stretch that I had to stop the test and retie it
Retied it broke at the sheath first (there may have been some minor sheath damage) then the whole shebang.
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7-May-2012 6:31:05 PM
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Do you consider that quite low Mikl? What kind of ballpark would you expect from an undamaged rope?
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7-May-2012 7:46:28 PM
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On 7/05/2012 mikllaw wrote:
>, the first pass resulted in so much rope stretch
>that I had to stop the test and retie it
Was this a permanent stretch, with little recovery ?
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7-May-2012 8:26:33 PM
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On 7/05/2012 ajfclark wrote:
>Do you consider that quite low Mikl? What kind of ballpark would you expect
>from an undamaged rope?
Dunno, it's one of those modern skinny things. strong enuff (which doesn't matter) but it had heaps of stretch (= energy absorbtion = low low forces).
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7-May-2012 8:30:27 PM
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I looked at these under a microscope, similar results to the BD investigations, these reults and the taste suggest acid. From where??
6 times maginification standard (no acid I think) rope break. Stretched squiggly fibres
6 times acid affected, clean 'brittle' breaks, no deformation
32 times maginification standard (no acid I think) rope break. Stretched squiggly fibres
32 times acid affected, clean 'brittle' breaks, no deformation
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7-May-2012 8:35:08 PM
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On 7/05/2012 mikllaw wrote:
>I looked at these under a microscope, similar resultas to the BD uinvestigations:-
>
~> so presumably your verdict (to be quite clear), is that the rope originally broke under bodyweight due to acid (of some kind), exposure/attack?
~> ~> Thanks for going the extra mile by testing the remains on this one mikl, and I find those magnified photo pics great!
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8-May-2012 9:52:22 AM
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Due to the similarity with the BD testing of an acid affected rope and the taste, it's likely to be acid attack.
I have a stack of 11mm static rope lengths that I have put various strength acid solutions on and will test them next week - results on Richard Delaney's Rope Test Lab
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8-May-2012 1:18:51 PM
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The closest I can get you to the origibnal BD report is:-
http://www.caves.org/section/vertical/nh/52/RopeBreakagefinal.pdf
Note that normal fibres break with lost of necking down and stretching, then spring back to be a fuzzy, blobby, twisted mess.
Acid affected fibres break at much lower loads and don't yeild, they look like a brittle broken piece of chalk.
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