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Fishy
climber
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Topic Author's Original Post - Sep 3, 2007 - 05:58am PT
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I have read in many places about how the climb-spec webbing is more cut resistant than the older mil-spec.
It got me thinking, have there even been any tests done? For example, how would a loop of climb-spec webbing through a bolt hanger compare with a loop of 7 mm cord for cut resistance?
Anyone have any experience with this? Seen any data?
Cheers
Fishy.
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Majid_S
Mountain climber
Bay Area
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This is what I think but I would like to know if anyone else agrees or disagree it with this.A 7 mm cord is related above 2200 +- lbs and the 1 inch webbing is rated to about 4200 lbs +- . Assuming the inside of the hanger is clean and it has smooth edges, the radius and the stress from bending the cord thru the hanger makes the cord weaker during pull test. On the other hand , the tension stress on the webbing is distributed in a larger flat area within the hanger therefore, it slightly has a better chance to survive than cord .Now ,if we had a 4K lbs rated cord and a 4K lbs rated webbing , I am guessing webbing still survives better than cord .
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dirtbagger
Ice climber
Australia
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Pete,
have you seen the info from BD, which did a bunch of tests, as far as I remember, on old slings etc! Also some new info about the Mammut micro slings (the ones I had last wkend), and how if they are damaged at all, they seem to cut themselves very easily!
see ya in the valley on the 23rd!
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Fishy
climber
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Topic Author's Reply - Sep 4, 2007 - 07:10am PT
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Good point about the difference in strengths - I just wondered if the comparison was a fair one, given that the structure/construction differs significantly between cord and webbing.
There is also the argument that you see far much more webbing for rap slings than cord...
I just thought that given the continual references to more cut-resistant webbing, there must have been some tests.
Thanks for the suggestion for the BD tests Arun - I will go and have a hunt. See you in a few weeks in Yos!
And coiler - you better come to the Sushi fest, and I will regale you with all the tales about how I got my Fishy monicker...
Cheers
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'Pass the Pitons' Pete
Big Wall climber
like Oakville, Ontario, Canada, eh?
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I know nothing of tests or physics regarding these things, but I can tell you experientally that webbing is hugely more abrasion resistant than cord. I don't know if it's because of the shape [wide and flat vs. round], the relative strengths of each, the static webbing vs. dynamic cord, or that the webbing is more slippery across an edge, or a combination of some or all of the above.
Tom used a lovely edge-test-rated lead rope - our beloved Kingsnake - for a hauling anchor at the top of Excalibur, and sawed a core shot through it. A piece of webbing would have had barely a scratch.
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Phil56898079
Boulder climber
New Mexico
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I still remember one inch webbing cutting half way through. It sounded like a pair of jeans under stress ripping. Just a sharp edge and a pendulum fall. I'm not an engineer, but from personal experience, and just looking at it: Webbing over an edge? You've got to be kidding.
Interesting you think otherwise. I'd think that just because rope rolls, that would be an advantage. I would guess that the sheath would have a lot to do with it. But I guess we have to leave that up to the engineers. Only problem is, we have to believe whatever specs the outdoor industry gives us. Not that anyone there feels under pressure.
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Fishy
climber
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Topic Author's Reply - Sep 5, 2007 - 05:30am PT
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So it doesn't seem that anyone can remember seeing tests of slings and webbing through bolt hangers.
I have shot a mail off to Bluewater to see if they have some more background to their climb-spec webbing claims, and also to BD, in case their testing guys have any thoughts.
I will let you know if/when I get a reply.
Cheers
Fishy.
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'Pass the Pitons' Pete
Big Wall climber
like Oakville, Ontario, Canada, eh?
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Sample response:
"Dear Fishy Pete,
Do not under any circumstances put nylon through a bolt hanger and expect it to hold. Use a carabiner, you cheap bastard."
Phil brings up an interesting point. Years ago I was having a discussion about abrasion of fixed ropes with Mike Boon, an eccentric caver who makes Chongo appear almost normal. However Mike had a lot of real-world experience in the deep and nasty river caves of Mexico, like Sumidero Yochib.
We were talking about the old-school Goldline rope, which is a "laid" rope, and comparing it to the new-style kernmantle caving ropes. Mike's premiss was that he felt the stretchy Goldline rope - which bounces like crazy when you jug on it - would be more abrasion resistant precisely because of its stretchiness.
Grabbing a piece of rope, Mike laid it across the edge of a table to simulate a fixed rope across a ledge. He put tension on the rope with his hands.
"Here's a piece of Goldline," he said, rubbing the rope up and down in two- or three-inch oscillations across the edge. "When you're climbing it, the abrasion is over a very wide area. Sometimes the rope will bounce a six inches or more across an edge."
Then he held the same rope across an edge, but put very small oscillations in it to simulate a static kernmantle rope. "With this type of rope, the abrasion is confined to a very small area, and will cut through in no time."
Thoughts?
He definitely has a point, however static kernmantle ropes have completely replaced Goldline in virtually all applications - especially caving - perhaps only because of its incredible strength approaching six thousand pounds.
This example may not be analogous to Pete's, because the sling or cord through the bolt won't be bouncing at all.
[I'm still not sure why anyone would ever want to put a sling or cord through a bolt hanger - did I miss something? Is the hanger too small for a crab?]
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knudeNoggin
climber
Falls Church, VA
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> Also some new info about the Mammut micro slings,
> and how if they are damaged at all, they seem to cut themselves very easily!
What new info is this?
(Not the Sherman myth, I hope.)
HMPE is quite difficult to cut, as fibres go.
*kN*
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G_Gnome
Sport climber
Everywhere, man...
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First, just because the ascender is bouncing 6 inches, I would never assume that the rope at the contact point was also bouncing much at all.
I think to a large degree, webbing is used for rap slings off bolts more because it still allows a biner to fit into the bolt than anything else. Also because traditionally runners were always made from webbing so it was what we had available to use/leave for rapping.
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TradIsGood
Happy and Healthy climber
the Gunks end of the country
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PtPP
I know nothing of tests or physics regarding these things, but I can tell you experientally that webbing is hugely more abrasion resistant than cord. ...
Tom used a lovely edge-test-rated lead rope - our beloved Kingsnake - for a hauling anchor at the top of Excalibur, and sawed a core shot through it. A piece of webbing would have had barely a scratch.
WTF. "Would have"! Nothing "experiential" about that. That is just an assertion of what you happen to believe. Not saying that your assertion is right or wrong, but your anecdotal claim is junk.
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wootles
climber
I've moved
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Cut resistance and abrasion resistance are not the same thing.
Climb spec webbing is basically a reinvention of mil spec. The difference being the denier of the fibers and the number of strands. If it actually is more cut resistant than mil spec it's because there is simply more material to cut.
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knudeNoggin
climber
Falls Church, VA
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Bouncing in ascending (or descending) in caving is a bad thing,
and how much movement there is at a point of contact depends where
that point is. If it's up near the anchor, the less bounce of the climber
and less stretch of the rope should limit the movement a lot, and also
abrasion. (Having 6_000# strength is not helping all so much.)
There was one reported case of a climber testing the feared sawing
effect of climbing rope through a typical sling; he used old rope and
practised essentially a StairMaster routine with the rope through the
sling: and the sling won !!! --so there's a dramatic difference in
area of exposure, but with results opposite to what one would expect.
(Now, the sling was also hurting after this, but it was connected.)
(And I recall another poster saying that this had been seen before,
but usually it has the opposite results.)
In _Outdoor Knots_, it's stated that "it is important to
realize that webbing is nowhere near as abrasion resistant as rope.
One study showed that 1-inch nylon webbing had only a quarter
the abrasion resistance of 9mm dynamic rope with the same
tensile strength."
(To another remark (maybe in another forum) about the effects
of UV and relatively thin webbing, the book remarks "polyester
is now used for nearly all seat belts."
*kN*
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Fishy
climber
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Topic Author's Reply - Sep 6, 2007 - 02:59am PT
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I got an answer back from Blue Water:
"The improvement of the climb-spec webbing vs mill-spec webbing has been documented in regard to abrasion resistance. We have no data on cut resistance as I have no knowledge on any recognized test that would provide such data. There is a definite improvement in the resistance to abrasion due to the weave pattern. How, this would relate to cut resistance, I have
no information."
Of course, they didn't offer any info about how they tested abrasion resistance, and so I asked them for more info about that.
As for leaving a biner through a bolt at a rap station - no thanks! And it seems I am not alone in this - even in the John Long anchors book, there are heaps of images of webbing through hangers for rap stations...
And yes, I am still a cheap bastard. Just trying to see if I can retain my cheapness, whilst minimising the risk of a gruesome/squishy death below a rap-route somewhere...
Fishy.
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Anastasia
Trad climber
California
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Hmmm....
Just waiting for Largo to put in his two cents. I learned how to set up anchors through his books so I consider him one of the most important teachers of my life. Without his work, I might not be here.
So Largo, where are you?
Anastasia
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G_Gnome
Sport climber
Everywhere, man...
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We have all been rapping off webbing for 50 years, at least. No one has died from it unless the webbing was old and rotten. Safe enough is safe enough. Worry about things that matter.
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BeeHay
Trad climber
San Diego CA
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Duh...use the tail of your knot to pad the hanger...you do carry one knotted sling don't ya'll?
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'Pass the Pitons' Pete
Big Wall climber
like Oakville, Ontario, Canada, eh?
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Awright, awright....
[edit]In my experience of having built and hauled huge loads on HUNDREDS of belay stations built in every conceivable situation from every conceivable material, it is my very strong belief that in the same situation, a sling would have suffered barely a scratch where Tom's rope received a core shot.[/edit]
OK, now I get it. You want to rap off the bolts. Hmmm, I would be inclined to use flat webbing, since I like the idea of the bolt hanger running across the entire width of the tape, rather than tangentially on the edge of the cord, which of course will deform to become thinner and wider, but never as thin and wide as webbing.
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Fishy
climber
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Topic Author's Reply - Sep 10, 2007 - 06:07am PT
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Bluewater were prompt with their reply to my second enquiry about how they tested abrasion resistance.
They described that they constructed a test with an abrasive wheel and an edge of "known radius", and then counted cycles to failue in different types of webbing.
However they said that because that there is no standardised test, that the results (and it seems also the details of the test) are not something they will make public. A pity, as it seems that many claims and beliefs are being based on tests and results which aren't publically available.
Kolin at BD also replied, and helpfully described some of his tests. Although he said he hasn't done enough testing to be conclusive, indications in the abrasion tests he has done indicate that flat (e.g. webbing) is better than round.
He hasn't tested relative strengths through a bolt hanger, and said he would probably be able to do that in the upcoming weeks.
I also suggested a cyclical loading test followed by a pull to breaking strength, to see if repeated moderate loads on a loop through a bolt hanger weaken cord more than webbing, or spectra more than nylon.
He said that he has had some results showing that spectra is more resistant than nylon...a suggestion I would not have expected. We'll see what comes back from some more tests.
Pete.
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TradIsGood
Happy and Healthy climber
the Gunks end of the country
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Sep 10, 2007 - 02:54pm PT
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Drift alert -
I used some webbing for an anchor around a pine with lots of sap. I figured I would probably just pitch the webbing afterward. I tossed it in with laundry just for the heck of it, and it came quite clean - no sap.
But, it also went through the drier, before I noticed that it was clean.
So, did the temperature of a normal laundry cycle damage it in any non-visible way?
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