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How much are Dyneema/nylon weaved slings affected by knots?
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By Dan Spirgen
From orem, ut
Jul 21, 2012
curious george, rock canyon
So I'm sure most everyone has seen the DMM video about breaking dyneema slings. This was done with the DMM brand slings that are almost all dyneema, except for the outside colored part. It was nice to see that the sewn runner held a factor 2 fall.

Anyways, my question is, has anyone seen any research done on the woven sewn runners like the Bluewater/spectra runner (rei.com/product/474003/bluewat... or any other mixed weave slings/runners?

I'm wondering how much a sewn mixed nylon/spectra etc runner is affected by tying it into a webolettes. I know that there are companies that make specific webolettes for this purpose, I just wanted to see if there have been any numbers out to the breaking strength after its knotted with the normal overhand or figure 8 to use it as an anchor.

Thanks

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By Greg D
From Here
Jul 21, 2012
Out of the blue.  Photo by Mike W.
All soft goods are affected by knots. 25-60% as an approximate number depending on the knot and material. Sewn slings are rated at 22kN. Even with a 60% reduction in strength after knotting most sling are still strong enough for most any situation. But, even if you tie a double, triple, over, under figure 19 knot, you're gonna die.

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By Josh Wood
From Oneonta, NY
Jul 22, 2012
hotlum / bolum route on Shasta
Here is a link to see some testing on slings, both dyneema and nylon. I was surprised how they fail. I only watched the video.

outdoorsafetyinstitute.com/ind...

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By bearbreeder
Jul 22, 2012
do you have a rope in the system? ... if so dont worry about it if the sling is in good condition

what many people fail to understand is that the DMM tests are for where there is no rope in the system ... they try to transpose the results to situations where there IS a rope ... ie anchor setups, runners, etc ... and insist that dyneema is unsafe even with a rope ... it isnt

ask yourself this .. if dyneema was truly an issue, why does DMM sell dyneema slings still ...

as for tethers, thats a whole different discussion, suffice to say that metollius is not taking the PAS off the market anytime soon as far as i know ... and people who use em aint dying in droves

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By Dan Spirgen
From orem, ut
Jul 22, 2012
curious george, rock canyon
Thanks for the input guys. Bearbreeder, yes there is a rope in the system. I do a lot of multi pitch trad and multi pitch sport climbing so I'm looking for material to use as a cord/webolette. It seems like there are a million different opinions. Right now I usually use the blue water titan spectra/nylon mixed weave sling on most climbs that are around 4 or 5 pitches or less. Any longer and I usually bring the mammut 8mm dyneema slings.

Even if I tie the cordeltte into a figure 8 knot, or figure 27 for greg d, apparently I will still die. On a serious note, I know there is a reduction in strength but as you said with the rope in the system it shouldn't be a worry. What do you guys use for multi pitch trad anchors?

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By Jon H
From Boulder
Jul 23, 2012
At the matching crux
spirg wrote:
What do you guys use for multi pitch trad anchors?


The rope, usually. There are many, many, many threads on this.

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By Scott McMahon
From Boulder, CO
Jul 23, 2012
Bocan
spirg wrote:
Even if I tie the cordeltte into a figure 8 knot, or figure 27 for greg d, apparently I will still die. On a serious note, I know there is a reduction in strength but as you said with the rope in the system it shouldn't be a worry. What do you guys use for multi pitch trad anchors?


Honestly how much has anyone read on anchor failure due to the cord material? I can't recall any. They've all been failure of the gear / rock or placement.

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By Jake Jones
From Richmond, VA
Jul 23, 2012
Me and the offspring walking back to the car after...
Here you go spirg. DMM dyneema knot tests

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By bearbreeder
Jul 23, 2012
spirg wrote:
Thanks for the input guys. Bearbreeder, yes there is a rope in the system. I do a lot of multi pitch trad and multi pitch sport climbing so I'm looking for material to use as a cord/webolette. It seems like there are a million different opinions. Right now I usually use the blue water titan spectra/nylon mixed weave sling on most climbs that are around 4 or 5 pitches or less. Any longer and I usually bring the mammut 8mm dyneema slings. Even if I tie the cordeltte into a figure 8 knot, or figure 27 for greg d, apparently I will still die. On a serious note, I know there is a reduction in strength but as you said with the rope in the system it shouldn't be a worry. What do you guys use for multi pitch trad anchors?



depends on the situation ... if im block leading ill use a cordelette or long dyneema or nylon slings ... if its swap leading, sometimes ill use the rope

what you use is up to you as long as its "safe" and it works efficiently ... everybody climbs differently ...

the nice thing about cord and nylon webbing though is that for more adventurous multi, you can use it as bail tat, etc .... without cutting up those $$$ dyneema slings

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By Derek Huff
Jul 23, 2012
Scott McMahon wrote:
Honestly how much has anyone read on anchor failure due to the cord material? I can't recall any. They've all been failure of the gear / rock or placement.


Well its conclusive. A guy who has been climbing a year or two has never heard of it happening so it MUST be impossible.

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By Jake Jones
From Richmond, VA
Jul 23, 2012
Me and the offspring walking back to the car after...
Well it's conclusive. Shitdick here ^ knows how to use the Straw Man fallacy poorly.

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By Scott McMahon
From Boulder, CO
Jul 23, 2012
Bocan
Derek Huff wrote:
Well its conclusive. A guy who has been climbing a year or two has never heard of it happening so it MUST be impossible.


Yeah you're right...funny how I've been a member of this website alone for 6 years. Please feel free to share your wealth of knowledge of anchor cord failure OUTSIDE of a lab.

And it's conclusive...you've been here for 9 days and you are making friends all over. Thanks for all your awesome contributions.

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