dyneema, nylon and mixed slings ...

from the DAV

- dyneema slings lose strength quicker with use than nylon or mixed ... after a few years ~50% of dyneema slings test under 16 KN

- fuzziness is a good indicator of the strength of a sling ... if its fuzzy like a bear its time to retire

- retire dyneema slings after ~3 years of use ... and even if rarely used no greater than 5 years or so

- thicker dyneema slings are stronger after use (even if they are rated the same when new) ... for example 10mm dyneema loses a bit less strength than 8mm dyneema (the weight savings are minimal)

- nylon and mixed may last longer with minimal use ... but even they should be retired after a few years if used heavily

alpenverein.de/chameleon/pu…

DAV panorama

personal note ... even a sling that loses half its strength on a cam is still rated more than many of the smaller cams out in the market, so its probably not something that will kill you right away ... but its not a bad idea to resling those suckahs

;)

but those are german slings, what about american slings?
(/s)

great find bear, thanks for sharing

I don't understand the bar graph. I see that green is full strength and red is very weak but what do the numbers on the side mean.

rocknice2 wrote:I don't understand the bar graph. I see that green is full strength and red is very weak but what do the numbers on the side mean.

I believe the numbers to the left of the bar graphs represent the percentage of slings that scored in a particular category during a test. The first bar starting from the left is green and at 100, representing all (100%) of the slings from that particular test.

For those whose google translate-fu is weak sauce ...

The vertical axis is the % of slings tested

The horizontal axis is the number of years

The colour is the strength according to the posted legend

So in short over 50% of dyneema slings fail to meet 16 KN after 5+ years ... While most nylon ones stiil do

In less than 5 years 100% of nylon slings tested to 22 KN where over 40% of dyneem ones failed to meet 16 KN

I use dyneema daily climbing but then i retire em in 2-3 years generally ... Mixed slings may last somewhat longer

This however may not account for long term environmental exposure .... Thats a separate article which ill post up later in the week after my lazy climbing

;)

and this is why i use nylon and question BD's ultra light cams. Given the ultra lights do have special protection around their dyneema but still do they loose 25% of their strength after 3 years??? or is all the strength lost purely due to the sun that they are being protected from.

Why can't those damn germans use XMLs or post results online, where google translate can just do the whole document. it's as if they're trying to keep their results to themselves.

On a more relevant note, this is why my "spectra" slings are the Bluewater Titan slings (13mm IIRC). minimal increase in bulk/weight with big increase in durability. plus I don't like the amount of space the mammut bartack takes up.

Also a question:
Would a spectra sling with a the diameter of a nylon sling be more or less durable than a nylon sling? Properties of spectra would say yes but my intuition says that, if it were true, we would see some thicker spectra slings being made.

I guess the question is if their loss in strength comes from abrasion and UV or from stress strain cycles and low elasticity.

I have 3 year old dyneema shoe laces...will I die?

Ray Pinpillage wrote:I have 3 year old dyneema shoe laces...will I die?

most definitely

Sooooooo, does Dyneema degrade because of age alone, duration of exposure to UV, other environmental factors? Seems like if we're going to be all sciency we could define what's causing the reduction of strength.

Here is something fascinating written in English.

fibtex.lodz.pl/2011/1/60.pdf

Ray Pinpillage wrote: duration of exposure to UV,

Dyneema has strong resistance to UV, much stronger than nylon.



Spectra is what you are looking at.

The Data is correct but your implication is wrong nonetheless. Even though spectra is more resistant to UV than Nylon, the rays don't penetrate Nylon material and therefore don't weaken the webbing that much. With spectra it's the opposite. UV goes right through the webbing affecting all strands. That does weaken the whole sling a lot more. Most decrease in breaking strength of Dyneema comes from UV.

There's a best of breed thing called TechWeb by Edelrid. It has it's downsides as well, because Nylon is less slippery and Dyneema doesn't stretch. So in climbing scenarios like anchors it's effect is even more static than Dyneema itself due to its less smooth surface.

So instead of the usual "should I retire my rope?" It's going to be should I retire my slings?

Bill Kirby wrote: So instead of the usual "should I retire my rope?" It's going to be should I retire my slings?

Ever notice that BD, DMM, Petzl, WC, Etc pull test everything and do environmental studies on gear available on the market? Ever notice how there is an absence of available data for Dyneema strength loss? There's not an actual absence of testing, Dyneema is used in bulletproof vests and accelerated environmental studies have been performed as I posted.

I know what you're thinking though, an absence of evidence isn't evidence in and of itself. You're right Bill, but there is a correlation between the lack of publicly released testing and the need by manufacturers. Further, if this were such an overwhelming problem we'd see injuries or deaths but we don't really.

Zeeee German's study seems poorly thought out from what I can extrapolate from BB's loose translation. Their graph is unreadable and I can't see any controls or causes. I think I'm going to call this one a swing and a miss.

The wear in dyneema comes from 3 sources

- abrasion

- constant flexing and knotting (which is a well known phenomenom for over a decade woth spectra/dyneema)

- environmental degradation, which is covered in another article

Just because one barely uses his dyneema slings and thinks theres never any an issue doesnt make it true =P

The quicker wearing of dyneema has been known for years ... Its no surprise

In climbing the slings we use are subjected to constant abrasion and and knotting ... Now i dont know if bulletproof vest are but i suspect we dont tie those into knots ... Isnt the dyneema in those vests covered as well

Ill post up the environmental article after i finish this thing called climbing

The simple fact is that if you use yr dyneema slings decently you should be retiring them after 3 years or so, 5 years max

Now if they sit around while you argue on MP rather than climb .... Well i wont guess as to what you should do except go climb

As to the graph if you cant read it then you simply need to try HAH-DAH ... The DAV is fairly respected not to say they are perfect ... But then perhaps other folks have their own sources of first hand information on test on dyneema used in climbing applications

;)

bearbreeder wrote:Just because one barely uses his dyneema slings and thinks theres never any an issue doesnt make it true =P

Please provide a citation to support your assertion that minimally used dyneema degrades over time (assuming no obvious signs of external wear).

bearbreeder wrote:The simple fact is that if you use yr dyneema slings decently you should be retiring them after 3 years or so, 5 years max

This statement conflicts with the above statement.

Ray Pinpillage wrote: Please provide a citation to support your assertion that minimally used dyneema degrades over time (assuming no obvious signs of external wear). This statement conflicts with the above statement.

Please provide a source to support yr claim that dyneema life in climbing applications doesnt matter there ray

Perhaps you should READ the actual article before going off on it... They five specific examples in it

Perhaps you dont use yr dyneema slings where there will be wear ... After all you cant wear out yr climbing gear unless u actually climb

;)

bearbreeder wrote: Please provide a source to support yr claim that dyneema life in climbing applications doesnt matter there ray Perhaps you should READ the actual article before going off on it... They five specific examples in it Perhaps you dont use yr dyneema slings where there will be wear ... After all you cant wear out yr climbing gear unless u actually climb ;)

I'm making no claims. You could be right, I just want proof. The German "test" was pretty full of holes from what I can see.

Also, there is a correlation between the use of Dyneema in bulletproof vests and climbing equipment. One of the measured factors is time in service (accelerated). They tested new samples but did not test non-accelerated aged samples. If time in service is basically environmental exposure, how does that correlate to samples aged without exposure if at all? My point is that while I think you are well intentioned to say the service life of Dyneema is 3 to 5 years I don't think there is a linear extrapolation from date placed into service until retirement because environmental exposure aren't static. In other words, "barely used" Dyneema should not degrade at the same rate as "decently" using a similar sample unless time is a contributing factor to degradation. If we're making the assertion that time is a contributing factor I would like to see a study concluding such results.

bearbreeder wrote:After all you cant wear out yr climbing gear unless u actually climb ;)

I'm glad you're starting to see my point.

Ray Pinpillage wrote: Ever notice that BD, DMM, Petzl, WC, Etc pull test everything and do environmental studies on gear available on the market? Ever notice how there is an absence of available data for Dyneema strength loss? There's not an actual absence of testing, Dyneema is used in bulletproof vests and accelerated environmental studies have been performed as I posted. I know what you're thinking though, an absence of evidence isn't evidence in and of itself. You're right Bill, but there is a correlation between the lack of publicly released testing and the need by manufacturers. Further, if this were such an overwhelming problem we'd see injuries or deaths but we don't really. Zeeee German's study seems poorly thought out from what I can extrapolate from BB's loose translation. Their graph is unreadable and I can't see any controls or causes. I think I'm going to call this one a swing and a miss.

I hear ya! The more I fall, hang and claw my way stuff the less I buy that the sky is falling.

Did you see the latest .2 X4 explosion? If my fat ass can hang from one than those cams are good enough for me.

To put it simply ...

The only reason many of us ignore the 10-15 year manufacturer recommendation for ropes retirement even if unused is because

- the UIAA did a study where they tested a whole shietload of ropes and found that if they were in good tactile and visual shape, all of em held at least one UIAA drop test .... Even 20+ year old ones ... As long as there was no chemical exposure

- there has yet to be a documented case in recreational climbing where a rope in good condition broke (not cut) except where there was chemical exposure

As far as i know there has been no such documented study on slings saying for example that even a large sample of 20+ year old dyneema slings im "new" condition is "safe"

Until we see such from a body like the UIAA, we should probably follow the retirement guidelines for slings ... Which is generally 10 years if unused ... If yr a climber who never uses their gear of course

If one climbs rather than yaps on MP the retirement would be much sooner especially for dyneema

Its a fallacy to believe just because a company like BD doesnt say "oh old lightly used slings arent unsafe" and they havent published tons of studies ... Means that its "safe" to use such ....

Heres what BDs director of quality control said
....

Now I wish I could say that we've done some high-tech super study on this stuff, but we haven't. We've tested old fixed gear (as stated above), and also helped a high school student do a science fair project a few years ago on the UV effects on slings.

Basically the best they have is someones high school fair project !!!

blackdiamondequipment.com/e…

The absense of safety data doesnt mean something is safe =P

Now for those who cant be bothered to use google translate-fu ... The DAV does have a short ingrish paper on slings ....

DAV

alpenverein.de/chameleon/pu…

Now some folks might think "hey 13 KN thats still SAFE" ... But lets take a real world example

You set up a rap with a sling extension ... Girth hitch that sling to yr harness and tie and overhand knot for the rap device ... A very common thing to do ...

Youve now cut the strength in half of that sling with the hitch and the knot to ~6 KN ... Is that enough of a margin for you if you slip at the rap station (or if you pull up to test yr rap and its screwed so you take a short fall on ur tether) ... Thats yr call

Ill post up the environmental factors article in a few days when im not on my iphone ... Just finished climbing and my beahs r V HUNGRY !!!!

;)