Dyneema/Spectra webbing lifetime?

[crackers]

A couple of random thoughts spring to mind, and I can't focus on work yet due to lack of sleep and bounciness, so I'm wasting time on the Internetz. Please forgive any agrammatic constructions. I'm sure most of you know, but just in case, I work with Dyneema, Spectra and other such fancy fibers every day in manufacturing.

 

N.B.: I do NOT work with life safety gear, my company DOES NOT work with life safety gear, and the below is strictly gossip type opinion that can not be construed as anything more than gossip.

 

Tugboat, I have reason to believe that slings are about 1/2 done with nylon and 1/2 done with bonded polyester. The poly costs a lot more, but in high UV environments, it pays off.

 

Dyneema and Spectra are chemically the same. The difference is from how the material is manufactured. The original patent on the stuff covered the manufacturing process, and by discovering an innovative way to gel spin the stuff with another solvent, Allied forced DSM's hand into arranging licensing agreements back in the day. Today, DSM has a pretty substantial production capacity in North Carolina, and the stuff is also made in Japan, Rhode Island (i think), Virginia, Germany and the Netherlands. Off label stuff is made in China and maybe Taiwan.

 

Apparently, the difference in manufacturing the fiber can have substantial differences in the durability of the fiber when made into ropes.

 

If you're serious about learning more about the dark arts of aging spectra or dyneema in slings, I'd highly recommend seeing if Kolin or Graham (no, not me or the one in Bellingham, the one in Wales) will share their trade secrets. I will say that I strongly suspect that any loss in strength you see in a few tests of old, weathered, slings are coming from very different modality than "exposure" and that they are not comparable AT ALL to the nylon/UHMWPE blends found in normal climbing harnesses and gear.

 

As an aside, Tom Moyer's article was great in 2000. And it's a great period reference to CORD. Cord is not webbing. And it's 2011: there has newer research and half the stuff in Tom's article isn't even made anymore.

 

enjoy!

[layton]

anyone notice the ad for dyneema at the top/bottom of the page?

[NotMessner]

Crackers said he works with non-rope application of Spectra. I know someone who has a Spectra Kelty White Cloud 5550 that for years has been kept in absoulute darkness, within moderate temperature ranges, and without contacting any chemical fumes. I wonder if this pack has been weakened by just the passage of time (I know I have been).

[tugboat]

Crackers....not sure what your saying in your quote about sling "composition" ie nylon and poly, in regards to my posts?. Maybe you could expand on what you are trying to say there? The slings i busted were pure spectra as well as spectra/nylon blend (no poly), sourced directly from the manufacturers for rockclimmbing .

 

You could be correct that there may be other "modalities" rather than exposure leading to the strength degradation... what do you suggest?... I just can't offer any other explanation since exposure and hand tied knots (not for climbing use) were all that the spectra was exposed to.

 

I have more salvaged lengths of that weather exposed spectra webbing, so i will sew more of it up and test,...as you would be correct in saying that 1 or two slings don't make for a great sample pool. As well... the spectra/nylon 3/4 inch sling was milled for the climbing industry.

 

Your points about DSM and Spectra are well understood.

 

All my Spectra materials came straight from the manufacturers.

(webbing, fabric and thread.... they are large, well know manufacturers from the USA (and one canadian broadcloth manufacturer) that supply both the climbing industry and military with spectra products.)

 

Anyway, just wondering what other factor do you think could be contributing to the lower break number? I'm interested in your ideas as i did not expect the lower reading. .... Perhaps speed of pull generating heat? Or the slow speed of my pulls thus lending to creep or the theory of spectra's inital/first load exposure being lower than nylon?

 

Anyway cracker's...my efforts here are to look at spectra itself,....not specific rock climbing products.

 

Furthermore....all my research has led me to much "commercial" hype and statments of spectra's durability ....but very little long time, real world tests. That is what i am trying to provide with my testing.

 

Do you have any mullen burst, or tougue tear etc type tests on new and aged spectra fabrics such as the cuban sailcloth (unwoven, fine strand spectra/mylar matrix)you use in some of your packs? Tests on old, well used samples, and new spectra? That would help us here.

 

I have not found any lower strength numbers on aged, but well stored spectra,...just (to this moment, ostensibly) on the weather exposed spectra.

 

Peace...

Edited July 9, 2011 by tugboat

[tugboat]

BY the way: Very nice Packs crackers:)

[tugboat]

Hmmm.... Yes i remember reading the Tom Moyer article once before. However it doesn't study "exposure" variables.

 

Apart from my semi-laymen testing, i have spoken with sailmakers of large racing sail making companies. They have atested to the excellent "exposure" properties that they have witnessed on ten year old sails. As well i have spoken directly to the manufacturers of both the spectra fibers i use and the material manufacturers that mill their product into the various forms i use...

 

on the old spectra harness that i tested in the video... the results were much lower that i would have expected. The pic point i pulled had never been loaded before,...and normally i would not see the a straight out pull (90 degrees to the torso) break the attatchment point at under 6000lbs. In fact i would not see the standard Wichard shackle used for stunt work (of thinner diameter) cut thru ONE half of the the vectored spectra webbings until 5000 lbs. This would have been a "worst case scenario" usage of the pic point given that i was loading only one half of the pic vs all four webs of the attatchment points.

 

In the video...one of the halves was sliced thru using a slighlty larger (than the typically used) wichard shackle at about 5000lbs. Assuming equal 4 way loading to all the strands, then the webbing was able to be cut the one half at 2500 lbs (a very low number that i have never witnessed before). Again that harness was one that had been left to the elements for about 4 years and was 8-9 years old since manufacturing.

 

That old harness also did not have the tactile texture of the original materials. While it did not have the extreme "crunchy" feel of nylon after weathering....it did have the same suppleness of the original.

[tugboat]

from Kolin Powick at the Black Diamond Quality control web site page.... 2006 however.

 

Kolin Powick

 

[tugboat]

some accelerated aging tests by Dsm and Euro textiles

 

dsm

 

euro fiber and textiles

[crackers]

Crackers....not sure what your saying in your quote about sling "composition" ie nylon and poly, in regards to my posts?. Maybe you could expand on what you are trying to say there? The slings i busted were pure spectra as well as spectra/nylon blend (no poly), sourced directly from the manufacturers for rockclimmbing .

 

Sorry, I was imprecise. I was talking about the thread used in sewing climbing slings.

 

Somebody asked if an old Kelty White Cloud would still be strong. The answer is probably. There is a lot more to it than just the spectra or dyneema fiber used to weave the fabric...coatings, thread, webbing just to start the list.

 

And as to whether I have proprietary information about the durability of different materials from scientific test methods and from field testing, the answer is yes.

 

 

[tugboat]

Graham, you suggested that my tests of my pure spectra slings in no way resemble modern spectra blends. in terms of "modality", i may concende your point. However, the tests were only to look at and isolate spectra fiber aging by itself... not to replicate current climbing spectra blend slings. But in this manner i can't see any issues with my aged pure spectra destruction tests. Please point some out if you can see some.

 

Now, today i found some of my old spectra/nlon blend climbing webbing that i got from the manufacturer, that had been left outside in the elements for the last 4 years. It is climbing webbing milled for a USA climbing gear manufacturer that the original mill allowed me to buy to test for my applications. For the gear companies privacy, i won't name them here. But suffice it to say, it is a,legitimate, mainstream climbing company.

 

Now, i have the old weather exposed webbing, and i have this same original webbing lot, on the spool, at my shop. The spool was properly stored for the last 8 years, since i received it. So a sling destruction test of the exposed material and the original, well kept webbing material, should be a good age effect test, as regards the elements....no?

 

On that note, im off to the shop now to tack up some slings for the test. Hopefully i can test them today too....if the darn rain doesn't start.

 

I will post video of the pulls when i finish them.

 

peace.

 

[JosephH]

I used, and then had tested, Mammut 8mm dyneema slings over a four year period. I used the slings in my climbing at Beacon Rock for approximately seven months each year. Bottom line is that by the end of year three they, on average, ended up breaking at 8-10k. That's less than 50% of their original rating.

 

Mammut said they make such slings for fast-and-light alpine applications and that we should consider them a 'consumable' item in that application. They are not and should not be treated like nylon slings which have a much longer usable life span.

[stevetimetravlr]

[tugboat]

Ok. So i just finished 4 hours of pull testing my sewn up samples of weather exposed vs well stored spectra/nylon blend climbing webbing. I established a baseline strength of a well stored webbing sling,... and then busted about 8 weather exposed slings. THe exposed slings have never been used in climbing or loaded in any way...the material was just left outside for the last 4 years...year round.

 

In general i found on average a 33% decrease in the weather exposed slings than the well stored, unused, sling material.

 

Just for kicks, while i was at it, i broke some new Blackdiamond carabiners. And i broke some Kong carabiners. As well i did some more esoteric tests, like busting a single bartack, trying to bust knotted spectra blend climbing slings (two different mills webbings) and i busted some parachute buckles.

 

I shot everything in high def 60fps. I just need to edity the footage and upload it to you tube for those of you interested.

 

First though, i need some coffee and food....'cause that was alot of work!

 

Should have it done in a couple hours.

 

[tugboat]

Ps....alll the webbing well kept webbing was off the spool and is about 7 or so years old.....from two differnet manufacturers/mills.

 

Also note: that while i found a 33% drop in strength in the spectra blend slings.... i have found a greater decrease in nylon slings from weather exposure. Spectra, in my findings, does endure the elements better than nylon (as manufacturers quote and other lab test have shown.). But this only speaks to weather 'exposure' over a long period of time... nothing else.

 

My test of pure spectra slings was to try and determine if the spectra was also being impacted upon by the elements,....or if the weak link in the spectra blend slings was just the nylon. So far, i have found that there is 'exposure' degeneration of spectra but not age degeneration. But i have found nylon weather exposure degeneration to be greater than spectra's.

 

This is too only speak of spectra material compositions from eight years ago; not to make conclusions of newer formulations of spectra or dyneema. The spectra in my pure spectra slings was the same spectra being woven into specrta blend climbing slings of the time.

Edited July 18, 2011 by tugboat

[JosephH]

It should be noted that it isn't weathering that takes a toll on dyneema slings but rather the repeated bending. Mine were used as trad draws and as such went through many repeated bending cycles. I'm guessing a straight weathering test has interesting results, however, it's probably unwise to use dyneema slings that long due to breakdown associated with repeated bending and flexing.

[tugboat]

Well Joseph...in my samples there has been no bending at all. The spectra just hung out in the weather for four years. And the new stuff from the same lot just sat on the spool for 7-8 years. Actually spectra's flex fatigue is pretty good from my studies. Kevlar, on the otherhand, being a fibourus aramid, has a significant flex fatigue problem compared to spectra.

 

However,... i have found studies showing that nylon is superior to spectra in the flex fatigue department.

 

In terms of Nylon having a longer more useable lifespan,.... i would think it all depends on the care taken with each product. Nylon has a tremendous shelflife as does Spectra. Nyoln has been shown to be able to absorb more punishment overtime due to its elasticity. But on the otherhand, if its not well cared for its no better than spectra or anything else for that matter....IMHO and tests. Indeed nylon does not endure the elements as well as spectra, but it does put up with flex better.

Edited July 18, 2011 by tugboat

[tugboat]

http://www.youtube.com/watch?v=ODni9l8TLRw Old Spectra Web Find

 

Baseline test

 

Another baseline test....using a thinner shackle.

 

1st weathered test

 

2nd weather test

 

3rd weather test

 

More to come/upload... including the "reaaders digest version of all the tests". lol.

Edited July 18, 2011 by tugboat

[tugboat]

reader's digest version of all the spectra pull tests in one video....