tugboat

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

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.

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.

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.

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.

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.

some accelerated aging tests by Dsm and Euro textiles dsm euro fiber and textiles

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

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.

BY the way: Very nice Packs 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 . 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...

Well....time to eat some crow. While in the past i have found well used and exposed spectra to maintain significant strength (up to 90% in specific cases....not climbing); todays tests show definite loss of strength when exposed to severe, year round conditions (snow,rain,sun). I tracked down some 3-5 year exposed pure spectra and tacked some slings for testing and compared to new spectra. I only did a couple of tests. But i found that in general that the highly weather exposed spectra was 65-70 percent the strength of the new spectra sling. I also recordered the knot slipping potential of a hand tied spectra sling for anyone interested. Furthermore, what is interesting as regards spectra shelf life, is what i found looking back at the brand new spectra breaking strength as compared to today's "new" spectra sling comparison sample. The "new" spectra sling material from today was taken of the roll from a batch that i stored in good condions from eight years ago. Looking back at test samples from that eight years, i found there was no change in sling strength (at least when pulled over an 8mm pins (UiAA calls for 10mm) at all. In 2003 i measured samples breaking at 5450 pounds, and today at 5500lbs over the same shackles. here's links to the videos: [video:youtube] [video:youtube]

For those interested, i have started a Blog on Stunt harness manufacturing (as this is my area of expertise). Since i came from a climbing background and then transitioned into film work.... the Blog will have applicable material to climbing sewing theory and practice. The Blog is just in its infancy. But i will try to work and ad to it everyday for this interested in following. This blog is presented as educational/information source, rather than a promotion of my company. http://stuntharness.blogspot.com/

jfs1978, no problem...its academic and practical for me too. Since i need to know the academics to get my product and knowledge correct for the customer. I guess the main reason i piped up on the spectra life issue is that the question has been popping up in my industry. I now have product returning to me that is 8-10 years old. It's entirely made of spectra fibers, and people are replacing them with new harnesses. IN exchange i get to bust the old ones. I've been finding full to over 90% strength much of the time (not all the time) But ten years ago i built things way overkill (read; liability). As the years have past and advanced materials and engineering have progressed.....manufacturers have found that they can pass "standards" using less and less material. THis, while still strong, leads to "life" or "durability" issue. In a way that's how i see the thin "ultra tape" (nylon/spectra) blend sewn slings climber's are using: you can decrese the size and weight of the product and meet specs.....but at what longterm cost? Rock and Ice did an interesting arcticle that might apply here: http://rockandice.com/articles/how-to-climb/article/494-busted Also the reason i mentioned "before and after" tests....is that i have found, on occasion, that some slings, and several harnesses, dont meet there rated UIAA specs when bought brand new.... this can be for several reasons....that i wont go into here (it doesnt mean they are unsafe). So if you don't have a real world average before the test, the "after" number is based on someone elses #'s. its all academic at this point. The stuff is so over kill... In all my testing, climbing and building the number one thing i have learned is inspect your equipment regularly and leave at least 3-4 inch tails extruding from any "joint" eg tighed water knot, double passed buckle etc.... without this tail your putting yourself in danger. F

Remember "bartacking" is quite particular to the climbing industry.....originating from modified blue jean bartackers. There are pros and cons to bartacking. Too big a topic to get into here. But the majority of the safety sewn goods industry do not bartack (for good reasons)...They use safety stitches developed over years of proven technique in industries such as Parachuting, sailing, Rescue Harnesses, Rigging and so on. Bartacking has its place, but it can be used incorrectly esecially when strength sewing webbing to fabric. Box X and multi point "W" stitching can be superior depending on the circumstances... You don't need a bartacker to strength stitch in general. Another good book is the "Parachute Manual"