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Tensile testing old slings
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I'm replacing all the soft goods in my rack, the majority of which is in the 7-10 year old range, part of that is runners and dogbones. Anyone have access to a tensile tester and want to see where they line up? I'll have 8 bluewater titan runners (27kn rated) and 8 omega pacific nylon dogbones, all visually fine, just old. I'd love to know how well they aged. |
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If you want to send them out to Seattle I could pull test them. |
Larry S wrote: Hey Larry, I am really curious about what you find in the event that you get your stuff tested. I have a bunch of similar gear (similar age) that I wonder about. If you get something tested, please post up what you find! Cheers. |
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I’m also very interested in what the results would be. Please share if you happen to find out! |
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Agreed!!! |
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I'm also interested to see the results if you get 'em tested. It would be even more helpful if you were to label and photograph them so we can see the level of wear and tear and how that correlates to breaking strength. I'd also be happy to chip in a buck or two for shipping costs and if the rest of us did as well then that should cover all of the shipping expenses. |
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Bury 1 and leave 1 each outside in the sun until you send them maybe. |
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I've PM'd Dante regarding his offer. I'll go thru and document everything I know about the gear and take detailed pictures of them before I send them out. |
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based on that, looks like fat nylon quickdraws are the way to go. |
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Subscribed since I’m in the same boat as everyone else. I don’t think I ever just replace a sling or dog bone due to age. Don’t pay much attention to they look ratty or dirty. |
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Sub’d |
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I honestly expect to see that these are all at or very near rated strength. I built most of my rack from 2007 and 2009. It saw a decent amount of use the first 6 years, but I don't get to climb outdoors much anymore as I've got 4 young kids at home now, so mostly it sits in storage and comes out a half dozen times a year. The dogbones have many more falls, the slings just a few, but the slings saw much more time on rock, occasional knotting, used as a prussik once or twice... No significant uv exposue. It's just at the age where I have doubts about it and I'd like the peace of mind of fresh webbing, and I can afford it now, so that helps too. I think many people are in the same boat. They have older gear, used, but taken care of and otherwise in good shape. Manufacturers are recommending 3-5 year life expectancies. I want to know what the reality is with normal use. |
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I will predict, based on tests of my slings, you'll see 12 to 16 kN breakage. |
Gunkiemike wrote: I´ve tested loads of old slings and dogbones over the years, 13-16kN is normal for anything that´s been used, stuff that´s been left on the cliff for 20 years is worse! |
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ooooh, this should be interesting. sub'd too! i'm using relatively old dog bones as well and depending on results I may be inclined to replace em... |
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Let me throw this out there... I'm finishing up my PhD in engineering. I will (hopefully) be starting as a faculty next year and I am always looking for projects for classes that have real world applications. Would the community be interested in an ongoing 'service' of taking in old or failed gear and testing/destroying it if the results were cumulatively published in some easily accessible way? I think that would be a great ongoing project that would be a great way for students to get hands on experience writing up failure reports. |
Todd F wrote: Yes, that would be great. A lot of this kind of thing is currently done my manufacturers but the results are often given only to the person sending in the gear, as opposed to having that information available to anybody. One thing that would be helpful is to make sure you label and document the condition of gear before you test them, preferably with photos, so that we aren't just looking at numbers without any context. |
eli poss wrote: Cool and definitely. OP, if the first comment doesn't work out, PM me and We can start something. Same offer extends to others. You want old gear destroyed or broken gear analyzed? Send me a PM. |
Todd F wrote: I'd be very interested. I haven't heard back from the second poster yet, if that falls thru I'll reach out to you. We could split the testing between you two potentially, see if we get reproducable results... |
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Larry message sent |
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Several years ago a friend of mine was able to test some slings that I retired. They were roughly 5 years old and dyneema. They had seen moderate use (once or twice a month) and caught some falls, but they were stored indoors and didn't have any obvious damage. I believe he only tested 2 or 3, but they broke between 16kN and 17kN, which is about 75% of full strength. That's a small sample size, but results are similar to what Gunkiemike and Jim Titt have found with much more testing (mine were on the high side). I think you will find similar results. Slings degrade with time and use, and especially with exposure (as demonstrated by the Black Diamond data linked above). And that's a good reason to periodically replace old soft goods. But it's also worth comparing the numbers to other parts of the climbing system. A large (.75 and up) full-strength C4 is good for 14kN. Medium sized stoppers are 10kN. Small cams are rated at 8kN and less. If you're OK falling on good gear, you should be OK with 5 year old used slings even though you know they have lost significant strength. For me, the main takeaways are... 1) Don't expect your slings to be full strength 2) Don't let that bother you 3) Despite #2, replace your slings when they're really old and ratty and they start to bother you 4) Don't trust soft goods left outside with unknown history. Glad to see folks testing gear. I will be interested in the results. |
