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fresh


Aug 26, 2007, 1:33 PM
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nylon life
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I recently had an argument with a climbing friend over nylon webbing's lifespan. I had rigged up a sliding X that we could quickly clip into toproping bolts. I used 1-inch webbing that had been purchased in 1999 by the boy scouts. I know for a fact that the webbing has never been used for anything but swiss seats and has spent about 7 of its 8 years locked in a dark, dry (but sometimes very cold) shed. he was sketched out by it, and although I wouldn't take it on a multipitch climb, I felt it was fine.

long writes about some tests that were done on webbing left on rapping anchors, and it seems that although most of the slings were fine, they were pretty inconsistent. but does webbing naturally break down over time regardless of use and wear?

fwiw the X was too small and I used a quad because, well, you can't mess with the quad.


joeforte


Aug 26, 2007, 3:38 PM
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Re: [fresh] nylon life [In reply to]
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fresh wrote:
he was sketched out by it, and although I wouldn't take it on a multipitch climb, I felt it was fine.

If you felt it was fine, why wouldn't you take it on a multi-pitch climb? Do you think the webbing cares how many pitches there are?

If you have to use it, use 2 sliding X's, so there are 2 independent points of failure.

But dude, webbing is like 30 cents a foot. Isn't your life worth the $3 it would cost for 2 new tied slings?


coastal_climber


Aug 26, 2007, 4:25 PM
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Re: [joeforte] nylon life [In reply to]
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joeforte wrote:
fresh wrote:
he was sketched out by it, and although I wouldn't take it on a multipitch climb, I felt it was fine.

If you felt it was fine, why wouldn't you take it on a multi-pitch climb? Do you think the webbing cares how many pitches there are?

If you have to use it, use 2 sliding X's, so there are 2 independent points of failure.

But dude, webbing is like 30 cents a foot. Isn't your life worth the $3 it would cost for 2 new tied slings?

What he said.

If you are concerned get new webbing.

>Cam


Basta916


Aug 26, 2007, 5:06 PM
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Re: [fresh] nylon life [In reply to]
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If in doubt, your partner or you ( if something makes you uncomfortable, or him), dont use it....nothing can replace a peace of mind on a rock...


fresh


Aug 29, 2007, 8:55 AM
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Re: [Basta916] nylon life [In reply to]
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thanks dudes. but I want to make sure--does nylon break down on its own over time due to magical/unknown factors? or is this hogwash?


ja1484


Aug 29, 2007, 9:01 AM
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fresh wrote:
thanks dudes. but I want to make sure--does nylon break down on its own over time due to magical/unknown factors? or is this hogwash?


Even under ideal conditions, Nylon loses about 2% of its strength per year via very slow chemical breakdown. Use, abrasion, UV light, cycling loads, and other wear and tear that are normal further decrease the strength.

I retire my soft goods every 4 years or whenever they display key red flags (nicks, cuts, excessive abrasion, discoloration, etc.). Closer to 1.5 - 2 years for high workload items like ropes.


fresh


Aug 29, 2007, 9:16 AM
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ja1484 wrote:
fresh wrote:
thanks dudes. but I want to make sure--does nylon break down on its own over time due to magical/unknown factors? or is this hogwash?


Even under ideal conditions, Nylon loses about 2% of its strength per year via very slow chemical breakdown. Use, abrasion, UV light, cycling loads, and other wear and tear that are normal further decrease the strength.

I retire my soft goods every 4 years or whenever they display key red flags (nicks, cuts, excessive abrasion, discoloration, etc.). Closer to 1.5 - 2 years for high workload items like ropes.
interesting. I guess I could say that after ten years it'll still have just over 80% of its original strength but that seems pretty sketchy still.

hijack time--how quickly do climbing ropes degrade in strength?


ja1484


Aug 29, 2007, 10:56 AM
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fresh wrote:
ja1484 wrote:
fresh wrote:
thanks dudes. but I want to make sure--does nylon break down on its own over time due to magical/unknown factors? or is this hogwash?


Even under ideal conditions, Nylon loses about 2% of its strength per year via very slow chemical breakdown. Use, abrasion, UV light, cycling loads, and other wear and tear that are normal further decrease the strength.

I retire my soft goods every 4 years or whenever they display key red flags (nicks, cuts, excessive abrasion, discoloration, etc.). Closer to 1.5 - 2 years for high workload items like ropes.
interesting. I guess I could say that after ten years it'll still have just over 80% of its original strength but that seems pretty sketchy still.

hijack time--how quickly do climbing ropes degrade in strength?


Well, they're made out of nylon (generally speaking - there are static lines made from polyester), so the same 2% or so per annum in proper storage.

Now, in use, it's impossible to say. Are you toproping? Sport climbing? Leading trad? All three? On what kind of rock? Do you wash it? Have you left it in the sun?

There are a million variables. Check with your rope manufacturer and get the lowdown on what you should be watching and *feeling* for regarding rope wear or damage. Petzl has a pretty good resource here:

http://en.petzl.com/...I/Abs/control_EN.jsp

That covers not just ropes, but a lot of other items as well. Read, learn.


Partner slacklinejoe


Aug 29, 2007, 6:23 PM
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Re: [ja1484] nylon life [In reply to]
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As someone who works with nylon a lot in industrial application I feel compelled to post. Yes, nylon has a shelf life. It isn't just a strength issue but a elongation issue as well as other characteristics such as handling.

In the best conditions 5-10 years of non-use is the max most manufacturers will say the product is still in usable condition due to this breakdown. Do not underestimate the importance of elasticity in nylon products. Small differences in elasticity make a product much more unsafe than small differences in overall tensile strength.

Also, I'm not sure I quite agree with that 2% solid rule, many products differ. I wouldn't expect spectra/nylon runners and a rope to be exactly the same. Also, many products will have something of a function curve going on over time, such as 2% first year, 3% 2nd, 3% 3rd, 3%4th, and 8% 5th but year 6 could be a 10% reduction (those numbers are purely for example only).

For any type of life saving nylon product 8 years is a significant amount of it's life used up, when you add actual wear and tear on it, it's best to be conservatively safe than injured or dead. Besides, your talking about a $3 runner here -- really, is it that hard to let go?


(This post was edited by slacklinejoe on Aug 29, 2007, 6:40 PM)


ja1484


Aug 29, 2007, 6:53 PM
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Re: [slacklinejoe] nylon life [In reply to]
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No, it really isn't that hard to let go.

Did you see my typical retirement timeframes?

The 2% rule is what I've seen quoted by knowledgable folks (some gear company or another) I forget where, but as stated, I'm no ME. Regardless, I like to buy my stuff new and retire it well before aging should be any issue.


(This post was edited by ja1484 on Aug 29, 2007, 6:54 PM)


steinmethod


Aug 29, 2007, 7:36 PM
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Re: [coastal_climber] nylon life [In reply to]
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In reply to:
But dude, webbing is like 30 cents a foot. Isn't your life worth the $3 it would cost for 2 new tied slings?

agree!! Does not hurt to replace it... for the few dollars it will cost get rid of the 8 year old webbing.. make your partner happy and you can then take it on a multipitch!


majid_sabet


Aug 30, 2007, 12:08 AM
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5-10 years !!


russwalling


Aug 30, 2007, 12:19 AM
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Re: [slacklinejoe] nylon life [In reply to]
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Here is some info from FISH and BD tests:

Loop strength for a quick and dirty number on nylon webbing is about 10% less than 2X tensile strength +/- 5%. This is for a tacked, not knotted sling.

Here is a test I did just last week:
9/16" regular tubular webbing, tensile strength 1500lbs (single strand) when new. So, a loop of this should go to 3000lbs - 10-15% = 2700 to 2550lbs before it breaks. I put a sling that was made in 9/86 (yes, 1986) tied with a water knot, into the test rig.... it broke at the knot at 2600lbs. This is within the range of BS provided by BD, and exceptional for a 21 year old sling. This material was kept in storage, probably away from light, heat , battery acid and cat urine. So if the 2% per year (+/-) was accurate on this particular sample, it would have failed at somewhere around 1560lbs. or below. It did not and went to what I would call full strength, or at least between the margins of acceptable failure. If there was no knot, it could well exceed the actual rated breaking strength of the fresh nylon.


pastprime


Aug 31, 2007, 11:56 AM
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Re: [fresh] nylon life [In reply to]
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C'mon guys, quit passing along this paranoid stuff. Make your decisions on facts, not how you feel about things. Nylon is not magic stuff that was made by your fairy godmother out of pumpkinvines, with a spell that turns it back at midnight.

Do you worry about the seatbelts breaking in a 10 year old car? Do the fibers in grandma's 40 year old carpet get sucked into the vacuum cleaner? BD and others have tested very old slings, and the stuff that looked and felt ok, was; the stuff that looked really ratty was better than expected.
The Europeans tested some really old ropes a few years ago, and the well used 30 year old rope still held up to the standards in effect when it was made.
I have nylon gear that is 45 years old. Pull a loose thread out of a 40 year old parka or sleeping bag, and it will cut your finger before it breaks. The fabric in my 35 year old sleeping bags is as tough as it ever was. I have some 60 lb test nylon fishing line my dad got in the early 1950's, and it holds about 72 pounds before breaking.
Nylon doesn't magically degrade over time. Chemicals, lots of heat, a whole lot uv light over a long time all will hurt it. Time alone does not, at least the kind of time available since the stuff was invented.
It can have losses of elasticity that are not as easy to check for as breaking strength, but elasticity is not signifacant enough in slings that it matters anyway.


pastprime


Aug 31, 2007, 12:12 PM
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I only have a few minutes before I have to get going for the weekend, but in a hasty search for standards on this subject I did turn up a government report saying their previous standard for retiring nylon parachute canopies at 10 years was not found to be justified, and the time was extended 3 more years (to 13 years) while they look into it some more.


(This post was edited by pastprime on Aug 31, 2007, 12:15 PM)


roy_hinkley_jr


Aug 31, 2007, 2:05 PM
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Re: [pastprime] nylon life [In reply to]
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PP, you are clearly overlooking the importance of microfractures, which are well-documented on this august forum.


fresh


Sep 1, 2007, 9:52 PM
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interesting replies, thanks a lot guys. I wouldn't take this so seriously if it wasn't something with as many unpredictable conditions as top-rope climbing, but in this arena you can't be too sure.


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