different sling material opinions?

[genepires]

so I am looking into replacing my old slings and was wondering what people's opinions where about the different kinds of sling materials. Maybe between nylon, dynex (BD), dynema (mammut ones), titan/spectra.

 

pros for

nylon- lasts longer and more resistant to cutting?

dynex and dyneema are obviously skinnier and lighter.

titan/spectra seems like a average of the previous two.

 

what about the cons for the different materials?

 

What is the suggested life span of the dyneema stuff? I have heard some scary stuff about the short life span of these slings.

 

[kurthicks]

Nylon or nylon/dyneema blend for cragging and frontcountry rock usage. Durability/abrasion resistance (and cost) is my key criteria given the amount of time I spend using this gear in this terrain. The added benefit of being more dynamic than dyneema is also a plus. My guests like nylon since it looks beefier than dyneema, especially for their rappel extension/anchor sling. Also easier to inspect for replacement since nylon fades over time.

 

Dyneema/Spectra for alpine and ice routes. Weight and bulk are my primary concerns for alpine routes; reduced water absorption is also key for ice routes, especially here in the PNW. Don't factor 2 while using this as an anchor sling (a.k.a. daisy chain) as it has basically no dynamic properties (google the DMM test video).

 

7mm cordelettes for cragging. 6mm for the alpine.

[tradhead]

I bought several 1/2" Dynex (BD) and two Dyneema (WC) shoulder slings just under two years ago. The Dyneema slings are still very supple and mostly not exhibiting any obvious wear while the Dynex slings are very worn and getting obviously brittle. I am planning on replacing them soon with WC dynneema and do not plan on buying Dynex in the future.

 

YMMV - just one data point obviously.

[bearbreeder]

i own and use the BD dyneema slings ... nylon is too bulky i find ... i find it much easier to tie knots with dyneema as well ...

 

each have their advantage and disadvantages ... if you have rope in the system i dont see any worry in using dyneema ....

 

even the often quoted "DMM dyneema death test" says this ... keep in mind DMM still sells dyneema slings ....

 

http://dmmclimbing.com/knowledge/how-to-break-nylon-dyneema-slings/

While the impact forces in the tests for the nylon slings are lower than the Dyneema® they were still high enough to snap wires. This isn’t to say Dyneema® is bad and nylon is good. On the contrary, comparing the two materials, Dyneema® has a strength to weight ratio higher than not just nylon but also steel, a significantly higher resistance to cutting and lower water absorbtion (important in winter), making it an ideal material for slings and quickdraws. It is also more resistant to ultra-violet rays and chemical attack than nylon but has a lower melting point. This is an important factor to consider when abseiling – pulling a rope through a Dyneema® sling, say as in poor abseiling practice, will generate enough heat to severely weaken the sling, if not melt through it.

[chris]

Nylon or nylon/dyneema blend for cragging and frontcountry rock usage. Durability/abrasion resistance (and cost) is my key criteria given the amount of time I spend using this gear in this terrain. The added benefit of being more dynamic than dyneema is also a plus. My guests like nylon since it looks beefier than dyneema, especially for their rappel extension/anchor sling. Also easier to inspect for replacement since nylon fades over time.

 

Dyneema/Spectra for alpine and ice routes. Weight and bulk are my primary concerns for alpine routes; reduced water absorption is also key for ice routes, especially here in the PNW. Don't factor 2 while using this as an anchor sling (a.k.a. daisy chain) as it has basically no dynamic properties (google the DMM test video).

 

7mm cordelettes for cragging. 6mm for the alpine.

 

[Coldfinger]

I have a mix of Mammut Contact slings (22kn) and 6 and 7mm cord.

 

The biggest question is: do you want to be able to untie the loop?

 

Think of it this way, there are runners (ie. used where one just needs a longer QD) and there are slings (i.e. used for all sorts of anchor making).

 

I like the Dyneema for runners, seems to be the best application for that textile.

 

A big negative of dyneema is its handling characteristics. The only safe and sure way to make a dyneema sling is bartacking and it is NOT recommended to girth hitch these to each other to make a longer sling. Mammut flatly states that the only safe way to join these is with a biner, so you lose the weight advantage when you link two of these with biners. It does not like knots either, BTW from both a strength and ease of untying once loaded view. So unlike knotted supertape, you can't untie for threads, trees, greater length etc.

 

Then there's the issue of using it as a personal link to an anchor.

 

The big plus with Dyneema is the water and cut resistance, weight, bulk and strength.

 

As for cord/slings, I like BW 6mm (8.4kn) for v-threads and rapping, but don't like using that for anything else due to it's low breaking strength and cut resistance due to its diameter. 6mm just doesn't seem to have much margin for strength loss due to knotting (~20%), aging, wear and/or abrasion/cutting from rough or sharp rock.

 

I just don't get why folks would use 5 or 6mm cord for anything other than rapping. If somebody used that to join their harness to the climbing rope you'd think they were nuts, so how is it that folks use that stuff anywhere else in the system and it's ok?

 

I have what would be a triple shoulder sling (180cm) length of the Sterling 7mm Dry cord, that I REALLY like for anchor building. It's advantages are robust strength (12.4 kn) and that I can untie it if i need a really long piece (about 300cm?) for getting around a tree or whatnot.

 

As I stated in another thread, I think the longer cord runners have so many other (prussik, texas prussik, etrier, etc.) uses that they are ideal for alpine and multipitch applications.

 

I looked into the 5mm Technora stuff and while it has a very high single strand strength, after doing a little digging I found that when knotted it loses almost half of it's strength as it tends to want to cut itself much like it's sister textile the Dyneema sling. (And is thus not practically much stronger than the 6mm and especially 7mm stuff.) Where I have seen the 5mm technora used wisely (imho) is as a rap/pulcord where it retains it's full 20kn strength. Given the cost, I chose to pass.

 

With all the bolting that goes on now, I don't ever need huge amounts of webbing to rig TR's or anchors much at all, unlike 20 years ago, but that would vary greatly by crag. I've used the standard webbing to pull trucks out of ditches, dragging deer out of the woods, dog leashes and not much more over the last 20 years.

 

That being said I have a bit of supertape that I'd bring for longer trad routes (but not alpine where the 6mm comes along).

 

Hope that helps Gene!

 

 

[genepires]

All very good info y'all!

 

thanks

 

[layton]

I have about 15 mostly un-used dyneema slings onces I realized sling weight is a petty concern.

I pretty much only climb on nylon slings. The extra weight is negligible compared to the extra force dispersion, resistance to wear/tear, ability to tell when they're getting sketchy, and cost. Keep in mind I climb in the desert a lot.

If I worried about bulk or water then I would use titan slings. I have some pretty old ones that look brand new compared to some much newer dyneema slings that scare me just looking at them.

 

I wouldn't consider using a daisy made out of that thin dyneema, and I no longer use fancy cordalettes with kevlar or spectra since I want some give in the system and don't want to be thinking $$ when I burn it for tat.

[JosephH]

I used Mammut 8mm dyneema slings for four of years and had a percentage of them tested every year. That made me switch to Yates 11mm dyneema slings. Love them, but I find they really are only lasting three-four years compared to the 8mm dyneema's two-three years. At the moment I'm not sure if I'm going to just replace all my 11mm slings or bump up to 13mm dyneemas. Likely I'll just bite the bullet and replace all the 11mms as I do like light slings. It's just important not to fool yourself into thinking they last longer than they do because, ultimately, skinny dyneema slings are designed, manufactured, and sold to the fast-and-light alpine market as a consumable item and not an enduring product for year-in, year-out cragging.

[JasonG]

So is it the use of the dyneema that causes the fast wear, UV, or do they degrade quickly over time regardless?

[JasonG]

A question for Kurt- Is the 6mm cord you use for your alpine cordelette the standard (i.e. non spectra) type? And if so, do you find that it is strong enough to use for anchor building purposes (as opposed to rap anchors only)? Thanks for any info!

[Coldfinger]

So is it the use of the dyneema that causes the fast wear, UV, or do they degrade quickly over time regardless?

 

No the dyneema is tough, there is NOT a lot of material, THAT is the difference durability wise, and why some posted here they like 10mm or 13mm slings or supertape.

 

Lots of grit in the desert, as layton posted, and that gets into textiles like rope and webbing and speed wear.

[Coldfinger]

A question for Kurt- Is the 6mm cord you use for your alpine cordelette the standard (i.e. non spectra) type? And if so, do you find that it is strong enough to use for anchor building purposes (as opposed to rap anchors only)? Thanks for any info!

 

You remember to factor the knot into the breaking strength?

[genepires]

Not meaning to speak for Kurt, but I think 6mm if plenty fine for alpine anchor making material. The high strength for anchor material is needed for the dreaded fall factor two onto the anchor. It is near impossible to attain a fall factor 2 in the alpine. (unless it is some uber hardman route that is 5.12 or something) The fall factors are based on the leader taking a free fall onto the piece of protection. In most of the alpine routes, there will be lots of bouncing off small and large ledges that will reduce the forces put onto the protection or onto the anchor if there is no protection yet. If there is no pro, the leader will most likely crash into the big ledge that the anchor is built from and possibly roll off which would yield a fall factor 1 at most. Fine for the anchor but sucks balls for the leader.

[genepires]

side question. I got some skinny mammut slings that are 5 years old. No use other than 3 days cragging in wet WA. What is the retired life of these skinny slings?

 

(I fully expect someone to say that I should toss them and that said someone will volunteer to dispose of them properly if I mail them to him...probably in portland)

Edited February 28, 2012 by genepires

[kurthicks]

I use standard nylon 6mm cord that is rated to 7.2kn in a single strand. Given that it is always at least doubled in an anchor (it forms a loop after all), I believe that it gives plenty of safety margin. In a three piece anchor, each leg is worth 14.4kn, meaning the anchor can withstand 43.2kn (minus the knot). The choice of joining knot doesn't really matter either, so go with whatever makes you feel good. I use the flat overhand on all of my cordelettes--this knot is often called the EDK--but for v-threads it is standard practice to use a double fisherman. I don't worry about the reduction of strength due wear or aging of my cordelettes since I probably go through at least 10 a year between replacing anchors, bailing, or just losing them.

 

Keep in mind that your internal organs rupture at between 10-12kn (the threshold of survivability as it's known), so all of this is just silly internet debate anyways.

 

link: http://theeyegame.com/speleo/Pubs/rlenergy/Default.htm

 

Edited February 28, 2012 by kurthicks

[Coldfinger]

BW testing (http://outdoorlink.org/ol/files/trdocs/research-papers/Knot-and-cord-strength.pdf)

 

The tensile strength of BW 7mm static cord is 2,600lbf. Loop strength on carabiner diameter test pins was 4,200lbf or about 80% of double strength. It was virtually the same percentage in BW 8mm static cord. Cords were tied with double fisherman knots and failure mode was the cord broke at the test pins. In 5.5 spectra we observed loop strength of 3,900lbf or 60% of double tensile. Failure mode with a triple fisherman knot was breakage at the test pin but with a double fisherman (not recommended to make loops in 5.5 Spectra) the failure mode was at the knot and at a slightly lower value. This was different than expected and it would be interesting to see if other high strength cords behaved similarly in single loop testing. Spectra seems to be much more affected than larger cord by the small radius of a carabiner.

[bearbreeder]

side question. I got some skinny mammut slings that are 5 years old. No use other than 3 days cragging in wet WA. What is the retired life of these skinny slings?

 

(I fully expect someone to say that I should toss them and that said someone will volunteer to dispose of them properly if I mail them to him...probably in portland)

 

ill test em for ya

 

3 days? ... and stored properly, no exposure to dampness, chemicals or uv? ... id still use em

 

 

[JosephH]

So is it the use of the dyneema that causes the fast wear, UV, or do they degrade quickly over time regardless?

It is the use of them; specifically the repeated bending of them breaks fibers over time. I rack mine as trad draws so they are constantly extended and shortened, unracked and re-racked. You can tell it's time because they go from being smooth and shiny to very hairy and dull as the fibers breakdown.

 

Three days of use / five years old? Likely good for a year of solid use and then I'd probably toss them.