Consensus on knots in slings

So is Wild Country trying to kill us all by selling a dyneema-sling cordelette?

wildcountry.com/products/sl…

I don't think that is what they mean, they say clip the screwgate to the mp and connect to harness ,i think they are implying connect with rope, not just a biner from your belay loop to the mp, otherwise fuck, wouldnt just be dangerous but massively uncomfortable

This comes up all the time ... The dmm videos get misinterpreted and everyone thinks dyneema is suddenly deadly

- have dynamic rope in the system and youll be fine

- for a tether should you use it, dont shockload the bloody thing ... Train yourself not to have slack in the system, a knot help prevent slack

- if you need to be above the anchors to set up a TR for example ... Then use a safety line from above

- if you cant do that then tie in with the rope till you get below

- or use a tether made from dynamic rope

Dyneema gets knotter and used all the time for anchors ... Just realize the limitations, as well as the benefits

DMM themselves sell dyneema slings in lengths that you would obviously be using knots in for anchors

;)

only to add, if you knot this material repeatedly, just plan on replacing it more often than you would for nylon.

also, if you suddenly turn to steel plates, you should probably go to the ER and get that checked out, otherwise chuck that dmm video in the garbage.

bearbreeder wrote:This comes up all the time ... The dmm videos get misinterpreted and everyone thinks dyneema is suddenly deadly - have dynamic rope in the system and youll be fine - for a tether should you use it, dont shockload the bloody thing ... Train yourself not to have slack in the system, a knot help prevent slack - if you need to be above the anchors to set up a TR for example ... Then use a safety line from above - if you cant do that then tie in with the rope till you get below - or use a tether made from dynamic rope Dyneema gets knotter and used all the time for anchors ... Just realize the limitations, as well as the benefits DMM themselves sell dyneema slings in lengths that you would obviously be using knots in for anchors ;)

This is the best advise in this thread and is spot on. Once again a thread becomes very convoluted.

In summary: Yes, it's okay to knot these materials in numerous circumstances, keep a dynamic rope incorporated in the system.

Spectra is ok for longer than a quick draw, shorter than a shoulder length. Also purchase nylon slings, cut them to whatever length you desire, and knot the piss out of them. Change your perspective on the sewn spectra to "use when a quick draw is too short only". You'll save money on buying sewn runners in the long run, and it only takes a couple of minutes to tie a water-knot in nylon slings. When setting up anchors, using knots in runners can rarely be avoided, so why not use the stuff that can be knotted in all cases?

knotting dyneema

I couldn't find the field failures of knotted dyneema but I know I have read of a couple. Hard to tell without seeing the failed gear if it melted, or was just weakened as anything would be, from being knotted.

Ryan-G wrote:it amazes me that people prefer to trust their life equalizing pieces on a single, sliding dyneema sling rather than to add a knot for redundancy...and extension limiting knots obviously won't help if the sling fails below the limiting knots...and limiting knots weaken, so why not use a knot at the master point to add redundancy there.

Why does this amaze you? A single dyneema sling with overhand knots on both sides of the sliding x is redundant and self equalizes better than a thicker sling (ie nylon).

In this setup, if a strand of sling fails below a limiting knot as you describe, there is still a second strand of sling to save you.

Nothing wrong with just tying an overhand at the master point, but if you are looking for a self equalizing rig, my suggestion is a good option. And as mentioned, use a dynamic rope in the system.

Lots of good stuff here, maybe the sling experts can help me:

It is very WRONG to mix slings: eg Dyneema/Spectra, girth hitched to nylon.
True/ False

It is very WRONG to girth hitch Dynema/Spectra to Dynema/Spectra.
True/ False

If you need to cut and retie Dynema/Spectra... there is NO knot that will hold the ends together. eg the knots will slip under a hi load.

True/ False

Serious question. I don't spend much time updating myself about new technology, and these are the rules as relayed to me from much younger climber (a guide- certified to)... Heck I just bought my first GriGri....

Guy - you need to be careful about girth hitching any type of nylon or dyneema sling to another nylon or dyneema sling. Nylon would be the safer option due to a higher melting point (mentioned previously in this thread). Either way, nylon on nylon friction is not a good thing and can at the very least shorten the life of your softgoods. However it is common to girth hitch slings to belay loops, and there are other instances involving body-weight loads where it is deemed fine.

Yes dyneema is quite slippery and has a low melting point (not a good choice as an autoblock for rappel backup). I wouldn't mess with a cut sling but a triple fisherman's knot is the gold standard for creating a loop with spectra CORD (think big bros).

Guy, look at this link I posted earlier from BD's QC labs. Lots of fairly hard data on girth hitched mixed materials. The moral of the story seems to be avoid it, and to use more symmetrical knots i.e. strop bend instead of girth hitch.
blackdiamondequipment.com/en/experience-story?cid=qc-lab-con>>>

Guy Keesee wrote:Lots of good stuff here, maybe the sling experts can help me: It is very WRONG to mix slings: eg Dyneema/Spectra, girth hitched to nylon. True/ False It is very WRONG to girth hitch Dynema/Spectra to Dynema/Spectra. True/ False If you need to cut and retie Dynema/Spectra... there is NO knot that will hold the ends together. eg the knots will slip under a hi load. True/ False Serious question. I don't spend much time updating myself about new technology, and these are the rules as relayed to me from much younger climber (a guide- certified to)... Heck I just bought my first GriGri....

False, false and false.

The tests pointed to already from BD and WC show that you should expect a 50% reduction in strength (and that you should join the ends with a triple fisherman's).

The question to ask is why might one be joining slings or knotting ends. If it is because you don't want to pay for draws and plan on making them by cutting up old dynema 4m slings, then it isn't sensible. If however you need to because you are rapping off a face, or need to join slings to get something around a monster thread, then girth hitching 3 slings will be so much better than not getting the thread and taking a longer fall.

50% of 22kN is 11kN, which most of the time is plenty strong enough. And stronger than many gear placements

You want a "consensus" on Mountain Project? LOL You're more likely to get a consensus out of the U.S. House of Representatives.

David.... I was thinking about the times when you need to have a tied sling.....for rapping, bailing.

I carry my chalk bag on a nylon sling, so I can have a good bail sling if need be.

Guy Keesee wrote:David.... I was thinking about the times when you need to have a tied sling.....for rapping, bailing. I carry my chalk bag on a nylon sling, so I can have a good bail sling if need be.

Guy, the WC tests showed that a triple fisherman's was the best in such situations, a flemish bend was also good.

Page 161, Rock Climbing: The AMGA Single Pitch Manual, By Bob Gaines, Jason D. Martin

books.google.com/books?id=V…

Below the sliding-x picture using a dyneema sling:

Details of Equallette Master Point rigged with a Dyneema sling. Tying an overhand knot in Dyneema reduces it's strength by 50%; it's better to use a 7mm cordallette when rigging an equallette, as you'll be tying lots of knots.

There you have it. Don't tie a knot in dyneema slings.

Gaz wrote: Don't tie a knot in dyneema slings.

You may want to careful about going from a statement like "Tying an overhand knot in a Dyneema sling reduces its strength by 50%; its better to use a 7mm nylon cordelette when rigging the equalette, as you will be tying lots of knots" to something as absolute as "Don't tie a knot in dyneema slings". Remember, most technical decisions in climbing are conditional and there is generally more than one solution to any particular issue.

Xam wrote: You may want to careful about going from a statement like "Tying an overhand knot in a Dyneema sling reduces its strength by 50%; its better to use a 7mm nylon cordelette when rigging the equalette, as you will be tying lots of knots" to something as absolute as "Don't tie a knot in dyneema slings". Remember, most technical decisions in climbing are conditional and there is generally more than one solution to any particular issue.

Sorry, I should've qualified it as: As a general rule don't tie knots in Dyneema/Spectra when you are concerned about the strength rating or a fall directly onto that sling.

Gaz wrote: Sorry, I should've qualified it as: As a general rule don't tie knots in Dyneema/Spectra when you are concerned about the strength rating or a fall directly onto that sling.

I don't really want to wade into this but after reading your other thread, I have to ask this pretty basic question: Do you understand that you should never be falling 'directly' on any static sling (dyneema or nylon or cord)? The belayer should always be attached via the rope (using a clove hitch or fig eight or whatever). The leader will also be on a dynamic rope. As such, you will always have a dynamic element in the system that will reduce your load on the anchor to well below the failure point of any commercial climbing sling, knotted or otherwise, even in a fall approaching a FF2. Snapped slings (knotted or otherwise, and people use dyneema slings for anchoring all the time) is a vanishingly small component in climbing accidents. Of course you have to use them correctly.

Don't waste your time with Gaz's response. He's just a bored drunk.