6/7mm accessory cord for quickdraws

I have a bunch of 6 and 7mm accessory cord and I was wondering if anyone had experience using the cord for alpine quickdraws. I typically see them made with dyneema slings but I thought maybe cord doubled and tied with a double fisherman's could work. Is this a terrible idea?

Nick Chandler wrote: I have a bunch of 6 and 7mm accessory cord and I was wondering if anyone had experience using the cord for alpine quickdraws. I typically see them made with dyneema slings but I thought maybe cord doubled and tied with a double fisherman's could work. Is this a terrible idea?

All those with experience are no longer able to type on a keyboard.

Don’t be cheap, just pay for dyneema

Nick Chandler wrote: I have a bunch of 6 and 7mm accessory cord and I was wondering if anyone had experience using the cord for alpine quickdraws. I typically see them made with dyneema slings but I thought maybe cord doubled and tied with a double fisherman's could work. Is this a terrible idea?

You’d be way better off cutting these into 9 foot lengths and double fisherman’s. You’ll get a 120 cm sling out of it that is way more useful. 

According to this page, a double-fishy will reduce breaking strength by about 20% on 7mm cord:

http://caves.org/section/vertical/nh/50/knotrope-hold.html

I'll assume that is correct and the decrease is similar for 6mm cord.

A loop will roughly double the strength.

According to UIAA-102 / EN-564, 7mm cord must have a minimum strength of  9.8kN, and 6mm cord must have a minimum strength of 7.2kN :

https://uiaa-web.azureedge.net/wp-content/uploads/2016/08/UIAA102-Accessory-Cord-1.jpg

So that would give us around 15.68kN for 7mm and 11.52kN for 6mm.

If my calculations are correct (don't count on it), that is definitely strong enough. Even the 6mm is stronger than a lot of cams.

That said, there is a reason people don't use knotted slings much anymore. Bulky and annoying to extend with a big knot in it. A bar-tack is better. You can get sewn nylon runners for a few bucks each.

Hangdog Steve wrote:  
A loop will roughly double the strength.

Where did you find that information? Thanks for the link to caves.org. That's an interesting set of tests.

Will it work? Yes. The rope takes most of the force anyway.

Will it look stupid and be a waste of supplies? Also yes, but it's free.

B G wrote:

Where did you find that information? Thanks for the link to caves.org. That's an interesting set of tests.

A loop roughly doubles the strength because you now have two strands rather than one, each strand will take half the force.

B G wrote:

Where did you find that information?

I don't have any kind of source for that. I just pulled it out of my ... "common sense". With two strands, assuming perfect load sharing, each strand takes half of the load. In reality, you have to take into account some messiness, like the load sharing not actually being perfect, and the bending around the narrow radius of the biner. Given that our lead falls aren't anywhere near 10kN, I think it's fine.

But just in case: You're Gonna Die!!!

Will it work: yes.

Should you do it: probably not.

The ease of use is gonna be shitty. There is a reason everyone uses dyneema, much easier to rack and extend and less cluttered. 

It will work and you’ve already got it so that’s a plus but as others have said it’s bulky and the knot will be annoying. A better use would be as cordelette and for alpine rap anchors or v threads. 

Shoulder slings with one biner yes.

I do this with the slings I rack my gear on.  Just had to replace them because I used them to bail on a route in the winds.  Much cheaper and easier than bailing on dyneema.

Would I make all my Alpine draws this way? No.  But a few are nice and cheap.  

rocknice2 wrote:

All those with experience are no longer able to type on a keyboard.

Examples? Accident reports?

Greg R wrote: It will work and you’ve already got it so that’s a plus but as others have said it’s bulky and the knot will be annoying. A better use would be as cordelette and for alpine rap anchors or v threads. 

As far as V threads go....  I would NOT recommend doing that.  It turns out that accessory cord loses a significant amount of strength when its wet, which is pretty typical for ice climbing.  In the case of 6mm that means there isn't a whole lot of Kn to begin with.  Use the rope itself.  Plus there is the issue of what happens to that cord once spring rolls around: it becomes trash.

As far as rap anchors.....   accessory cord loses a significant amount of strength when it's wet, so I'd say keep that in mind when rigging with 6mm.  There is a lot to be said for 6mm in terms of its potential use as an emergency prussik BUT.....  It turns out that nowadays everybody (almost) has an auto block style belay device, which is one ascender, and quite a few people bring a dedicated second hand sling (Sterling Hollowblock for example) and there are a number of newer innovations in sewn sling material (Beal, Edelrid, Mammut) that allow one to use a sewn sling as the second ascender.

rocknice2 wrote:

All those with experience are no longer able to type on a keyboard.

Thanks for the chuckle.

r m wrote:

Examples? Accident reports?

I think he is making a joke that the people who tied their own alpines are all too old to respond.  Knotted appropriate cost and sling material is plenty string.  I still have an old BD .75 slung with cord and my hexes (which I still use kiddies) are mainly slung on cords.  But all of my alpines and draws are sewn.

Can you use cord for draws and alpines?  Yes.  Should you?  No.

Save the cord for cordalettes and quads.

Nick Chandler wrote: I have a bunch of 6 and 7mm accessory cord and I was wondering if anyone had experience using the cord for alpine quickdraws. I typically see them made with dyneema slings but I thought maybe cord doubled and tied with a double fisherman's could work. Is this a terrible idea?

I've been reslinging mine with 7mm cord for years and it's been totally fine. It started because I wanted to try some longer, 10"-12" draws for trad and I had extra from just reslinging my chocks.  I liked it so much I just kept using them until they needed reslinging.  Now I usually carry 3 or 4 as part of my standard rack. I Isolate my knot though and tie it around both strands so it can't move and also captures the bottom 'biner.  

You could, but why? Keep the cord for anchors. Buy some nice, thin slings for the alpine draws. Slings are way cleaner, stronger, and easier to manage for that use.

6-7 mm cut into 5’ foot sections

Perfect for holding your chalk bag around your waste and can be used as a emergency sling or tying a prusik knot.

The only reason to do this would be to simply be different. Not exactly a bad reason but not a real good one either. It’ll generate a lot of comments and maybe some good conversations. It’s certainly safe enough.

Have fun with it!