|
climber1
May 17, 2002, 7:50 PM
Post #1 of 19
(3490 views)
Shortcut
Registered: May 5, 2000
Posts: 484
|
someone told me that the pre-packaged, pre-tied cordlettes are stronger than the ones you tie yourself. anyone heard this?
|
|
|
|
|
bradhill
May 17, 2002, 9:37 PM
Post #2 of 19
(3490 views)
Shortcut
Registered: Mar 22, 2002
Posts: 486
|
It depends on the material in each case. Just get strong enough cord. I use 5.5 mm Spectra core and hand tie them with a triple fisherman's knot. You could probably buy cordalettes that were both stronger and weaker than this.
This link from the AMGA compares cordalette and webolette strengths. A very informative read.
Not sure I'd trust a hand-tied webolette, though. Especially with Spectra or Spectra blend slings bar tacking is more reliable than knots..
[ This Message was edited by: bradhill on 2002-05-17 14:39 ]
|
|
|
|
|
dustinap
Deleted
May 17, 2002, 11:17 PM
Post #3 of 19
(3490 views)
Shortcut
Registered:
Posts:
|
I like 7 mil cord with my knot in it.
The problem I understand with spectra is that the bending of the material makes the internal fibers break down.* This happens because it is so stiff.*
* I read that on this site somewhere, I do not have any credible information regarding my notes abuot spectra other then this.
|
|
|
|
|
sizzlechest
May 18, 2002, 12:58 AM
Post #4 of 19
(3490 views)
Shortcut
Registered: Sep 23, 2001
Posts: 139
|
i got news for you chief, the difference in strength isn't very much, you don't need to worry if your going to exert that much force on it you'll be dead anyway. 7mm has been used for years and works fine
|
|
|
|
|
rickoldskool
May 18, 2002, 6:00 PM
Post #5 of 19
(3490 views)
Shortcut
Registered: Apr 25, 2002
Posts: 214
|
sizzlechest is tellin' the truth. there isn't a significant diff' in strength between perlon and spectra when used as a cordelette. Just by 18'-20' of dynamic 7mm cord tye it yourself. use a double fisherman to tye it. Spectra, use a triple. Good climbing
I should have read the link above, before I posted. Everyone should read it! But it confirmed my suggestion (thank god) 7mm, nylon cord.
[ This Message was edited by: rickoldskool on 2002-05-18 11:36 ]
|
|
|
|
|
duskerhu
May 20, 2002, 7:39 AM
Post #6 of 19
(3490 views)
Shortcut
Registered: Apr 13, 2002
Posts: 1023
|
Quote-"someone told me that the pre-packaged, pre-tied cordlettes are stronger than the ones you tie yourself. anyone heard this?"
They are not climber1... In fact, most of them that I've seen are just regular 7mm cord that may or may NOT be already tied, and they give you a little sheet of directions/explanation.
If you know what a cordalette is, you proabaly already know how to tie it. If you don't, there are MANY books that will show you in detail.
As Far as SPECTRA, yes it is a bit stronger but is so stiff, it's tough to tie, and you have to make appropriations to prevent it from coming untied; ie - triple fishermans.
For my money, I'd go to your local gear shop and for about $0.35 or 0.37 a foot, get a 20 foot chunk of regular 7mm (8mm works too but is thicker and heavier)and tie it yourself.
As far as the above mentioned webolette, and I haven't read the article yet but I will; "hand tied" webolettes are very popular here in the land of 10,000 top ropes. Regular 1" tubular, using a water knot to connect the 2 ends. Make sure and leave about 6 - 8 inches of tail on each side and tie overhand backups on each side.
Live Free!
Play Hard!
Climb On!
duskerhu
|
|
|
|
|
blueman
May 20, 2002, 1:11 PM
Post #7 of 19
(3490 views)
Shortcut
Registered: Feb 7, 2002
Posts: 19
|
yea! a webolette fan
|
|
|
|
|
duskerhu
May 20, 2002, 2:06 PM
Post #8 of 19
(3490 views)
Shortcut
Registered: Apr 13, 2002
Posts: 1023
|
You too blueman...
|
|
|
|
|
bradhill
May 20, 2002, 5:18 PM
Post #9 of 19
(3490 views)
Shortcut
Registered: Mar 22, 2002
Posts: 486
|
I can't imagine carrying 40-60' (2 cordalettes) of 7mm cord around. 7 mm cord is almost twice the volume of 5.5 mm. Clipping your biner (or a couple) through the loops at the power point is a pain with fat cord, too. Spend the extra $$ for 5.5mm Spectra.
If you read the link above, you'll find that Aramid fibers (like Kevlar) break down quickly with flexing, but after a small initial decrease in strength, pure Spectra is pretty stable.
[ This Message was edited by: bradhill on 2002-05-20 10:25 ]
|
|
|
|
|
dustinap
Deleted
May 20, 2002, 5:27 PM
Post #10 of 19
(3490 views)
Shortcut
Registered:
Posts:
|
7 mm is almost twice the size of 5.5 mm?
|
|
|
|
|
talons05
May 20, 2002, 5:28 PM
Post #11 of 19
(3490 views)
Shortcut
Registered: Aug 23, 2001
Posts: 1435
|
Hmm... Well, that's ok, I was never very good at math either...
I like to tie my own cordellettes, because that allows me to get EXACTLY the length I want.
AW
|
|
|
|
|
bradhill
May 21, 2002, 2:56 PM
Post #12 of 19
(3490 views)
Shortcut
Registered: Mar 22, 2002
Posts: 486
|
The area of a circle, and therefore the volume of a tubular solid, is proportional to pi * radius squared. So it's not quite twice as much, but there's a lot more rope in 7mm diameter cord than 5.5mm diameter.
|
|
|
|
|
radistrad
May 21, 2002, 5:04 PM
Post #13 of 19
(3490 views)
Shortcut
Registered: Feb 25, 2002
Posts: 800
|
I have both a "rabbit runner" and a tied cordalett.
I really like the rabbit runner, its is strong, low on bulk and quickly allows equalization of multiple anchors.
I like to use the rabbit runner on trad where there are no bolted anchors, it is longer than my cordalett and allows for more varaiation in my gear placements (distance mainly).
My cordalett is a bit shorter and works well for trad and works better for bolted anchors, it is shorter and there for does not extend too far from the bolts.
My cordalett is a hand tied loop by me, my rabbit runner has loops sewn into each end by Mtn someone?
Edited because I did not answer the question.
I think as far as strength the cordalett would be weaker. As I recall the cord was good to about 1500lbs, the rabbit runner is good to 20kn or about 4000lbs. I hope this is right.
[ This Message was edited by: radistrad on 2002-05-21 10:42 ]
|
|
|
|
|
hunter
May 21, 2002, 5:29 PM
Post #14 of 19
(3490 views)
Shortcut
Registered: May 3, 2002
Posts: 121
|
I would imagine the strength of purchased versus hand tied Cordettes would have a lot to do with the knot used and if it's properly dressed.
As to Spectra: Spectra is an incredibly strong fiber (much like Vectran though Spectra has better abrasion resistance than Vectran and Vectran has slightly less stretch than Spectra).
Thier strength to weight ratio and practically zero stretch properties make these fibers popular for a lot of applications. Both fibers have one important weakness and that is that the fibers themselves are very brittle. Both fiber types can be severly compromised from a strength standpoint from sharp bending without showing much wear. If you use ropes made with a large percentage of spectra I would recomend retiring it long before it looks worn out.
This info is based on my use of these fibers in areas other than rockclimbing though the nature of the fibers remains the same regardless of application. Still, take it or leave it as you see fit.
Hunter
|
|
|
|
|
boretribe
May 21, 2002, 5:38 PM
Post #15 of 19
(3490 views)
Shortcut
Registered: Jan 17, 2002
Posts: 208
|
bradhill thanks a lot for the web link for cordalette strength test. Someone was telling me about this study this weekend when I was in Joshua Tree. I was just about to start looking for the report online when BAM there was your post.
Thanks for saving me the search time.
|
|
|
|
|
bb_guns
May 21, 2002, 7:32 PM
Post #16 of 19
(3490 views)
Shortcut
Registered: Apr 25, 2002
Posts: 15
|
20' of 7mm cord runs about $7.
The 5.5mm prepackaged cord run about $20.
I mention this because there have been a few times where I arrived at a rapel that was composed of old slings and cords. I am much less hesitant about leaving a $7 cordlette behind than a $20 one.
So in a way, I am saying cheaper is safer.
By the way, I also carry along at least one double sling (long enough to loop over my shoulder twice) that is tied with a water knot. If all you have are sewn runners, leaving one behind is expensive and you have to cut it and retie it (you will loose about a foot in the new knot - so in some cases it will not be long enough anyway).
|
|
|
|
|
talons05
May 21, 2002, 7:53 PM
Post #17 of 19
(3490 views)
Shortcut
Registered: Aug 23, 2001
Posts: 1435
|
Radistrad -
You said that cord used to tie cordelletes is rated to almost 1500 lbs.? The stuff I use is Maxim Tech Cord, and it's rated to 5,000lbs.
A.W.
|
|
|
|
|
radistrad
May 21, 2002, 8:05 PM
Post #18 of 19
(3490 views)
Shortcut
Registered: Feb 25, 2002
Posts: 800
|
I may be wrong on the strength rating, I think I hinted towards that. But I do think it had a low rating, I bought it at REI, I'm pretty sure its 7mm, but it is also several years old and I am quite foggy on its spec., like I said I thought it was low. However I will be looking for the cord with the 5000lbs breaking strength, especially because I think mine breaks at a 1/3 of yours, yikes that is sacry...
|
|
|
|
|
bradhill
May 21, 2002, 9:03 PM
Post #19 of 19
(3490 views)
Shortcut
Registered: Mar 22, 2002
Posts: 486
|
Rappelling is a completely different matter from building a belay anchor. I want a belay anchor system that may take a factor 2 fall to be capable of handling forces of up to 16 kN. I use the lightest, least bulky material that is safe for that purpose, 5.5mm Spectra.
I don't use my $20 cordelette for a rap anchor because it's not what it's designed for. For rappelling, a system needs only hold about 2 kN. (more for safety, but the realistic load on a smooth rap is never trust for a belay anchor) to leave as rap slings or V threads.
The stuff's feather-light and you can daisy a 25' piece of it to the size of a screamer, so you can cary LOTS. It's great for slinging big horns, flakes and boulders for long alpine retreats. Plus if you're tradding and use it all you can go do another couple pitches of walk-off or fixed anchor 'cuz you didn't just chop up one of your key pieces of gear.
|
|
|
|
|
|
|
|
|
