Sterling PowerCord Cordelette - 6mm

Aaron Crabb

July 4, 2013

Knots always reduce a textile's strength somewhat, however Dyneema is especially problematic because of its very low friction causing Dyneema knots to not bite properly.

HOWEVER, this cord's sheath is good old nylon. So I would not worry about knotting these.



On the dynamic question: Yes I think this cord's core does make it less dynamic and therefore would absorb less force in the event of a shock load. This is a concern whenever your anchor is even remotely questionable. But everything is a compromise...just be sure you make the RIGHT compromise when climbing. :-)

Colin W.

June 2, 2015

This cord has a Technora core not a Dyneema core so it is not as slippery and holds knots better. It does not have the stretch or dynamic properties of nylon so factor this in when using it. Strength is reduced by knots more than in Nylon but I have done destructive testing with knots in Power Cord that really impressed me.

Angus Bohanon

June 2, 2013

You wouldn't use a Dyneema sling for friction knots because of its shape, not because of the material. If there were such a thing as braided Dyneema cord (which, as far as I know, there's not), it would be fine. To your question, this cord will perform perfectly well as a friction knot. Keep in mind that if a friction knot is being utilized properly, there should be no sliding and thus no heat. There's some heat if you're backing up a rappel with it, but not nearly enough to threaten the material.



To throw some numbers at you, one test of a fast 450-foot rappel saw the ATC achieve temperatures of 175 degrees F. Certainly enough to burn you, but Technora begins to melt at 932 degrees F. Perfectly safe.

Cody

June 21, 2013

High-tenacity cords use aramid fibers (the technora core). Aramid has a significantly high breaking strength (higher than Spectra or Dyneema). It has very low stretch and a very high MP (900F). This Sterling cord has a breaking strength around 19kN (4,271 lb.). The only downside to these cords is that they have been shown to break down more quickly with repeated flexing.I read one study that showed when one section of Technora fiber cord was loaded with a 40 lbs weight and flexed over and edge 1000 times, the material lost approximately 50% of its strength, while nylon cords lost virtually nothing.

dulfersitz

June 21, 2013

Directly from Matt at Sterling:



It is ok to use as a Prusik as long as the diameter of the host rope is large enough for the PowerCord to synch down. Generally speaking, PowerCord is too stiff for use as a Prusik so, it won't work well enough on small diameter ropes but, larger diameter stuff it should work fine.



Heat is not a problem for Technora in this application. Typical Nylon melts around 400 degrees F and the Technora degrades around 900 degrees.



While tight radius bends should be avoided with higher modulus materials like Technora it is not really a strength concern as a Prusik since the Prusik generally slips on the host rope well ahead of the break strength.



Matt Andrews

Climbing & Outdoor Market Manager

Sterling Rope Co., Inc.

WelshGuy

May 31, 2014

OK, so the concern is with the temperature melting the prussik is probably moot IMHO. If using nylon cord as a prussik, you'd either be ascending or descending slowly which would not be enough friction to raise the temperature to melt the cord. Also nylon 6mm is typically 7.2kN MBS. Plenty enough to hold your weight. If you're zipping down the main rope, you'll probably be in one of these 2 scenarios. 1) you're falling - you should have a backup knot from the main rope tied/'binered to your harness, 2) you're rappelling quickly - you should have a rap device for this.

Cody

June 21, 2013

I don't believe sterling makes any other "Powercord" cordlettes in diameters other than this 5.9mm because this uses the Technora core, but if you wanted a cordlette in another material they do offer other diameters.

James Jenden

April 9, 2012

This would be fine. The 4800lb breaking strength is 21kN, which is more than enough. The 8mm stuff wouldn't slide as much in the holes though, which could be a bonus.

Mathew Lavery

August 13, 2012

It's important to note that the breaking strength for static weight is 4800lbs but this does not directly translate to a dynamic force. Since this uses non stretching material for its core a fall would only have to generate 7.2kN to break this stuff.
It's super safe as an anchor or for other static purposes when used with a dynamic rope but should not be used as a rope or personal anchor point.

As for this exact question, this SHOULD be okay but you have to be very careful when modifying gear like this. Creating burns in the hex could easily shred the cord.

Luke Smith

March 15, 2012

Yes, just make sure to set up a proper anchor.

Brian S.

August 17, 2011

This is definitely strong enough for anchors and any types of falls. The breaking strength is 22kN unlike what is advertised in the spec sheet here. That is the same as the breaking strength of your carabiners...

Mathew Lavery

August 13, 2012

Sorry to repeat what I said on another question but :
It's important to note that the breaking strength for static weight is 4800lbs but this does not directly translate to a dynamic force. Since this uses non stretching material for its core a fall would only have to generate 7.2kN to break this stuff.

It's super safe as an anchor or for other static purposes when used with a dynamic rope but should not be used as a rope or personal anchor point or anywhere else where slack may be introduced into the cord.

Dane

May 19, 2011

Yes, it is stiff. Makes good rap tat. But nothing I want to sue on a regualr basis.

peterslug

November 19, 2012

It is stiff. I have managed to tighten clove hitches just fine. Comparatively, dressing the knots can be a little bit more time. Excess portions of the cord tend to remain straight, so in the case of the equal-ette setup, the slack portion makes a stiff loop - giving the anchor a 'not as nice clean' look, though utility is not diminished. I rack it untied, butterflied, and clipped to a biner. Its compact and easy to tie a masterpoint.

knanier

March 4, 2010

If I'm understand your question correctly, you're looking to tie a piece of this cord around the wire portion of the hex nut? If this it the case, then no, I would not recommend it. As the force of a fall is applied to the cord, it seems the wire would potentially generate enough force to cut through the cord, similar to a rope or cord being weighted over a sharp rock edge.

Lyric Rosatti

March 4, 2010

I think we may need a bit more information before we can help you. Are you planning on re-threading the hex nuts with cord (ie: replace the wire with cord) or are you looking to use this as a sling to carry a rack of protection?

Bucket

April 26, 2011

I believe you can if your hex nuts have holes big enough to use this cord, without modifying the nut holes. And never put cord next to cable when putting cord as the attachment point for a hex nut! that should be an obvious point. The advantage of using cord in a hex nut is the matter of being able to customize the length of sling from anchor to rope attachment point. This is a key point when determining how the load (you falling), etc. actually hits the protection point i.e. on a very zig-zag route, or one with deeper protection points,taking care to align the rope in a straighter line will ultimately make all protection anchor points safer by keeping them aligned as to how they were placed. I've found that the larger the hex nut, the longer the cord should be. About an inch per size, make sure you tie a triple fisherman knot, and keep the knot midway between nut and attachment bight in the cord.

Bryan Vernetson

June 25, 2009

That is a good question. Usually the tensile (static) strength is in lbf. and the breaking (dynamic) strength is in kN. Since this is a static cord the breaking strength is weaker because this should be used only for static conditions (anchors, etc). I think i am right, hope this helps!

Nathan Webster

February 28, 2011

lbf and kN are both units of force. I would guess it is a typo. From Sterling Ropes website, the mean breaking strength is 4271 lbf/19.0kN

http://www.sterlingrope.com/product/299384/A060PC%20cordelette/_/6mm_PowerCORD_Cordelette

James Jenden

August 22, 2011

The impact force of a rope refers to what the force of impact would be on a climber if he/she took a fall of factor 1.77. Therefore the figure would mean the impact force would only be 7.4kN. Whether this number is actually correct or not, I have no idea...

Mathew Lavery

August 13, 2012

Backcountry wrote the specs correctly.
The breaking weight for static loads is 4800 lbs. Meaning you can hang anything less than that weight from this rope.
The 7.4kN rating refers to impact. Not meaning that this will cushion a fall to only be 7.4kN (it has no stretch and will not cushion a fall at all) but rather that 7.4kN of force will break the cord. That can be generated very easily by a body in motion. A fall factor 1 will generate over this much force. So make sure there is not slack is the system.

Lots of great info here: http://dmmclimbing.com/knowledge/how-to-break-nylon-dyneema-slings/

WelshGuy

May 31, 2014

Worth a read .... http://wallrat.com/PDF_Files/forcesinleadfalls.pdf

Bob Gipple

April 2, 2009

it's made from the hair of club gear managers that didn't go on the spring break trip...

Hydrophilic

June 14, 2009

I use this as my cordelette for canyoneering and trad climbs...EXCELLENT durability and strength...the only 2 things you give up with it is a little weight (it's lighter than a 6 or 7 mm of the same length of regular cord) and it's very low stretch (not dynamic) so don't expect it to absorb force if shock loaded. Once you figure that into your set up, then your ready. I have sat on mine dragging it across many sandstone canyons in Zion as i have squeezed through tight slot canyons and it BARELY retains a blemish. This is hardcore cord...no pun intended...
PS: Despite what Mr. Bohanon says below, it is not just a standard nylon cord, just read that product description above closely..."The 6mm PowerCord is stronger than standard nylon, breaking at a astronomical 4800lb." So it's as strong as a solid carabiner or any other part of the system (rope, harness, etc.) so unless your planning to hang your Mini Cooper from it, you have no worries. (but it still most likely would hold it)

Angus Bohanon

June 24, 2009

Despite what Mr. Pretzel says, he's full of crap. It IS nylon cord, and the only thing proprietary to Sterling is the braiding pattern that makes it different. Also, the breaking strength is 7.2 kN, which is around 1600 pounds, not 4800. The description is wrong in that respect. That also means that it is NOT as strong as a solid carabiner (usually around 24kN/5400 pounds) OR a rope. Add to that the fact that a knot like a figure 8 decreases the strength of the material by around 15% and this is undoubtedly the weakest point in the system. That said, it is perfectly safe. Unless you tie in directly to the cord and fall on it (don't), you will never be able to generate 7.2 kN of force on a given point in the cord. If it's looped and equalized, you can count on at least double the strength of one strand, so you're looking at a strength of around 15 kN. The WORST lab-generated factor 2 lead falls have been logged at around 12.5 kN, so you're golden. A fall like that is going to seriously mess you up anyway.

James S.

July 12, 2010

Sterling's website (http://www.sterlingrope.com/product/299074/A060Power/_/6mm_PowerCORD) lists the following for 6mm powercord strength:

MBS lbs (kN) 4,789 (21.3)


There is no mention of "7.2 kN" anywhere on the product page; so, it seems reasonable to assume the "7.2 kN" listed here at backcountry is a typo. I would go with the manufacturer's stated minimum breaking strength (MBS) of 21.3 kN.

Also, in Sterling's technical manual (available at the link listed above) they refer to the Technora® core fibers as "High Tenacity Aramid Fibers" akin to Twaron® and Kevlar®. I don't no if they're still technically "nylon" or its chemical equivalent, but it's clear they're not simply 'standard' nylon.

I hope that helps.