I was thumbing through a catalog today, and I saw for the millionth time "accessory cord". It made me curious for the hundredth time, and I started looking into it. And I found this.

5mm dia, supposedly a one TON breaking strength, and it's $20+shipping for a 20 foot spool. It's pricier than paracord, but for tthe added strength, it might be worthwhile even though I like a dynamic line better for most things.

My question is, has anyone worked with this kind of cord before, and if so, how does it knot compaired to paracord?

I use this type of cord often, for knot tying practice (a hobby of mine). Notice I said "type of cord". I have several different 5mm cords I practice with and they are all different. Some are stiffer, some are harder, some are softer, some are more flexible than others. They were all bought at outdoor recreation and/or climbing supply stores, so they are all good quality cord - just different from each other.

You can't really tell how a cord handles by looking at a picture or reading a description. And "holding a knot well" depends on the use. For example, stiff, hard cords do not hold bends as well as softer cords, but they're great when used for constrictor knots around softer material.

Thicker cords do not usually tend to jam up as much as smaller cords. So a smaller cord may feel like it holds "tighter" (because it's jammed). However, untying a knot in thinner cord can be near impossible sometimes. Sometimes you have to give up and cut the cord.

The above are just generalizations, and are not hard and fast rules for every cord in every situation. That's why you need to know several different knots for a given purpose. Depending on the specific cord you have, your previously tested "secure" knots may slip and other knots you considered less trustworthy may hold like a bulldog. In my experience, a softer more flexible cord tends to find use in more varied situations than a stiff or hard cord. YMMV of course.

This looks like the tech cord from New England Rope, commonly refered to as New England Tech Cord. I've not seen it branded as "Maxim" before, Google turns it up as the 'climbing' page on the New England Rope site:

Maxim Climbing
click on accessory cord
click on Tech Cord; Technical Data Sheet

You can compare that to the sheet from the Safety & Rescue page. It's the same stuff. The key is the Technora Core.

I carry some 3mm (3100lbs) New England Tech Cord in my pack and it is very cool stuff. However, there are trade offs. It is somewhat stiff and you can't melt the ends due to the high melting point (this could be an advantage). Probably the best bet is to use waxed whipping twine.

You can find some ramblings about high tech cords in this CPF thread.

The 3mm is going to be thicker and much stiffer than paracord, and the 5mm even more so.

My understanding is that they can lose a lot of their strength depending on the knot.

big pic of 3mm tech cord

-john

* I haven't found a source for the 3mm in a long time.

(oh, also be careful. they also sell an 'accessory cord' which is not the same as their 'tech cord')

OK, so does anyone know the difference between a "tech cord" and an "accessory cord"?

Basically, what I'm really interested in is using it replace paracord in shelter making, specifically the hanging of the hammock (550 line hasn't broken and dumped me yet, but I'm coming across such stories more and more) and to act as a "ridgeline" when using tarps as structure under snow in winter.

A couple of things to consider are cost and multiple use potential. Tech./accessory cord is not designed like paracord and does not have the distinct multiple inner core bundles; it is a single bundle of continuous fibers, which might not provide as much potential in terms of various uses.

Paracord will likely pack down better then tech/accessory cord and costs considerable less. Yes, tech./accessory cord has greater load capacity then paracord, but if you plan on using it for shelter construction, I would stick to the paracord.

Pete

If you're concerned about the strength of 550 cord, here's a story of how we've used it. We raised a 50' radio tower with antenna by running a double length of 550 cord from the tower, through an eye hook on the roof peak of a garage down to the bumper of a Jeep. I was more concerned about the Jepp keeping traction than the strength of the 550 cord.

In this *specific* case, they are very different beasts. The tech cord has a Technora (fancy, high tech fiber) core and the accessory cord has a more normal core. (Nylon).

I think you need to make sure that you examine the specific cord when comparing as I don't think you can assume a given "tech cord" will be made the same way.

As far as I understand, the weakness of this product is tying/untying knots or otherwise sharp bends. I think this is related to what Pete says -- there is no weave to the inner core, so if you break a fiber anywhere along the length, it stays broken and reduces strength. Over time, that would add up.

I think the knot issue also is part of a "shear" concern, where the knot acts as a sharp bend which increases the chance of breakage. I assume this is partially due to the lack of give in this material, but I'm certainly no expert.

How much of an issue this would be, I don't know. But I tend to keep my tech cord for emergency use where I want to have a very strong cord, and would plan to retire it fairly quickly.

Again, as Pete suggests, for your utility use, the paracord/accessory cord may be better.

Probably just inspect it and replace it before it gets too ratty, and maybe carry some spare.

I tend to also like Spectra cord which is another (but different) high tech cord. This is braided and much more flexible. It is a bit 'slippery'. The 7/64" is very small, light (I think it floats) and rated for 1200lbs. It melts (makes it easier to deal with the ends) and has some give.

While you may perfer paracord/accessory cord for everyday use, the Spectra cord is a nice backup cord because it is very light and compresses well.

YMMV.

-john

Spectra line does not melt, the sheath does but the core will not.
I used to work in a climbing shop and cut the stuff for customers all the time. You need to cut back the core and the melt the sheath around it sealing the core.
Spectra and its cousins are for climbing applications such as creating anchors. It is not ok to use as a prussik. The Maxim product is a little different in that it can be used for friction knots.

All in all 550 is a better all around choice.

I know from direct experience, Spectra cord from Berkeleypoint.com does melt (it has no sheath), and Technora based core of the New England Tech Cord does not (but as you point out, the Nylon sheath does).

Take a look at this test of high tech cord and you'll see the melting point of Spectra is noted as low.

Comparative Testing of High Strength Cord

-john

550 cord has an almost mythical status as the end all be all of cord here. I've got hundreds of feet of it and I use it for a number of things. However I also have vairous sizes of tech cord that I use. Paracord is great but it has a lot of stretch, it can be almost impossible to untie knots from in some cases, and while it's strong, it's not umbreakable, it's abrasion resistance isn't as high as tech cord and I'd never trust my weight to it. On the other hand, tech cord is expensive, some knots don't work as well with it (easily worked around by tying knots that do work with it.) For holding a hammock up, I use tech cord, I don't want to roll over and fall when the paracord breaks. For hoisting my pack in a tree though to keep critters out of it I use paracord.

Different cords for different uses. Paracord works for most but like I said, I'd never trust my weight to it.

I am only familiar with what is used for rock climbimg.
I am not familiar with what BerkeleyPoint is selling; it must be a version for marine applications. I will have to drive by the BP store in Berkeley and check the stuff out.
Sometimes it looks like it melts but it is not melting with the sheath and the ends are not sealed.
.

Take a look at that document I linked. Spectra (R) by Allied Signal has a fairly low melting point. Technora (R) by Teijin has a quite high melting point.

Of course, you have to look at the specs for any given product to determine what materials they use.

-john

John,
So you have been able to fuse together the seperate strands of the Spectra cord sold by BP? Please tell us how you did it. It will melt with plain old fire for me, but the strands do not fuse together. BP recommends using whipping twine.

Yes, I melted the end of the Spectra cord from BP with a lighter. You are right, it tends to melt back and not fuse together as easily, but you should be able to get something good enough to keep it from unraveling.

As a side effect, you may get a bit of a 'ball' of melted stuff. If that isn't acceptable you'll probably have to try a different approach. Maybe wipe it against a hot object like a soldering iron or something.

-john

This is from a website;
http://info-central.org/recovery_cordinfo.shtml
Spectra Cord
Spectra cord comes in 2.0mm and 5.5mm diameters and is much like Kevlar in its properties. Spectra will not melt or stretch and is extremely strong for it's size and weight. It is so strong, climbing manufacturers routinely say it is 10 times stronger than steel. What makes this cord different is that the spectra fibers are on the inside with a nylon sheath woven over them to protect them from abrasion. Note: The spectra cord is relatively stiff and slick, because of this, only a triple fisherman's knot is recommended to tie it with.


This is from REI's website;
Cut about an inch longer than you need. Work a half inch of the core out of the sheath and cut it off. Smooth the sheath back and melt it into a smooth, hard "cap" on the end of the cord. This method of finishing will allow the cord to fit into the holes drilled in hexentrics. To get a clean cut on Spectra® cord, it may be necessary to use cable cutters.

The mfg web site claims 300F.

http://www.honeywell.com/sites/sm/afc/spectra_fiber.htm



This jives with what Tom Moyer's study states:

http://www.xmission.com/~tmoyer/testing/High_Strength_Cord.pdf



Compare to Kevlar (~932F) or Technora ~900F.

If I recall my Ray Bradbury, paper burns at 451F, so therefor it makes sense that it should be possible to melt Spectra with an open flame.

Also note that in the link you provided, they refer to Maxim as a Spectra product, but as we found, Maxim appears to be the name of a New England Rope Technora product, not a Spectra product.

-john

Well, part of why I was looking at tech cord for the hammock is becuase I haven't been called a lightweight in a while. :P I usually use a wrap of nylon webbing when camping, and then attach my cords to that, but if I can have my main lines also be how I anchor to the tree, that means that when I make a new hammock this winter, I'll have one that packs smaller.

As for shelter building, the idea I had was to make a something I can only call a "speedy cave" in winter, which is your basic tarp A-frame pitched in a spot you've dug down to ground in, then you pack the snow on top. I've tried them before, the cordage has a habit of breaking when there is a foot or so of snow on top of one of the heavy duty survival blankets (not the baked potato ones, the green on one side, silver on the other tarp ones). Never having had much luck with them in the past, I've not tried to build one in years, but after looking at Buffalo last week and them getting hit about a year after we got a nearly identical storm here, I've been giving it some more thought.

I'm just looking for somethign that is about as thick as paracord, maybe twice as heavy, and able to hold about 700 pounds reliably. And no, I'm not THAT big, wet snow is heavy. :P

No you are right; I just grabbed a piece of spectra off my climbing harness. After citting a piece I took out the spectra core and melted it with a lighter.
I think I associated the fact that the hot knife at the store could never make a cut; we always used a FRESH razor blade to make a clean cut. Then we melted the sheath by itself.
Turns out it does melt it just melts very differently than the sheath material which is regular perlon.

A lot of climbers refer to all varieties of specialty cord wrongly as spectra. But that website turned out to be wrong on more than one thing.

Ironraven,

I can picture your speedy cave, and can imagine the paracord breaking! :-)

I think a 3mm Technora cord would support the weight you suggest just fine. It's very small, light and very strong. You should try it out and let us know how it goes! ;-)

Billy,

Several good points. I've found a fresh razor as one of the few ways to get a nice clean cut on most of these high tech cords, esp. the Technora. That stuff is packed in there tight!

I'll have to try the melting-the-sheath technique you reference from the REI web site. I have really struggled with finding a good end for the Technora cord.

And lastly, yes, I think a lot of the high tech cords tend to blur together. For a long time I mistakenly thought the Kelty Triptease cord was Technora, when in fact is is Spectra.

Triptease is cool cord too BTW. Very thin and light but still quite strong. Very flexible (not tightly packed internally) and has reflective material woven in.

-john

Have you a favored source for 3mm Technora? Preferable one that is wallet friendly- mine is kinda bruised.

Well, there's the rub. I haven't seen any in a while.

After a fair amount of Googling, I found this:

http://www.wesspur.com/rope/bulk-prusik-cord.html

I don't have any experience with the products on that page, but the Ultra Tech prusik cord with Technora core sounds similar.

Interestingly enough, they also have what appears to be braided Technora cord. Hmm.

-john

Then yes, tech/accessory cord would likely be best. Just keep in mind, when wrapping the tree for your hammock; it may take several wraps to obtain the same degree of friction that you obtain from the webbing. You may want to consider padding under the tech/accessory with some canvas, tarp, cloth or carpet, to protect the trees from damage.

Pete

This cord is made out of SPECTRA that is even stronger then KEVLAR. Its main disadvantage is it has a low melting point. I use it for climging and it is great for making slings etc... One of the hard thing to deal with is cutting it. I usually have the climbing shop cut it with an electric heat knife. It will work if you want to haul some thing or as a lifeline etc... but 550 cord is better for all purpose. You can also get it in I think a 3 or 2 mm for tent guidelines.
cheers

Atoz,

Check my post in this thread dated "10/16/06 11:05 PM". The product discussed has a Technora core, not a Spectra core. But similar to Spectra, and as you point out, Technora can be a bit of work to cut. As BillyM points out in his "10/17/06 06:31 PM" post, a fresh razor usually works pretty well.

-john

I was thinking of using a length of 1" tubular as a shroud around the cord for that very reason.

Excellent idea, you may still need to wrap more then once to achieve the necessary friction to prevent the “loop” from working it’s way down the tree.

Pete

That was the plan. I've got a couple of lengths of 1" tubular that are really beat up that are pretty well worn, but clean, so I figured they'd also protect the line from grit getting ground in and from having to pick pine pitch out of the line.