How to Tell the Difference Between a Nylon and Polyester Rope

The purpose of this entry is to provide a test that will distinguish between a nylon and polyester rope. There exists a common dye called Black Rit. Nylon will absorb this dye and darken. Polyester will not darken. It will retain its original color when soaked in this dye.

The benefit of this test is that it prevents the improper use of a nylon rope in the dynamic climbing line system, where the rope system encounters potentially damaging friction over a tree crotch and at the friction hitch.

This is the link that defines this test: http://www.tensiontech.com/tools_guides/fibres_guide.html

This link goes on to define a similar dye test that actually differentiates between a Nylon 6 and Nylon 6,6 rope. Not all nylon ropes are made the same. The Nylon 6 rope is rated at a melting point lower than a polyester rope. The Nylon 6,6 rope melts in a range similar to a polyester rope.

It's unfortunate that the rope manufacturers over emphasize the melting point rating. There are other characteristics that define performance. All nylons weaken dramatically below the melting point. All nylons also weaken when exposed to water. Polyester is significantly more resistant to heat and water.

Thus a polyester rope is preferred for the friction systems used in tree climbing. This simple dye test will confirm that the right rope is in use. Your rope is an investment of money. Moreover, it's your life line. You should know your rope.

Regards,
Jim

Thanks for posting the link. I'll be studying that one.

If a climber has a rope but doesn't know the manufacturer, then maybe they shouldn't be climbing on it. The climber should be able to go to the maker's website and pull up all related information without having to do forensic testing.

Having a test available is academic. Knowing your tools is more important.

Maybe I'm missing something though. Can you explain a time when a person might want to test a rope? Would the test be able to tell if the fibers are a blend of materials? It seems like this dye test would be like using the spray bottle that the CSI crew uses to find blood. Fine and dandy, but who does the blood belong to? That requires more tests.

Tom

Tom,

I have a personal concern that there will be people to convert their nylon rock climbing ropes into tree climbing ropes. The professional publications fail to offer alerts. Easily 96% of the people that read this entry will not do the test. However 100% will be better informed that there are serious consequences in not regarding the type of rope. Let's face it. All ropes look the same. In reality they aren't the same.

The fact that nylon readily absorbs dye is a clear demonstration that it is absorbing water. When water is absorded, a rope weakens. Polyester absorbs less than 1% water, and it retains its strength.

Your other points are well understood. Such a test is only qualitative, not quantitive. However it's interesting that you brought up the issue about fiber blends in ropes. I'm curious if more ropes will have some blending. I'll be testing.

Regards,
JimK

Umm, can somebody do a test for me, because I don't have the materials handy-
doesnt nylon and polyester have different burnsmoke characteristics?

I think, but am not sure I read a chart in On Rope or Budworths "Challenging Knots,"

Nylon is, umm, black smoke and melty,
while polyester is white fishysmell smokey? I cant exactly remember, but if someone has the gear to burn, let us know how they differ.

Isn't this testing rather academic? So, there is a rope that has been id'ed to be nylon. Now what do you do? What is the strength? What's the use history? Would anyone use a rope that they didn't know about for anything besides dog leashes or tieing down brush?

There are vendors at the flea market who have short hanks of rope. Nice looking stuff. I ask them what company makes it and they have no clue. If you know who makes the rope you can probably find out the specs by giving a pic description. Also, some companies weave in a tiny tracer ribbon with id information.

Tom

The objective of this thread is to support the mission of TCI. The result of that mission is to ultimately grow the number of safe recreational climbers. The voice of the experienced climbers will be the force that draws new membership. Education and training of the new members will retain them and keep them safe.

There exists a specific beginning point that motivated the initial entry of this thread. The beginning point of this discussion originates from the fact that TCI reports the DRT will destroy a nylon kernmantle rope. Similarly, there exists a specific end point to this thread. New members need to be educated to the subtleties of rope properties.

The beginning point is the TCI statement as follows:
http://www.treeclimbing.com/treegear.html

Tree-climbing rope, or arborist rope, uses a polyester-Dacron exterior sheath instead of the nylon sheathes found on rock-climbing ropes. Unlike nylon, polyester has a high heat tolerance… The main technique used by tree climbers, double rope technique, requires the rope to run over a branch …If you were to use one of those pretty (nylon) mountain-climbing ropes (kermantle), you'd melt the thin (nylon) outside sheath on the first climb! Not good!
This TCI statement is one of very few published statements that explicitly states do not use a nylon rope in the DRT method over a tree limb. The TCI statement is validated on the polymeric differences between nylon and polyester. The parameter that makes this distinction is the glass transition temperature (Tg), not the melting point. Ropes are designed first on the basis of Tg. The melting point is important but ranks lower as a design characteristic. The advertisement of the melting point by the rope manufacturers is a marketing decision. Because the melting point makes a significantly higher number than the Tg, it establishes confidence in the consumer. The Tg is a more complex concept and opens the door to discussing the potential of product failures. The Tg helps you to see the true mechanical properties of a rope. Though a polyester and nylon filament can have similar melting points, the nylon has a lower Tg, meaning the nylon fiber loses rigidity before the polyester. This is why the polyester filament is more abrasion resistant than the nylon. A wet nylon filament has an alarmingly lower Tg than a dry nylon filament. Wet polyester filament remains basically unchanged. The concern for the arborist is on the contact surface of the rope cover, not the core. This is why New Tribe’s ropes have polyester covers with various types of cores. The focus of this thread was to educate the general public on the benefit and safe use of a climbing rope made with a polyester sheath. Given that the arborist is always using a polyester cover/sheath in a DRT, is the nylon core safe when wet? The answer is yes, but the strength is reduced. When dry, the strength returns.

This site supports the statement that Tg is more important than melt point in the mechanical properties of ropes. A rope is literally a lot of polymer filaments woven together. http://www.missouri.edu/~crrwww/katti/Thermal%20Behavior%20of%20Polymers.pdf

This site provides the chemistry in simple terms that establishes the differences between polyester and nylon polymers. http://www.psrc.usm.edu/macrog/nylon.htm

The end point of this thread is to create an educational module for the new recreational tree climber from the voice of the experienced climbers. That educational experience needs to concisely establish the knowledge that there are differences between a nylon and polyester rope. Moreover, they need to understand with certainty that the polyester rope(cover) is the right choice for DRT in a tree crotch. How can that message be conveyed? Imagine 30 boy scouts sitting around a camp fire the night before climbing. Imagine 5 have attention deficit syndrome. The objective is for them to completely understand and identify the proper rope selection for DRT in a tree.

This generation of participants in the Message Board represents the current voice of the experienced climber. Like other organizations throughout history, consensus will derive the best practices and those practices will evolve. Growth comes from the retention of new members. Retention of membership comes from the experienced climber providing an educational process to the new member. Safe recreational tree climbing is endowed with a depth of learning experiences.

Regards,
JimK

Originally posted by JimK
...Let's face it. All ropes look the same. In reality they aren't the same...

I beg to differ. If I took you to the coast of Antartica and brought you to a flock of 2000 penguins and asked you to find a particular one, you probably wouldn't be able to. You might comment that, "they all are the same!"

If I brought a baby penguin to that same flock and asked it to find it's mommy, it would find it quite quickly.

To the baby, they are not all the same. He knows what to look for.

Tom and Jim both have good points. Jim is showing some good ways to figure out part of the puzzle. But it's just a piece. You cannot just dip a rope in some dye then say it's good to climb on...and it doesn't seem that Jim is insinuating that. Using what Jim is showing, you can put it into what Tom is saying. It seems like Jim is helping you to find one piece of the puzzle and Tom is talking about the whole puzzle.

It's important to look at things from both perspectives. And most importantly, know what you're looking for. Learn about your equipment. Be the baby penguin.

love
nick

The purpose of this entry is to summarize the key points thus far.

In this thread, there's no agreement that nylon or polyester are different in mechanical properties below the melting point. It's agreed that some types of nylon and polyester have an overlapping melt point. Additionally opinions fail to agree that nylon should be avoided in a crotch using the DRT.

Survey of the rope suppliers has shown only polyester covers for arborist. New Tribe was provided as one example.

Can someone provide a link where a rope supplier specifies a nylon covered rope for use in a tree? At that point, the purpose of this thread doesn't exist.

There is agreement that polyester is more abrasion resistant than nylon. There's disagreement that abrasion resistance is a factor in selecting a rope for DRT in a tree crotch.

Regards,
JimK

The purpose of this entry is to provide a survey of ropes for aborists. These sites are promoting exclusively polyester ropes for the arborist.

This link where the UK arborists have published that a polyester rope is preferred for tree work.
SELECTION AND USE OF ARBORIST ROPE
http://216.239.39.104/search?q=cache:7wxWNIpoBawJ:www.treevolution.co.uk/documents/SELECTION%2520AND%2520USE%2520OF%2520ROPES%2520FOR%2520ARBORISTS.doc+SELECTION+AND+USE+OF+ARBORIST+ROPE&hl=en&ie=UTF-8

This is the general rule for tree work. It is accepted that polyester has the perfect compromise of properties required for tree work operations i.e. high melting point and high strength

This tree climbing site from The Netherlands speaks exclusively on the use of polyester ropes for arborists.
http://www.euronet.nl/users/kazil/bi-tree.html

The website for New England Rope was surveyed. They're only selling polyester ropes where the adjective arborist is used.
http://www.neropes.com/arborist/default.htm

100% of Yale rope for the arborists is polyester. http://www.yalecordage.com/html/pdf/Arborist.pdf

The Sampson catalogue continues the trend without exception. All of their arborist ropes are polyester.
http://www.samsonrope.com/home/pdf/new/ARBCAT_F.PDF

In conclusion, the arborists aren't strongly specifying the proper rope to the general public entering into recreational tree climbing - polyester.

Regards,
Jim

The purpose of this entry is to present examples of the arborist community missing the opportunity to publish polyester as the specified rope for tree work. There exists the voice of the experienced tree climber which keeps the newer climbers on track. However as a broad community, the arborist publications by-pass the opportunity to report on the numerous beneficial properties of the polyester rope. Perhaps there's a tendency to default on the technical issues to the rope supplier. At the end of the day, the rope supplier is only focused linear feet of rope sold, not about the general public making a rope selection for tree climbing.

This Tree Climbers International site makes one of the few black and white statements from an arborist community that polyester is the choice for a tree climb. "The Tree Climbers Companion to Tree Climbing" Jepson, 2nd makes no productive reference to rope selection. The USDA “National Tree Climbing Guide” overlooks any mention that polyester is the right choice. http://www.fs.fed.us/treeclimbing/policy/pdf01672802pt1.pdf
http://www.fs.fed.us/treeclimbing/policy/pdf01672802pt2.pdf

The fundamental reason that polyester is the right choice is in the chemistry of the rope filament. Polyester and Nylon soften differently under the melting point. Additionally, nylon softens alarmingly more when wet. The Perlon Nylon 6 rope is significantly worse than the Dupont 707 Nylon 6-6 filament. The rope engineers are talking about Tg, not melt point with Dupont. The rope companies are specifying polyester for tree work.

There exists a continuum of how the general public can choose a rope. The worse case is based on price at the hardware store. A likely case is the rock climber crossing over, assuming the same techniques apply.

Thus the purpose of this thread is to ask of the arborist community how to better educate the general public on rope selection for tree climbing.

Regards,
JimK

The purpose of this entry is to ask if there are tree climbing publications that deal with rope specification. As mentioned previously, "The Tree Climber's Companion" Jepson 2nd defaults to quoting ANSI Z133.1-2000 which states the arborist rope will have a minimum diameter of 1/2 inch or 12.5mm and a minimum breaking strength of 5400 pounds or 24kN. Jepson mentioned exceptions, but he didn't elaborate.

Regards,
Jim

The purpose of this entry is to provide comments for the record.

I have a nylon kernmantle rope and plan on using it in tree climbing. I also have a polyester rope. I'll use each under specified conditions.

Stevebullman sounds like an intelligent climber. I would climb with him.

All materials degrade. Nylon degrades faster under abraisive conditions and UV exposure. Of course wet nylon has an accelerated degradation. Polyester degrades slower under tree climbing conditions. I plan on using my polyester rope as if it was made of nylon.

I remain focused on the education of the general public until they reach a knowledgeable level and have control of the conditions.

TCI shared an experience that one climb resulted in the destruction of a nylon sheath. This is impossible to dispute, because we don't know the conditions. If it was a thin sheath of Nylon 6 used on a wet day, it's very feasible. Other factors are the abraisive characteristics of the cambium and the weight of the climber. Why use a thickly sheathed Nylon 6,6 rope on a dry day in an unprotected tree crotch knowing this potential?

I'm here for recreation, not suggesting the experiences of others is invalid.

The more that I learn about TCI, the more I like. They seem to be a group of people that deeply care with passion. I don't see the need to cast arbitrary disputes.

There seems to be a common ground. I'm curious if it will be recognized?

Regards,
Jim

Boy, you guys have sure been going at this for a while!

One thing to keep in mind is that dynamic (nylon, kernmantle) lines have no use in tree climbing, unless you are anticipating a leader fall. I have had occasions working dead trees where I have needed to climb on lead above my tie in. At these times a dynamic line would be appropriate. At all other times, a polyester low stretch line is what you want, as low stretch is your friend when doing tree work, as you are constantly going on and off tension on the line.

Of course abrasion and UV factors are important, however, dynamic kermantle lines are built tough enough to survive the sometimes abrasive conditions found on a climb on rough ground.

I'm surprised to hear that the Fly uses a nylon core, as nylon typically has much more stretch and thus energy absorption than polyester. And I'm sure it is similar to other arbo lines, having extremely low stretch, which is under half what trad static rescue and caving lines have.

Here's a pic from the fir where I took out 15 feet of very dead snag top, and was belayed up on lead while doing it. It is a 5.5 foot dbh fir, still 120 feet tall at its 28 inch new top diameter. I've been in it twice, most recently this winter, to cut out more deadwood and lighten some heavy branches. Likely, we'll be removing this poor old declining tree soon, as a new hiouse has been built 30 feet away. Good thing it leans away from structures, and may be able to be felled, as I'd figure I'd have to charge $10-15K to dismantle it. either way, the landscape plants and fence will have to be moved, as no wood lowering is possible or in any way safe! Nor would limb lowering up high be safe, due to the badly decaying tree.

damn i love this thread! so many excellent points brought up!!!!!

as far as the NEW climber is concerned, YES i feel they should be on nothing but Arborist rope, BECAUSE THEY WILL NOT BE AWARE OF THE VARIOUS TYPES OF FIBERS/CONSTRUCTION/MELTING POINTS ETC!!

HOWEVER having said that, i think it is LUDICRIOUS to say that ONLY a certain type of rope should be used....(oh boy, here comes the hatemail... ) . There are rope users out there form many backgrounds, whoa re VERY WELL EDUCATED on the different kinds of ropes, fibers, melting points, abrasion issues etc. They are better able to pick and choose a rope THAT SUITS THEIR NEEDS better than the beginner tree climber. Should we tell cavers/SARtechs to abandon their nylon kernmantle ropes that they rappel on in wet, muddy, and high degrees of friction conditions? no. those ropes work just fine with water on/in them, work just fine in high friction conditions, and any experienced rope user will be aware of it and any risks. Tree climbing might be newer than these activities, but the concept of running a rope through friction saver rings at the anchor point and bridging it at the harness is'nt new at all, it dates back to caving & big wall climbing times of the early 50,60's 70's80's90's. nymon kermantles work just fine for that area, just as it works for trees. nothing new here other than running rope on rope (Blakes) which is seriously frowned upon in many SAR/SRT circles. (hence my adaptation to Hybrid DRT/SRT). Sometimes i really have to wonder if arb rope was created to move away from using hardware, and to distant ones self from the wall rats/cavers...after all all of these activities have their elitist "lookdowntheirnoses" at other areas of rope use dont they now however having said that i do appreciate the simplicity of using just a rope with a B42/52 and a harness and cambuim saver...less gear to lug around....i do both for the record...



I for one have evolved a DRT/SRT "HYBRID" style, (using static kernmantle rope,) where there is NO ABRASION or heat issues when ascending or descending, because my rope runs thru a pulley at the anchor point, and instead of B42/B53 or prussick knots in the system, there is mechanical "prussicks" (hardware). I also NEVER climb above that anchor, and if i do i switch over to arb rope and conventional ddrt drt dddddrtr dddrrrrttt (this is confusing for a lot of people yes???) style. That static kernmantle rope has thousands of hardware (gear) ascends/decends on it, and NOT ONE single mm of glazing or other damage. it looks new. By eliminating the high amount of friction of DdRT/drt, (by eliminating the rope on rope contact of the Blakes)i have made it perfectly ok to use a static kernmantle nylon(with polyester btw) rope for treeclimbing. I put static Kermantle ropes thru FAR GREATER STRESS AND ABRASION AND HEAT when i'm lowering a stretcher over a rockface, muddy caves, etc. Tree Climbing is a relatively sterile and clean environment, when it comes to ropes. Oh sure, you have a branch., well whoppdedoo...use a ringed friction saver (btw stainless steel rings run WAY cooler than aluminum or reg steel) or rig a pulley at your anchor point. No friction, SMOOTHER than "traditional treeclimbing methods), and faster.




I also am fully AWARE of what combo's of rope (for the splittail/blakes/prussick) will or will not work with the ropes i own...because i have tested all of the them on low angle scenarios.

so as you can see, there are many views on the subject. each to their own, but we all seem to agree that fresh climbers should be restricted to trad arborist rope!!

SRT-TECH, always pouring gas on the fire!