Home » Knowledge Library » Rope Fibers

Rope Fibers

Disclaimer: The information on this page is the result of JRB’s research and experience, offered in good faith and without bias. If anything on this page is incorrect or missing, please leave a website comment and it will be researched and corrected as appropriate.

Page contents:

The fibers documented on this page can be used in the construction of ropes, cords and webbing. Be aware that rope and cord are frequently designed with different fibers in the core vs the sheath.

Cord
Rope
Webbing

Application knowledge

This page is about the fibers, not the applications. The person who is choosing to employ a cord or rope for an application needs to understand the application. For example, a simple Google search reveals the following. It would seem obvious that we can’t use ropes and cords on a lifeline which are not highly heat resistant. And yet, they are for sale.

How hot can a friction hitch get in a climbing fall?

Attributes

JRB’s research identified the following list of considerations regarding fibers which are used to make our ropes and cords:

  1. Strength
  2. Heat Resistance
  3. Abrasion Resistance
  4. Density / weight
  5. Stretch / Elongation
  6. Flexibility
  7. Resistance to UV light
  8. Water resistance/absorption
  9. Memory / hysteresis
  10. Typical Applications

Modern Fiber Families

Beyond Polyester and Nylon (which have been around for a long time), there are an evolving set of ‘families’ of modern fiber types. Understanding the families will help us understand the similarities and differences in the fibers given that there are trademark branded variants of some of these material types. Also, this reference from our friends at Marlow Ropes is an EXCELLENT summary.

Marlow Ropes – Material Types

  • Aramids – Aramids are a family of low stretch, high strength fibers with good resistance to creep and which can tolerate extremely high temperatures. However, they have generally poor UV and abrasion resistance. Aramids do not bend well and not ideal for tying knots. Nominal stretch is <5% at break.
  • HMPE – High Modulus Polyethylene. Evolved after Aramids. High strength and low stretch: Nominal stretch is <4% at break. Poor heat resistance, and therefore not ideal for climbing ropes and related accessory cords for friction hitches.
  • UHMWPE – Ultra High Molecular Weight Polyethylene, is considered a subcategory of HMPE. Stronger than HMPE, resistant to impact, abrasion, cuts, chemicals, and UV. Very little stretch. Like HMPE, poor heat resistance. This family includes these alternative names as well:
    • UHMPE – Ultra High Modulus Polyethylene
    • HPPE – High Performance Polyethylene

The Fibers

Manila

This natural fiber rope was once the standard for ropes, used in nautical applications since the 1600’s, with evidence of usage from many centuries before. Manila rope is made from fibers of the abaca plant. In modern day, although you may find some at a hardware store, it is not recommended for any life safety applications. Manila must be handled and stored with care as any dampness will cause it to rot.

Nylon

Nylon (or polyamide) is the fiber used in the first synthetic fiber rope manufactured. Nominal stretch is 28% at break. Therefore popular in dynamic ropes due to its elasticity, and shock absorption potential. Good abrasion resistance. Does not rot. Is not damaged by oils, gasoline, grease, etc. Good UV resistance.

Polyester

Polyester is a thermosetting plastic, meaning that it cannot be re-melted with heat. Very strong and excellent abrasion resistance (better than nylon). Lower stretch than nylon, nominally 18% at break. Better UV resistance than Nylon.

Polyethylene (PE)

Polyethylene is a thermoplastic substance (formed with heat, and hardened by cooling). Polyethylene ropes are lightweight, strong, and float, making them popular in marine applications. Does not rot and is unaffected by water, oil, gasoline, and most chemicals. Better abrasion resistance than PP. Good UV resistance.

Polypropylene (PP / Poly)

Generally lighter and stronger than PE. Typically used in industrial applications. Good UV resistance. Not buoyant. Stiffer than polyester. Nominal stretch is 22% at break.

Technora®

An aramid fiber with high strength, extremely heat tolerant, and good chemical resistance. Technora® is a registered trademark of Teijin. Note: JRB likes Technora on the sheath of a rope or cord, but generally not in the core, due to the excessive ‘memory’ it causes after removing a knot.

Dyneema®

Dyneema is an UHMWPE fiber. Very strong, very little stretch, light weight (floats), but poor heat resistance. Dyneema’s melting point is between 144°C and 152°C (291°F to 306°F) . Dyneema is available in different formulations including: SK-60, SK-75, SK-78, SK-90, listed in order of increasing strength. Dyneema® is a registered trademark of DSM Dyneema. Because of the lack of heat resistance, JRB does not recommend it as part of the rope or cords on the climbing line, but fine on a bridge or accessory application.

Spectra®

Spectra is an UHMWPE fiber. Very strong, very little stretch. Poor heat resistance. Spectra® is a registered trademark of Honeywell. Because of the lack of heat resistance, JRB does not recommend it as a material in the rope or cords on the climbing line, but fine on a bridge.

AmSteel®

AmSteel® is a registered trademark of Samson Rope. Effectively, it can be considered Sampson’s branded variant of Dyneema, a HMPE/UHMWPE fiber. It is formulated as a non-sheathed, single braid, 12 strand rope, which is very flexible and fatigue resistant. It has very high strength and very low stretch. It is difficult to find precise information on its melting point, except that it is similar to Dyneema, and not not recommended for any application where heat can be generated (such as a friction hitch on a lifeline). It can be spliced but is not recommended for tying conventional knots. There are several variants. See the following references for more information:

Samsonrope.com

Dutchweargear Amsteel 101

Google returns these answers; make your own conclusions:

JRB’s perspective: AmSteel® has become popular in Saddle Hunting applications, with many vendors selling Amsteel products. Unfortunately, JRB is unable to locate evidence that the manufacturer recommends it for the types of applications it is being used for in saddle hunting. Regarding temperature:

  • The Sampson product webpage for AmSteel® (link above) refers to it as an HMPE fiber, but does not cite its temperature specifications.
  • The “How cold can you go?” link above contains a chart with a clear temperature degradation at moderate heat.
  • The warning statement a page stating that HMPE melts at 149°C (300°F), but has no recommended maximum operating temperature.

Especially because of the low tolerance to heat, the application needs to be carefully considered and tested before use, especially in DIY applications. Just because somebody is selling something, that does not make it a good idea. For example on a stick attachment system, JRB concludes that there is no slack and therefore low risk of heat generation. However on a tether or lifeline, climbers often have slack and this allows the possibility for a fall, with a shock load and high heat (a friction hitch can slide and that can generate high heat very quickly). Please use only highly heat resistant materials in any such applications. And don’t assume that a knot that works great with cord/rope will also work with Amsteel.

KEVLAR®

Kevlar is an aramid fiber. Kevlar® is a registered trademark of DuPont.

Dacron®

Description: Dacron is effectively DuPont’s brand/version of polyester fiber. Less elastic than nylon, with slightly lower strength. Not affected by common alkalis or acids. Excellent UV resistance. Very good wet or dry abrasion resistance. Dacron® is a registered trademark of DuPont.

Vectran®

Vectran is an Aromatic Liquid Crystal Polymer which is another high strength / low stretch material. Vectran has very low creep and a higher tenacity than Aramid and is also very resistant to heat. Vectran® is a registered trademark of Kuraray.

Twaron®

Twaron is an aramid fiber. Twaron® is a registered trademark of Teijin.

Webbing

This is a great reference:

Dutchware Article on Webbing

References