The Basics: Kevlar vs. Steel

Author: Ashley Moore, Porter Volleyball Division Manager

Is this article about volleyball top cable materials? Yes.

Is this interesting to you?  It better be if you’re going to stay engaged the 5 minutes it will take you to read this blog post.  Will it be worth your time?  In our opinion yes.  While it might not be the best ten minutes of your life, we’re fairly certain it won’t leave you feeling like, “That’s ten minutes of my life I’ll never get back”. In fact, we can also almost guarantee with absolute certainty that you will learn something. So without further ado, we give you, TOP CABLES!

The Great Debate: Kevlar vs. Steel

Kevlar or Steel.  Which of these words sound most appealing to you?  First, let’s give these words some context; volleyball net top cables.  Which is the best material? Which of these options is superior? These are questions volleyball coaches, athletic directors and manufacturers are asking themselves and industry experts all the time.  The following are conclusions drawn come from scientific evidence;  they may elicit surprise and be hard to believe, but be rest assured that you don’t have to take our word for it; its science talking.

Stephanie Kwolek (Photo credit: Copyright 2016, Smithsonian Institution)

In 1965 a female chemist, Stephanie Kwolek, was searching for a material that would be lightweight and stronger than steel fiber.  After much persistence and investigation, Ms. Kwolek found a solvent which would dissolve long chain polymers into liquid form (#chemistryisamazing).   This liquid solution could then be “spun” by a device called a spinneret (thanks to Merrium & Webster I now know what a spinneret is).  A spinneret is defined as, “a small metal plate, thimble, or cap with fine holes through which a chemical solution (such as that created by Ms. Kwolek in 1965) is forced in the spinning of man-made filaments”, also known as fiber.  The fiber created from this process was Kevlar fiber and was in fact stronger than steel; five times stronger by weight to be exact (Whoa!).

How can this be you say!?  “It’s a rope cord and rope stretches. Steel is static and durable and strong.”  These statements are all true.  Kevlar is more flexible than steel.  Kevlar has a much higher tensile (pulling) strength than steel cable which makes it significantly stronger in this particular application.  It also makes it safer and gives it a much higher threshold to reach before failure.  However, when compared in a different application where compressive forces (squeezing and squashing) are high, steel would be the preferred choice over Kevlar.

Therefore, strength is relative and not all strength is equal.  To circle back around to the original question, Kevlar vs. Steel, in the context of volleyball top cables, we can say based on these findings that Kevlar is the superior choice over steel.  A useful analogy would be to compare automobiles.  An automobile’s function is to be a vehicle for transportation.  If that were the only requirement, all cars would be considered equal.  However, we know that all cars are not equal.  Safety, reliability, durability and performance are factors which consumer’s value and manufacturers adapt their products to meet those needs.  Volleyball equipment is no exception.  Sure, a steel cable and a Kevlar cable both serve the same purpose – to create tension and achieve a taut net.  The difference is in their performance, reliability and safety.  In short or TLDR (too long didn’t read) fashion, knowledge is power; choose wisely and base your decisions on science whenever possible.  Kevlar is stronger than steel (for this application).

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