May 17th, 2008 Posted in Do-It-Yourself Articles | No Comments »
Choosing Appropriate Webbing Materials
The most popular webbing is tubular 1″ nylon in a Mil-Spec Weave. The second most popular webbing is tubular 1″ nylon in a Climb-Spec weave. In general choosing between these two options is more of a personal preference. Climb-Spec is slightly stronger and more abrasion resistant but is more slick. Mil-spec has better grip for the feet and is usually cheaper. Both have very similar elasticity and both will hold up for years of slackline use and under normal considerations the strength is not an issue. I have noticed that climb-spec seems to get retired a bit sooner but I cannot make any definitive judgements to that effect.
There has been recent attempts to blend various “static” threads into the web. We’ll see where it ends up in the long term though as there is usually a cost premium to add in other fibers such as dyneema, spectra or polyester threads into the webbing and there simply isn’t a conclusive way of testing all performance aspects of a slackline. The other issue is that dyneema / spectra / polyester only have lower elasticity than nylon as they aren’t truly static. Having used hybrid lines like that, it does change the feel a bit, it removes some of the bounce in the system through reduced dynamic elasticity at typical slackline loads. It produces a more uniform curve for surfing but may not be ideal for any movements that utilize the dynamic properties of the webbing. Basically, I’ll hold judgement for the time being and I certainly wouldn’t recommend spending more on such lines until there is a real definitive reason to drop more money in such a line.
While there are many types of webbing out there that might work in theory, there are however some materials to stay away from. If you find cotton or hemp webbing, don’t even bother. Even if it has 1,500 lb tensile test or more, it’ll shred under use. I’ve tried several types and they all failed within a couple sessions.
Far less popular materials are polyester and polypropylene. However these materials can make a decent slackline if you understand the trade offs involved. Poly pro is quite stretchy and not very abrasion resistant but it can make a good surf line as long as it is properly padded. You can get monster arcs with these lines and the offer a great soft bounce back. On the other end of the spectrum, polyester is usually more static than nylon and can make great robust long lines in many forms but some others are quite spongy so you’ll have to shop around. Flat polyester weaves can make some very strong slacklines. Use caution however as both come in dangerously low tensile strengths that look identical to higher tensile products. If you are interested in trying out some short to medium poly pro lines we have several rolls in stock but it isn’t as strong as mil or climb spec so you have to be careful with how you use it.
Tubular vs Flat
Tubular is most common, but it really doesn’t need to be. It just so happens that the cheapest options that fit the necessary criteria of elasticity and strength are almost all tubular. Tubular is basically a “hose” of webbing that has been pressed flat. Flat being a solid weave similar to what you would see on a backpack strap.
Lately ultra long liners have been moving to flat lines instead, trading off the dynamic feel for more static lines that offer higher tensile strengths. For a typical line, this isn’t necessary but for ultra long liners the tensile strength becomes a major hurdle. Flat lines are more common in Europe where the cost of webbing is much higher regardless of which way you go so it’s only a little bit more to get the really strong stuff. Here in the states we would have a hard time coughing up for 50KN 1″ webbing since 1″ tubular is dirt cheap in comparison, but there isn’t not too much more than typical tubular. Generally though, if you go with flat, go with a thicker weave - your feet will thank you.
Widths
One inch may be king but it isn’t the only game in town. Thin lines are make great surfing lines as they often have great elasticity levels that make for less harsh rebounds on the side of the surf and nice graceful arcs.
On the thicker end 2″ offers extremely low elasticity which can be useful if you want to get a very long tight line. Even hand tight with no tensioning system you can setup a 30 foot 2″ line. The downside is that it seems to tip and tilt with your feet making it more likely to pop off rather than letting your feet grip the line positively. Try as I might I just can’t get into walking 2″ lines very well. They are easy enough but they just don’t offer the challenge and fun that a dynamic line offers - again, that’s just my opinion. I have pondered the idea of letting beginners learn on 2″ lines but it is a difficult trade off to give them a more stable system but then take away their traction at the same time. If you’d like try one of these out, give us a shout, we’ve got them developed nicely we just aren’t sure about the marketing and could use some tester feedback.
Weaves
Different weaves of webbing control how the fibers are woven together which will control characteristics such as thickness, stiffness, abrasion resistance and texture. Basically the only bad type of weaves are ones that are so thin and noodley that they will form an upside down “U” under your feet or have such a thin edge that if you land against the line you can get very bad rope burns that cut into your feet & legs. A thicker weave is far more ideal with climb-spec and mil-spec being about perfect on the thickness and stiffness to allow good feedback and just enough support to not hurt your feet. Basically, don’t be afraid to play around with different weave types, there are plenty of weaves that make great slacklines that aren’t mil or climb spec and some bridge the difference offering a different balance of abrasion resistance and positive texture for gripping the line.
Threaded or Not?
Threaded lines are one option to add redundancy into a slackline system. Usually threaded lines consist of a 5/8″ to 11/6″ piece of webbing threaded through the center of a piece of tubular 1″ webbing. Honestly though, it has it’s trade offs that take careful consideration as it isn’t for everyone.
The good:
- If one piece breaks, the other is usually still intact.
- It changes the elasticity of the overall system.
- They are redundant but can be tensioned together as one piece.
The not so good:
- The thinner webbing has a different elasticity than the 1″ which means that the thinner webbing will stretch more easily than the 1″ on the outside. This makes for an unusual elasticity pattern when you start comparing surfing arcs. It’s kind of like a 1″ like with a wobbly less tight line in the center that can shift around just enough to be noticed
- The thinner line in the middle makes the webbing heavier, slower and rounder. This can throw off your game a bit.
- The 1″ isn’t likely to break in the first place but if it does the load is likely to exceed the strength of the thinner webbing too.
- You cannot inspect the thin web easily
- They are a complete pain in the arse to make. Once you get the process down it’s “ok”, but still tedious.
I guess it’s apparent that I’m not a huge fan of threaded lines. Others however like them, so I keep building them. If I get asked about it however my preferred options are bonding a 2nd piece of 1″ to it using bartacks (permanent) or tape (temporary) every so many feet or taping a climbing rope to the bottom if you are building a highline. Both of these options negate a lot of the downsides of threaded lines listed above.
Overview
Get out there and play. Keep the major points in mind when shopping for webbing such as necessary strength and otherwise pick your webbing depending on how you are planning on using it. I hope that some of these points give you a bit of food for thought to how much thought goes into picking a specific type of webbing and hopefully next time you are looking for a line with a special characteristic you are now better armed to make a decision.
Balance In Life,
Joe Kuster
Slackline Express
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It’s been very, very long overdue but I was finally able to patch our web based storefront with the code to support the US Postal Priority Flat Rate boxes. This should help out greatly with international orders. I was also able to negotiate a slightly better rate on UPS packages with our volume. This should lead to cheaper shipping options all around. 
