Build a Slackline

Maybe you've tried a friend’s slackline, or read the How to Walk a Slackline featured article, and now you're keen to figure out how you can build one on your own. This article will show you how to build your own slackline, using a couple of trees, some ordinary climbing gear, simple knots, and a carabiner pulley system to tighten the line. The end result is a fusion between a tightrope and a trampoline--a bouncy, highly-tensioned, single-line playground that you can carry around in a stuff sack. Once you learn the steps and gather your supplies, you can set this up in just five minutes.

Steps

  1. Gather your supplies. Slacklines are typically built from 1" (25mm) tubular webbing, although other materials can be used. A typical setup includes:
    • 50 feet (15 meters) (or more) of webbing for the main line
    • 2 pieces of 10-15 foot (3-4.5 meter) lengths of 1" (25mm) tubular webbing for the anchors
    • 5 carabiners (climbing-strength, oval-shaped)
    • 2 pieces of carpet, cardboard or other sturdy material for protecting the tree anchors.
  2. Select the anchor points. A good length for beginners is about 15-20 feet between anchors. Find an area clear of sharp objects--smooth grassy areas are ideal. Shorter spans are easier to learn on than longer spans and allow for a lower line.
  3. Build the anchors. Choose anchors capable of holding about 500-1000 pounds (226 kg-453 kg) of lateral force: medium-to-large trees, cemented poles, truck hitches, eye-bolts, etc. When using trees for anchors, make sure to protect the trees by padding the area of contact with carpet or other sturdy material. Wrap the loop of webbing around the first anchor about 2-3 feet (60-90cm) off the ground for a 15-20 foot (4.5-6 meters) length. Attach a carabiner to the two ends. Repeat for the second anchor using two carabiners instead of one.
  4. Attach the line to the first anchor. Wrap a tied loop of webbing around the anchor and attach a carabiner through the two end loops.
  5. Set 'line locker' and carabiner 80% of the way to the second anchor.
  6. Build a 'primitive' 4-carabiner pulley system [1] to secure the line.
    • From the line locker, pass the webbing top-to-bottom through carabiner_1 attached to the anchor, then top-to-bottom through the carabiner with the line locker.
    • Next, pass the webbing bottom-to-top through carabiner_2. You should have a zig-zag pattern connecting the carabiners--the "pulley".
    • Now for the tricky part: pass the webbing bottom-to-top UNDER the loop of webbing on the line locker carabiner. This creates a friction lock on the webbing. No additional knots are required.
    • Pull tightly, using about 50-100lbs (or more) of pulling force.
    • Test the line by sitting or bouncing on it. This helps take the stretch out of the anchors and knots. Tighten the line until you can walk the middle of it without it touching the ground.
  7. Tighten your line. You can experiment with tying the line very taut or moderately taut. If the line is too loose, it will lose many of its dynamic qualities and sag excessively.
  8. How to release the friction knot when finished. This is easily and safely done by pulling the webbing in the opposite direction that you tightened the line. Normally, this means pulling the webbing away from the nearest anchor.



Tips

  • Buy more webbing than you need for the span between anchors. Although, you may only want a slackline that’s 20 feet long, you’ll need about 20 more feet to operate the pulley system.
  • Use different colored webbing for the anchors and main line. This makes it easy to sort out your supplies when setting up the slackline.
  • Piggy-back pulley systems to maximize tightening for long lines. Instead of pulling directly on the webbing used for tightening, run this webbing through another pulley system attached to another nearby anchor. Ideally, the other anchor is in line with your line. Although somewhat complicated, this will provide an enormous amount of leverage, for those extra long lines.
  • Get more leverage when tightening the line by wrapping the webbing around a sturdy stick. As the distances increase, you’ll need more leverage to tighten the line. Tie the webbing to a stick with a girth hitch and several wraps around the pulling end of the webbing to get a better grip on the line.
  • Combine pulling strength with two or three friends. Get a friend or two to help pull the line with you. If using a stick with a girth hitch, you can each pull on a side of the stick. Careful not to wrap the webbing around your fingers.
  • Buy a commercial tightening system. If you want a fast and easy method for setting up a slackline, consider investing in a kit. Several manufacturers offer professional tightening systems and complete slackline kits.[2] Expect to pay about US$100-$200, depending on the model.

Warnings

  • Slacklines generate enormous forces on the anchors when weighted. Carefully choose anchors that can withstand up to 1000 pounds of force.
  • Do not use webbing or carabiners for climbing after they have been tensioned in a slackline.

Things You'll Need

  • Two anchor points
  • 50 feet (15 meters) of 1” (25mm) tubular webbing for a 25-foot (7.5 meters) main line with pulley system
  • 2, 10-15 foot (4.5-6 meters) pieces of 1” (25mm) tubular webbing tied into loops for the anchors
  • 2 medium to large trees or other anchors
  • Padding to protect the trees
  • 5 carabiners

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Sources and Citations

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