After viewing this article over on NWSlackline, I decided to try my hand at using chain links instead of rap rings in my Slackline setup. I ventured out to my local Lowe’s home improvement store and bought one foot (nine links) of 5/16″ 3900lb working load limit (WLL) chain*. Total bill was $2.89 including tax. After cutting every other link I will have 5 good links, so the cost comes out to about $0.58 per link – not bad when you compare the cost of a rap ring at $4.75 (plus tax). A rap ring weighs about 30% less than a link, which is why climbers probably wouldn’t do something like this, but chain links are perfectly useful for Slacklining.
I used a grinder and a cutoff wheel (and some safety equipment) to cut the four odd links. This left me with 5 links for use as line lockers.
I filed down the weld on each link. As Adam points out, over time the weld on each link can cause damage to the Slackline. (Click on the picture above, and zoom in, to see the welds on the links) Using a file, some 80 grit sandpaper, and some elbow grease I removed the weld protrusion. The following picture shows a link after the process.
After smoothing things over with the link, I replaced two of the rap rings in my Slackline setup, one at each end. This picture shows the fixed end using a chain link instead of a rap ring. (The rap ring seen in this picture is part of the system to remove the tri-loading, and cannot be replaced with a chain link).
For size comparison, here is picture of a link and a rap ring:
Chain links are nearly 1/10th the cost of rap rings, and two links can eliminate both rap rings of a basic primitive setup. This saves about $9 and gets the job done quite well.
* Note: I used 5/16″ Grade 43 chain that has a 3900 lb Working Load Limit (WLL) and a breaking strength of over 11,000 lbs (52kN). You’ll also find 3/8″ Grade 43 chain available with a WLL of 5400 lbs, and a break strength over 16,000 lbs (72kN). Either of these are good choices, and both accept a 1″ wide Slackline. I stayed away from the chain with lower rating (ie. 2650 lb WLL) and went with the Grade 43. More information here.