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Lockers used to tension a Slackline safe to climb with?

Charlie S · · NV · Joined Aug 2007 · Points: 2,391
20 kN wrote:The primary concern is fatigue, which is a very real problem with aluminum. I have seen aluminum and steel components used in slacklining fail from fatigue. Just a few days ago, a slacklining company posted a photo of a Fixe 40kN hanger that failed from long term use in slacklining where the slackline was rigged 24/7 in a gym. Anyway, if you're just setting up a loose line for a day, sure, using some biners off your rack is fine. If you're going to be using your slacklining rig regularly, I would strongly recommend getting dedicated biners. You can get some lockers for like ~$7-8.
Dude, awesome pictures. In my office, we call that "crack porn." Would love to look at those under a sterioscope.

My slackline gear is different from my climbing gear. Though I think the perspective may be wrong...
Perhaps it's not so much about the slacklining gear being unsafe for climbing;
It's the climbing gear that's unsafe for slacklining.

When I look at my climbing carabiners, they are dinged, scratched, paint is gone, all indicative of a good time. The low loads imparted by climbing/falling are generally not "cyclic" in nature, but rather discreet. Fatigue is a relatively low concern for climbing applications.

However, slacklining is high load, high cycles. All those dings and scratches serve as crack nucleation points. Once it starts, it's only a matter of time.

My slacklining biners actually look just about perfect.
Greg D · · Here · Joined Apr 2006 · Points: 883
Brandon Seerup wrote:
Rock Climbing Photo: BD Carabiners not for slacklining

This photo is not about tri axial loading.

Old Lady and Brandon are correct.
Greg D · · Here · Joined Apr 2006 · Points: 883
ViperScale wrote:I think all those pictures are more talking about setting it up so that there is 3 pull directions on the same biner. As long as you only have pull on the major axis of the biner it is probably going to be fine. It makes sense the cross loading a biner is bad so if you have it setup so it is pulling in a direction other than the major axis there is a high chance it will fail.
Wrong.
20 kN · · Unknown Hometown · Joined Feb 2009 · Points: 1,346

Here is a good article talking about fatigue in aluminum carabiners:

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0ahUKEwjGtNfMws7KAhWmk4MKHVFjCxEQFggdMAA&url=http%3A%2F%2Fweb.mit.edu%2Fsp255%2Fwww%2Freference_vault%2FFatigue_Presentation.pdf&usg=AFQjCNFArWsXf-7U5g_Fd7zKrYZXFYzHkQ

Anonymous · · Unknown Hometown · Joined unknown · Points: 0

Like I said the slackline at one of the gyms I goes to has been setup with a BD biner and is never taken down. Every time I am in there people have been on it and I have not seen it break in 3 years.

At some point the biner is going to fail because anything will fail at some point and I can't say the exact amount of hours that people walk on it for it to have lasted 3+ years of time being setup (only taken down rarely to reset stuff around the area where it is at).

Anyone got pictures of a slackline setup with biners in the real world that broke?

Brandon Seerup · · Unknown Hometown · Joined Sep 2015 · Points: 6

Another amendment to the math I put forward. Cyclic fatigue on Aluminum is usually studied with fully reversing cycles, meaning if a slackline is set up and left up for a long time, the load is never released, and the cumulative damage is significantly less.

Getting back to the original question, the above statement should tell you that carabiner life in a slackline setup is going to be different on a case-by-case basis. Anecdotal evidence of some slackline setups lasting for years without parts replacement should probably not be used as assurance that every slackline carabiner is safe for climbing use.

At the end of the day, the fact that the folks at BD put enough thought into this to specifically single out slacklining as an unacceptable use case for their product is enough to convince me to keep my gear separated.

eli poss · · Durango, CO · Joined May 2014 · Points: 525

Just out of curiosity, how does titanium compare to steel and Al when it comes to fatigue. For slacklining a foot of the ground, it doesn't matter that much if a biner breaks every couple years, but for high-lining the biner CANNOT fail. Perhaps this could be a new use for titanium

Ken Noyce · · Layton, UT · Joined Aug 2010 · Points: 2,648
eli poss wrote:Just out of curiosity, how does titanium compare to steel and Al when it comes to fatigue. For slacklining a foot of the ground, it doesn't matter that much if a biner breaks every couple years, but for high-lining the biner CANNOT fail. Perhaps this could be a new use for titanium
In fatigue, titanium is fairly similar to steel with the obvious exception that titanium in general has a lower strength than steel which means that the endurance limit will also be correspondingly lower than steel. The best bet for slacklining is to use beefy steel components so that you aren't stressing them beyond their endurance limit so you won't have to worry about them breaking due to fatigue.
Jon Zucco · · Denver, CO · Joined Aug 2008 · Points: 245

yeah, you should be using dedicated steel biners for your slack line, and dedicated aluminum for climbing.

20 kN · · Unknown Hometown · Joined Feb 2009 · Points: 1,346
ViperScale wrote: Anyone got pictures of a slackline setup with biners in the real world that broke?
Yea, I have seen over 20 on Slackchat. It's actually not that uncommon, although it's usually from triaxial loading. The photos I posted are from "the real world." They failed when someone was actively using the slackine.
Anonymous · · Unknown Hometown · Joined unknown · Points: 0
20 kN wrote: Yea, I have seen over 20 on Slackchat. It's actually not that uncommon, although it's usually from triaxial loading. The photos I posted are from "the real world." They failed when someone was actively using the slackine.
Yea, but none of those you posted were biners. Not saying it would never happen I am sure any biner will fail at some point with enough use but how often does this really happen?

Love to see some examples of a biner failing from a slackline that wasn't because the gate was open or it was loaded in a strange way.
Nick Turtura · · Unknown Hometown · Joined Feb 2015 · Points: 25

20+ years climbing I have never had a biner break on me. 2 years slack lining and I have broke 2. Don't play the "it looks good game." There is clearly a lot more stress on those things in a slack line. Keep the gear separate.

Anonymous · · Unknown Hometown · Joined unknown · Points: 0

A slackline under 150ft creates a max of 10 kN force (read this somewhere, also depends on how your line is setup). Mean from your cyclic test shows that at 10 kN it takes an average of 5500 loads of this force to break the biner.

That means you should be safe with putting some massive force, big jumps, lets say 4000 times before you should worry about failures.

20 kN · · Unknown Hometown · Joined Feb 2009 · Points: 1,346
ViperScale wrote: Yea, but none of those you posted were biners. Not saying it would never happen I am sure any biner will fail at some point with enough use but how often does this really happen? Love to see some examples of a biner failing from a slackline that wasn't because the gate was open or it was loaded in a strange way.
slackline

slackline

slackline

slackline

slackline

Even steel carabiners are not that suited for longlines and highlines. Steel shackles are the best option for anything seeing over 1500 lbs tension.
Anonymous · · Unknown Hometown · Joined unknown · Points: 0

I don't know I have been using basic oval biners for years and never had any problems with mine. Had to replace a few sets of webbing from it wearing out but no problem with biners.

Alot of those pictures you posted looks like the webbing was touching / pulling on the gate and caused the failures. I am not sure you can really call that a biner failure as much as a setup failure. The purple webbing tree one definitely had pull on the gate itself (or at least very close), which is likely to weaken the gate by at least a 3rd.

Guideline #1: Don't be a jerk.

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