Forums: Climbing Disciplines: Slacklining: Re: [NJSlacker] Threaded Mainlines Vs Bonded Mainlines: Edit Log




Partner slacklinejoe


Jul 21, 2008, 9:17 PM

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Registered: Nov 5, 2003
Posts: 1423

Re: [NJSlacker] Threaded Mainlines Vs Bonded Mainlines
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NJSlacker wrote:
A bonded line may be a little stronger (I think the 9/16 is rated to 3000 instead of 4000 for my 1 inch), but 8000 lbs to 7000 isn't that big of a difference.

I don't think tensile ratings necessarily add that way since they aren't actually bonded together. You can break each one independantly as they move and elgongate seperately - my limited understanding of elasticity suggests that you could actually have one taking most of the load before it's stretched the other one tight enough to carry much of a share.

An extreme example would be a chain backed up with a climbing rope. The chain doesn't stretch enough to let the rope share the load, thus they both blow at their rated strengths, just one, then the other.

Overall, I'm not sure what to expect realistically but I don't think they simply add together; I'd suggest that break testing should be done to know the resulting strength and mode of failure. In the case of a threaded line I'd expect one to blow at slightly higher than normal then the other immediately taking the load and blowing if the same tension is kept on it, however once the first one blows the tension is lost in a load tester thus having a lower force on the 2nd unless you keep tensioning. It's all just theory though... I think I should make some calls.

My biggest usage complaints so far with threaded lines are the rounding and shifting of the outer webbing of the line. A bonded one stays 100% flat with no shifting.

It also just seems that any redundant line artificially slows the line down, but I'm convinced that that reaction is good or bad - just different.


(This post was edited by slacklinejoe on Jul 21, 2008, 9:37 PM)



Edit Log:
Post edited by slacklinejoe () on Jul 21, 2008, 9:37 PM


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