Strength loss in amsteel and friction degredation

[rfwoodvt]

I posted a similar question under rigging, but since this is more of a rope question I'm tapping here too.

Am considering using Amsteel to create an endless loop (double fishermans nots) to use for suspending a load under a zipline trolley by way of going around the two .75 inch load pins.

The questions I have are how well does amsteel put up with abrasion, and, if I install an alpine butterfly or 8 on a bight in the middle of it, how much will those knots degrade in strength?

Further, as the knots settle and set upon repeated and sometimes abrupt loading, what is the likelihood and extent of any friction melting of the amsteel?

 

[tuttle]

I salvaged 100's of meters of amsteel 11mm line.
we have used it across a few industries, tree work, rigging. boating, 4x4 etc.

it is very strong, sometimes better when wet, knots hold up, but could 1/2 the strength.

it has excellent abrasion resistance.

I have a quantity of 7m lengths left available.

 

[NickfromWI]

It has the tendency to unknot itself when pushed too far. If you are knitting amsteel, you could be knotting a similar sized polyester rope for better performance

Splice it. It's not hard to do and yields very satisfying results. Other that being a pain in the to cut, there are few better ropes to learn how to splice on

Yes- it handles abrasion well. It handles heat poorly. It melts about 200 degrees LOWER than nylon and polyester.

 

[Norm_Hall]

I wouldn't "knot" amsteel. Tests have shown that knots pull out. It's an extremely slippery fiber.
Another choice would be a polyester cover/dyneema core DB for knotting.
I've been using Amsteel crane slings (spider legs) for years in 1/2" and 5/8" diameters. The stuff wears like Iron.

 

[rfwoodvt]

Nick, is it correct to assume that light shock loading from catching a small to medium chunk of tree, however infrequent, will cause unacceptable friction damage in the knot with the amsteel?

 

[tuttle]

TBH - my whoopies for blocking down have been amazing, i have tested them with no fails, we set them up slack on one tree to see the results, the dyneema was unaffected.