* Amsteel Blue, the line referred to in the original post is a high tech fiber called Dyneema, which IIRC is a Spectra/Nylon blend, and is not comparable to most of your run of the mill line of similar thickness.
I use Spectra/Dyneema string for flying kites. It that use, it is known for very low stretch and being very slippery. Both desireable for stunt kite flying. But because it is so slippery it does not hold knots well (that's an understatement!) You "sleeve" it where you need to tie knots. You thread it through an external sleeve (similar to the covering over the 7 strands inside paracord), and then tie your knot in this added sleeving.