A commonly asked question we get at DMM is why is knotting Dyneema® tape generally considered a bad idea and why isn't it readily available in outdoor shops to buy off the reel.
The main reason climbers have been reluctant to use Dyneema® tape to create their own slings is down to the low coefficient of friction that gives Dyneema® a ‘slippery' feel. This causes it to have a poor knot-holding ability in day-to-day use.
However, we also conducted some slow-pull and dynamic tests to give an idea of how knotted Dyneema® slings do behave and the breaking strengths you could expect.
The video shows although it is possible to achieve quite high strengths in slings tied together with certain knots, it is very hard to judge how they will behave when loaded, especially as the knot alters over time (read full article: dmmclimbing.com/knowledge/knotting-dyneema%C2%AE-vid/)
Overall, we should stress that we strongly recommend that you do not construct your own Dyneema® slings by tying lengths of loose Dyneema® tape together.