How bad are knots in Dyneema?

You are supposed to splice Dyneema to retain most of its strength. What happens if you tie a figure 8 in it?

Our Results with Sk75 Dyneema with figure 8s:
3mm - 4.06kN (MBS 10.2kN)
4mm - 8.86kN (MBS 21.8kN)
6mm - 12.93kN (MBS 34.25kN)
8mm - 20.77kN (MBS 54.7kN)

Our main channel is @HowNOT2

[rickace]

Just for those that are wondering, Dyneema is a brand name. The name of the material Dyneema is made out of is UHMWPE. Spectra is also a brand name made out of the same material.

[harlanstockman]

I use a supermunter or munter with an extra loop, on a light d-shaped screw gate. Longest rap was 150' doublestrand 1/8". I use small quicklinks instead of knots between spliced eyes, to connect ropes. I definitely use warpspeed II, because I can also ascend it with spyderline schwabisch knots. That's what I'm doing in profile pic.

[IvanHennessy]

I would love to see another video, or a series, looking at rappelling on different materials. The setup you used to look at different canyoning descenders was brilliant.

[hoggif]

Fast, simple and task oriented informative video. I liked it.

[Twopennysau]

Rapping on the 3mm, I’d be more concerned with heat or pancaking, than the knot. Imagine the pucker factor if you had to stop along the way down - the visions of your descender sizzling through the cord and then that last backward free fall you would ever do….

I hate my imagination.

[paulgush]

I'm impressed that the knots broke and didnt just slip.

[Airsails]

In general a knot cuts the strength of any line in half.
A proper finger-trap with tapered tails the right length can yield 100% of the line strength.

[geoninja]

Nice video. I must say I like them short and to the point, which you've done. Unless I had done *a lot* of practice abseiling on 3mm anything, I'd activate an EPIRB before I tried it for the first time at height! :)

[MystickPhoenix]

One other issue w/ rappelling with dyneema is it starts to lose strength _quickly_ when it's heated up. IIRC I think it starts losing strength around 120 degrees f, which given ambient air plus the friction of a rappelling device could hit quickly.

[AusyG]

In short yes dyneema is way more than adequately strong enough. Im curious though about how rappelling devices and rope grabs act with its different almost waxy sheen. Polyester grabs very different than nylon

[dannyCOTW]

Awesome man! I was also wondering about this.

[RogerBays]

Short form good. Long form good too. But nice to have a mix. I don't always feel like long form. Probably always feel like short form.

[mrln]

Would/could you test termination knots with a couple extra wraps around the carabineer so it's more like a friction anchor? Might be a way to get a bit more of the strength out of it.

[TrueHelpTV]

Lol this video just caused me to get someone to pull their 4mm blue rope out of their kit.. He kept it as a backups backup and shit himself looking at this. Thank goodness he never used it for his intended purposes.

[Mooff]

I was pleased to see that a figure 8, knot will break rather than slip. I always thought that every knot in dyneema would simply untie itself by slipping rather than break.

[Rock_Appreciator]

Is it safe to leave knots permanently tied in on dyneema? Like for an anchor. I leave knots in mine, never bother untying it, but I worry that constant loads on the same knot will cause issues in the long run even though I have no evidence to support that fear

[SmallCraftLifeNews]

What about the knot on the end of a soft shackle? Or Ester knots? All knots on dyneema.

[SimpleGrn]

Looking for information on spectra twine

[christopherrowley]

Wait I'm confused, you aren't supposed to tie knots with it? How is a rope useful without tieing knots in it?
Every time you use it you have to splice it? I bet it just won't get used much then

[blue]

These are from one of the innovators of soft shackles for sailing