6mm cord for rappelling

Christian Heschwrote:

though it may be surprising, I actually did learn to read by time I quit school in 7th grade, thus I did indeed read the other responses. I appreciate weight savings but not sure I can confidently place my trust in a cord that weighs 9g/m compared to something weighing 32g/m. YMMV...

Do you trust your black totem? Or any other piece of small gear? So, why wouldn’t  you trust something that’s rated 8kn regardless of how much it weighs?

Mostly bc I have yet to spend adequate time researching 6mil cord. I might reconsider what I’m willing to used for a rap line in light of how strong some of these cords are... as that’s a lot more weight/space savings than I expected on the uneducated guess.

Def handles a bit different in the rap device but some care and caution can usually overcome any potential slippage, so maybe the 6mm is worth a try 

edit: just looked again and it was listing weight in g/foot!!! Thus, 8.6g/ft = about 27g/m, which is, IMO, insignificant compared to a 32g/m half rope. Less than 3/4lb, I would use an actual rope for a 300g penalty, 10/10. 

Hell, I use the 5mm Beal 5mm Backup Line (12kn) all the time. That thing is light as hell and tiny! 

https://libertymountain.com/beal-back-up-line-5mm-ntn18753.html

Anyone have a 7mm tag line that they don't need anymore (in decent shape) and want to sell (or give away)?  Thanks!

Joshua Tree Runnerwrote:

Anyone have a 7mm tag line that they don't need anymore (in decent shape) and want to sell (or give away)?  Thanks!

I’d sell you my 6mm 65m static. I’m on the Beal Escaper train these days

Demetri Vwrote:

I’d sell you my 6mm 65m static. I’m on the Beal Escaper train these days

Ha ha - I recently saw one of those at Red Rock. We were at the base of some climb waiting with another random party who demo’d it. Very tempting. He did say though that he often felt a moment of doubt as the number of pulls needed to release got worrisome,  Still, I’m a gambler.

Thanks guys but I should added that I need a 70m line so I can max out my rappels... Also, a 6mm x 70m would work for me too.  Thanks.

Joshua Tree Runnerwrote:

I need a 70m line so I can get my rope stuck more frequently.

FIFY ;-)

Bug Boywrote:

i've done it a bunch, joined to a 9.0-9.4 rope (i wouldn't go much thicker than this) with an EDK. Just make sure the thinner cord is under the rope when tying the EDK otherwise the rope could roll over the 6mm cord. The ropes can definitely feed through device at different rates causing the knot to move and the ends to become uneven. In order to avoid this I have my partner pre-rig their rap device then the first person down stays on rappel so the rope doesn't slip for the second. Lots of benefits to this over the biner/knot block and pull cord method, just make sure the 6mm cord is in good shape.

I use the Beal backup line (5.5mm), and if the difference in rope diameter is more than 3mm, you'll need to use a double flat overhand (double EDK if you insist on calling it that). 

Jake Gwrote:

I suggest an 8mm or the strongest 7mm cord you can get your hands on. The reason for this is there is a slight chance if your rope gets stuck you could be ascending or lead climbing off the little cord that was only intended to be a pull cord. Scary stuff. I still use one though, love it. Something to consider though.

The backup line is rated for crevasse rescue, it works fine with a tractup or a rollnlock. A tibloc will grab but I wouldn't wanna trust it. I keep meaning to practice using a grivel scream in guide mode, it should work in theory, I've definitely rapped on that device.

Mx Amiewrote:

I use the Beal backup line (5.5mm), and if the difference in rope diameter is more than 3mm, you'll need to use a double flat overhand (double EDK if you insist on calling it that). 

That’s oddly specific. I have broken this “rule” often. One flat overhand bend has worked fine for me.

Demetri Vwrote:

If the 6mm cord ends up being through the rings instead of the rope, I add an extra rope bearing biner to just the 6mm cord at the rappel device. This makes it so there is the same amount of friction on both sides of the device, and the knot doesn’t creep.

Can someone explain this extra carabiner position in more detail? An image would be amazing.

Kyle vHwrote:

Can someone explain this extra carabiner position in more detail? An image would be amazing.

I suspect like in this picture except only the skinny cord goes around both biners while fat goes around just one biner.

Never tried that.  I'd experiment with a backup before going live ... as with most off-nominal applications.  :)

I tried this arrangement before posting originally, but it didn't seem right so I posted here. Curious if anyone else has feedback...

I can't tell if the second biner is also clipped to your harness or free-floating...

both biners are on the belay loop as a normal rap, the larger one is on both cords and the smaller one (say a small edelrid bulletproof) is on only the 6mm cord. 

Funny to read my own responses on this thread from two years ago and see how much I've changed my tune on the small rap lines, I use them almost exclusively nowadays, got my first Esprit APER and now I have three of them, love em and trust em completely.

Christian Heschwrote:

both biners are on the belay loop as a normal rap, the larger one is on both cords and the smaller one (say a small edelrid bulletproof) is on only the 6mm cord. 

Funny to read my own responses on this thread from two years ago and see how much I've changed my tune on the small rap lines, I use them almost exclusively nowadays, got my first Esprit APER and now I have three of them, love em and trust em completely.

So the smaller biner kind of pulls the 6mm lower, which causes more friction?

Thank you for chiming back in. Cool your POV changed

Anyone have thoughts on 6mm uhmw/dyneema lines as a sole rap line? My particular use case is ski mountaineering where there's not a need protect on the way up but there is a need to rap. Mammoth sells their kevlar rap line for this specifically, and there's the Petzl rad line but I'm not in the market for a new rope.

I picked up 60m of Salewa mastercord in Italy last year for like $50, the sales person thought they were selling me conventional 6mm accessory cord and I honestly didn't know better until I looked it up later. I just saw that the spool said 15kn on it and was like I'll take this stuff. https://www.salewa.com/master-cord-6mm-spool-00-0000000639

I wouldn't give it a second thought other than pondering how to manage friction with a rappel device - but I have read some people claiming it's not suited for rapping due to uhmw/dyneema's low melting point. Yes an atc can get smoking hot on a long fast rappel but I'm till pretty sceptical you could get things so hot as to damage the rope.

I've used 6-mil nylon as  main rappel line canyoneering & ski-touring  for decades.  too skinny for most manufactured belay/rappel brakes, but works fine as dulfersitz, carabiner-brake, or munter-hitch.  I can't speak to dyneema (too cheapskate for that) but 6-mil, even 5-mil nylon/perlon is perfectly adequate for the bodyweight static load.

-Haireball

Thanks Curt, good to hear. Using a dulfersitz with a 6mm cord sounds scary haha.

I just found this guide from Petzl for rapping with their 6mm 'rad line'. Looks like a decent resource and suggests two biners on an atc would be good. m.petzl.com/US/en/Sport/Rap…

yeah - the dulfer is pretty much a winter solution when I'm wearing LOTS of clothes...

-Haireball

Kyle vHwrote:

Can someone explain this extra carabiner position in more detail? An image would be amazing.

check out my post from this thread a few years ago. page 3 has the photos that I took while experimenting.