To end up black like that suggests to me that there was a (brief) flame. Did you see or smell any smoke? I suppose a fuzzy sheath might have a chance to ignite from the heat of the belay device or carabiner, but I've never heard of it happening.

I'm not up to date on modern gear, though know that the heat is continuously building up in the metal all the time the rope is passing through it. And the heavier the load and greater the speed - the more heat. Braided rope sheath generates more heat than rope without sheathing.

So long as the rope is always moving quick enough its okay for the rope. Any stop, however, the heat will go straight back into the rope, which will burn as in the photo. So it's essential to keep the rope moving, and when you touch down, keep it moving too.

Why not remove the belay device first, and then the klemheist/backup?

I suggest that you consider losing some weight.

PS: Slow down... what's the hurry?

If you are worried about the heat issue, get one of these. V-Twin by DMM. Made out of SS and never gets warm on long ass multi-pitch raps:

I have always wondered about this happening, I use an ATC- XP and it gets hot, and extra hot on dirty ropes. When I hit the deck I keep the rope moving while I clip in or walk around.

The Chief wrote:I suggest that you consider losing some weight.

PS: Slow down... what's the hurry?

If you are worried about the heat issue, get one of these. V-Twin by DMM. Made out of SS and never gets warm on long ass multi-pitch raps:

Chief... so your saying your device dose not get hot because it's stainless steel?

How does that work?

Friction is friction.

Friction makes heat, the heat goes someplace, in this case the hot device burned the sheath.

just saying

Just use a carabiner to pick the ATC off the rope, no gloves needed

In the video, they used a nice clean (and I assume) new rope for the test.

I know dirty ropes make more friction.

You have proof that this can happen.

Good to know you just burned a cord only, at least it's near the end of it.

gk

Unless this is somehow a cigarette burn? Perhaps even sustained at belay or during transport or storage and was only noticed after the long rappel. You or anyone else smoke near this rope recently?

CSI: Summitpost. Where on the rope was the burn? Middle? End? Does the burn line up with some place you might have paused after a fast hot rap?

Is there a possibility some jerk flicked his hot ash butt into your gear pile (not a member of your party)?

Guyzo wrote:

The Chief wrote:I suggest that you consider losing some weight.

PS: Slow down... what's the hurry?

If you are worried about the heat issue, get one of these. V-Twin by DMM. Made out of SS and never gets warm on long ass multi-pitch raps:

Chief... so your saying your device dose not get hot because it's stainless steel?

How does that work?

Friction is friction.

Friction makes heat, the heat goes someplace, in this case the hot device burned the sheath.

just saying

I love my V-Twin. It NEVER gets warm..NEVER!

Alum doesn't dessipate the heat as quickly as the SS.

Go here and learn why SS is better...

http://www.dmmclimbing.com/productsDeta ... 6&pid2=100

The Chief wrote:

Guyzo wrote:

The Chief wrote:I suggest that you consider losing some weight.

PS: Slow down... what's the hurry?

If you are worried about the heat issue, get one of these. V-Twin by DMM. Made out of SS and never gets warm on long ass multi-pitch raps:

Chief... so your saying your device dose not get hot because it's stainless steel?

How does that work?

Friction is friction.

Friction makes heat, the heat goes someplace, in this case the hot device burned the sheath.

just saying

I love my V-Twin. It NEVER gets warm..NEVER!

Alum doesn't dessipate the heat as quickly as the SS.

Go here and learn why SS is better...

http://www.dmmclimbing.com/productsDeta ... 6&pid2=100

Interesting topic. Can't get the link to work but I think aluminum dissipates heat faster than steel, but steel takes much longer to heat up, so this makes sense.

Edit: sp

fyi....a falling piece of rock, noticed or not, can cut through a rope and does so with a burn which is generated from rock hitting rock causing a soldering type effect....I have had ropes completely severed from rock fall, only a piece of sheath holding them together.....with completely blackened and burnt ends.

sergio wrote:In the video (I posted the link) they say that it takes over 250F to burn through the nylon sheath. I guarantee you that if a device is over 250F you are not going to be able to touch it, with or without gloves. And I don't think that was ever the case. I then have to assume that the sheath on a skinny rope melts way below the 250F mark.

Often for me, after a longer rappel, my rappel device (ATC-Guide) is so hot that spit sizzles on it. In other words, it is well above the boiling point of water, 212F (at sea level pressure). There are times where the rappel was just barely enough for this to happen, and there are other rappels where it gets this hot, and then some, where it is still hot enough to sizzle water for a while afterward.

Of course I have no way to exactly measure the temperature, but based on the above information, I have little doubt that 250F is that hard to achieve, at least for a big guy like myself.

And as you guessed, there is no way I can touch it. I have permanent burn scars on my stomach from second-degree burns I got on some rappels I did a while back in Death Valley (warm weather = no shirt).

Chief, I could certainly lose some weight now, but even when I am lean, I still weigh about 210 pounds. So unless I want to start hacking off limbs or muscle, I could never be as light as the average adult weight, and certainly not as light as the average skinny elite climber.

sergio wrote:Then I increased the temp to 200F. The rope melted through within seconds, and I guess it would have slower but equally melted at a lower temp.

The way those toaster ovens work, with a lot of radiative heating, not just conductive and convective, it's possible there were hot spots on the rope, much above 200F, even though the oven's thermostat and even the air inside were only at 200F.