How to Mark the Middle of the Rope?

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Burchey

 
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Re: How to Mark the Middle of the Rope?

by Burchey » Tue Sep 18, 2012 8:06 pm

TimB wrote:Guess what I am trying to say is that your trolling is getting old. You have some good things to offer, from what I see, but some of your threads and comments detract from this forum-not help it. And I think that is a pity.


Tim - fair enough. Although I feel I've been tasked to call moronic posts/posters out on the nonsense that they toss up, I agree with you that things tend to get clogged up in the open forums. I'll do my best to keep it in Off-Route.

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Kahuna

 
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Re: How to Mark the Middle of the Rope?

by Kahuna » Tue Sep 18, 2012 8:18 pm

Burchey wrote:I guess we should all thank the Sky Wizard to have certain folks around to tell us which routes are worthwhile and which ones are rubbish.

Not at all.

Just some experiential technical equipment advise when considering taking on any obscure far less traveled route that folks like FB and others had a tendency to put up.

Route finding can be less than straight forward in many of those cases. Having a well Middle Marked cord can be a very valuable navigational tool.

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Burchey

 
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Re: How to Mark the Middle of the Rope?

by Burchey » Tue Sep 18, 2012 8:20 pm

A5RP wrote:
Burchey wrote:I guess we should all thank the Sky Wizard to have certain folks around to tell us which routes are worthwhile and which ones are rubbish.


Route finding can be less than straight forward in many of those cases. Having a well Middle Marked cord can be a very valuable navigational tool.


I will also thank the S.K. for middle-marked ropes.

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Buz Groshong

 
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Re: How to Mark the Middle of the Rope?

by Buz Groshong » Tue Sep 18, 2012 8:26 pm

MoapaPk wrote:Remember-- this stuff has a "0" MSDS Health rating. It's not likely to contain something really nasty.....

Positing that a chemical will have very similar properties to another, just because of similar structures, formulas, or chemical families is a little off-the-wall, isn't it?....


Take a look at the two statements above. You are doing the same sort of thing you are criticizing him for - comparing apples and oranges. Health ratings have nothing to do with how a chemical might affect a textile. Sand probably has a "0" MSDS Health rating, but can definitely wear out a rope.

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TimB

 
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Re: How to Mark the Middle of the Rope?

by TimB » Tue Sep 18, 2012 8:40 pm

Burchey wrote:
TimB wrote:Guess what I am trying to say is that your trolling is getting old. You have some good things to offer, from what I see, but some of your threads and comments detract from this forum-not help it. And I think that is a pity.


Tim - fair enough. Although I feel I've been tasked to call moronic posts/posters out on the nonsense that they toss up, I agree with you that things tend to get clogged up in the open forums. I'll do my best to keep it in Off-Route.


Burchey,
Thank you. It's appreciated.

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Kahuna

 
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Re: How to Mark the Middle of the Rope?

by Kahuna » Tue Sep 18, 2012 8:44 pm

Burchey wrote:
A5RP wrote:
Burchey wrote:I guess we should all thank the Sky Wizard to have certain folks around to tell us which routes are worthwhile and which ones are rubbish.


Route finding can be less than straight forward in many of those cases. Having a well Middle Marked cord can be a very valuable navigational tool.


I will also thank the S.K. for middle-marked ropes.


You most certainly should. It clearly appears that you had a confusing time on you recent trip up the Classic EB of Whitney.

Appears you were at mix and almost got totally lost trying to exit the last pitch on your latest first time outing on the EB of Whitney. Kind of odd that you just now got on this very well traveled and straight forward Ancient Classic with all your decades of climbing experience.

I am also amazed that someone could actually give you directions from the summit when you were still some 8-900 feet below them and if were on route proper, would have been totally out of sight. You see, the route proper exits left and then a tad bit south the lower last tower before you scramble around it and then meet up with the exit portion of the East Face route. Then one heads up the last 6 or so hundred feet of Class 3 to the summit. You clearly depicted and voiced that the summit was "out of site" in this with this photo:

http://www.summitpost.org/east-buttress ... ney/812182

From your TR:

"I wasn't sure if I was still on route until I topped out right across from the lines heading up to the summit. The guide yelled down to us from the summit to "go that way", indicating to head up to our left a bit."

Very confusing at best isn't it.

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MoapaPk

 
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Re: How to Mark the Middle of the Rope?

by MoapaPk » Tue Sep 18, 2012 8:54 pm

I want to apologize now, for offending anyone in the future. Now I'm good to go!

In my humble experience -- dealing with MSDS sheets since they came into existence -- a health rating of "0" in this sort of application means something that is very unlikely to react with the organic materials in human bodies (e.g. collgen).

Buz(z), do you have a 1990s msds for "sand"? California required cancer warnings on bags of sand. I had to get rid of half the reagent grade silica in my lab because of concerns (not mine) that people might inhale it, causing silicosis. The problem is generally not the people who handle chemicals, but the lock-step zealots who enforce what they perceive as dangers, and make grand leaps of reasoning based on a their special knowledge.

I'm making the wild guess that companies who work with rope fiber, markers for fiber, and so on, have a little experience with chemistry as well.

Plus the fact that no one has attributed a rope failure to laundry pen marks, well that is a little key too.

According to the UIAA tests, dihydrogen monoxide (DHMO) is a far more serious issue with the strength of ropes-- and I bet you guys are getting DHMO (as well as sand, NaCl, and other salts) on your ropes all the time.

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Burchey

 
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Re: How to Mark the Middle of the Rope?

by Burchey » Tue Sep 18, 2012 8:57 pm

Chef, taking it to OR - don't want to clog.

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Kahuna

 
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Re: How to Mark the Middle of the Rope?

by Kahuna » Tue Sep 18, 2012 9:03 pm

Burchey wrote:Chef, taking it to OR - don't want to clog.


Maybe you should follow suite from Tim B and just take it all (your insistent trolling) to OR and completely disappear on the General Forum.

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TimB

 
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Re: How to Mark the Middle of the Rope?

by TimB » Tue Sep 18, 2012 9:23 pm

MoapaPk wrote:I want to apologize now, for offending anyone in the future. Now I'm good to go!

In my humble experience -- dealing with MSDS sheets since they came into existence -- a health rating of "0" in this sort of application means something that is very unlikely to react with the organic materials in human bodies (e.g. collgen).

Buz(z), do you have a 1990s msds for "sand"? California required cancer warnings on bags of sand. I had to get rid of half the reagent grade silica in my lab because of concerns (not mine) that people might inhale it, causing silicosis. The problem is generally not the people who handle chemicals, but the lock-step zealots who enforce what they perceive as dangers, and make grand leaps of reasoning based on a their special knowledge.

I'm making the wild guess that companies who work with rope fiber, markers for fiber, and so on, have a little experience with chemistry as well.

Plus the fact that no one has attributed a rope failure to laundry pen marks, well that is a little key too.

According to the UIAA tests, dihydrogen monoxide (DHMO) is a far more serious issue with the strength of ropes-- and I bet you guys are getting DHMO (as well as sand, NaCl, and other salts) on your ropes all the time.


I could just about write a book on the kind of BS that goes on with MSDS ' misinterpretation', especially by Regulators. California seems especially bad in that regard. I wonder if they even have any chemists working for the Cal. DEQ or EPA or whatever name the agency goes by?

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Buz Groshong

 
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Re: How to Mark the Middle of the Rope?

by Buz Groshong » Tue Sep 18, 2012 10:31 pm

MoapaPk wrote:I want to apologize now, for offending anyone in the future. Now I'm good to go!

In my humble experience -- dealing with MSDS sheets since they came into existence -- a health rating of "0" in this sort of application means something that is very unlikely to react with the organic materials in human bodies (e.g. collgen).

Buz(z), do you have a 1990s msds for "sand"? California required cancer warnings on bags of sand. I had to get rid of half the reagent grade silica in my lab because of concerns (not mine) that people might inhale it, causing silicosis. The problem is generally not the people who handle chemicals, but the lock-step zealots who enforce what they perceive as dangers, and make grand leaps of reasoning based on a their special knowledge.

I'm making the wild guess that companies who work with rope fiber, markers for fiber, and so on, have a little experience with chemistry as well.

Plus the fact that no one has attributed a rope failure to laundry pen marks, well that is a little key too.

According to the UIAA tests, dihydrogen monoxide (DHMO) is a far more serious issue with the strength of ropes-- and I bet you guys are getting DHMO (as well as sand, NaCl, and other salts) on your ropes all the time.


Perhaps sand was a poor example; the point is that just because something is safe for humans does not mean it is safe for all sorts of things, and I'll bet your dihydrogen monoxide (DHMO) also gets a "0" health rating. :wink:

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MoapaPk

 
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Re: How to Mark the Middle of the Rope?

by MoapaPk » Fri Sep 21, 2012 4:08 pm

http://www.rockclimbing.com/cgi-bin/for ... st=1947671

Interesting "thread." See note of "Safe" marking method with thread.

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Re: How to Mark the Middle of the Rope?

by Wastral » Sun Sep 23, 2012 1:51 am

Buz Groshong wrote:
Perhaps sand was a poor example; the point is that just because something is safe for humans does not mean it is safe for all sorts of things, and I'll bet your dihydrogen monoxide (DHMO) also gets a "0" health rating. :wink:


Can't be 0... Too much of a good thing has rather bad results...

If you want to mark the middle of your rope, place middle of rope in a 120F bath of RIT dye/water of your choice. Boom done. Use body temp thermometer, works fine. DO NOT go above this temperature.

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MoapaPk

 
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Re: How to Mark the Middle of the Rope?

by MoapaPk » Thu Apr 13, 2017 10:07 pm

I think I have a possible answer to the mystery of sharpies supposedly decreasing rope strength. The supposed strength-reduction always struck me as odd, since the marking is very superficial, doesn't even saturate the sheath, and the core is about 85% of the rope strength. I'm betting that if you tested the sharpie-marked sheath alone, as by pull-test, it would retain nearly all its original strength as well.

Remember that the UIAA tests were done on dynamic ropes; remarks from the UIAA head suggested the tests were arranged so the marked region would be on the metal edge during the drop. The drop tests don't really measure "strength," but a rope must survive so many tests to consider to have "passed."

I measured the coefficient of friction of nylon rope on nylon fabric, both with and without marking. The sharpie-covered rope/fabric had a 47% higher coefficient of friction than the unmarked nylon. Hence when the sharpie-marked rope pulls over an edge, substantially more frictional energy will be absorbed in the rope and steel (the capstan equation for the 150 degrees specified for UIAA gives an extra 7% change in the tension over the bend). Since many "light" ropes are engineered to barely pass the UIAA test, this difference could put them over the edge.

The Sharpie doesn't have to alter the nylon chemistry in any way; and if it does, it is only a very, very small amount of the nylon that is changed. But is does put an anti-lubricant coating on the very surface of the rope that significantly increases the energy absorbed near the bend.

This mechanism means that the strength of the rope will be essentially unaffected in a pull test. The marking will not affect a rope used primarily for rappels at all. As the UIAA chief noted at the time, a fall on a 60m rope, where the marked middle portion exactly coincides with a sharp bend over protection, is probably catastrophic for other reasons.
-----------

UPDATE:

I've since done straight pull tests on sheaths pulled off off nylon ropes; saturating the sheath with sharpie made absolutely no difference in the strength of the sheath before breaking (in fact, the sharpie-saturated sheath came out slightly stronger, but within estimated error of the unmarked). I've also used Attaway's analysis, and concluded that pulling the sharpie-marked sheath over the tight bend in the UIAA test could result in about 1/3 more melting of the rope. I've no doubt that the "failure" on sharpie-coated ropes had nothing to do with the inherent strength, but rather with the increased surface coefficient of friction.

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