all tied up

Post by **Paul3eb** » Fri Dec 12, 2003 5:13 am

and what's the deal with "dry" ropes? i've heard that sterling are the only true dry ropes. how about edelweiss? and can you climb in the rain or is it where you can finish the pitch and then get out of the rain? thanks guys

Post by **Legion** » Fri Dec 12, 2003 7:41 am

Those Edelweiss Stratos are BURLEY ropes. I have guided on them for several years and they are tough as nails.
But if you are mainly sport climbing you might not need as burly of a rope as if you were doing alot of multipitch. You will wear your rope out by repeatedly falling on it and it will lose it's elastictity. You might be better off buying two less expensive ropes in the 10-10.2 range and plan on rotating them.

60m is the size to get.

I wouldn't worry too much about a dry rope unless you were ice climbing or something.
I just read some recent test results that suggest that a dry coating may not prevent the core of the rope from becoming soaked - which is the part you really want to keep dry. They also suggest that even a rope splashed with water is significantly weakend.
The jury is still out IMO on how well the treatments work but the bottom line is that a wet rope is a weak rope. (1/3 strength) So your best bet is to either keep your rope dry or don't take any screamers.

Post by **ynot** » Fri Dec 12, 2003 4:54 pm

The dry treatment works great when the rope is new.It also wears off in about a year weekend use.Other than that I love my sterling.After 3 years of heavy use its still a good rope.I cant see how being wet causes a rope to lose strenght.Can you explain?

Post by **Legion** » Fri Dec 12, 2003 6:29 pm

molecules of the nylon lose their ability to stretch. That is about all I can tell ya since I am not a polymers chemist

Guest · Post by **Guest** » Fri Dec 12, 2003 6:31 pm

I was thinking about this last night (I'm a geek) - how many of you untie your knot and let the rope rest and recover after taking a significant whipper (ie 20 or more feet)? Did you even know you were supposed to do this?

Guest · Post by **Guest** » Fri Dec 12, 2003 6:36 pm

whoops, I meant to put my above post in the MAXIMUM FORCE thread.

Post by **TradMike** » Fri Dec 12, 2003 6:45 pm

Water affects the mechanical properties of the hydrogen bonds in nylon. Nylon is crystalline in nature and made up of a polymer chain. Climbing ropes are made from Nylon 6 which has six methyl groups that are on each side of the nitrogen atoms (amide groups). When a climbing rope absorbs water through capillary action the water molecules produce polar bonds with the amide groups in the nylon molecules. Even though a water molecule is very tiny they do take up significant space and displace the nylon molecules. It results in the nylon molecular matrix swelling. As the matrix swells the molecular mobility is increased because of the absorbed water. The increase in spacing between nylon molecules lowers the secondary forces allowing easier translational motion. This translational motion results in less resistance to applied stress because there is less intermolecular friction. The change in molecular mobility is significant enough to reduce the strength of the rope. The decrease in strength can be as great as 30%.

Post by **ynot** » Fri Dec 12, 2003 7:18 pm

wow. Ok I believe.

Post by **tomdarch** » Sat Dec 13, 2003 1:00 am

Given that we're talking about 'mostly sport and a little trad', dry treatment won't matter. Other than ice, dry treatment is most important for alpine and multi-pitch climbing. In most sport situations, if it starts raining, you lower off and pack it in. On multi-pitch, you're a lot more likely to get your rope wet and then keep climbing (showers, puddles, runoff, pissing in your pants, etc.) Some people like the feel of a dry-treated rope and they may wear slightly less quickly, but those factors may not justify the price by themselves.

About the up to 30% loss in strength, I don't think that it's likely that that reduction in strength would make a difference (thinking about the 'maximum force' thread - but there always is that chance of a 'one in a million' situation... (Basically, there's a ton of 'safety factor' built into climbing gear, which is why people don't die from wet ropes snapping.)

Also, for summer sport climbing, I keep hearing great things about Wild Iris/Sinks Canyon in central Wyoming.

Post by **ynot** » Sat Dec 13, 2003 1:13 am

I have been caught in showers more than once at the Red. In one case the dry treatment was effective because a couple hours later the sun came out ,my rope dried fast , we went on climbing and had a great time.