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bio website lightandmatter.com
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visits member for 1 year, 5 months
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I live in LA and enjoy day hikes, backpacking, rock climbing, and mountaineering.


Jun
22
comment Climbing Mt Kazbek in Georgia
More info on this route: summitpost.org/normal-from-georgia/164922
Jun
17
awarded  Nice Answer
Jun
17
revised “Used” top rope when bouldering
added 810 characters in body
Jun
17
comment “Used” top rope when bouldering
I gave a link to the Aging Rope article in my answer. Re your direct experience with ropes in a gym wearing out, isn't this likely just the result of abrasion? A toprope is getting pulled repeatedly over a pulley, through a belay device, and possibly over the rough surface of the climbing wall (what is that stuff, gunite or something?). Those ropes get used a lot compared to a rope used by an individual climber.
Jun
16
revised “Used” top rope when bouldering
added 810 characters in body
Jun
16
revised “Used” top rope when bouldering
added 810 characters in body
Jun
16
comment “Used” top rope when bouldering
[...] sounds to me like it doesn't have much to do with what we're talking about. It sounds like they're describing a catastrophic failure of a rope, not damage from taking a top-rope fall.
Jun
16
comment “Used” top rope when bouldering
@Mr.Wizard: I disagree with your addendum. The general idea is that materials have an elastic limit, and when you subject them to a strain that's less than the elastic limit, they return to their original size and shape when the strain is removed, and there is no damage. Your first quote (CMC) references a paper by Bruce Smith, "Aging Rope," which it turns out you can find online. They tested dynamic and static ropes. What they found with the dynamic ropes (the type we're talking about) is that it was generally impossible to get them to break on their test machine. The second quote [...]
Jun
16
answered Chacos: Toe strap or no toe strap?
Jun
15
comment When should I retire my rope
there is a tendency to look at a short wall and figure it's small stuff and won't really stress your equipment, when in fact the forces can be quite high and they get concentrated on a short section of rope near the ends. I don't think that analysis is right. The fall factor is actually a measure of how much the force is concentrated per unit length of rope. So I think if you compare a long fall-factor-1 fall to the kind of short fall-factor-1 fall you're likely to see in the gym, the damage per unit length is equal, but in the long fall there's simply a longer damaged section.
Jun
15
comment When should I retire my rope
related: outdoors.stackexchange.com/questions/5856/…
Jun
15
revised “Used” top rope when bouldering
added 204 characters in body
Jun
15
comment “Used” top rope when bouldering
Nice answer, +1. I'll edit my own answer to address the issues raised about the sheath. I've corrected the incorrect sentence that you quoted in your second paragraph.
Jun
14
revised “Used” top rope when bouldering
deleted 12 characters in body
Jun
14
answered “Used” top rope when bouldering
Jun
14
comment When should I retire my rope
Short falls with little rope out (in a gym) may have a higher fall factor than longer falls with a lot of rope out (outdoors). But the maximum fall factor you can get in the gym is 1, because the belay station is on the ground and it's not possible to fall past the belay station.
Jun
14
comment “Used” top rope when bouldering
related: outdoors.stackexchange.com/q/5270/2169
Jun
12
comment What is SPF in sunscreen cream?
At very high SPF levels, the limitation is probably just how long the stuff will stay on your skin. It's going to come off as you sweat, wash your hands, etc. It also matters how much you apply. I have a lot of summit victory pictures where I look like a dork because I have sunscreen caked on my face unevenly.
Jun
10
awarded  Enlightened
Jun
10
awarded  Nice Answer