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Disaster Master
Sport climber
Arcata, CA
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Paul Humphrey here.
I have had more experience placeing / replacing bolts, especially in corrosive conditions than a lot of folks.
Bottom line: things break.
1/4 inch bolts are freakishly unpredictable. might hold, might not. do you want to take that chance? I,ve had a 1/4" partially pull under body weight and have cleaned several with a pittiful tug of a quick draw.
3/8" bolts vary widely in strength. My rule of thumb is tht if there are exposed threads, i.e. the` hanger attatches with a nut,it should be eyed with suspission if rusty. Fully rusy 3/8" bolts breakquite easily at the rock when exposed to a hrd sideways blow, a rock or hammer. Usually in normal use they are safe, but I have one 3/8" bolt that broke at the threads in a 10 foot fall. The bolt was near the coast, but was less than ten years old.!
3/8" & 1/2" hex head bolts are awsome. Even when I have tryed to force rusty specimens from the rock, the effort has been significant.
Glue ins are all about the glue. Its whole different game.
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paul roehl
Boulder climber
california
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Watched a friend pull a quarter inch bolt out of the weeping wall at Suicide. It just came right out as he clipped in. I don't remember the climb, though it wasn't Serpentine... ended up dropping a line to him from above as he was mighty freaked at that point.
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hb81
climber
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Dr. Sprock, do you have the second part of that article as well and could post it?
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gonzo chemist
climber
Crane Jackson's Fountain St. Theater
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I have a very good friend in Colorado who took a 3 foot fall on a 3/8" compression bolt, on a slab on Wigwam Dome (if I remember correctly). This was about 2 years ago.
He wrote up an account of it, and posted it on MP.com. Long story short: the bolt sheared off in the hole, and that resulted in a really nasty fall. He ended up with some cracked ribs, but otherwise mostly just really beat up. Its amazing he even lived, let alone that he walked away. I flew to see him about a month after this happened, and man he looked rough. Long healing process.
Anyway here's the moral: don't place compression bolts unless you like to gamble.
-Nick
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Mungeclimber
Trad climber
sorry, just posting out loud.
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"if there are exposed threads, i.e. the` hanger attatches with a nut,it should be eyed with suspission if rusty."
what's the theory here Paul? Less material at the threads, add to it 'near the coast' with corresponding corrosion issues and you have a weakened form factor?
Nick, can you expand on this?
"Anyway here's the moral: don't place compression bolts unless you like to gamble."
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gonzo chemist
climber
Crane Jackson's Fountain St. Theater
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Munge,
I guess that was a bit hyperbolic on my part. Admittedly I'm no bolt-placing expert. But as I understand it, when you hammer the bolt into the hole, the shaft compresses. Or rather gets "squished" in diameter. And that can potentially compromise the integrity of the shaft. There can also be problems if the hole is not deep enough and you hammer the sucker in.
However, there's no way of knowing whether that compression bolt is good or not. You just can't tell by looking at it. As I understand it, the FAist of the route went back and pulled all the old compression bolts, and replaced them with nice expansion bolts.
Anyway, I'm pressed for time right now so I can't dig around, but I feel like I read all of this from the ASCA website back when the incident occurred. I'm not pulling this stuff out of my rear end. But as I said, I'm certainly no expert. I would however, like to hear the opinions of people experienced in placing bolts.
-Nick
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Disaster Master
Sport climber
Arcata, CA
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Paul here.
My theory about threaded bolts is that there is some flex in between the nut/hanger and the rock due to the groove of the thread. Also water, salt is moved up the thread into the bolt. In the end, the test is in how easy bolts of a near age are to remove. My work shows that threads are a point of weakness.
Even in a five piece bolt where the actual bolt is 5/16, since that bolt is a solid shaft until well into the hole, it will last longer.
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Mungeclimber
Trad climber
sorry, just posting out loud.
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thx for the replies
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