jharman2 wrote:I don't know how or if a SS anchors age factors into its integrity. I guess this is a question for a material scientist.
I don't think this is a question for a material scientist; it is common sense that the older an anchor is, then the more general use, wear-and-tear, intrusion of the rock-bolt interface by humidity/water, potential shock-loading, subsequent fracturing of rock along an artificially-weakened hole, etc. that the anchor system may have seen. Replace "anchor" with "car", "ox", or "knee joint" and the answer is exactly the same. More age equals more use equals more
potential for wear of the
system, regardless of whether the stainless steel bolt itself
ever corrodes or weakens.
jharman2 wrote:Does the method of drilling really matter if the placement is solid and the bolt is torqued down?
This is a question I'd love to have answered with hard data; my suspicion (fear?) is that, yes, a hand-drilled hole may have a lower pull-out strength than a hole drilled with a rotary hammer drill (or, saying it another way, a hand-drilled hole is easier to screw up). If I know that a bolt was placed this decade rather than in the 1980's, I'm more likely to assume it was placed with a hammer drill, and not have that doubt in the back of my mind, encouraging me to place a new bolt that I know is drilled with one. [If someone wishes to comment further on
this topic, please start a new thread.]
jharman2 wrote:I don't think that labeling bolts it is a bad practice but I certainly caution against trusting an anchor just because it has a label. Inspection of the anchor is the only way to definitively determine if it is safe to use.
Excellent, then we are in agreement. I felt it unnecessary to even put the disclaimer on my original question that one still need inspect a bolt that your life depends on, despite it having a warm fuzzy "born on date" attached.
My question for you, then, is if you believe that placing a label like in the above example is a
good practice, and if not, why?
jharman2 wrote:If I come across a 30 year old rig that is redundant and clean, I will happily use it.
And this is exactly my goal! To prevent the bolt garden in Carpenter-Swago from turning into the bolt
farm in Cass Cave. I personally feel that in caves like this, adding a label to a bolt may help the user evaluate that rig.
Edit for clarification: So it doesn't sound like I'm contradicting myself by saying at the same time both "older bolts may be more suspect" and "making a bolt's age known prevents over-bolting"... The example cave, Cass, has been explored heavily since the mid-1940's has no fewer than 17 bolts placed at the Belay Loft, including two brand new(???) stainless 3/8" diameter, unknown length bolts inexplicably-placed next to a one-ton natural tie-off boulder, rather than out over the drop. I believe that at least two of the four large, rusted, steel anchors over the big drop were placed in the 90's based on oral tradition, but I sure have no way of being certain of that; and despite the fact that I can yank on them or crank on them, I can only guess as to whether they are suitable for a rescue load. If a tag told me they were 6" deep and placed in 1995, I'd let you haul me up on them without protest; probably even if it said 6" deep and 1975.
Perhaps I'm totally wrong and modern-looking manufactured stainless hangers on "solid enough" bolts are good enough for everyone to trust 10 years from now? 20 years from now?