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General Climbing Discussion

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Bundaleer - June Update 29-Aug-2006 At 7:38:29 AM tmarsh

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On 28/08/2006 Big Arms wrote:
>I think this topic really requires somekind of scientific / metalurgical
>experience. Maybe even the manufacture's recommendations.

This is part of the problem: the sort of uses climbers put bolts to are not recommended or even sanctioned by any manufacturers. If you followed standard industry procedure for anchors that will be used to safeguard human life, then even HB's bolt at the bottom of Angular would be considered marginal.

In-situ testing isn't straightforward. Manufacturer data on the effect of heat in this sort of application is non-existant. Hilti, Powers and Ramset don't list anything on their websites on the effect of elevated temperature post installation. My own somewhat unscientific experiments with glue-in carrots in a bluestone block would seem to suggest that the sort of temps you need to seriously degrade a 2-part epoxy are waaaay in excess of the sort of temperatures you'd get on a rock face in a bushfire.*

My guess as to the safety of the bolts at Bundaleer is that they are as safe as the rock they are in. And even then, longer bolts, particularly expansions, could well remain safe enough even in rock that has suffered mild exfoliation.

* heating the bolt till it began to glow produced some evil smoke and bubbling at the glue interface. Once it cooled, everything looked to re-solidify and the bolt was as difficult to remove as the non heated one. But I would hardly call this a scientific investigation.