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Matthew Fienup
Apr 11, 2009
All on one page!  
Matthew Fienup
Ventura, CA
Matthew Fienup   Ventura, CA  
For more information from Duane Raleigh and others, visit the American Safe Climbing Association.

Mechanical Bolts - the Nuts & Bolts, by Duane Raleigh

Dangerous Bolts - Bolts to Avoid, by Duane Raleigh Dec 16, 2009
Matthew Fienup
Ventura, CA
Matthew Fienup   Ventura, CA  
In regard to my parenthetical note about Central Coast Sandstone...

In the study, Duane Raleigh actually tested bolts in custom-made blocks, which were chosen for their specific hardnesses. Soft Rock was simulated using 1,000 psi concrete. Medium Rock was simulated using 2,000 psi concrete. Hard Rock was simulated using tombstone-grade marble and granite blocks.

Here on the Central Coast, I have seen sandstone that is likely softer than 1,000psi (the Foot and parts of San Ysidro come to mind). I have also seen sandstone that is likely in the 2,000 psi category (Wheeler Gorge and parts of the Fortress). Derrydale Cliff, above Ojai, likely has some rock softer than 1,000 psi and some which is closer to 2,000 psi. When assessing the hardness of sandstone, it is important to keep in mind that the hardness of the surface (the patina) is not the relevant figure. What matters is how hard the rock is below the patina, where the bolt actually grips the rock.

My own anecdotal evidence, while pulling bolts in the Santa Barbara and Ojai areas, has been consistent with Duane Raleigh's results. Dec 16, 2009
half-pad-mini-jug
crauschville
half-pad-mini-jug   crauschville
pitons are safer... Dec 15, 2009

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