The Book of Rocks
““The harder it is, the better it is.”
EPISODE: Climbing bolts are only as good as the ROCKS you put them in
The Bolting Bible
This is free resource by HowNOT2 and our way of contributing to the community. It's nice to understand what you are clipping and trusting with your life, even if you never plan on installing or removing bolts. We also believe that if you are going to spend time and money to bolt something, you should do it well.
This book is in a blog format. This page points to all 17 chapters, and the end of each chapter points to the next.
A downloadable PDF is available HERE.
Bolts Don't Hold You, Rocks Do
Bolts are only as good as the rock you put them in. Some rock is soft and some rock has more layers than onions. The rock, not the bolt is holding your life, the bolt is just hanging onto the rock. So let’s learn the basics to have a “rock solid” foundation!General Rock Biology
Hard Rock (not the cafe)
Hard Rock would be any rock that is, wait for it, incredibly hard, typically unweathered granite and quartzite sandstone.
Quartzite Sandstone is quartz-rich sand, cemented together with quartz cement. So the whole rock
is nearly 100% quartz. Quartzites are the typical ridge-formers of sedimentary basins, like the
Sandstones at New River Gorge, WV.
Bolts in hard rocks can be installed closer to an edge (within a foot or two). Strength of hard
rocks is above 14,500 psi and goes up to 30k and even 50k psi for some.
- MECHANICAL BOLTS - Granite or other hard rock is perfect for all kinds of mechanical bolts, just be sure they are stainless steel.
- GLUE IN BOLTS - These work just fine in hard rock but there are 2 schools of thought. Glue ins can be frowned upon in granite as it can be considered overkill and replacing them can possibly be more difficult than mechanical bolts. The reason some people choose to use glue ins with fixed eyes is because there are no threads to get screwed up, no one can steal hangers, and the fixed eye allows highliners to thread static rope through rather than needing quick links. Glue ins typically have less visual impact than a standard climbing hanger.
Soft Rock
Soft Rock can be sedimentary or magma based. These are typically non-quartzite sandstones (where the sand-grains, or the cement, or both, are not quartz-rich, and thus prone to weathering and weakening), limestone (calcium carbonate), volcanic rocks, and excessively weathered granites. Just like tall tales, porous rocks with a lot of holes don’t usually hold up!Bolts installed in soft rock need to be placed further back from edges in the most solid part you can find. It’s also quite unsafe to put pressure on bolts installed in soft rock when they get wet, like after a rainstorm. Cyclic loading mechanical bolts in sandstone compromises placement integrity. In Moab, Utah, it’s highly recommended to let the rock dry out thoroughly before highlining on those bolts. In Zion National Park, you are not supposed to climb on that soft sandstone for 2 days or it will compromise the rock and gear placements. Soft rock strength (dry) can be as low as 500 PSI and up to 7,000 PSI.
- MECHANICAL BOLTS - The softer the rock, the less force these will hold. Wedge bolts are not recommended because the engagement contact point is quite small which can compromise the placement in soft rock. Some sleeve bolts are ok because there is more contact area (like 5 piece Power bolts - STAINLESS).
- GLUE IN BOLTS - This is where glue shines. Glue gets into all the rock pores therefore can pull on the entire rock surrounding the bolt stud rather than all the pressure being placed on a few millimeters of the sides of the hole with mechanical bolts.
Layered Rock
- MECHANICAL BOLTS - can promote more cracking and are NOT recommended.
- GLUE IN BOLTS - Glue can grab the whole sandwich of rock layers giving better holding power.
Rock Inspection
BIG ROCK - Be sure you are not just on some large flake or suitcase sized rock. Check to see if the rock is thoroughly attached to all the other rock around it and not just a boulder sitting in the dirt. Sometimes even car-sized rocks are just barely attached to a rock face. Your bolt might hold but the rock might not!
Think about the big picture of how that rock is attached to the earth.
Nothing is Forever
What's Next?
Chapter #3 - The Book of Holes