Glue-in Bolt Test Results at Muir

Post by **weber** » Tue Apr 18, 2006 12:23 am

Results of the long FIXE glue-in bolt test!

There's a famous line in the movie "Jaws" where Matt Hooper (Richard Dryfuss) says, "We need a bigger boat."

Seems we need a bigger testing machine. The new long FIXE eyebolt was glued in with HIT 500 epoxy. Yesterday we broke the quicklink at 5700 pounds without fazing the eyebolt. Today we returned with a bigger one and managed to damage the hydraulic pump before the eyebolt broke its weld at 7600 pounds! The bolt is still solidly adhered to the rock. The epoxy never failed. And the rock showed no signs of failure, i.e. cracks, ruptures, etc.

Now, this is a bolt I can learn to love! We will be putting them in those locations where mechanical bolts tend to loosen -- like the roof move of the Rising.

More later.

Rick

Post by **Saxman** » Tue Apr 18, 2006 12:36 am

Those results are incredible. Sounds like a bolt we all can love. As asked above, what is the lifespan of the epoxy? Does it become brittle over time?

Post by **Overcammed** » Tue Apr 18, 2006 2:56 am

Hmm...certainly seems like the glue really helps with the compression strength of the rock (since I'd guess that most sandstone would crumble on its own at 7600 lbs!)

I wonder, is there a way to "treat" the rock that you're going to put a mechanical bolt into in a way that it would strengthen in a similar way? That is, if the problem with the mechanical bolts is that the stone on the outside edge crumbles and sets off the chain of events towards weakness, could some sort of "penetrating" sealer, strengthener or other voodoo magic cause that sandstone on the outside to have a stronger internal bond?

I guess I'm just thinking of those penetrating concrete sealers you buy for bricks, etc. Granted those are for water protection, but I wonder what effect something like that would have on sandstone...

Post by **dhoyne** » Tue Apr 18, 2006 11:55 am

Sandstone is pretty porous. Depending on how viscous the epoxy is when you inject it, it will wick into the surrounding sandstone and strengthen it.

Post by **Cobra13e** » Tue Apr 18, 2006 12:30 pm

Rick, have you considered "publishing" your results and methods? Nothing like a scientific, peer-review or anything, but I personally think this project is a great example of stewardship, climbing ethics, responsiblity, etc. all. Good PR for the RRGCC/PMRP, not to mention I'm sure there are other climbers out there who would benefit greatly from your work...

Just a thought.

Post by **Eric** » Tue Apr 18, 2006 12:52 pm

those results are alot more consistant with what I have read in the past about glue ins and pull out strength. Usually they are in the tens of thousands of pounds of strength and should pull out the entire rock surrounding the bolt before the bolt comes close to failure. The glue ins should not fail gradually like an expansion bolt, but all at once. The areas that have glue ins usually have no long term maintenance with those types of anchors and they should last a very long time.

Post by **pigsteak** » Tue Apr 18, 2006 2:08 pm

so is it now a money issue? and is this overkill, except in very soft stone?

Post by **Feanor007** » Tue Apr 18, 2006 11:15 pm

rick, thanks, you deserve a million stars beside your name in the book of life. some rag should put you on the cover instead of just another guy climbing hard. thnaks so much.

Post by **weber** » Tue Apr 18, 2006 11:57 pm

pigsteak wrote:so is it now a money issue? and is this overkill, except in very soft stone?

Good questions.

Is it a money issue? Depends on how much value you put on your time and the safety of climbers who climb your routes. The retail price of an expansion bolt/hanger bracket combo is about $2.50 to $3.50 to do the initial installation. The retail price of a FIXE 3.5-inch glue-in is $5.40, and the 5-inch version is $6.70. Each glue-in installation requires about $.80 worth of epoxy.

The expansion bolt can require several revisits to re-tighten it --especially in those locations where repeated falls tend to pivot the hanger bracket and loosen the assembly. The glue-in bolt should stay put for a much longer period of time. So, in the long run, the glue-in may be less expensive. This is all based on the assumption that responsible developers will periodically check out hardware on their routes.

Is this overkill, except for very soft stone? I don't think so, based on the number of properly-installed expansion bolts that have loosened over short periods of time. Granted, there are relatively few of these cases (despite the "sky-is-falling" reports on this forum.) But, ideally, I think we should strive toward a no-loose-bolt world.

There are some bolted hangers that are located such that they tend to loosen. And, for these cases, I think the glue-in definitely should be used. As for typical horizontal-axis placements -- the majority-- I believe properly installed expansion bolts will be adaquate.

The glue-in promises a much lower risk of a blowout --especially on downward angle placements. That is why we will be requiring glue-in 3.5 or 5 inch FIXE s.s. eyebolts be used for "problem" bolt locations in M.V. My guess is that one in 15 bolts will need to be a glue-in. I will try to come up with some guidelines for determining when a glue-in should be used at Muir. For example, when Methane Rising is rebolted, the bolts above the first set of top anchors will definitely be 5-inch FIXE glue-ins.

Rick

Post by **weber** » Wed Apr 19, 2006 12:11 am

pigsteak wrote:so is it now a money issue? and is this overkill, except in very soft stone?

PS

Pigsteak: I'm offering you and all the other developers of MV routes free FIXE glue-ins and epoxy and use of the gun to replace any questionable expansion bolts on your current routes. So, for these placements, it should not a money issue.

Rick