The Bolting End-Game

Jeremy in Inyokern wrote: A vacuum does not. Air is a lot of different things. If air was not an electrolye all you would have to do to protect metal would be leave it outside.

I'm sorry, but you have no idea what you are talking about. It's not the air that causes the metal to corrode, but water, this is why if you leave something outside in a desert environment it will last much longer than if it is left outside in a tropical environment. An electrolyte is an electrically conducting solution, and air is not an electrically conducting solution by any stretch of the imagination.

jonathan knight wrote: Not a very good comparison, but here's some 304 SS. The reassembled bolt was <10 years old, and the rest were around 12 years in the rock. There's no rust from what I can see.

That picture of the SS bolt that was pulled is exactly my experience here in the Portland area. I've pulled multiple 304 SS bolts that were over 10 years old to check them, and there hasn't been a spot of rust on a single one yet. And we get plenty of rain out here... I personally think that a glue-in SS 316 bolt out here will last longer than 100 years even in our wet climate, which means they will probably last much longer in the dryer areas.

kennoyce wrote: I'm sorry, but you have no idea what you are talking about. It's not the air that causes the metal to corrode, but water, this is why if you leave something outside in a desert environment it will last much longer than if it is left outside in a tropical environment. An electrolyte is an electrically conducting solution, and air is not an electrically conducting solution by any stretch of the imagination.

You just agreed with me. Air has water in it. Air forms a thin film electrolyte on metal surfaces. The more humid the air is the worse the reaction will be. Air is an electrolyte.

kennoyce wrote: I'm sorry, but you have no idea what you are talking about. It's not the air that causes the metal to corrode, but water, this is why if you leave something outside in a desert environment it will last much longer than if it is left outside in a tropical environment. An electrolyte is an electrically conducting solution, and air is not an electrically conducting solution by any stretch of the imagination.

Remind me again, how does lighting work, last time I checked it flows through the air, no?

Its pretty obvious he was reffering to air as in the sum total of the atmosphere here on planet earth, not a vacuum in a lab experiment. You can get off your high horse.

jonathan knight wrote:Here are some shots from American Fork. My guess is that we are seeing galvanic corrosion <5% of the time. Most all of the placements are SS hangers/plated rawl sleeve bolts around 25 years old. They have been solid which is reassuring, but all of the plated bolts, even some newer ones, are corroding in the limestone. The control from the same route: Not a very good comparison, but here's some 304 SS. The reassembled bolt was <10 years old, and the rest were around 12 years in the rock. There's no rust from what I can see.

Rusting plated bolts does not necessarily mean galvanic corrosion. Of course, with a SS hanger and plated bolt you would see differential corrosion, one is Stainless Steel! As Jonathan points out in his post, the bolts are corroding, but it is not galvanic corrosion.

I have pulled numerous rusted plated 3/8" grade 5 carbon steel bolts as shown in the photos and they still test out at 5000lbs in shear which is the manufacturer's rating for a new bolt.

Morgan Patterson wrote: Remind me again, how does lighting work, last time I checked it flows through the air, no? Its pretty obvious he was reffering to air as in the sum total of the atmosphere here on planet earth, not a vacuum in a lab experiment. You can get off your high horse.

yes, it flows through air, but it's not because air conducts electricity, or because air is an electrolyte. In order for lightning to flow through air it requires a significant amount of energy to ionize the air and turns it into a plasma thereby allowing the electricity to flow. I stand by my point, air does not conduct electricity.

Jeremy in Inyokern wrote: You just agreed with me. Air has water in it. Air forms a thin film electrolyte on metal surfaces. The more humid the air is the worse the reaction will be. Air is an electrolyte.

again, no, air may deposit water on the surface of the metal (through condensation) which I think is what you are talking about, but the air itself is not an electrolyte because the water molecules in the air are not close enough together to conduct electricity.

wrong meme

jonathan knight wrote:Like this? The hanger doesn't look too bad. btw, another good thread. Thanks!

Yeah...I'd guess not galvanic corrosion. Looks like white zinc oxide on the bolts too.

They just rusty...nice pics!

Here's a shot from a few years back from AF:

Bolts pulled from Division Wall in American Fork Canyon. Placed 1991? Pulled 10/23/2004.

Both your bolts and the ones above have little mass loss...be interesting to pull test them to failure...hmmm...

Cheers!

Oh god now air is causing galvanic corrosion? Hahaha. I don't buy that galvanic corrosion is significantly speeding up corrosion in most environments, it certainly isn't the problem people make it out to be. Places where galvanic corrosion would be an issue are having issues even with all stainless steel set ups. Here at the Red 90% of routes excluding the Miller Fork Preserve are ss hanger/carbon steel bolt combos. Isn't galvanic corrosion more of a problem when you have one bolt that is non ss on a huge sheet of ss?

DrRockso wrote:Oh god now air is causing galvanic corrosion? Hahaha. I don't buy that galvanic corrosion is significantly speeding up corrosion in most environments, it certainly isn't the problem people make it out to be. Places where galvanic corrosion would be an issue are having issues even with all stainless steel set ups. Here at the Red 90% of routes excluding the Miller Fork Preserve are ss hanger/carbon steel bolt combos. Isn't galvanic corrosion more of a problem when you have one bolt that is non ss on a huge sheet of ss?

Yep, area does play a huge role in galvanic corrosion. The larger the area of the cathode and the smaller the area of the anode, the bigger the problem is. You still need the presence of an electrolyte though.;) It really has to do with the area of the cathode that is in contact with the electrolyte to the area of the anode that is in contact with the electrolyte.

kennoyce wrote: again, no, air may deposit water on the surface of the metal (through condensation) which I think is what you are talking about, but the air itself is not an electrolyte because the water molecules in the air are not close enough together to conduct electricity.

I think we can reach an agreement..

Electrolye: An electrolyte is a substance that produces an electrically conducting solution when dissolved in a polar solvent, such as water. The dissolved electrolyte separates into cations and anions, which disperse uniformly through the solvent.

Air, for all intensive purposes, has at least some quantifiable amount of water in it. That water is capable of carrying electrolytes. Of course "air" is composed of many different elements in varying concentrations depending on different things. A notable case is "marine air," which contains a high concentration of Na and Cl ions, as well as other elements.

It's also important to keep in mind that pure H2O will not conduct electricity - it needs electrolytes in solution. This applies to the water in the air as well.

Have we attained harmony?

Who Dat wrote: I think we can reach an agreement.. Electrolye: An electrolyte is a substance that produces an electrically conducting solution when dissolved in a polar solvent, such as water. The dissolved electrolyte separates into cations and anions, which disperse uniformly through the solvent. Air, for all intensive purposes, has at least some quantifiable amount of water in it. That water is capable of carrying electrolytes. Of course "air" is composed of many different elements in varying concentrations depending on different things. A notable case is "marine air," which contains a high concentration of Na and Cl ions, as well as other elements. It's also important to keep in mind that pure H2O will not conduct electricity - it needs electrolytes in solution. This applies to the water in the air as well. Have we attained harmony?

Yes, I can agree with everything you just posted.

The question then becomes, what am I supposed to do with myself all afternoon if we have reached an agreement?

At least we can agree that there is corrosion, haha.

I have seen a pattern of accelerated corrosion of some of the plated bolt heads. Most others have looked pretty clean as in Brian's photo. Sometimes it's obviously in a wet area of the cliff, other times the correlation isn't as obvious. We are dealing with steep limestone where water can seep from the bolt holes.

jonathan knight wrote:At least we can agree that there is corrosion, haha. I have seen a pattern of accelerated corrosion of some of the plated bolt heads. Most others have looked pretty clean as in Brian's photo. Sometimes it's obviously in a wet area of the cliff, other times the correlation isn't as obvious. We are dealing with steep limestone where water can seep from the bolt holes.

I know what you mean, I've replaced several bolts in AF myself. I'm sure some bolts in AF suffer from galvanic corrosion, but most that I've seen just appear to be uniform corrosion that usually starts at the bolt threads and works its way back up the shaft until the whole bolt is rusty.

Jim Titt wrote: Trust you to compare with the most expensive bolt ever made, I´d sell you a certified 316L anchor for $3.11 without even starting on discounts.

So what? If the Ti bolt lasts two centuries, and your 316 bolt lasts 50 years, then the cost of the bolts is the same. Now, lets add the cost of two extra applications of glue to your bolt. And lets actually count the cost of the labor needed to replace them, adjusted for inflation. Gee, Ti still wins easily.

Jim Titt wrote: And exactly which resin manufacturer gives a 50 year guarantee on their products in natural stone outdoors? None of the ones I talk to (including Hilti)give ANY guarantee for our application or even are willing to discuss the suitability of their products for our use.

All true. It's because it's not worth their time to get the guarantee in real rock past their legal department. It has nothing to do with the actual performance of the product.

Jim Titt wrote: The oldest stainless steel bolts I know of were installed in 1967 using quick-setting cement, they are still in fine condition (or were last year when I clipped them).

That's a good data point which defines one end of the spectrum. But as I said, there are low corrosion environments, high corrosion environments and everything in between. I don't know of any stainless bolt placed in the U.S. that has lasted 50 years (1965). Anyone?

We also know that 316 stainless bolts have broken in 9 months in Thailand, which is at the other end-point of the spectrum, and 98% of of the bolts in the world live between those points.

Bruce Hildenbrand wrote: John, I agree that SS bolts should be used and that is exactly what I use when rebolting(thanks ASCA and AF!). The point about including testing information about grade 5 carbon steel bolts is that they last much longer than most people think. These, for the most part, aren't ticking time bombs that need to be replaced ASAP, especially in Colorado and California.

Bruce,

It's GOOD that the grade 5 carbon steel bolts are stronger than they look. For example, I just replaced some of these bolts in Rifle this summer. I was scared to climb on them, but when I replaced them I found that they were still quite strong. But breaking may not be the predominant failure mechanism.

The bolts low on the route I unscrewed with a wrench. The bolts higher up, showed not only much more corrosion on the head, but couldn't be unscrewed due to excessive internal rust. I broke them off with by bouncing on a 16" breaker-bar and a 6-sided socket.

Now, with that much internal rust, how much longer would it be before the bolt pulled out? Bolts DO fail this way, most recently #2 on Easy Skanking pulled out this summer. Last summer, I think it was on the Path, and didn't a bolt pull on Pump O'rama in the last year?

And these bolts I replaced were no more than 10 years old.

John Byrnes wrote: ...98%...

Really? I'd bet that there are more bolts in Colorado and California than in the rest of the world combined. I am not disagreeing with the spirit of your post though. Each situation needs to be evaluated it its context.

Jeremy in Inyokern wrote: Really? I'd bet that there are more bolts in Colorado and California than in the rest of the world combined. I am not disagreeing with the spirit of your post though. Each situation needs to be evaluated it its context.

I'll take that bet! Ah, what are we betting? Beer?

Definitely don't want to get between Mothra and Godzilla on this one, but maybe a better question is the documentation of SCC in spatially defined areas?