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Stainless Vs Carbon Steel Bolts

Original Post
mschlocker · · San Diego, CA · Joined Apr 2006 · Points: 3,195

Been doing a lot of research and a little action on bolting / re-bolting lately. Determined that stainless Rawl/Powers bolts were the way to go. I couldn't believe how hard these things were to find in stainless. Seems everybody is going carbon steel. Living in San Diego, you wouldn't think that this would be a problem, but on a recent hanger replacement trip I saw a nice fat 1/2" carbon steel Rawl bolt with 6 years on it was starting to rust superficially in its hole. Looked fine on top though. Be wary. I'd give it a 30? year lifespan.

Rusty Underworld (Mission Gorge) Bolt. 6 years new carbon steel 1/2" Rawl/Powers bolt.
6 year old Rawl carbon steel 1/2 incher

Not sure how much the fat guys cost but would think your money is better spent on stainless than big. Especially in this bulletproof granite. If you're affixing permanent anchors to the rock, you have the responsibility to do it right.

As a note I tried out some wedge bolts. They are harder to replace later on and there are some 10mm wedge bolts being sold as 3/8 that myself and a few I spoke with have got stuck in the smaller 3/8 hole before they made it all the way in. Something to do with a mix up when they were being imported (spoke with distributor and they were aware of this). Nice that the Powers bolts are individually labeled.

Old school Mission Gorge bolts.
30 year old (or less) carbon steel wedge bolts (removed with force with crow bar). FA of this route - 70s, one hanger has 89 stamped on it, hard to read or know what this means.

What do other people think about using carbon steel bolts? I won't be using them but a lot of people are.
Mike Lane · · AnCapistan · Joined Jan 2006 · Points: 880

A matter of semantics, but important none the less..
Rawls come zinc-plated standard, not raw carbon steel;
carbon steel is literally grey/black and no one in their right mind would install those outside. The zinc plating on the bolt gives the illusion its an an all-weather unit. The threads on a standard Rawl are rusty within a year, the corrosion then grows over time.

Stainless Rawls are available, but usually on a special order basis; and cost quite a bit more. And they aren't neccessarily fail-safe either, read up on what Sam Lightner is doing in Thailand.

Sport-bolts first started appearing in the mid-late 80's, that means there are lots of bolts nearing 20-25 years old. Sooner or later this is going to become an issue. Lets hope that the degradation is visually obvious before a string of bolt failures begins....

mschlocker · · San Diego, CA · Joined Apr 2006 · Points: 3,195

Good point about the plating. The carbon steel bolts are Zinc plated. Powers is calling them "carbon steel" in their catalog. Don't be fooled by the shiny plating as seen above. It hides problems below the surface of the rock.

I paid 5.60 ea for 3/8 X 2.25" stainless Powers bolts and you can get them cheaper in bulk (box of 50) from a fastener or construction supply company. There are other cheaper stainless options as well. If you are unsure about what you are buying, bring a magnet, it will not stick to stainless.

Brian in SLC · · Sandy, Utah · Joined Oct 2003 · Points: 21,711
mschlocker wrote:Don't be fooled by the shiny plating as seen above. It hides problems below the surface of the rock.
But...the problems seem to be only surface corrosion, which, can proceed rapidly or slowly depending on environment. That shiny plating actually works pretty well for inhibiting corrosion for awhile. And, I've never seen a shiny bolt on the surface, that wasn't also shiny below the surface. If you have a rusty grade 5 powerbolt visible from the surface, then you can bet the shaft of the bolt is rusty too. So, my point is, that it doesn't really hide problems below the surface. The bolt condition on the surface is typical to the subsurface condition, in my experience. The bolt in your picture I'm betting hasn't lost much strength at all (or mass, or material so its diameter is significantly smaller, etc).

Stainless bolts are there own timebombs, depending as well on environment and installation (ie, installation torque). Putting too much stress into a stainless bolt might not be a good thing (and sometimes, a really bad thing, as folks near the ocean are finding out, especially in humid areas).

In the dry, interior of the west, especially, these zinc plated bolts seem to last a long time. I've pulled several in the 14 year old time frame, some in wetter areas with porous rock like American Fork, and there mass loss due to corrosion was very very minimal. I'd bet they'd still meet their specs on shear strength.

If I lived near a marine environment, I'd probably look at Titanium, ala Thailand. Although, having climbed seaside in Greece, where folks are using almost exclusively stainless bolts, they seem to be holding up pretty well, but its also really dry there too. SCC is the major concern with stainless bolts/hangers. A carbon steel bolt isn't susceptable to that type of failure. Visually, you get what you get, ie, surface corrosion. With stainless, you don't know what you have, ie, you'll probably never see the SCC issue until the bolt snaps off.

mschlocker wrote:I paid 5.60 ea for 3/8 X 2.25" stainless Powers bolts and you can get them cheaper in bulk (box of 50) from a fastener or construction supply company. There are other cheaper stainless options as well. If you are unsure about what you are buying, bring a magnet, it will not stick to stainless.
If you have a source for inexpensive powerbolts in stainless, please list it!

Also, magnets barely stick to 300 series stainless. They stick well to 400 series (try your stainless cutlery, for example). I have some bolt hangers from Europe that I think are 440 stainless. Have never seen a bolt or stud that is stainless in anything besides 303, 304 or 316 stainless, though, so its a pretty good test. Fixe, Petzl, Raumer and Metolious are all 300 series stainless.

-Brian in SLC
mschlocker · · San Diego, CA · Joined Apr 2006 · Points: 3,195

I found a new place to get a good deal on Powers Power Bolts (AKA Rawl 5 Piece) in Stainless. mcmaster.com. Look up concrete anchors. Their sleeve bolts are Powers, they have a great price and you can buy as few or as many as you want. Mcmaster has the fastest shipping of any company I have ever ordered something from.

Also try fastenmsc.com

Mike Lane · · AnCapistan · Joined Jan 2006 · Points: 880

mschlocker: of all the people you know, are any involved at a foreman level or above in construction? Simply ask them if you can use their account for a "cash sale" (you pay at the counter) at a fasteners and anchors supplier. Half price of retail, no waiting for shipment.

So, if large quantities of bolts is of interest to you; methinks you have yourself some little project crag, eh?

ibcies c · · Unknown Hometown · Joined Jan 2013 · Points: 0

Keep in mind that one of the worst things you can do is mix metals (e.g. Zinc Plated blot and Stainless Steel hangers). There is plenty of info on the web about metallurgy. I've come across lots of problems with this in the past couple of years (too many clueless peps out there with pop's hammer drill and an ego for attention). Be wise when replacing bolts, and wiser when putting new lines in.

Thank you to all who are putting time and money into replacing the sketch out there!

John Byrnes · · Fort Collins, CO · Joined Dec 2007 · Points: 392

There's some good info here and some not so good.

Concerning the bolt you sent a photo of... I've never seen a steel expansion bolt of any type, galvanized, stainless, etc., that did NOT have corrosion on the shaft after a year or two. Crevice corrosion always happens, but it may not proceed at the same rate over many years, depending on environmental conditions.

Putting in a galvanized bolt is never a good idea IMO. It's planned obsolescence, and you're just kicking the can further down the road.

P. Muraleedharan, a highly regarded metallurgist, wrote that Stress Corrosion Cracking (SCC) of austenitic stainless steels (e.g. Series 300) in ambient conditions "depends on the patience of the observer." This is a huge divergence from previous doctrine, when metallurgists didn't think SCC could happen in the Real World under 80C.

Now, it's clear it does. In Thailand: 9 months to failure. In Kalymnos: 9 years. Sea-side, inland, wet, dry, sandstone, limestone, basalt; it's just a matter of time, and not enough time.

For this reason the UIAA's upcoming corrosion guidelines* will NOT approve of Series 300 bolts for (almost) any outdoor environment. Following the guidelines means the bolts should not need to be replaced in less than 50 years; and most places should far exceed that.

If you look at MP forums (and every climbing forum world-wide) over the last 5 years, replacing bad bolts is a very hot topic. And if we don't change our ways, it will continue to be a very hot topic. We need to get out of the rebolt mind-set, and get into the bolt-it-once-mind-set.

mschlocker, if you're bolting in desert granite, a good stainless bolt is a pretty good choice. And you're right to think that a thicker bolt isn't necessarily going to last any longer. However, you might think about some of the new glue-in bolts made of 2205 and other specialty stainless steels. These will still be strong when your grand, grand, grand kids are climbing.

But as Brian says, it you're bolting sea-side, you may need titanium.

  • The guidelines are due out this Fall. I will post them here as soon as I receive them.
Syd · · Unknown Hometown · Joined May 2013 · Points: 0
John Byrnes · · Fort Collins, CO · Joined Dec 2007 · Points: 392
Syd wrote:http://www.safercliffs.org/code/bolt_guide.html
Well, I looked around on this site, and it's clearly ten years out of date.

I'm guessing this was written in the era of "let's replace everything with Stainless Steel", because they're only concerned with basic strength, rust and galvanic-corrosion, and there's no mention of Stress Corrosion Cracking, titanium, 2205 steels, etc.

Once you actually replace everything with stainless, you remove another layer of the onion and discover that stainless is vulnerable to SCC. Of course this takes time, and while Australian cliffs in desert environments will be fine for another 20 years, I know wetter cliffs already have problems.

And BTW, the advice about recessing the eye-bolts... Recessing has its own set of problems/advantages which I can illuminate if necessary, but in general it's not necessary or recommended with modern glue-in bolts.
C Williams · · Sketchy, Blackvanistan · Joined Jul 2013 · Points: 1,556

Climbtech recommends that you do not counter sink their glue in bolt.

Syd · · Unknown Hometown · Joined May 2013 · Points: 0
John Byrnes wrote: Well, I looked around on this site, and it's clearly ten years out of date.
Still current practice.

John Byrnes wrote: And BTW, the advice about recessing the eye-bolts... Recessing has its own set of problems/advantages which I can illuminate if necessary, but in general it's not necessary or recommended with modern glue-in bolts.
Please do.
Allen Sanderson · · On the road to perdition · Joined Jul 2007 · Points: 1,203
John Byrnes wrote:... the advice about recessing the eye-bolts... Recessing has its own set of problems/advantages which I can illuminate if necessary, but in general it's not necessary or recommended with modern glue-in bolts.
Syd wrote: Still current practice.
There is a difference between a practice and recommendation. Smoking is still practiced but not recommended.

With Petzl ring bolts recessing is not shown to be a recommended practice.

petzl.com/en/Sport/Anchors/…

(Download the instructions).

Though Fixe does recommend a very slight recess.

fixehardware.com/shop/glue-…

(Watch the video about 5-7 minutes)
20 kN · · Unknown Hometown · Joined Feb 2009 · Points: 1,346
Allen Sanderson wrote: There is a difference between a practice and recommendation. Smoking is still practiced but not recommended. With Petzl ring bolts recessing is not shown to be a recommended practice. petzl.com/en/Sport/Anchors/… (Download the instructions). Though Fixe does recommend a very slight recess. fixehardware.com/shop/glue-… (Watch the video about 5-7 minutes)
I would definitely recommend a recess on the Fixe bolts. On more than one occasion, I have seen the bolt head bend over from failing to recess the Fixe bolt properly. When I visited the Fixe-Faders plant in Spain they told me the head needs to be recessed as well.
Syd · · Unknown Hometown · Joined May 2013 · Points: 0

The danger is not so much bending but a torque on the bolt breaking the glue bond if not recessed.
The Australian standard is 100mm, not Petzl's 73mm.
I can't see any reference to Climbtech saying don't recess. Link please?
Recessed 100mm rings is recommended practice in Australia. Those who don't are castigated.

C Williams · · Sketchy, Blackvanistan · Joined Jul 2013 · Points: 1,556

Syd, climbtech.com/wp-content/up…

Says " Anchor loop should sit flush with surface." Even has illustrations.

Jim Titt · · Germany · Joined Nov 2009 · Points: 490

Some bolts it´s better to recess and some it´s unescessary, there´s no hard and fast rule.

Bending is irrelevant since stainless and titanium don´t care particularly.
Torsional resistance in the glue is supposed to be incoporated in the bolt design, not by manipulating the rock, in two-legged bolts one needs to do nothing and on single-stem bolts the usual practice is to cut the end at 45°.

The downsides to recessing are it´s more work and rock damage, makes core-drilling out later very difficult and depending on the eye shape brings the karabiner gate into contact with the rock with the attendant risk of gate-open failure. With some commercially available bolts which are commonly recessed the bolt is no longer installed as per the requirements of EN 959 as the two test bars will no longer fit through the eye.

Some eye designs are better recessed though, certain styles leave a Vee slot between the bolt and the rock if they aren´t. Underneath this tends to trap the rope preventing upward movement and in the worst case of a fall causing a huge increase in impact force. Above the bolt this Vee slot can allow the karabiner to lie across the bolt which may fail if fallen on and trap the rope as well.

We don´t recess any of our bolts and recommend they are not recessed.

John Byrnes · · Fort Collins, CO · Joined Dec 2007 · Points: 392
Syd wrote:The danger is not so much bending but a torque on the bolt breaking the glue bond if not recessed.
If this is possible (hard to believe) then use a better glue.

Jim Titt's post says it all perfectly but I'd like to add one thing:

Recessing requires a good deal of time and skill to do well. Often the installer does not get a perfect glue/rock/bolt seal, leaving a crevice that water can wick into. Crevice corrosion is a concern for both titanium and specialty steels, so avoiding crevices is highly recommended.

So Syd, if it's within your power, have that webpage updated.
Syd · · Unknown Hometown · Joined May 2013 · Points: 0

Interesting. Rings are the most common for new bolting in Australia, followed by U's and machine bolts (needing bolt plates). FH's are rarely used now.
Recessing rings is standard and takes seconds.
It would be interesting to hear what the experts like Mike Law, Neil Monteith and Rod Wills have to say.

20 kN · · Unknown Hometown · Joined Feb 2009 · Points: 1,346
Syd wrote:It would be interesting to hear what the experts like Mike Law, Neil Monteith and Rod Wills have to say.
Never heard of them. The correct answer has already been posted anyway: it depends on the bolt. You mean Miki Law?

facebook.com/mikl.law
John Byrnes · · Fort Collins, CO · Joined Dec 2007 · Points: 392
Syd wrote:Interesting. Rings are the most common for new bolting in Australia, followed by U's and machine bolts (needing bolt plates). FH's are rarely used now. Recessing rings is standard and takes seconds. It would be interesting to hear what the experts like Mike Law, Neil Monteith and Rod Wills have to say.
I never heard of them either.

Jim Titt's company manufactures bolts and he is in the forefront of modern bolt technology. I founded the design team for the first titanium bolt and have been working for 15 years for better bolt design. These issues have been hashed out with professional metallurgists and tested to near-absurdity.

And as far as taking seconds to recess a bolt... see how long it takes you in granite or basalt. Ready, go.....
Guideline #1: Don't be a jerk.

Sport Climbing
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