Stainless Vs Carbon Steel Bolts
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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. 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. |
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A matter of semantics, but important none the less.. |
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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. |
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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 |
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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. |
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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. |
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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. |
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There's some good info here and some not so good.
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Syd wrote:http://www.safercliffs.org/code/bolt_guide.htmlWell, 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. |
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Climbtech recommends that you do not counter sink their glue in bolt. |
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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. |
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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) |
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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. |
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The danger is not so much bending but a torque on the bolt breaking the glue bond if not recessed. |
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Syd, climbtech.com/wp-content/up… |
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Some bolts it´s better to recess and some it´s unescessary, there´s no hard and fast rule. |
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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. |
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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. |
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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 |
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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..... |