Zinc plated va stainless steel, anchors chains and quick links


Original Post
Jan Tarculas · · Riverside, Ca · Joined Mar 2010 · Points: 808

Question for route developers and people with knowledge. Are hangers and bolts mostly zinc plated? And if they are how important is it for attaching non-zinc plated (stainless steel) quick links to them and using SS vs zinc plated chains. This is in regards to galvanic corrosion

Ken Noyce · · Layton, UT · Joined Aug 2010 · Points: 2,067
Jan Tarculas wrote:Question for route developers and people with knowledge. Are hangers and bolts mostly zinc plated? And if they are how important is it for attaching non-zinc plated (stainless steel) quick links to them and using SS vs zinc plated chains. This is in regards to galvanic corrosion
Hangers are almost always stainless steel, bolts used to be mostly plated but for the past 10 or so years have moved to being mostly stainless as well. A stainless quick link on a plated hanger or a plated quick link on a stainless hanger is not a problem at all in 99% of environments including southern California where it appears you are from.
Brian in SLC · · Sandy, Utah · Joined Oct 2003 · Points: 13,772

Hangers and bolts are a mixed bag of whoever buys whatever. I'd like to think most folks are using all stainless...or they should at least consider it. I wish plated hardware would go the way of the dodo...

Fixed link on bolt at Stone Mountain, NC.

Gunkiemike · · Unknown Hometown · Joined Jul 2009 · Points: 2,740

OP - spend some time on the Fixe website and you will learn all you need to know about metals. It's still very easy to buy plated steel bolts AND hangers, but there's no reason to use them anywhere any more, except that the route developer is a cheapskate who cares little for the long term safety of his route.

Jan Tarculas · · Riverside, Ca · Joined Mar 2010 · Points: 808

I guess my question is, is it ok adding stainless steel fixe draws to zinc plated chains/quick link to a SS ring attached to the anchors

J Achey · · Unknown Hometown · Joined Aug 2009 · Points: 145

It's worth noting that the "galvanic corrosion" caused by mixing metals effects one metal at the expense of the other. That's in fact how zinc plating works - the zinc is slowly sacrificed to protect the steel underneath. Eventually the plating is consumed and you have the raw steel, which then corrodes. In the case of mixing plated and stainless components in an anchor, it's the plated ones that will suffer. The most important component to protect is the bolt shaft itself, which is exposed to the most corrosive environment - the inside of the bolt hole. If the bolt and hanger are stainless, then as kennoyce says, it's probably fine in most dry-ish climbing areas. Any metallurgists out there know the actual galvanic potential between 304 stainless and zinc and/or grade 5 carbon steel?

frank minunni · · Las Vegas, NV · Joined May 2011 · Points: 96

We gave up on the zinc plated a long time ago. We put in stainless exclusively. We didn't want to be responsible for someone getting hurt, especially considering the weather in the Adirondaks. When you think about the effort you put into a new line, what's a few dollars anyway?

Bruce Hildenbrand · · Unknown Hometown · Joined Apr 2003 · Points: 945

I think the reason why many people are concerned about rusting and galvanic corrosion is that not all plated hardware is created equally. There is some really good plated hardware such as the grade 5 and grade 8 carbon steel bolts that Powers uses in it's "5-piece" bolts. Then there is the really crap stuff you see with many wedge bolts and quick links.

I strongly recommend using stainless whenever possible. However, I don't think you can use a blanket statement as to how long plated hardware will last since the quality varies greatly.

Jan Tarculas · · Riverside, Ca · Joined Mar 2010 · Points: 808

thanks for the info...

p.s. I've been told 3/8 is the way to go for chains/quick links. My next question is what is an acceptable working load for a quick link that is use to attach chains to an anchor? I've seen at home have 2,200 lbs and other same size quick links at 3,600 lbs. Local developer mentioned he uses towing rated quick links at 5,000 lbs

Luc-514 · · Montreal, Quebec · Joined Nov 2006 · Points: 8,953
frank minunni wrote:We gave up on the zinc plated a long time ago. We put in stainless exclusively. We didn't want to be responsible for someone getting hurt, especially considering the weather in the Adirondaks. When you think about the effort you put into a new line, what's a few dollars anyway?
Anyone feel like changing the bolts on Eat Yourself a Pie ?
frank minunni · · Las Vegas, NV · Joined May 2011 · Points: 96

Sorry. I don't live there anymore.

Gunkiemike · · Unknown Hometown · Joined Jul 2009 · Points: 2,740

A factoid re. quicklinks - the "safe working load" typically is 1/5th of the ultimate strength, so even the Homely Depot links are plenty strong enough. I know some climbers steer clear of them b/c they don't come from a reputable climbing company or carry a UIAA seal, but they're good enough for me. Use 'em in pairs if you want and put your fears aside.

jaredsmokescigars · · Unknown Hometown · Joined Jun 2014 · Points: 65

I was pretty disappointed to listen to the Enormocast on "the Choss Wranglers" - knucklehead developers down in the Roaring Fork Valley. "Can't justify say a...200-250 percent increase in price to develop a crag just because someone wants stainless - it's just not economical". I've lost my confidence in going to places like these where these guys are bolting/retro bolting - Rifle included.

20 kN · · Unknown Hometown · Joined Feb 2009 · Points: 1,352
Jan Tarculas wrote:thanks for the info... p.s. I've been told 3/8 is the way to go for chains/quick links. My next question is what is an acceptable working load for a quick link that is use to attach chains to an anchor? I've seen at home have 2,200 lbs and other same size quick links at 3,600 lbs. Local developer mentioned he uses towing rated quick links at 5,000 lbs
Depends on what the SWL factor is. The industry standard is 5:1 for non-life-critical applications, although some companies use 4:1. If the SWL factor is 5:1, then 2,000 lbs equates to a BS of 11,000 lbf, which is more than fine. Even if the SWL factor was only 4:1, it would still be stronger than any 3/8" bolt at 2,200 lbf SWL. Pretty much any reputable 3/8" SS quicklink is going to be stronger than most 1/2" bolts.
Noah Yetter · · Lakewood, CO · Joined Jul 2015 · Points: 105

http://www.climbing.com/climber/built-to-last/ topical, worth reading

David Gibbs · · Ottawa, ON · Joined Aug 2010 · Points: 6
Noah Yetter wrote:http://www.climbing.com/climber/built-to-last/ topical, worth reading
Yep. On important point from it...

"Class 3 anchors will have “moderate” corrosion resistance. There will be no tests for SCC. Anchors in this class should be suitable for the bulk of climbing areas that have no special corrosion concerns, and it will be the minimum level of corrosion resistance recommended for outdoor climbing. Since this standard is being generated in Europe, it seems very likely that anchors in this category will have to show corrosion resistance equal to 304, and possibly 316 stainless. If so, this requirement is sure to cause some controversy in the U.S. "

They have come out with 316 stainless for class 3 anchors -- saying that 304 stainless are not appropriate for outdoor anchors at all. (And, of course, carbon-steel, zinc-plated/galvanized, etc are, also, not appropriate.)
J Achey · · Unknown Hometown · Joined Aug 2009 · Points: 145

We need to wrap our heads around a higher standard for hardware. It's coming. The fact is, very soon, you will be considered a rogue bolter if you are using plated hardware, even in the desert. Certainly, already, any European equipper would look sideways at your work. I've certainly placed my share of plated stuff, and made even worse hardware decisions before our state of knowledge got to where it is now, and I understand the under-funded developer mentality as well as anyone alive. But if you pry off a block in Indian Creek or an arid limestone crag in Nevada, you'll find damp dirt behind it. The inside of a bolt hole is the same. A long-lasting anchor in rock outdoors simply needs to be stainless. The more remote your crag, the more important it is to get it right the first time, because no climbing coalition is going to be following along behind you re-equipping your route, ever. 30 years is not that long.

The main problem for US developers right now is that 1/2-inch stainless-steel sleeve bolts, of any brand, are extremely expensive, while 1/2-inch plated sleeves are/were quite cheap. But the price gap has narrowed, now that the tried-and-true plated Powerbolt is discontinued, replaced by the more expensive Powerbolt Plus. If a 1/2-inch stainless sleeve bolt became available that was just a little cheaper, we could make a fairly painless transition to all-stainless.

Currently, you have viable options. Good quality 3/8-inch stainless wedge bolts work very well in a lot of rock types (including most limestone), and are very affordable - about $5 per bolt/hanger placement. If you're financially challenged (like most of us) and have reasonably hard rock, that should be your low-end bolt of choice. Make sure you know how to place wedge bolts correctly - don't over-torque and do use Loc-tite on the nuts - and consider a different bolt for first-bolt placements (which tend to loosen), inverted placements, or bolts you expect to get particularly rough treatment. 1/2-inch stainless wedge bolts are super burly, work in even softer rock, and are surprisingly affordable. A lot of the re-equipping done in the New River Gorge uses these. You'll need hangers with 1/2-inch (or 12mm) holes.

RE types of stainless, it's my understanding that in Europe, standard construction codes specify 316 when stainless is called for. Unlike here, 304 is rarely used. Hence, 316 isn't much more expensive than 304 in Europe - the small amount of molybdenum in the alloy doesn't really make the raw stock much pricier. It's more of a demand problem in the US that makes 316 so much more expensive than 304. That's an important issue. 316 is much more resistant to the pitting corrosion that is the likely "weak-link" mechanism for degradation of a stainless-steel rock-climbing bolt. But even 304, to the best of my limited knowledge, really should put us on a good path where new bolts in non-coastal climbing areas will be good (at least corrosion-wise) for 100 years.

Anyway, there are smart and dedicated people working on this problem. If everyone stopped using plated bolts and hangers and demand for stainless equipping hardware went up, that would help bring costs down and new products to market.

Micah Klesick · · Vancouver, WA · Joined Aug 2013 · Points: 3,894
J Achey wrote:We need to wrap our heads around a higher standard for hardware. It's coming. The fact is, very soon, you will be considered a rogue bolter if you are using plated hardware, even in the desert. Certainly, already, any European equipper would look sideways at your work. I've certainly placed my share of plated stuff, and made even worse hardware decisions before our state of knowledge got to where it is now, and I understand the under-funded developer mentality as well as anyone alive.
Agreed. We've pushed the topic so much here in the Portland area that now the climbers/developers are beginning to understand (and even expect now) that SS is the only reasonable choice, and almost all the developers have quit using plated as of this year. We've been pushing the education and reasons, and its starting to take effect. Now to get through to the Smith Rock developers...
SS wedges work well in hard rock, as you're saying. But I think SS glue in bolts are the way to go, with either the Jim Titt bolt, or the ClimbTech Wave bolt being the prefered bolt. No need to countersink, they hold themselves in to the tune of 6-8kn without glue, and are pretty easy to install, and will last much longer than any SS sleeve or wedge bolt. And the cost is pretty cheap, with both bolts coming in at less than $6 a bolt, without bulk pricing.
Noah Yetter · · Lakewood, CO · Joined Jul 2015 · Points: 105

Even 316 SS can corrode inside the bolt hole in a surprisingly short period depending on the environment. Titanium glue-ins titanclimbing.com/Titan%20C... are around $13 each, but should last more than twice as long (50 years, allegedly). Still a tough cost to swallow without outside financial support.

Micah Klesick · · Vancouver, WA · Joined Aug 2013 · Points: 3,894
Noah Yetter wrote:Even 316 SS can corrode inside the bolt hole in a surprisingly short period depending on the environment. Titanium glue-ins titanclimbing.com/Titan%20C... are around $13 each, but should last more than twice as long (50 years, allegedly). Still a tough cost to swallow without outside financial support.
It's far more than 50 years for SS in most environments. I've pulled 15 year old SS bolts out, and there has been NO sign of rust or corrosion whatsoever on them. I believe its reasonable to assume that SS bolts can last over 100 years in most places. Ti bolts certainly will last even longer.
20 kN · · Unknown Hometown · Joined Feb 2009 · Points: 1,352
Micah Klesick wrote: I believe its reasonable to assume that SS bolts can last over 100 years in most places.
I dont think that they will. Some will, but the problem is that some will not. Corrosion is an extremely localized mechanism. I have pulled bolts off routes and tested them to find the first bolt failed at 2kN, the 2nd failed at 35kN, the 3rd at 39kN and the 4th at 4kN. They were all the same bolt, same hanger, installed at the same time by the same person. So while most stainless bolts may last 100 years, random bolts here and there will not. Then the problem becomes that if you cannot trust a random bolt here and there, and you dont know which bolts can be trusted and which cannot because the corrosion is occurring in the hole, then you need to replace them all. The entire area is limited by the lifespan of the weakest bolt, sorta speak, unless you can be confident no corrosion is occurring in the hole, which you could never be if the bolt was 100 years old.
Guideline #1: Don't be a jerk.

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