Hi,
I'm on the UIAA Safety Commission. I know about the IC Resin anchor, and I'm curious if you've started making them in any quantity.
It is a very nice design, and inherently pretty strong, with a fairly small hole size. And is good that it doesn't have a weld.

But it seems quite expensive to make: both to cut, as well as in terms of wasted material from a plate. The best way might be to have it stamped out (using a die). But although you can reduce stamping costs with volume, you still have the wastage issue.

I was looking at it as a way of making an anchor out of 6Mo stainless steel (super austenitic stainless steel: like 254 SMO, for SCC resistance). As an alternative to titanium. But the wastage from stamping (or cutting) is a big issue: it really pushes cost up.

I've seen your discussions about corrosion/SCC concerns: I might be able to help you with that. We've got good data on risk of SCC to 316 as a function of relative humidity and temperature. That's assuming you have chlorides present, and I'm sure you do.

If there is any interest in discussing this, I can tell you what we've been finding with our SCC and corrosion testing. And my thoughts on a suitable anchor for your case.

If you've been using duplex, I'm assuming you know about the Fixe recall of duplex anchors?
http://www.theuiaa.org/home/recall-notification-from-fixe-climbing

Best,
Alan Jarvis
UIAA SafeCom

Hello Alan, welcome to the forum.
I'm sure Simon will be along to discuss his designs shortly.
Thanks for the duplex recall note.

Recall for corroded duplex! blimey.

Hey thanks.
Yeah I've been lurking on it: you have some very good posts.
And i've looked at Simon's IC anchor design.
It's VERY well designed: very systematic design.

We're in the process of issuing a revised UIAA anchor standard: I'm the Working Group Leader.
But it's hard going.

We have a bigger range in conditions than cavers do, and many more anchors, so total cost is a major issue.
Nobody knows for sure, but we think there are several million anchors globally, with hundreds of thousands in potentially quite corrosive locations.
And a lot of bolting is done by individuals and not bolting funds, so the cost is a major factor for them.

We've started having SCC failures in Europe, both on the Med and the Atlantic coastline. And there have been some unusual failures to 304 anchors on climbing walls in Denmark, Germany and the UK. And of course there are quite a few in the tropical regions.

Then add in corrosion issues: which is worse actually. Many anchors are showing corrosion issues, whilst SCC is still somewhat rare in total.

We're doing some location testing too: looking at local environmental factors such as chloride/salt types, pH, humidity, rain/washing and other things. There's a possibility we also have some microbial induced corrosion (MIC) from sulphate reducing bacteria (SRB) in some places.

Alan

By the way, Fixe uses a range of duplex stainless steel, ranging from "lean" (2304) to "standard" (2205). I haven't heard the details yet from Fixe, but they say their issues were with the final surface finish.
http://www.bssa.org.uk/topics.php?article=668&featured=1

You need to do a careful cleaning of stainless to remove surface contamination if you want to get the surface in its best state to resist attack. Quite often it's a citric acid wash.
There's a good link here to that:
http://www.bssa.org.uk/topics.php?article=68

I believe you've had some duplex anchors from Jim Titt of Bolt Products. He uses 2205, and does'nt have any welds, plus his overall passivating knowledge is very good.

2205 can suffer some pitting and crevice corrosion in aggressive solutions, and we have seen issues with all the duplex we've tested in our initial corrosion testing.

Since duplex is by nature a two phase material, the ideas of PREN and related crevice corrosion are not the same as for single phase 300 series. So even if the PREN for a given duplex might seem good, remember it's only an empirical value, and there are exceptions to it.

But caves are different in terms of humidity, chloride levels/salt types and temperature. You might be OK with standard duplex 2205. That is if you do indeed have a SCC issue. If you don't, I'm not sure you need duplex. Might introduce more problems than it solves.

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