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Do RPs and Brass nuts degrade with age?

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I have a bunch of old RPs and HB Brass nuts, some stupidly small. Most are from the 80's. Whilst I understand that older Rocks etc are still good to use, I was wondering if the swaging etc. on a brass nut which has a steel cable/wire going into the head; was there any metallurgical effect that would weaken that connection over time?

In reply to Duncan McCallum:

Soldering is a very secure bond. I would be more worried about fatigue from use unless they've been stored in poor conditions.

 smally 06 May 2021
In reply to Duncan McCallum:

I'm still regularly and happily using some of mine from the 80's.

 PaulJepson 06 May 2021
In reply to Duncan McCallum:

One of my old HB offsets has gone a bit blue/green in places on the surface. I tried putting some brasso on it but it only seemed to make a minor improvement. 

Does anyone know the ratings on older brassies? I have a few HB offsets and Wild Country Stones and was never able to find any info on their original ratings. 

(sorry to derail topic somewhat)

Post edited at 12:27
 Lankyman 06 May 2021
In reply to DubyaJamesDubya:

Mine definitely did start to fray where the wire entered the solder

In reply to Lankyman:

> Mine definitely did start to fray where the wire entered the solder

...and that is what I would worry about rather than corrosion or 'ageing'. Definitely time to retire if visibly frayed.

 Lankyman 06 May 2021
In reply to DubyaJamesDubya:

> ..Definitely time to retire if visibly frayed.

And that's the story of my life

 nniff 06 May 2021
In reply to PaulJepson:

> Does anyone know the ratings on older brassies? I have a few HB offsets and Wild Country Stones and was never able to find any info on their original ratings. 

It's a sensible enough question, but I just work of the principle of 'four fifths of f***-all' and generally not to be trusted, but better than nothing, but best not to fall off.  Even if I did know the rating, the principle would be same, because any test would be in a straight pull and not as it would be oriented naturally, and I have no idea how strong that tiny bit of rock is.   Besides which, I don't know how much force a slump, tiny fall, fall etc actually generate (or how much real slack there is in the system, or stretch).  So, better than nothing, but how much better?  Well, that would depend.  I have some 1980's RPs, still in good working order because I have taken my own advice to heart.

 PaulJepson 06 May 2021
In reply to nniff:

I asked both WC and DMM a couple of days ago by coincidence so I'll post here if I hear anything back. I doubt either will have any info as DMM changed the manufacturing process (from cast to machined) when they took over the production from HB and I don't know how much info WC still have after Oberalp bought them.

I think the RP ratings were a bit weird as they were given something like 'the maximum expected strength' rather than the minimum you could expect them to fail at. 

 John2 06 May 2021
In reply to PaulJepson:

It is often possible to increase the strength of RP placements by stacking them.

 PaulJepson 06 May 2021
In reply to John2:

As Dawes said, "RPs are great. Even a zero gives something to fall on."

In reply to DubyaJamesDubya:

Thanks, 

In reply to PaulJepson:

It will be very interesting to see if they do make a general comment about brass soldering.

In reply to DubyaJamesDubya:

Thanks, they are in good nick, or at least the ones I have not lost or broken. Soldering I agree seems like a solid bond. 

In reply to nniff:

> ... I don't know how much force a slump, tiny fall, fall etc actually generate ...

Here's a hint: https://www.petzl.com/DK/en/Sport/Forces-at-work-in-a-real-fall?ProductName...

 nniff 06 May 2021
In reply to Stefan Jacobsen:

Hmm- of those, the FF 0.3 one is the most relevant I think and with the runner below his feet, that's definitely into do not fall territory with RPs in my book - I'm head to knee height for those, else I'm mostly running away.  There are notable exceptions - I remember a very long run out from an RP3 on Memory Lane in 1983, which may have had much to do with not possessing much gear and being young and stupid.  The RP3 in question is still on the rack and still not fallen on.

 biggianthead 06 May 2021
In reply to Duncan McCallum:

I hope not! I still use my RPs and HBs (of same vintage)

1
 mrjonathanr 06 May 2021
In reply to nniff:

> Hmm- of those, the FF 0.3 one is the most relevant I think and with the runner below his feet, that's definitely into do not fall territory with RPs in my book 

I went 40’+ off Flashdance onto micro rock 2. I trust RPs to the hilt, have several sets of originals, happy to fall on them.

1
 PaulJepson 24 May 2021
In reply to PaulJepson:

> I asked both WC and DMM a couple of days ago by coincidence so I'll post here if I hear anything back.

DMM didn't have the info and WC never replied, so it's guesswork. 

 Rick51 24 May 2021
In reply to nniff:

> Hmm- of those, the FF 0.3 one is the most relevant I think and with the runner below his feet, that's definitely into do not fall territory with RPs in my book - I'm head to knee height for those, else I'm mostly running away.  There are notable exceptions - I remember a very long run out from an RP3 on Memory Lane in 1983, which may have had much to do with not possessing much gear and being young and stupid.  The RP3 in question is still on the rack and still not fallen on.

I eventually bottled out of that runout in 1984 and got a top rope off a guy that had just finished Right Wall. I'd actually done most of the last section of Memory Lane when I did Epitaph so I was pretty sure I could do the move but every time I looked down to the couple of HB's they looked further and further away and smaller and smaller. It's definitely not somewhere you want to fall.

 beardy mike 24 May 2021
In reply to PaulJepson:

As far as WC Stones are concerned I would imagine the people at Wild Country wouldn't even know what you were talking about. There's not a single member of staff left from the original Tideswell company, and even then they are so old that it's more than likely that any data about them would not have been digitised, so would be stuck on a piece of paper somewhere. I would say the person to have tried would have been Mark Vallance, but well, you're out of luck on that front...

 nniff 24 May 2021
In reply to Rick51:

After all these years, I'm glad it wasn't just me!

 Rick Graham 24 May 2021
In reply to nniff:

> After all these years, I'm glad it wasn't just me!

Circa 1984 , I held a Lakeland climber of this parish taking an 8 or 9 metre fall onto an RP2 on Memory Lane , so maybe not the stuff of nightmares. No obvious damage to the nut, just went back on Bobs rack.

Around the same time , I sent some original HB s back to wild country for comment. We had managed to fray the wires on a couple of HB 1s during some over enthusiastic route attempts but what concerned me most was some silver soldering that looked incomplete, with voids.

Wild Country tested the faulty looking nut  but it still failed at the rated strength. They then cut some new nuts to one third height , they still failed on the wire and not the soldering. So perhaps a safety factor of 3+ on the solder.

 From this I would surmise that the wire thickness is a good indicator of a soldered nut strength with few major differences in strength  between the various makes. 

FFIW, some of my brass nuts still probably date from the early 80's, I just discard the ones with broken wires. 

Wonder if the RPs I bought off Roland in Yosemite in may 1979 were the first in the UK? 

 timparkin 26 May 2021
In reply to PaulJepson:

> Does anyone know the ratings on older brassies? I have a few HB offsets and Wild Country Stones and was never able to find any info on their original ratings. 

I compiled this spreadsheet a while back...   Ordered by minimum width with colour coding for strength (red being "worry")


 lithos 26 May 2021
In reply to timparkin:

can  i get a copy (too lazy to type it all in !)

1
In reply to lithos:

Screenshot??

 mark s 27 May 2021
In reply to Duncan McCallum:

I wouldn't have thought so, but my trust in them does 

 Toerag 27 May 2021
In reply to beardy mike:

I would guess an old magazine 'new gear' or test article would be our best chance of an answer.

 Toerag 27 May 2021
In reply to timparkin:

I think I might have some Stones on my micro rack, do you want me to measure their dimensions so you can add them into your spreadsheet? I've got brass offsets and imps too so can get an accurate comparison.

Post edited at 11:55
 lithos 27 May 2021
In reply to DubyaJamesDubya:

great why didn't i think of that, it's so obvious....

how do i get the screen shot to sot by strength though

In reply to lithos:

Optical Character Recognition?

(I’ll get my coat)

 Michael Hood 27 May 2021
In reply to timparkin:

I have an SMC 1 (1mm wire, 10x3.5mm) and a DMM 00 (1mm wire, 9x4mm) - both on wire loops. Can't find my Clog micros - must have thrown them away due to fraying - the smallest was similar in size to those other two.

Don't think I'd trust them much 😁

They're on similar thickness wire to my RP1 (thinner than my RP2 and BD Swedge 3) which I'd be much more likely to "trust".

However I did use one of them (SMC 1 or DMM 00) near the start of Cave Gully Wall (HVS 5a) in a non load bearing way to lock in a slightly larger nut (rock 1 or 2 - can't remember) in a horizontal slot. Was quite pleased at that piece of trickery.

Also, are your measurements for unused nuts, because I'm finding mine are slightly smaller - probably due to wear.

Post edited at 23:05

In reply to lithos:

> great why didn't i think of that, it's so obvious....

> how do i get the screen shot to sot by strength though

True but given that it's a fairly small sheet and already sorted for strength...

Screenshot might be obvious to you, might not be, I wouldn't know.

 timparkin 28 May 2021
In reply to lithos:

> can  i get a copy (too lazy to type it all in !)

Here's the google document publicly shared

http://bit.ly/microwires-doc

and here's a web based version

http://bit.ly/microwires-web

 timparkin 28 May 2021
In reply to DubyaJamesDubya:

> True but given that it's a fairly small sheet and already sorted for strength...

Not sorted by strength but if you look at the shared google doc (or web version) one of them is sorted by strength and one by minimum width. Colour backgrounds show the general minimum width. The strength column yellow orange red should be obvious. 

I think the rating on the IMPS and HB's etc should be sigma rated and hence actually stronger than the RPs, in which case I would suspect there's little reason to prefer RPs over IMPs (for strength anyway)

In reply to timparkin:

> Not sorted by strength


Ah yes, didn't look close enough. Odd that they include Wallnut 1 and 2 (which aren't really micro) and not the Rock 1 and 2 (which are a teeny bit smaller)

 FatRob 15 Jun 2021

I did some testing by making some of my own and destruction testing them, 316L SS 1x19 (stronger than 7x19) wire silver soldered into 360 Brass with 1.7mm holes.  Around 4mm of soldered length. 

The wire failed every time around 4.odd kN. 

So I conclude if you solder them properly, then look up the MBS for the wire type,  and multiply by 2 if there are 2 strands.

 wercat 16 Jun 2021
In reply to FatRob:

I know nothing of the way these joints are made structurally but soldered joints are subject to failure by thermal cycling and vibration in electronics (the sort made to last 20 or 30 years)

Would the main strength of the joint not be the solder but sleeve clamping with the solder to damp any play causing fraying/friction damage?

I'm probably talking rubbish but I was brung up that solder was used on an already mechanically sound joint, not to be the joint structurally.

I speak as one who still has some quite old nuts on wires, not RPs though as I don't qualify to own or use them things.

Post edited at 16:59
 jimtitt 16 Jun 2021
In reply to wercat:

Silver solder is a different beast to ordinary solder, technically it's a braze anyway due to the temperature used.

 FatRob 16 Jun 2021
In reply to jimtitt:

Exactly that.  You are brazing with silver solder,  it's not got much in common with electronics solder.  The flux, the cleanliness, and the grade of the solder is totally critical, use the wrong stuff and the joint is pants.

My first attempts were barely making 1,5kN before I sorted out my process.

The joint is a chemical bond almost an alloying, between the two metals,  as has been pointed out,  cold working and fatigue of the cable close to the soldered joint tends to be where they start to fall apart.

I note Dmm now use aluminium bronze rather than straight brass,  probably because it's harder and stronger.

 wercat 17 Jun 2021
In reply to jimtitt:

ah, that is interesting.  What temperature is needed?

 jimtitt 17 Jun 2021
In reply to wercat:

600°C to 1200°C, depends on the alloy. It's as strong as some welding.

Post edited at 13:09
 wercat 17 Jun 2021
In reply to jimtitt:

ah, completely different animal - I had always thought soldering was at lower temperatures.

So is it this that creates the structural strength on its own?

 jimtitt 17 Jun 2021
In reply to wercat:

Well soldering is, lower than 450° is one definition which is why above I said that really it's silver brazing. The better grades are considerably stronger than mild steel for example, realistically nothing to do with electrical solder! 

 Phil79 17 Jun 2021
In reply to Duncan McCallum:

As with all micro wires (old or new) they'll be absolutely fine providing you don't fall on them!

 iainJ 18 Jun 2021
In reply to FatRob:

Have you got the stress - strain curve for the tests you did? It'd be interesting to see what the yield point / elastic limit is, and at what point you can load to prior to limit failure without lasting weakening. I.e. for a 4kn nut do repeated 3kn falls cause it to lose strength, or do you need 3.9kn fall before any permanent weakening occurs (excluding variability etc.)?

 jimtitt 18 Jun 2021
In reply to iainJ:

With the 316L that he used it's of no concern, if you go over the elastic limit and relax the load it just gets stronger. The certification test is a straight pull at a speed which effectively prevents work-hardening, repeated loading however gives completely different results.

I've pulled bolts made from 6mm rod and a continous pull will give around 32- 36kN whereas repeat pulls with increasing load gets them up to around 45kN. 316 has a nominal of around 620MPa but you can go up to over 800 at 0.2% strain and well over 950 if you try a bit. There are a few reports of over 1000MPa around but I haven't the patience!


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