South coast galvanisers? - wedge no longer do chain

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gregcope

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Hi

Thinking of getting our chain redone. After good reports of Wedge (VicS i think), contacted them to only find out they no longer do it.

Any other recommendations?
 
In 2011 I asked Griff Chains ltd, who made my anchor chain, where I could get it re-galvanised. This is the answer I got:

"Depending on the weight involved would determine which galvanisers we use
Small lengths upto 20/25kg - Joseph Ash Tel: 0121 552 1682
Longer lengths - B E Wedge Tel: 01902 630311"

These are not South Coast firms so you might have to travel to get it done. Sending it would be expensive, my new chain 65 metres of size 8mm cost £50 +VAT for carriage in 2006.
 
I always thought the best galvaniser for chain was in Scotland and well worth the, possible, extra cost for transport as, apparently, they know exactly what is needed of anchor chain

:)

Jonathan
 
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Hot Dipped Galvanising is very 19th century we, personally, have moved on a bit and use late 20th Century technology - Thermal Diffusion Galvanising. Fortuitously we have such an operator in Newcastle (the Oz one) a mere 200km away who did a series of trials for me before we committed. You need a sympathetic processor - and I cannot comment on anyone in the UK. TDG is proving more than acceptable, its harder (so more abrasion resistant) it has polished itself, so does not 'tower' (this was fortuitous and unplanned) and is a process better suited to coating 'higher tensile' chain than HDG. Also the coating is all alloy, unlike HDG where some of the coating is soft zinc. Along with the chain we had connectors and 'hooks' etc coated at the same time - if its on the rode, we coated it (anchor excepted :) )

There are at least 3 different processors, worldwide, for TDG - we used the Armorgalv process.

A second chain was coated but has not yet been used as the client's cat has not yet been launched. The process is used by the US Navy for small craft anchor chains and tie downs of military vehicles on landing craft. The US Navy chose TDG because they use HT chain and the process has proved for them to be more abrasion resistant. Their specification is for an 80 micron coating, unaware of this at the time I chose 100 micron - and do not regret our decisions.

If you read some internet chatter there are always sceptics - most of whom know nothing about the background.

Jonathan
 
gregcope said:
Thanks @Neeves. I read about Armorgalv on your Snubber article, which I thought was really good BTW.
Click to expand...

Thanks Greg.

The original process was called Sheradizing (a good British process) and quite old but it involved rotating large ovens (sort of like hot ball mills) full of silica sand, zinc powder and the article to be coated. Handling hot silica has become a No No and there are at least 3 competing processes now. They dispensed with the sand and now add zinc powder and some sort of catalyst. There happens to be a local Armorgalv plant ( and none of the others) in Australia. There is an operator in the UK - whose name I inconveniently forget (but I think if you google 'distekna' who own the license the name of the operator is there Bodycote??). Distekna's website is pretty poor - I think they have a list of licensees. They might do chain - but you need special 'racks' to load chain into a drum and they may not have them. The US Navy get, or did get, their chain done by Spencer Industries who specialise in finding 'solutions' for the military.

I have a detailed article on our experience with Armrogalv - but its a massive pdf and I cannot load it via YBW. if anyone wants it send me a PM with an email address - and its yours. It covers upto when we started using the chain - I need to do a follow up - its boringly successful but did prompt development of use of snubbers (as we had sacrificed catenary in favour of saving weight - but clawed the 'loss' back through using 'better' and then better snubbers.

Jonathan

Sorry for the drift.
 
I thought the process sounded like Sherardising, and I see the Armorgalv website says it is but with modifications to the process and powder composition. Sherardising is the process used for galv nails and similar small parts.

A company called Spirol SPIROL Introduced ArmoGalv® apparently covers UK but also much of Europe. Not sure where they are based.
 
Thanks Vyv - I've never heard of Spirol and could not find the client list on the Distekna website

but I did find this:

Sherardize UK Why Sherardize?

and who suggest they might do chain.

Here in Oz one of the big markets is for the HT 'bolts' used to hold up the wind farm towers.

Because they use rotating ovens they do not coat large components. The ovens I see are about 20' long and maybe 1.5m diameter and smaller.

The 'secret' appears to be in the charge of zinc powder + pixy dust - and I have no idea what the pixy dust might be.

Jonathan
 
It would be interesting to get Geoff's take on Thermal Diffusion galvanising. He's bound to have studied it.
I wouldn't condemn Hot Dipped, just because it's 'so 19th Century'. It works.
 
gregcope said:
So my struggle is still finding someone to redo my chain ...
Click to expand...
Many galvanisers will do chain in a batch process, all tied together with wire in a large clump. BE Wedge had a dedicated chain line that it seems is no longer offered. Its beauty was that the chain came out in a long length, whereas in the batch process you may find many links 'welded' together, requiring attention from hammers to separate.
 
NormanS said:
It would be interesting to get Geoff's take on Thermal Diffusion galvanising. He's bound to have studied it.
I wouldn't condemn Hot Dipped, just because it's 'so 19th Century'. It works.
Click to expand...

I'm not condemning galvanising, just being flippant. It has proved itself over the decades. But there are alternatives that merit airing and consideration - and Geoff's comments would be invaluable. The fact that the US Navy have approved the process for chain does imply it merits, maybe, a bit more than just consideration.

HDG does have comments that are not entirely encouraging - think of the posts on poor galvanising life. Though I suspect this is more of a problem of the operator than the process. With TDG you can specify to within 5 or 10 microns the thickness of the coating - and that's what you get. Given that chain life is a function of the thickness of the gal - having a specified gal layer that is accurate seems - a no brainer (but you cannot specify gal thickness with the same confidence with HDG. The fact that TDG gives a harder coating is just another process. The process is very good for small items, like nails for nail guns, and intricate items like nuts and bolts. The process is not as hot at HDG, which operates at about 450 degrees, TDG can be operated at 375 - and maybe lower - and this is better for Q&T steels. TDG is not suited to large items, steel beams etc and the batches, I think, are smaller. The old chestnut of hydrogen embrittlelement has been removed, no acid is used (everything is shot blasted) and temperature regimes remove any fears of HE.

If you are sailing round the world with TDG HT chain and need it regalvanised (and this will become an issue with time) then you would need to choose your schedule with care - being a new process there is not the geographic coverage of operators.

The big problem with TDG is that its use on chain is fairly new, maybe 10/15 years, so feed back is sparse. The other problem being that HDG last quite long anyway, if done properly. But comparing the 2 'in real life' is very difficult. How do I compare my anchoring activity with 6mm chain on silica sand seabeds with anyone else?

For us - so far, very good.

Jonathan
 
I've not read the thread so don't blast me if you've said but did wedge give you a reason they don't do chain any more? The only reason I ask is I work 30 seconds away and if it's a logistics thing I could always try to help out.
 
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