Chain finish

zoidberg

zoidberg

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I'm changing my anchor chain spec and have been looking for G70/G80 6mm short-link. So far, I've found G80 6mm by Crosby, but in a BLACK finish intended for commercial uses.
Who can advise on how such a finish will be affected by salt water exposure - and could I live with that?
 
zoidberg said:
I'm changing my anchor chain spec and have been looking for G70/G80 6mm short-link. So far, I've found G80 6mm by Crosby, but in a BLACK finish intended for commercial uses.
Who can advise on how such a finish will be affected by salt water exposure - and could I live with that?
Click to expand...

Need more information. Is the "black" a quick blow over with paint or one of the many metallurgical processes?
 
I would avoid using grade 80 lifting chain due to the inevitable rust and I believe that if you try galvanizing this grade of chain it can cause hydrogen embrittlement. I would suggest it is best to source a marine grade chain from a reputable marine supplier.
 
penberth3 said:
Need more information. Is the "black" a quick blow over with paint or one of the many metallurgical processes?
Click to expand...
I think it is a metallurgical process - but I haven't managed to raise an answer yet.
Sumara of Weymouth said:
I would avoid using grade 80 lifting chain due to the inevitable rust and I believe that if you try galvanizing this grade of chain it can cause hydrogen embrittlement. I would suggest it is best to source a marine grade chain from a reputable marine supplier.
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I haven't yet found a 'reputable marine supplier' who can/will supply G70/G80 galvanised in 6mm.

My objective is to reduce the excessive weight of chain I have with a specification that will meet my needs. Changing UP to G80 6mm chain will save 1.5kg/metre over the G40 10mm stuff I have and do not wish to carry.
 
Sumara of Weymouth said:
I would avoid using grade 80 lifting chain due to the inevitable rust and I believe that if you try galvanizing this grade of chain it can cause hydrogen embrittlement. I would suggest it is best to source a marine grade chain from a reputable marine supplier.
Click to expand...
According to @Neeves there is some embrittlement but it takes a g80 chain down to g70 or thereabouts. Plenty of posts by him on this.

I would have a search but tablet and poor Internet means I would struggle.
 
Black chain is a technical term, but I forget what as it is not relevant to your application. It will rust quickly it has no protective coating.

I would contact Crosby who own Gunnebo or ring Gunnebo and ask about their galvanised G80. It comes in a metric size but, say, 6mm + 10%, as the wire from which the gal G80 is made is 10% thicker. I note that in following a recent thread on a Lewmar windlass their windlass has a gypsy for 6/7mm chain and the extra wire thickness on the Gunnebo G80 might fit the gypsy, or a gypsy, neatly. So contact Crosby/Gunnebo and ask for a 200mm sample and try it on your gypsy.

This chain is specifically developed for the aquaculture industry.

There are techniques, processes to ensure that Hydrogen Embrittlement is not an issue - ignore the problem - Crosby and Gunnebo are not going to sell a gal G80 if there is any risk of HE. The US Navy/Marines are using a gal G120 - so don't worry.

I thought after the demise of Maggi there was another Italian chain maker offering a gal G70 through Jimmy Green? When Maggi sold their gal G70 there was never an issue with HE.

The other option is that Crosby, Gunnebo and Peerless are all part of the same company Kito Crosby and Peerless are well known for their gal G70, which they have been selling for decades. I know they made a metric version, but this may not be the case today. Crosby/Gunnebo are the best people to ask as they are 'European' and now all one big happy family.

Jonathan
 
The other option is to contact Bodycote, who I think are Bristol based and see if they are still operating their Sherardising or Armorgalv process, aka Thermal Diffusion Galvanising, TDG. If they are and show an interest in producing a length of TDG G80 - I'll provide more detail. The process is operated by two Isreali companies for chain - but I don't know if they are economically viable from a UK freight perspective and what effect the current war might have on their production schedule.

A final option is to contact Geoff at Knox anchor as he knows all the galvanisers, he is a renowned international galvaniser consultant - he may know of TDG processes, Armorgalv is one Greencote, Home - Greenkote another, both developments of Sherardising.

I'd actually put feelers out to 'everyone' and see what options come back.

I used the Australian Armorgalv process for my 75m of 6mm G100. When I last contacted Greencote and the Israeli operators they were all keen to process chain (and the Israelis had done it as a standard process).

Jonathan
 
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zoidberg said:
I think it is a metallurgical process - but I haven't managed to raise an answer yet.

I haven't yet found a 'reputable marine supplier' who can/will supply G70/G80 galvanised in 6mm.

My objective is to reduce the excessive weight of chain I have with a specification that will meet my needs. Changing UP to G80 6mm chain will save 1.5kg/metre over the G40 10mm stuff I have and do not wish to carry.
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I had the same problem trying to find a small diameter G70 chain ten years ago and ended up with 8 mm from Maggi. If you can persaud the likes of Crosby to supply a marine galvanized grade 80 in 6 mm it would be perfect but I certainly couldn't get it a few years ago. Good luck with the search.
 
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I think black steel maybe a metallurgical term but black lifting chains is simply a thin black paint coating that protects the chain, from corrosion, during transportation, short term storage and delivery. It is sometimes oiled (diesel) and stored in sealed oil barrels. It does not last long when abraded on the seabed (I did some tests on black painted G80 or G100 in comparison with gal). I have heard of black steel being used in a mooring application but commonly the abrasion on a mooring removes galvanising and 'corrosion/abrasion' is kept at bay by simply having a lot of steel (big fittings).

In terms of an anchor chain - forget it.

Jonathan
 
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Gunnebo short link gal G80

https://www.gunneboindustries.com/Lifting/Products/Aquaculture/Hot-dip-galvanized/Chain-KLZ-HDG/

I suspect the feedstock is a G100 (or maybe even G120) to compensate, along with the extra 10%, for the degradation during the gal process.

Its a fairly new product but you would think there would be a focus on aquaculture (salmon farming in Scotland) and there would be UK stock.

I think they may also sell a long link gal chain- you don't want that unless you are deploying/retrieving by hand (quite possible with 6mm chain)

Because of the rapid development of the Kito - Crosby entity you may find that Gunnebo comes under either or both of Crosby, Kito as well as Gunnebo

Jonathan
 
I have always used bog- standard galvanised chain from a chandlery and my efforts to find a cheaper source were unsuccessful. I have no idea what all this G80 stuff is about.

You say that the grade you want will weigh 1.4kg per metre less but isn't weight in a chain a good thing?

Forget about all fancy treatments like sherardising. Only hot-dip galvanzing is a suitable method of protecting anchor chain from rusting.
 
Kenneth, Salty Auld Mannie, at times ye sound chust like wan o' they Meenisters o' ra Wee Free Kirk.
'G80' is kinda posh an' a'... Ah ken yous tcheuchters in ra back o' beyond dinna hae much use for posh, an' ah ken fine that onywhaur sooth o' Oban is 'furrin' and fu' o' nonsense, but we cannae a' live in The Land o' the Leal. Some o' us cheils hae tae earn a living whaur we can....

Onyhoo, 'weight in a chain' isnae ony guid tae me 'cos I huv a bad back an' ma wee wifey cannae haul muckle mair than 6mm chain.
 
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Don't use Black it will rust like hell.

I have only ever seen galvanised or stainless chain on a yacht.

If you are using a windlass the chain will need to be calibrated so that it fits the gypsy on the windlass, if it is not calibrated it id unlikely to fit and it will slip or jam.

A good local chandler may lend you a short length to try for size or against a deposit.
 
Aye, laddie. Ah ken.

The local chandlers are NBG and the good chandlers are no local. Mind you, they'll a' take yer monnie! :LOL:
 
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