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Anchor chain re-galvanising


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Thanks for link to earlier topic. Possibly a piece of string question, but what are the guidelines on assessing need for new chain/galvanizing. We all know a lousy thin weak corroded one when we see it, but how to get it the stage when it's needing doing?

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Yeah ballystick, same here! My Chain is 10mm PB from Ausy. KM says it's good stuff, and despite having already been re-galv 2x, Wheels tested a bit of it for me - still pretty close to spec!

Kevin, I'll let KM answer that, but for me, when the chain starts to drip rusty water, or looks rusty, time to do it again.... And some say it can only be done twice. That's why I tested mine first, before a third go..

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At the moment re galvanising is still about 1/2 the cost of new good stuff.... even new bad stuff.

 

You can re galvanise more then twice AS LONG AS the galvaniser knows his game well or they can over cook it which can bugger it. That's even more important if you have the seriously strong chain like Maggis AQUA7 or ACCOs G70.

 

Not too sure how you'll fair re galvanising some chains that have the newer types of finished like PWB's ArmourCoat but I suspect it'll be fine. I know re galvanising over Maggis Zinc-O-Met finish is fine, which is handy as there is now a lot of that in use.

 

What we heavily suggest is that if you are into your 2nd or more re galvanising (even after the 1st if you 'aren't too sure' it went well) you get a bit tested just for the peace of mind, like IT wisely did by the looks. To do that get 500-1000mm off each end of the chain and get it tested. This is to check you still have the strength you think you have. We can do that or there are others, anyone with a test bed should be able to do it for you. Costs? Hard to say what some would charge but I can't see it being much, to test 2 lengths doesn't take long. Doing that will give you a good indication of where it's at.

 

As a FYI - in the last couple of months we have tested a fair bit and most has been OK. 2 stand out cock ups were a 10mm Stainless that should go to at least 5000kg went as low as 880kg after flying through a visual test good as gold, no one saw that coming. The other was a 8mm that should have gone to at least 3200kg if it was what the seller sold it as, it failed at a tad over 2000kg, it was brand new never used and is still currently being sold around NZ. mostly the Auckland area, as being good stuff. Both of those 2 chains were made in the east. So I'd suggest any 'chain bargain' is only someone deciding to be fair and reasonable with chinese made.

 

 

 

I'd say 'Chain Bargains' don't exist in NZ. There is the Maggi and PWB being sold at tiny margin as most can't see the difference between those and the chinese, which is being sold with massive margins, so the price of good chains in NZ are already bloody low. And sorry to pop the bubble of the 'it's away cheaper to buy offshore' brigade but you can buy Italian made chain 25-30% cheaper in NZ than you can in Italy. Same applies to the aussie PWB made as well, it's cheaper in Akl than it is in Sydney.

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It would surprise me greatly if any 15-20 year old chain is eastern made, it just doesn't last like good stuff and I doubt you have regalved it 5-6 times as you probably would have needed to do with eastern made of that vintage. The eastern stuff has only started flooding in inside the last 10 years and most of that inside the last 5.

 

I know of quite a few boats still using anchor chain that's over 15 years old, some even older. All of that would be either PWB or Maggi made and some of it is still on it's 1st galvanising and some has only be re galved once in all that time.

 

As thI say often - 'As new and improved as it maybe today, the sh*t our parents used was still better'.

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We charge $25. No idea what others charge.

 

If your chain was new and now starting to look a bit rusty I doubt you'll have any strength issues, assuming it's wasn't a shitter to start with or Stainless.

 

Yes we have seen rusting Stainless chain.... more than you'd expect.

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I have had the boat since 2006 and it was 10 years old chain then its good chain IMHO.   I will look at cutting off a M each end and get that tested, it really does need a regalv....

 

Will need to look at the anchor chain swivell thing to see how it locks the chain in?

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Just go park in kaiarara bay for a while and that will do the stripping process for you anyway.

 

Anyone else experience this phenomenon this year?.. a bit of a new thing.

 A buddy was going spare about it ,and we didn't believe him until...........

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Just go park in kaiarara bay for a while and that will do the stripping process for you anyway.

 

Anyone else experience this phenomenon this year?.. a bit of a new thing.

 A buddy was going spare about it ,and we didn't believe him until...........

Yeap, but not this year..... so far. Don't know what it is but this maybe the 3rd time in 10-12 years we've seen not rust rust and weird sh*t happening a bit like you describe. Not massive and many wouldn't have noticed but for us it's been significant. Some sort of algal bloom or that sort of thing that makes some things look like they are rusty as a rusty thing yet they aren't. A bit of accelerated galvanising wear also happens. Also weird sh*t that has to be connected like when I dry docked my boat not long after I got her. She had about 6 month old anti foul at the time. When the dock came up WTF??? the bottom foot of my keel was a massive rust feast. Err.... hang on lead and antifoul paint don't rust, WTF?? It hard water blasted off but not all, back to anti fouling paint with no metal in sight. At the same time were we getting boats with rusty chains they shouldn't be, again it was this whatever it is bloom thing.

 

It seem to happen in smallish areas but a few of them happen at the same time. If this is the same again it will be the third time I've seen it. The last time was my keel so about 5 years ago. It lasts for about 4 months +/- then just fades away, quite quickly.

 

If you think it maybe this grab a sample and get it to me, I'll get it tested or something.

 

Coral sand can strip galvanising super fast, watch for that if you're around it. Seen new go to naked in 3 months.

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Corrosion in dissolved salts, acids and bases. Zinc is not used in contact with acid and strong alkaline solutions, because it corrodes rapidly in such media.


Very dilute concentrations of acids accelerate corrosion rates beyond the limits of usefulness. Alkaline solutions of moderate strength are much less corrosive than corresponding concentrations of acid, but are still corrosive enough to impair the usefulness of zinc.


 


http://www.keytometals.com/Article40.htm


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In Malaysia, in the tin mining areas, there is something in the mud that removes galvanizing almost overnight. Well known by the locals, but they don't know what it is!

I put it down to whatever minerals/ acids that have been washed down the valley and into the bay from the storms in June . The destruction to the forest and river bed and banks has to be seen to be believed . I was in the same bay last year for that ex TC and have anchored there many times over the last few decades. Its never happened to me before.  I should have taken a photo of the links  , like I said my chain is a bit light on galvanising at the moment and any slightly rusty link was either bright or in the process of becoming bright metal as the rust was being converted... literally bubbling off it.

 

 Enough that after we went around the corner we  put everything we'd had out in Kaiarara out and in a couple of times to wash it.

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