rust on nearly new stainless rigging

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We had our rigging renewed two years ago by a local yard.

It's starting to look quite rusty around the top of the swages and the wire half an inch or so above the swages. Noiced this less than a year after installation.

Is this likely to be superficial (i.e. surface oxidation which stops there), is it even remotely normal and if not should the yard who made it replace it?

- Nick
 
Dont know what caused your rust problem but having been involved for over 25yrs. with steel boats I cannot recommend Comma Wax Seal too highly, tried the Wax Oil by another firm but not as good.If you spray it on its soaks into and around. If you get it on paintwork you just polish and it shines like wax polish.If you could have got it on when when stainless was new I am sure it would have prevented it.
 
OK, that is encouraging . . . but how do I know it is just surface? Presumably if it is not gone after 10min with this oxalic acid treatment then I should begin to worry . . .

Is there any danger of the oxalic acid damaging the stainless, and where do I get it?

I assume it is happening because of an electric potential between the wire and the swages, as this is the only place this is happening. (Oh, andd a wee bit where the thread goes thorugh the bottlescrews - it suggests that the swages are maybe cheap stainless??)

It's a bit worrying because this is where most rigging failures occur.

- Nick
 
I dunno the exact bits you mean.

But yes, stainless going rusty in a short time is a bit orf imho and need to be tackled. Stainless open to the elements should stay unrusty. Like the lots of stanchions and mobo stanchions stay shiny regardless of lazy gitisshnes of owners.

You can reduce/remobve stainless by

1) reverting to supplier in appropriate level of pottiness. It is from surface inwards, where teensy fault is ekeed out. Yep it can carry on and on and is obviously a big point of weakness. Stopping it back is good - it won't just stop really.
Rustwise, it does seem a matter of chance eg at charter place a 1-year old boat had rusty stainless fittings, identical 3 year old boat same fittings were all shiny and none cleaned very much if ever.

2) the supplier of supplier has either fitted not the right material (unlikely but possible) OR has worked the metal using tools that are high in carbon (like wot mild steel is) OR has used tools that have also worked steel. Of of course, it's a "bad batch".

3) Wessex Chemicals (use google) will help with oxalic. The Part 2 of the two-part chemical cleaner is oxalic acid, bout 3quid a litre. Nice people. The gear should be sort of whammed around with a knackered toothbrush frinstance. A plastic pan scourer also an option. obviously not a metal file qv carbon steel as above. It hardly harms grp. Well, i've used loads and tis fine.

4.) the rust is er worsest in the deepest darkest bits. Much easier to keep track of this if the shroud frinstance is one big chunk instead of multistrand wire. Except when one fat wire goes i spose it really goes. I hate multistrand stainless wire. The gits who make the plastic covered guardrail wire seem to use low quality so-called stainles - i stripped the plastic on one boat and the so-called stainles went rusty-tinged in a month. It might make you fel better to lash grease around but this just slows not cures it. I am told than stainless parts should be assembled dry.

5) Electrical considerations seem very valid, and worse if u have constant shorepower. I fitted a galvanic isolator 50quid ish or less, and since then the tendency for stainleess things to rust has masively decreased.

6) you need to get the rusty things de-rusted with oxalic, polished as best you can, and then re-passivated which is the surface thingy you leave for half an hour an wipe off, and apparently "witchinox" does this. Any summink that repassivates is what you want. Though a new item is obviously a better bet...
 
Oxalic shouldnt hurt stainless 316, but you shouldnt leave it on the surface - wash well.

You shouldnt have this sort of oxidation on good 316. I previousl;y suggested to someone that they should specify wire of UK or at least EU origin, only to be told when I went for some rigging myself that it all now comes from Korea. 2 more riggers said the same thing. You can take it that that is not because its better quality but because its cheaper, so I suspect the alloying might be being shaved a bit.

None of the riggers had any certs of compliance with BS or EU standard either. So what happens when there is a failure I dont know.

Mind you, in their defence, I chose my rigger on the basis of who was cheapest so I cant blame them for doing the same.
 
Discoloration is not something I make a habit of looking for on boats unless there is an obvious physical problem but I don't recall seeing a boat where discoloration from oxidation was not present at the top of the swages. Ours certainly have it and I have never worried about it.

Is to be expected as there will be wet oxygen deprived crevices around the area where the wires enter the swage and maybe some metal composition differences too. I assume that sealing as others have suggested would stop it but I don't know of anyone who does that (not that I have ever asked anyone).

Same is to be expected on the rigging screws as you describe - in our own case we have a type of screw which is a single ended barrel type ("Sea Rig" where a screwed terminal is swaged to the wire). We do seal those, but only because we would like to be able to undo them sometime /forums/images/graemlins/smile.gif and would suggest the same for bottle screws.

John
 
[ QUOTE ]
Use a magnet to see if it is magnetic. If it is, its clearly crap. If its not magnetic, I would watch it carefully.

Peter

[/ QUOTE ]And how exactly do you come to that conclusion?. Is the use of a magnet some form of definitive test to the quality of the stainless steel?
--------------------
hammer.thumb.gif
"Artificial intelligence is no match for natural stupidity"
 
Use a magnet to see if it is magnetic. If it is, its clearly crap.

Eeeek. My propeller shaft which is supposed to be a very, very classy bit of stainless steel is magnetic (just double checked as I am on board). However, methinks that I have more faith in my propeller shaft being ok than I have in the reliability of the marina myth of the magnet test telling good from bad.

John
 
400 series stainless steel will attract a magnet. 400 series is based upon 13% chromium, not much nickel. Has the advantage that it is heat-treatable and therefore can be stronger. Pretty good chloride resistance and probably what your shaft is made from. Widely used for machinery in refineries, where chlorides are a persistent problem. Also most cutlery except the very expensive stuff.

300 series s/s is austenitic and therefore not attracted by a magnet. based upon 18% chromium, 8% nickel (+2% molybdenum for 316) Not heat treatable and not very tough unless hard drawn, as in wires.
 
Hi John,

Your post is somewhat reassuring, but our old rigging - which we replaced - did not show as much oxidation round the top of the swages.

Is there any test / inspection I can do on a bit of it? I am minded to take one of the shrouds back to the yard for their comment.

- Nick
 
there are tests tho i think most involve sawing up the stainless to make test piecs for looking at thru a microscope. At which point off course you def need new gear.

I spose also it will be a bit strange to say" excuse me my good man i have a complaint about the surface grain structure of this stainless steel!"

Would the best option be to find other gear of similar age and (initially) fling yourself on their commerical mercy and askem to take a look? It mite be an idea to get a really rusty thing or some flakes of rust and grind it up a bit, then carefully sprinkle lots of rust over it and on to the deck to make it look impressively catastrophic "yes, i've had a go at it already..." but I cannot recommend this dreadful approach at all.

For others, i reckon a high pressure water blasted at the thing would keep things nicely oxygenated and fairly free of rust, possibly?
 
Nick, I had a bit of a look around the marina today to see how prevalent it is (here in Wellington anyways).

Most swaged terminations had staining where the wire enters but a few did not (maybe they just clean them tho', but in some cases the boat had stained and non stained ones) - the real swaged fittings seemed to commonly have it but the few terminations I saw which have no swaging eg Norseman or whatever type, did not appear to have any although for them where the wire enters the collet is hidden by the nut. Same with the turnbuckles as the thread enters the centre piece. Had a peek at a friend's new boat less than a year old but recently returned from over 6,000 nm ocean racing and the staining is appearing on that - visible between the wires about an inch or so above the swage down to the swage (our own are about the same and get worse after alot of exposure during cruising).

If it looks like dark tea staining I don't think I would worry but if there is a build up of it rather than just a thin surface effect, brown dust/flakes or pitting to the wire I think I would ask the riggers for their opinion, as others have suggested. 316 ss will get some staining, even in fully exposed to oxygen applications if it is not highly polished. I think that one thing that happens at the top of the terminations is that as they are upward facing they tend to stay wet longer and salt and staining collects there - the staining includes that that washes down between the wires from further up the stay/shroud and collects on top of the termination.

John
 
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