Stainless Steel

[vic008 17]

Am making the odd thing out of 314. Now, if I dont polish the SS will it stain/rust or do I absolutely have to polish it?

[Steve Pope 243]

maybe you are thinking 304?? if it is passivated and polished it shouldn't be a problem. beware of contaminating it with cut off / grinding discs, files, wire brushes etc. that have been in contact with steel. they will contaminate the SS and will lead to rust stains. 316 is a better option but the same applies re contamination. Neither grade should be used below the water line, other than as a prop shaft / rudder stock etc.

[wheels 543]

Am making the odd thing out of 314. Now, if I dont polish the SS will it stain/rust or do I absolutely have to polish it?

As steve said, you might be thinking 304. 304 and 316L are the two most common SST's to be found on boats, apart from a SST anchor, of which the good brand names use a duplex SST for extra strength. 304 can be bent easier with less fine grain stress cracking than 316L. So it is often used for rails etc. 316L tends to get microscopic cracks if bent and is more susseptable to stress cracking and this allows crevice corrosion to take place. 316 has slightly more Chromium added and this results in a slightly greater brittileness, but less suseptable to corrosion and most importantly, attack by Chloride. Salt is Sodium Chloride od course. As such, if SST ever needs to be below waterline, 316L is the better choice to use.

It is always best to polish SST. The better the finish, the more resistance to corrosion the product has. Polishing causes two key points to corrosion resistance. The surface has less crevices for contamination to get stuck in and there is enough microscopic particles in the air that can lead to corrosion starting. The second part is that he Chromium is much harder than Steel and so the steel tends to be cut away when polished leaving behind a much richer Chrome content and thus more corrosion resistance.

[Freedom GBE 27]

We have a few SS washers and bolts creating rust stains down the hull. 

 

Does anyone know how to prevent those rust stains?

[erice 732]

have been in the habit of using a wire wheel to clean up rust stains 

 

but as Steve says 

 

the stains reform from the wire brush residue

 

so presumably #1000 wet'n'dry? 

[chic014 0]

Use an oxalic acid paste. Don't leave it on  too long though. Can't remember what it's called commercially but usually called gel coat cleaner or such like.

[Clipper 343]

Grunt?

[Vorpal Blade 89]

That waterline stain remover stuff from Burnsco gets it off, its probably just an acid of some sort - I will get a chemical expert to check the label and report back.

[erice 732]

thanks

 

Mix a paste using water and oxalic acid. Oxalic acid is a mild bleach that is sold in hardware stores, usually in the form of small crystals. In a plastic cup, mix 3 parts oxalic acid crystals to 1 part hot water, stirring until the mixture is dissolved. Do not use a metal container or a metal utensil when making this mixture, as the oxalic acid can discolor the metal.

 

http://www.bunnings.co.nz/jac-jay-oxalic-acid-500g_p00728384

 

I looked up a store-bought hull cleaner'sMSDS (material safety data sheet which lists ingredients) and lo and behold...it is 1 to 5 percent 2-Butoxyethanol (a degreaser, like a soap) and 5 to 10 percent oxalic acid!

 

Optional: if you want it to "stick" better to a surface, you can add up to 10 tablespoons of powdered wallpaper paste.

 

First off, wear gloves and goggles when using oxalic acid.

Applying it is simple. At first we wiped it on with a rag.

Later we used a gallon pump sprayer, sprayed it on and let it sit for a few minutes. Then we went back and hosed it off with lots of water.

Don't leave it on metal for long. It can remove rust, but also zinc from brass.

For really thick algae growth, I scraped the hull with a plastic scraper (I even used a plastic ruler sometimes).

 

http://www.greendept.com/maximpulse/oxalic/

 

I mix mine with fairy liquid.
I have a 500ml plastic container. Add two tablespoons of oxalic acid powder, add enough hot water to dissolve, but leave some room for the detergent. Add about 50ml green fairly liquid, and stir gently.

When applying I use a washing up bush and brush vigorously to get a lather. The lather keeps it moist long enough to do the job, and the detergent removes a few things the acid won't. The bubbles also show where I've been and where not yet.

Cheap and effective.

[wheels 543]

Grunt Emmergel is what the SST/gelcoat cleaner it is called. But there are others as well. Both Phosphoric and Oxalic acid can be used. Phosphoric is non toxic. Oxalic is toxic.

 

NEVER EVER use a steel wire wheel on SST. Use a proper SST wre wheel if you need to use a wheel, but then the best thing is, NEVER use any wheel or abrassive. It only scrathes the surface and that in turn causes corrosion area's.

NEVER trust all SST bolts nuts and washers. There are genuine 31g and that stuff is expensive. There is genuine 304 and that stuff is not badly priced and then there is genuine crap and that stuff is cheap and just plain garbage. 304 and the cheap SST bolts etc are easier to machine threads. 316 is very hard to machine a thread and are often threaded but cutting a thread. Slower and expensive tools required. Softer SST materials have the threads rolled onto them,. Fast and repetative for the tooling, thus much cheaper.

 

[Steve Pope 243]

Anzor carries a huge range of most SS bolts and fittings, marine and used in building houses etc, 304 and 316. You can open a cash account with them (credit card) if you are not near one of their outlets and they will courier to you.

[erice 732]

Anzor Fasteners West Auckland www.anzor.co.nz

 

9 Patiki Rd
Avondale, Auckland
09-828 9070

 

 

Anzor Stainless Fasteners Ltd East Tamaki www.anzor.co.nz

 

41 Trugood Dr
East Tamaki, Auckland
09-273 2121

 

 

Anzor Fasteners Albany www.anzor.co.nz

 

8 Arrenway Dr
Rosedale, Auckland
09-476 0001

[wheels 543]

I have never bought directly from Anzor, so this is not first hand experience. But I have worked alongside an ex Anzor staff member and he had very little good to say about their product quality. Apparently it is all cheap stuff out of China and they often had customers come back complaining of their SST items rusting. Now to be fair, it is possible for SST to be contaminated by contacting a steel item of even from a Spanner that has high Iron content and apparently that was the common excuse from their staff. But this person had other thoughts as to why. Just to qualify him, he left Anzor of his own accord, so I don't think he had a personal axe to grind.

[Steve Pope 243]

You may be right Alan, but to date I haven't had cause to complain.

[180S 20]

Hi I,'m Andrew; have a Spencer 30 down on WHaven G.

 

The nuts&bolts i got from Anzor were good, but the 316 staunchion wire started with crevasse type rust within 2 years.

Find it challenging to determine 'Good 316 SS from Not Good SS.

[wheels 543]

That's good to hear Steve. Maybe it was just contamination issues.

Andrew, wire is a difficult one. Firstly, buy from someone that can show you a certificate of what the wire is. There is a lot of cheap Chinese wire being brought into NZ. If you want good wire, see KM. Secondly, wire is a big issue re what is called Tea Staining. It catches rubbish from the air and that can start rust. The movemet or the wire can cause wear of the Chromium and allow iron to be exposed and cause rust. The wire can move in the hole in the staunchion doing exactly the same thing. So wire can sometimes be an issue without it actually being it's own fault. I have heard of people wiping an oily rag on the wire every now and then. I have never bothered.

[jamiehunt 1]

Hi guys - as an Anzor rep I thought it would be good to help with some more info:

 

You are right Wheels - iron contamination from tooling can be a problem, get a some loose iron onto Stainless Steel and that will kick start tea-staining for sure.  However (and I know you got it second hand) I'm not sure your ex Anzor source quite got their facts right.  Most of our fasteners are from Taiwan and not very much is from mainland China at all.  You are right though there is a lot of out of spec Stainless being produced in China and India - typically low level Nickel/Chromium or Molybdenum  grades such as 201 being sold as 304 or 316.  We combat this by only buying from the best factories - typically Taiwanese with top rate QC.  Additionally we have an X-Ray Spectrometer here in NZ and so we test the material of the fasteners that arrive to ensure their composition is up to spec.

 

Secondly Wheels you are also right re the wire and how easy it is to Tea-stain.  Often Chinese, we get ours from Korea and find this better.  However the source doesn't give all the answers - I have seen plenty of tea-staining from wire that is 316, often just 1 strand.  This can be caused by a couple of things.  The wire is made in the same factory as galv/steel wire and the same tooling is used (i..e Iron contamination at source) OR more commonly, the strands that make up the wire rope are drawn down from larger diameter wire (this is normal in the process of making wire rope strands) but they are incorrectly over-drawn from larger than ideal strands - this over-drawing can cause reduced corrosion resistance.  Finally if Stainless Steel isn't passivated (this is when the Chromium Oxide passive film which makes stainless work is made thick and strong - usually with a dilute Nitric Acid bath) then the finished product (albeit bolt, wire or a fitting) might be 316 but will not have the corrosion resistance it should.  So in summary yes you have to get the supply right - ensure the importer (us - Anzor) have the best factories and testing equipment to check, but at the end of the day it is not so simple as which country it comes from.

 

In summary though at Anzor we buy very little from mainland China, we only deal with the best factories and we test material composition when it arrives - at that end of the day our commitment is absolutely only for quality products.  Also we have a good article on other things that can cause and affect tea-staining such as surface finish, rain washing and tool contamination you might find useful:

 

http://www.anzor.co.nz/blog/the-dos-and-donts-of-using-stainless-steel-fasteners/

 

Also really good for putting on Stainless (especially wire rope) to prevent tea-staining and corrosion is Lanolin (E.g. Prolan) - it's from sheeps wool and works really well.  But the for the best result the shinier you can get the finish of the stainless (staunchion etc - passivated/pickled on any welds) the better it will perform.

 

I am happy to help if you have any questions on stainless steel and tea-staining,

regards

Jamie Hunt

Anzor Fasteners Ltd

[180S 20]

Lots of interesting info thx Jamie.

Have often wondered why my pulpit, stanchions and shrouds ( as was the original wire) unblemished, yet the rear rail always needs polishing.

I did change to a higher strand count with the tea stained safety wire, maybe a lower count wire would be less susceptible to tea staining.

[speedy 0]

I used Automotive "Mothers" polish with a light scotchbrite and on serious marks used a soft brass rotary brush, hands go black but seems to leave a coat behind for protection.

[southernman 73]

Two words Phosphoric Acid - cheap and buy it in bulk works a treat on all stainless and good for steel surface preparation.  

 

Anzor are not too bad but don't pay their cash sale account rate- God that's asking for it!!