Metallurgy - stainless steel stain removal

[crystal ball]

When I was in Australia my company paid for a corrosion/metallurgy course, so dreary cannot remember a thing.

 

[Harry Bloomfield]

If you know, or can find out, the name of the design, you may be able to get some to match your other stuff.

It's a one of type in the drawer, just handy for whipping the gravy. It's not a problem, it is clean, just discoloured. I have no idea what caused it, I am just curious to find what might remove the discolouration.

 

[Deleted member 174758]

When I was in Australia my company paid for a corrosion/metallurgy course, so dreary cannot remember a thing.

My brother was a tool steel metallurgist (really). It never seemed dreary or boring to him, but I suppose it depends on the level you are at and whether or not you, personally, are interested in the subject. If you want something really dreary, try being an actuary - a friend of mine tried that, but eventually be found it so mind-numbingly boring that he decided to do something much more exciting. So he retrained to be a chartered accountant

 

[Harry Bloomfield]

My brother was a tool steel metallurgist (really). It never seemed dreary or boring to him, but I suppose it depends on the level you are at and whether or not you, personally, are interested in the subject. If you want something really dreary, try being an actuary - a friend of mine tried that, but eventually be found it so mind-numbingly boring that he decided to do something much more exciting. So he retrained to be a chartered accountant

I had to look that word up

 

[Nozzle]

Autosol.

Nozzle

 

[Harry Bloomfield]

Autosol.

Nozzle

Got some in the garage, I will try that too. The stains look like the blueing you get if you heat ordinary steel then quench it in oil.

 

[crystal ball]

My brother was a tool steel metallurgist (really). It never seemed dreary or boring to him, but I suppose it depends on the level you are at and whether or not you, personally, are interested in the subject. If you want something really dreary, try being an actuary - a friend of mine tried that, but eventually be found it so mind-numbingly boring that he decided to do something much more exciting. So he retrained to be a chartered accountant

TBF it was out of my interest range, I am an electrician and was working for a corrosion control company at the time. our boss thought it might look good to our major clients.

 

[securespark]

Bar Keepers Friend will do it, it contains oxalic acid and is non abrasive to stainless steel. Most supermarkets sell it as does Home Bargains which is where I last bought some.

Second that!

It also blitzes tea and coffee stains from porcelain and teaspoons, and stains from worktops and SS sinks.

 

[Justin Passing]

Stainless steel is interesting stuff. Some odd bits, might be relevant. It's /they're not stainless at all, just covered in chromium oxide, "passivated", which you could call a "stain", but you can't see it and it's protective. As soon as you scratch the chromium oxide off, it reforms.
Chlorides are the nemesis though. They disrupt the protective layer fixing & allow other things in. They also react with the iron in the grain boundaries, just below the surface. So that can be hard to remove by surface treatments. Any stress and it goes much deeper & you get cracks. Heating and cooling would do it. Food must have a load of chlorides. NaCl obviously. I thought gravy was diluted cow, I don't know.

Mo helps a lot, that's the 2 if you see 18/10/2 (Cr Ni Mo) stamped on good cutlery. Cheaper is 18/8. Mo gets to and stablizes the oxide layer and active sites on the grain boundaries. You need oxygen in there. That's why oxalic acid would be good, with abrasion. Household bleach can work too, but it's full of chloride so don't try it. I've not tried oxalic acid on metal, only wood. It's good for ink and whatnot.

There are microscopic fissures in the CrO (Cr2O3 ). Surgeons using even the best St St instruments often have to treat them as one use only, because things like prions are so small and tough they can lodge in there, irremovably. Mad cow disease has been transmitted that way.

More waffle than you wanted, for your spoon. Got a Brillo pad? Dremel? Wet & dry paper?

(I've removed some bits in case people get themselves in trouble)

 

[Deleted member 174758]

And we're back to oxallic acid and abrasion...

 

[Harry Bloomfield]

Second that!

It also blitzes tea and coffee stains from porcelain and teaspoons, and stains from worktops and SS sinks.

I'll see if I can find some in Home Bargains on my next visit. Purely in the interests of satisfying my curiosity you understand - it will probably exceed the cost of a new spoon.

 

[securespark]

But you can use it on so much more!

Cheapest I can find it is 2 quid for 250g in The Range or Dunelm.

 

[Deleted member 174758]

At this rate, Harry, I've a good mind to stick some oxallic acid crystals in an envelope and post it to you...

 

[Justin Passing]

And we're back to oxallic acid and abrasion...

Well exactly - I hadn't heard of the Barman's stuff. The Victorians worked a lot of this sort of stuff out!

It's in rhubarb sticks, if you have any lying about....

 

[Justin Passing]

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