- Thread starter sardine
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henry Kadzielski
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Pickling paste, gel, or electro polish weld clean. I will post some pics later today as am doing some stainless myself at the moment.
Ross365
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There have been quite a few threads on here about using citric acid solution to remove rust, and that may well be the safest and cheapest way of doing it. In the past I've often commented that you can buy citric acid as a powder at Wilko's, but sadly, that option may be ended but it's available on eBay.
Re "Pickling paste", pickling of stainless steel often refers to the use of a mixture which includes hydrofluoric acid, which is seriously dangerous stuff and does attack not just the rust stains, but the stainless itself. I think it would be overkill for what you want.
Re "Pickling paste", pickling of stainless steel often refers to the use of a mixture which includes hydrofluoric acid, which is seriously dangerous stuff and does attack not just the rust stains, but the stainless itself. I think it would be overkill for what you want.
henry Kadzielski
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As promised pic to follow
Untreated
Treated
Now has has been mentioned above, pickling past is very nasty stuff and the good stuff that works good is even worse on the human body, which is why the new alternatives have been developed. Down side of the new 'stuff' is the cost of the equipment to do the cleaning. Up to you what you want to do!
Untreated
Treated
Now has has been mentioned above, pickling past is very nasty stuff and the good stuff that works good is even worse on the human body, which is why the new alternatives have been developed. Down side of the new 'stuff' is the cost of the equipment to do the cleaning. Up to you what you want to do!
sardine
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I've already got citric acid i use for my derusting tank, how do you use it for cleaning big items you can't dip ?
Agroshield
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Soak a cloth or sponge/piece of foam in it and leave on top of the stain. Wrap with clingfilm to stop it drying out. Come back in the morning.
White vinegar is also good and might be cheaper than citric.
Ross365
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Yes, a soaked sponge should work. I think I'm right that citric is about 40 times more acidic than acetic ( but still a very weak acid) and citric does not smell. I once visited a workshop where they were using lots of vinegar to clean some big steel vessels - after a while the smell becomes a pain in the bum.
Pete.
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Harpic power plus 10x might shift it or even an iron fallout remover like iron out.
Munkul
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Yeah the crap on the stainless in the first post, i wouldn't have thought citric would touch it. Even nitric acid pickling paste would take a while. I think you did the right thing in abrading it off. Poly abrasive wheels work great on stainless, at least the 3m blue ones do.
chrismac
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Totally agree the strip and clean 3M scotchbrite wheels are great,
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This stuff remove light marks....a mix of hydrochloric, nitric and phosphoric acids I think.
We tend to give everything a good wash down with that after cleaning welds with Antox or electro wand. Removes light rusts marks from forming, forks, benches etc.
We tend to give everything a good wash down with that after cleaning welds with Antox or electro wand. Removes light rusts marks from forming, forks, benches etc.
DAPPH
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White vinegar in the UK is usually 6 % , American stuff in their pickling recipes is often only 3 %
Munkul
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What do you use for neutralizing?
I've just geared up for a load of passivating for upcoming work, I'm using a bymat electro cleaner, and a couple of different phosphoric acid based cleaning solutions. I'm going to use elmer wallace mainclean, its at 10% dilution ratio which makes it way more cost effective than other brands neutraliser. But whatever i do i need to avoid white staining.
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Water
So the Enerjex we would use after tig brushing.
Use the acid solution on the brush, wipe off, spray with neutraliser. Then wash with Enerjex. It get that skanky residue off nicely.
Ross365
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Re "passivating" is your customer calling up something specific on that?
I retired some years ago, and it may well be the case that H&S and environmental factors have forced changes in the methods used to process stainless. But back in the day, we always thought in terms of three-step processing of most stainless steels;
>cleaning - invariably an alkaline cleaner
>pickling - a mixture of ~3% hydrofluoric acid and conc nitrc acid
>Passivating- conc nitric on its own.
-with lots of water washing between each stage.
Such treatment appreciably improved the corrosion resistance of 300 series steels and was beaten only by electro-polishing.
I never used phosphoric on stainless, nor did I ever become aware of anyone else using it, but Google now shows it's fairly standard practice and it's apparently biodegradable.
