Safety Pickle for Steel

[aw1931Participant @aw1931]

Is sodium bisulphate (safety pickle) suitable for pickling steel with? In the past, I have used citric acid but this has left a dull grey finish on the steel (I believe due to the formation or iron citrate) which I preferably want to avoid. Would pickling the steel in sodium bisulphate leave me with completely bare steel?

[FulmenParticipant @fulmen]

That’s what I’m using. Now all acid will corrode steel to some degree, but bisulfate is pretty gentle. It doesn’t dissolve the mill scale as much as loosening it so it can be brushed off.

[Paul LousickParticipant @paullousick59116]

Vinegar is also a mild acid and good for cleaning metal. Household cleaning grade is cheap and available at the supermarket. Can be used a few times before discarding.

[Paul Lousick]

On Paul Lousick Said:

Vinegar is also a mild acid and good for cleaning metal. Household cleaning grade is cheap and available at the supermarket. Can be used a few times before discarding.

I’ve used vinegar in the past however it has also left a dull grey finish due to the formation of iron acetate.

On Fulmen Said:

That’s what I’m using. Now all acid will corrode steel to some degree, but bisulfate is pretty gentle. It doesn’t dissolve the mill scale as much as loosening it so it can be brushed off.

Does it leave any sulphates or any other compounds on the surface or does it leave you with the bare steel after brushing off the mill scale? In the past I have used citric acid and vinegar which have both left a dull grey finish due to the formation of iron citrate and iron acetate respectively.

[FulmenParticipant @fulmen]

The surface will always be dull after pickling. But it shouldn’t take more than a quick rubbing with 400 grit to clean that up, it won’t be heavily pitted or anything.

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