Pickling acid

[duncan webster 1Participant @duncanwebster1]

copied from a post in 2009

The "dry salts" I use are termed safety pickle – commonly sold into the jewellery trade, the composition portion of the data sheet reads:-

 

"Sodium hydrogen sulphate (a modified salt based predominantly on sodium bisulphate). The product is not corrosive if kept dry but in damp or wet conditions it readily absorbs water, forming an acidic liquid which is mildly corrosive when in contact with skin, eyes or by ingestion or inhalation."

 

One common source of the main component is swimming pool consumable suppliers – it is used to lower the ph ! (ph down is one brand name).

 

I've no idea what it all means. I suspect that sodium hydrogen sulphate might be what we called sodium bisulphate in my youth NsHSO4

 

Edited By duncan webster on 10/04/2018 00:12:45

Edited By duncan webster on 10/04/2018 00:13:09

[JonParticipant @jon]

It also means the ban in effect of home or cottage industry blacking, plating, anodising etc without appropriate licence.
Tried getting a explosives licence, forget it.

[Roderick JenkinsParticipant @roderickjenkins93242]

We can probably manage with 15%.

Rod

[Bill PhinnParticipant @billphinn90025]

I come from a jewellery making background and for many years have used "safety pickle" in place of sulphuric acid. It's not quite as effective as the "unsafe" alternative, no, but when used at the right concentration and heated in a slow cooker or dedicated "pickle pot" it is still very effective at removing flux residues and oxidation from brass, bronze, copper, silver and gold after brazing. One bonus besides the safety is it isn't so effective at leaving holes in your carpets and clothing when it splashes where it shouldn't.

[David TaylorParticipant @davidtaylor63402]

I use phosphoric acid. It works well and I can buy it from a hardware store in Australia. Not sure what it's intended use is but I think it is used for rust prevention too.

[nigel jones 5Participant @nigeljones5]

NaHSO4 works well if you keep it warm, but that means leaving the power on in the workshop all night which im not keen on, when it cools it forms a crystaline structure in the bottom of the tank.

[Brian HParticipant @brianh50089]

I note that there is no suphuric acid for sale on ebay but battery acid (which is sulphuric) is, at 31% to 37%.

Amazon seem to be happy to sell sulphuric though.

I've always used about 10% because it is not too aggressive.

Brian

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