Pickle

HI, I am looking for a supply of acid pickle for boiler making . Acetic acid has been suggested as easier to get than sulphuric. Does anyone know what concentration to use please?

Hot and strong.

But rather than mess with a smelly slow acid, why not try dry pickling salts? This example is mainly Sodium Hydrogen Sulphate, sometimes called 'half-neutralised sulphuric acid'. Not as fast acting as Sulphuric Acid but quicker than any of the organic acids.

Dave

This guy reckons you can use sodium hydrogen sulphate for anodising as well. **LINK**

Rod

Citric acid is becoming popular. While acetic may be smelly, or make you hunger after chips, it has the advantage over sulphuric of being human friendly. I am using ex pickled onion vinegar for derusting and it is convenient to be able to stick your hand in and know you are not at risk.

Buy drain cleaner, this one is 91% sulphuric acid.

**LINK**

Citric acid is really good, safe and cheap. you can get 1 kg bags on flea bay for a few quid and I use about one large tablespoon in a mop bucket. cleans up copper easily and quickly and if you have a spill there are no nasty consequences particularly for pets For steel I use brick cleaner. again cheap, easy to buy and as I rarely silver solder large steel items I keep it in a large screw top jar and just drop the item in hot and put the lid back on loose to contain any fumes.

Where from? All sulphuric acid products in my local hardware store have been taken off the shelves and replaced by a notice explaining the recent changes in UK law.

Rod

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Citric acid wins hands down no nasty fumes and benign to skin, ok doesn’t work as fast as the more aggressive acids but is all you need when using copper, and is cheap and readily available from the internet. As a bonus will descale coffee machines and kettles, perfectly safe.

Dave W

Where from?

South of the border?

HI thanks for all the input, bit confusing though, not sure what to try. I will see what is easiest to get .

I find that citric works a lot better if you heat it up. For small items I pour some into a glass jug and microwave it, before putting the brass bit in. You still ned to use scotchbrite, but just to wipe away the deposit. As others have said a lot safer than sulphuric

Concentrated acids, high potency ones such as Sulphuric, Hydrochloric, or Nitric must carry the risk of dissolving the parent material, plus the fumes generated. That should be reason to avoid them, in any form.

Some of the organic acids such as Acetic, (Vinegar) or Citric may be slower acting, but will be less risky to operator and the material. Hydrogen salts of acids will be mildly acidic, and so rank with Acetic or Citric.

Citric acid might be obtainable from a Home Brew store.

Howard

You can purchase citric acid from your supermarket, look in the cooking section.

An easier way is just use lemon juice,it works better if you heat it up.

10g of ethanoic per litre of water? 1%w/v? Do you really mean that?

Might just as well buy (proper) pickling vinegar. That should be about 9% v/v.!

Avoid the usual supermarket stuff as that is only about 6%, these days.

Copper does react with concentrated sulphuric acid and with nitric acid in any concentration. It doesn't react with hydrochloric acid at all nor with dilute sulphuric acid. Hydrochloric acid produces corrosive fumes so isn't nice in the workshop hence the traditional recommendation for using dilute sulphuric acid for cleaning boilers of oxides and flux.

Sulphuric acid isn't terribly dangerous when diluted to about 5% concentration (add the concentrated acid to the water not the other way round). Wear goggles to protect your eyes and if it is splashed on the skin wash it off with plenty of water.

Russell