Pickle

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Pickle

This topic has 50 replies, 22 voices, and was last updated 25 July 2018 at 12:46 by Phil H1.

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21 July 2018 at 17:24 #363233
John Rutzen
Participant
@johnrutzen76569
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?
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21 July 2018 at 17:24 #1737
John Rutzen
Participant
@johnrutzen76569
21 July 2018 at 18:46 #363240
SillyOldDuffer
Moderator
@sillyoldduffer
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
21 July 2018 at 19:05 #363247
Roderick Jenkins
Participant
@roderickjenkins93242
This guy reckons you can use sodium hydrogen sulphate for anodising as well. **LINK**

Rod
21 July 2018 at 19:26 #363248
Bazyle
Participant
@bazyle
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.
21 July 2018 at 20:03 #363253
KWIL
Participant
@kwil
Buy drain cleaner, this one is 91% sulphuric acid.

**LINK**
21 July 2018 at 20:11 #363256
RRMBK
Participant
@rrmbk
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.
21 July 2018 at 20:22 #363258
Roderick Jenkins
Participant
@roderickjenkins93242
Posted by KWIL on 21/07/2018 20:03:43:

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

**LINK**

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
21 July 2018 at 20:28 #363260
Former Member
Participant
@formermember19781
[This posting has been removed]
21 July 2018 at 20:29 #363261
Samsaranda
Participant
@samsaranda
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
21 July 2018 at 20:29 #363262
not done it yet
Participant
@notdoneityet
Where from?

South of the border?
21 July 2018 at 20:39 #363264
John Rutzen
Participant
@johnrutzen76569
HI thanks for all the input, bit confusing though, not sure what to try. I will see what is easiest to get .
21 July 2018 at 20:41 #363265
duncan webster 1
Participant
@duncanwebster1
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
21 July 2018 at 21:24 #363273
Howard Lewis
Participant
@howardlewis46836
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
21 July 2018 at 23:38 #363284
phil gardiner
Participant
@philgardiner73127
You can purchase citric acid from your supermarket, look in the cooking section.
21 July 2018 at 23:47 #363285
phil gardiner
Participant
@philgardiner73127
An easier way is just use lemon juice,it works better if you heat it up.
22 July 2018 at 02:52 #363288
David Wasson
Participant
@davidwasson11489
Traditionally, the acid for cleaning copper has been sulfuric acid, which is basically battery acid like found in a car battery. Another acid, but much safer, is acetic acid. You can find it at a grocery store and is used for canning. It is a food product and is completely safe, that is to say, it won't eat holes in your clothes and the fumes will not rust your nearby tools. Sulfuric acid will though. You can also put your hands right in the solution without fear, if you have any cuts or abrasions on your hands, it will let you know about them! Acetic acid is probably not as aggressive as sulfuric acid, but, if you are willing to let a part soak overnight, or for a few hours, it works just as well and is so much safer. The cleaning on my copper boiler between soldering events, was done entirely with acetic acid.

I successfully built a 1" scale copper boiler, 5" barrel diameter and 19" long. All silver soldered and all parts cleaned with acetic acid. I bought two plastic bins large enough to totally immerse the boiler in. One bin had the acid, the other had fresh water. The stronger the solution, the quicker it will do the cleaning.

David
22 July 2018 at 07:35 #363294
Keith Hale
Participant
@keithhale68713
Hi John.
Answering the original question..

10 gms per litre of water and
Get it from cupalloys.co.uk

Regards

Keith
22 July 2018 at 08:09 #363295
not done it yet
Participant
@notdoneityet
Posted by CuP Alloys 1 on 22/07/2018 07:35:21:
Hi John.
Answering the original question..

10 gms per litre of water and
Get it from cupalloys.co.uk

Regards

Keith
22 July 2018 at 08:17 #363296
not done it yet
Participant
@notdoneityet
Posted by not done it yet on 22/07/2018 08:09:12:

Posted by CuP Alloys 1 on 22/07/2018 07:35:21:
Hi John.
Answering the original question..

10 gms per litre of water and
Get it from cupalloys.co.uk

Regards

Keith

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.
22 July 2018 at 09:23 #363306
Russell Eberhardt
Participant
@russelleberhardt48058
Posted by Howard Lewis on 21/07/2018 21:24:56:

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.

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
22 July 2018 at 10:03 #363312
pgk pgk
Participant
@pgkpgk17461
You can also buy glacial acetic acid from auction sites and dilute to your choice. Take some commonsense care.

pgk
22 July 2018 at 10:25 #363317
SillyOldDuffer
Moderator
@sillyoldduffer
Posted by Russell Eberhardt on 22/07/2018 09:23:13:

Posted by Howard Lewis on 21/07/2018 21:24:56:

…

…

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

That's good advice Russell and I'd suggest taking even more precautions when handling strong Acetic Acid. Chaps seem all too happy to believe dilute Sulphuric Acid is hideously dangerous while Acetic Acid is completely safe: far from it!

No excuse these days for not looking chemicals up on the Internet. Read the Material Safety Data Sheet (MSDS) for the item concerned and take due precautions. Acetic Acid has a cuddly safe reputation because we're familiar with Vinegar. Yes you can eat Vinegar in small quantities, no you wouldn't want it in your eyes. Strong acetic acid is a lot nastier: it can burn skin, blind, and you don't want to breath the fumes.

Gloves, googles, careful pouring, good ventilation and other simple precautions are often sufficient to de-risk most operations. I suspect most Model Engineers are careful in practice, even those gung-ho about H&S on the forum. My other hobby (Amateur Radio) is a good deal more dangerous. Not due to electrocution as you might expect, more usually inexperienced chaps falling off something high whilst erecting antennae.

Dave

Edited By SillyOldDuffer on 22/07/2018 10:26:38
22 July 2018 at 10:29 #363318
not done it yet
Participant
@notdoneityet
Noo! Not quite! Take all precautions to avoid spilling any concentrated sulphuric acid on oneself. There should be no chance of ‘splashing’ it directly onto skin. Even 5% acid splashed on the skin requires plenty of irrigation to avoid irritation – or worse.

Concentrated sulphuric acid simply removes water from wherever it might get it – even as water combined chemically in tissue, leaving behind carbon as solid, in many cases. So on skin, it removes water from it.

Try it on sawdust – you will be left with charcoal! Or perhaps best not to try it.

Concentrated nitric acid on sawdust will likely cause it to go up in flames.

One is a desiccant, the other an oxidising agent. We used conc sulphuric as a desiccant in chemistry-type desiccators when it was appropriate.

Concentrated hydrochloric acid is pungent but probably not as dangerous as the other two (as long as not affecting the eyes!). Dissolves most metals, especially if there is nitric acid, as an oxidising agent, in it (aqua regia) when it will even dissolve precious metals. As an aside, hydrochloric is usually used with chlorine (as an oxidising agent) for dissolving precious metals these days – recovery of the last traces of dissolved precious metals, from the bulk solutions used, is impossible while any oxidant is present. BTDT.
22 July 2018 at 10:56 #363325
Russell Eberhardt
Participant
@russelleberhardt48058
Posted by not done it yet on 22/07/2018 10:29:05:

Take all precautions to avoid spilling any concentrated sulphuric acid on oneself. There should be no chance of ‘splashing’ it directly onto skin. Even 5% acid splashed on the skin requires plenty of irrigation to avoid irritation – or worse.

Agreed, so what are you objecting to? I have found from experience that 5% sulphuric acod splashed onto the skin is not problem if washed off within minutes however I always wear goggles and gloves when pickling copper. In school metalwork in about 1960 we were not even supplied with those, just tongs.

Russell
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