Citric acid as pickle

[PETER AYERSParticipant @peterayers98304]

  Can any one please tell me how much citric acid powder I will need to make 25 litres of pickle? The pickle will be used for boiler making  Thanks PeterA

[PETER AYERSParticipant @peterayers98304]

[John Somers 2Participant @johnsomers2]

Hi Peter

 

Not a very precise answer but I bought a small pack of citric acid powder from my local chemist and tipped it into a one litre plastic screw top jar and the same brew has served me well for over a year. For your requirements I think you should try and buy bigger packs. Maybe a couple of these 1 kg packs http://www.goodnessdirect.co.uk/cgi-local/frameset/detail/461479_Citric_Acid_1kg.html might do the trick. Alternatively I understand home brewing shops sell citric acid powder in bigger pack sizes.

As I am sure you know citric acid is  quite a weak acid in the general scale of things and you could always add further quantities of powder as required. Some say Coca Cola has a similar pickling action.

John S

[Dave Jones 1Participant @davejones1]

i bought some citric acid for a few £’s for ebay, I was recommended by another model engineer to use a few tablespoons in a bucket of water.  This has worked fine for me.

[Ian S CParticipant @iansc]

Go to your nearest home brew (ale and beer) its much cheaper.Also agricultural chemical suppliers,although they may not sell a few grams,you might be offered it by the tonne.Ian S C

[KWILParticipant @kwil]

Citric Acid is fine, particularly for brass/copper items. Steel seems a little slower.  Coca Cola is phosphoric acid, cleans copper but not so sure about fluxes.

[Ian S CParticipant @iansc]

For 25L a cup full should do,if after a few months it starts to grow a mold,add a bit more,it won’t do any harm,but the extra strength will kill the bugs.Ian S C

[CirclipParticipant @circlip]

Ya don’t grow nasties on the top using H2SO4

 

   Regards  Ian.

[chris stephensParticipant @chrisstephens63393]

Hi Guys,

If you warm it up a bit it should work quicker. Seem to recall from dim distant school days, 10*C or K rise in temp, doubles the speed of a reaction.

You may not get nasties growing on H2SO4, but with Citric acid you don’t have to worry so much about fumes or acid mist causing holes to appear in your jeans.

chriStephens

[CirclipParticipant @circlip]

A brand new pair of jeans used to last approximately 3 minutes on a Saturday night —- that was the time it took to get to the first serious left hand bend on me Velo. NOT falling orft, but the acid spill from the battery given the angle of dangle on the bend.

 

   Mummy was AWFULLY Vexed, they used to Bu**er everything else they were washed with.

 

 

  Regards  Ian.

[Ian S CParticipant @iansc]

Oh for a mag and no battery-James 197 back in the 60s,not mush light,but no acid!Ian S C

[DMBParticipant @dmb]

Hi Circlip,

A fellow model engineer once showed me his Sulph. Acid pikling tub 4 small items – washing-up bowl under the bench, which after long use, developed large brown objects that looked like sea anemones. He said they had grown in the acid but I dont know whether this was a leg-pull or not.

As regards clothes that are more hol(l)y than righteous, Sulph. will dry out whitish but when next wetted, comes alive again and starts attacking cloth, skin, wood or I suppose, anything organic. The stuff is very difficult to eradicate.

Take Care!

John.

[DMBParticipant @dmb]

Circlip and everyone,

Sorry I forgot to mention that  all acids are neutralised by alkalies and vice versa. Just use a strong one  to kill the other strong one e.g., Caustic Soda to kill Sulph. Acid, or other way round.

John

[Martin WParticipant @martinw]

John

 

You need to be very careful when mixing these compounds as the reaction can be highly exothermic to the extent that the solutions can boil and in a small vessel could easily spit their contents onto the operator’s skin etc. Secondly without having an indicator, i.e. litmus paper or similar, you won’t be able to tell whether the acid has been fully neutralised or in fact whether too much alkali has been added and the solution is now alkaline.

 

I would prefer to use calcium carbonate or similar, the same proviso as above with regard to heat reaction plus the fact the CO2 will be evolved so extra care needed, but when the reaction stops gassing then all the acid is neutralised; a visible indicator of solution status. Also if too much carbonate is added then the solution does not become highly alkaline as calcium carbonate, like most carbonates, is close to insoluble in water.

 

Still its a matter of individual choice and being aware of the risks involved, if the acid is nearly spent then either way will suffice. A I say my preference would be using calcium carbonate, chalk, as it is easier to store and in its dry/wet state poses no health risk unlike caustic soda.

 

Another interesting and informative thread.

 

Cheers

 

 

Martin W

[Ian S CParticipant @iansc]

To neutralise,use washing soda,please don’t use caustic,one danger replaced by another.Ian S C

[Martin WParticipant @martinw]

Ian

 

I completely agree with your approach to the problem, again CO2 will be evolved and when this stops the solution left should be neutral.

 

The big advantage of washing soda, sodium carbonate, is that it is one of the few soluble carbonates and the neutralising solution can be made as dilute as required which will reduce gassing and heat generation.

 

Good tip

 

Cheers

 

Martin W

Edited By Martin W on 14/12/2009 13:59:04

[mgjParticipant @mgj]

Gents,

 

While we all get terribly excited about acids and alkalis and what you add first to whom.

 

Could I please make 2 points.

 

We are talking about a weak solution of citric acid. So weak that you can fish parts out if it with the bare hand and carry it over to the sink, and if you have an exposed wound its going to sting a bit no more. Nor is there any problem, even though its better not to, about pouring it into water, or water onto crystals. Even battery strength sulphuric you can put oyur bare hand in – not recomended and get it  under fresh  water quick, but it can be done., and without any injury.

 

Second point. The best always the enemy of the good. If you want to neutralise it, salty water. It will work, and a good dose of salty water will do a lot of good, even if its not perfect. Its a lot better than not neutralising it.

 

Now if we are talking about neutralising IRFNA then it becomes a different matter and you start having to be very careful..

 

But we are not.

 

A couple or 4  ounces of citric crystals per gallon is fine. Don’t overheat objects to be pickled to burn on the flux, and wear eye protection when you dunk stuff.  When you have finished with it, add water to the citric to dilute it further, add salty or any other alkali water to the dilute citric, and stand back exhausted.

 

Ditto battery strength sulphuric.

 

Wow, gents is all I can say about this.

 

The best is very much the enemy of the good.

 

Or

 

Its much better to be approximately right than exactly wrong.

[Ian S CParticipant @iansc]

Meyric,I seem to remember some thing about suphuric acid and salt water forming chlorine gas,think it was a problem with submarines.I also use washing soda in a plasic bucket for the electrolitic treatment of rusty steel.Ian S C

[CirclipParticipant @circlip]

Ja Ja mien Capitain, re-run “Das Boot”

[Martin WParticipant @martinw]

Hi All

 

Just a quick query, can hydrochloric acid be used as a pickling agent? If so the ‘Brick and Mortar Cleaner’ sold by Wickes is between 5% -10% hydrochloric acid according to their coshh sheet. A trite more aggressive than citric acid I suspect.

 

Ian you are right regarding chlorine being given off when sulphuric acid is mixed with common salt solution. Hence the submarines always carried strong alkalies to neutralise acid spills from split batteries etc.

 

Cheers

 

Martin

[mgjParticipant @mgj]

Yes it will form chlorine and so will sodium hypochlorite and all sorts of things. The point is how much, and will it affect you. Now you sit in a submarine with a pile of battery acid and no ventilation, and thats one circumstance. A very dilute solution of salty water added to a diluted and rather tired exhausted solution of sulphuric or citric is quite another.

 

But team I stress we are talking about lemon juice and not much more. So your chances of being gassed are about as remote as next Christmas. And if you eyes start to sting abit, well wow, just leave the room.

 

Hell fire, you put neat hypo onto relatively strong phosphoric – (cleaning floors/stainless flow plates and allowing them to mix in error) now that does give off chlorine. But even so, you still have plenty of time to go “Oh bother” and open windows and open doors. Mainly because chlorine is heavier than air, and it takes quite a long time, and quite a lot of it to build up to nose height in a reasonable sized room  – but don’t do it standing on your head.

 

I leave it to the experts, who would I suspect have us all in full personal protective kit while doing a bit of pickling.   But forgive me if it continue to do what I have done for ages. Dilute, neutralise and dispose of , outside or in an open garage.

 

 

Edited By meyrick griffith-jones on 15/12/2009 18:10:25

[LenParticipant @len48873]

Citric acid is better used as a balancing agent in winemaking, trust me it works !

[Ian S CParticipant @iansc]

Thats why its best to buy it in the Home Brew/ Wine shop, here at least they haveit in larger packages, and cheaper than the Super Market. Ian S C

[David LittlewoodParticipant @davidlittlewood51847]

Missed this one earlier. The problem with using salt solution to neutralise strong acid, in addition to the very slight* risk of chlorine generation, is that salt is not alkaline and will do nothing to neutralise the acid. For small quantities, sodium carbonate (washing soda) or even sodium bicarbonate (baking soda) is fine – though be careful not to add too quickly or it could start climbing out of the container. Avoid sodium hydroxide (caustic soda) as it is highly corrosive, extremely dangeroous to the eyes (worse than acid) and dissolving it is very highly exothermic (i.e. it gets very hot – will boil the water and spit).

I also strongly recommend you avoid using hydrochloric acid as a pickle; it is a solution of hydrogen chloride (a gas) in water, and unfortunately it gives off HCl gas when exposed. The rapidity with which this will rust your precious machinery and steel stocks is breathtaking. Sulphuric acid is fine in this respect as it is not volatile, though all the other precautions (acid to water, slowly, with careful stirring) apply.

If you are not used to handling strong acids, probably better stick to the citric acid.

* Acid and sodium chloride is unlikely to produce significant amounts of chlorine unless something else is present, but could give off HCl if heated. People have been killed by inadvertently mixing strong acid and hypochlorite bleach – very rapid Cl generation – but sodium hypochlorite is quite different from sodium chloride.

David

Edited By David Littlewood on 04/04/2013 11:41:42

[Speedy Builder5Participant @speedybuilder5]

I wish I hadn't used citric acid – I am (lead /tin based) soft soldering brass side tanks for SPEEDY, using FLUXITE as my flux. All going well. Went to clean it all up before closing the tank with its last side, so put it in CITRIC acid overnight. Next morning, the brass was a bit cleaner, still residues of fluxite, but all the soft solder has turned BLACK and is no good for sweating in the last side.
Suggestions please.
BobH

[Author]

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