Pickling Brass

In message , Lionel writes You could try brick cleaner from a builder's merchant - contains Hydrochloric acid.
If you are anywhere near Whitchurch, Shropshire, I have 2Kg of Citric acid in crystal form - works well in solution.
Spirit vinegar from grocer/supermarket? Acetic acid.
Emergency - find knackered car battery (ies), tip out electrolyte - Sulphuric acid.
If you are really stuck, you might like to buy a couple of kilos of lemons and use the juice - Citric acid again.
I've never tried peroxide. What about bleach (Sodium Hypochlorite)? I've not tried that either, mind you.
Hope this helps?

ISTR citric acid was readily available during the Foot & Mouth debacle as a disinfectant, I think even our local commercial motor factor was selling it. If you have an agricultural supplier nearby it may be worth trying them.
Cheers Tim
Tim Leech Dutton Dry-Dock
Traditional & Modern canal craft repairs

I buy mine in 3kg bags from the local winemaking/brewing shop. ttfn

Don't think you'll have much luck with a bleach solution.
I use sulphuric acid, mixed 1-7 with water as a pickle. Works slowly, but is less likely to damage the metal. I couldn't say what the ratio would be with hydrochloric acid.
For a really fast pickle, nitric acid mixed 1-1 with water is about as rapid a pickle as you'd ever want to work with - but you do need to keep your eye on the job.
Always remember to add acid TO water - the other way round could result in a nasty accident.
If all else fails, hardware stores and chemists sell proprietary drain and bath cleaners that are typically based around a 40% formic acid mix. It'll be relatively slow in action ( might help to warm the pieces before immersion ).
Regards,

a hour or so. Need to remove the flux tonight contains Sulphuric Acid? with Hydrogen Peroxide? morning on their weekly collection service from my I used some of the 'One-shot' drain cleaner from B&Q. Approx 90% Sulphuric acid, according to the box. Mixed it up with water at a 10:1 ratio, and it works well as a pickle.
HTH
Anthony Remove eight from email to reply.

Thanks to everyone for the comments and suggestions.
Local B & Q here has a label on the shelf for the One Shot drain cleaner but the shelf is empty and the label and barcode crossed out with thick felt pen.
Bought some caustic soda to try, brass pieces have been in about half an hour and all the silver solder residue has gone now, just left with the pink staining and a few dark red patches. Doubt whether these will go so will take is out now and give it a rinse, see if I can polish out the pink marks.
Cheers
Lionel

I use pickling vinegar, from the grocery store. Previously, citric acid from a home brew beer & wine shop did the job.
Steve R.
a hour or so. Need to remove the flux tonight contains Sulphuric Acid? with Hydrogen Peroxide? morning on their weekly collection service from my

the shelf is empty and the label and and all the silver solder residue has whether these will go so will take is out What brand of flux were you using, btw?
Regards,

There's been threads on this subject before. . . . .
Citric acid is OK but it creates green copper citrate from the black copper oxide which is formed after heating on the surface of the brass. I find this stuff can be a sod to remove completely as it lodges in the cracks & crevices when the part dries out. 'don't recommend old battery acid unless you're sure you'll do no more silver soldering on that piece. It will contain suspended lead sulphate and this may create problems for subsequent silver soldering.
Conc. sulphuric diluted to about 10% is good of course (bears repeating that you ALWAYS add ACID to WATER slowly) but it will cause the brass to redden as it removes surface zinc. (that's why any thread crests can eventually disappear if you repeatedly de-scale a brass or gun metal fabrication in sulphuric). Immersing once or twice is unlikely to do much damage if you don't mind the copper colouration. If you can't get the conc sulphuric drain cleaner from Buy and Queue just go to a plumbers merchant.
Another fairly easy solution is to use a proprietory rust remover. These are usually a mixture of hydrochloric and phosphoric acids. Just paint it on and leave it for a while.
All-in-all why not use strong ammonia solution? It doesn't attack the brass/bronze and cleans off the oxides a treat. It's safer to have around the workshop than strong mineral acids.

In article , Stephen Howard writes "Always do what you oughta, add the acid to the water".
Motorcycle shops sell bottles of battery acid, I use some of that diluted as a pickle and it works fine.

the shelf is empty and the label and and all the silver solder residue has whether these will go so will take is out Easy Flow 2 Stephen. Caustric soda worked in about an hour.
Lionel

the shelf is empty and the label and hour and all the silver solder residue has Doubt whether these will go so will take is Thanks - I'll do some testing. I use Tenacity No.6, as the name sort of implies it tends to hang on a bit!
Regards,