Pickle for Cartridge Brass

I have a pair of very dirty WW1 German (fired) 150mm mortar cartridges. If I use sulphuric acid pickle which has been used for pickling copper boilers, it will leave a pink deposit behind. Should I use another type of pickle which would not leave the copper deposit.

I am expecting to buff them up using buffing soap etc after pickle.

BobH

Fresh acid would be my choice... Sulphuric or citric..whatever comes your way..

Even new sulphuric acid does this, it removes the zinc leaving the copper in place and is a real pain to get back to brass. I never put brass in any pickle. Some say use citric acid but it has ecactly the same effect, just takes longer. Wipe them down with a solvent then clean them up with a fillament abraisive wheel, then a scotchbrite wheel then polishing mop and paste - i use this method several times a week so I know it works.

I've used vinegar to remove oxide coating from phosphor bronze, and I think it'd work for brass. It hadn't occcurred to me that it'd preferentially react with one component of the alloy, but I think the effect would be minor unless you left it in for days.

I'd think it depends on the depth of the corrosion and how much metal's going to be sacrificed. It's usually important to preserve manufacturing and inspection stampings - abrasive polishes can be very destructive to those.

I've used Coca-Cola to clean very dirty brass items very quickly with no apparent damage. Try putting a dirty penny in a little Coke and it'll be clean in 10 minutes.

John

Have you considered clock cleaning solution recipes? Ammonia, oleic acid (liquid soap) and a pinch of acetone diluted down with water. But don´t leave it in too long.

Hate to think what Coca-Cola does to your insides !!

I have known it to make short work of a 6" nail. !

Not sure how it would work on copper, but Apple Cider Vinegar will dissolve the worst corrosion imaginable on brass and leave it looking like new.

I have a locomotive tender body that has a fair amount of oxide. It has brass beading soft soldered to it round the edges. Apart from elbow grease and emery/ wire wool - anything that might work?

Phil H

Apple Cider, Coca Cola, or any fruit drink will work, but citric acid is probably the best and safest method. The fruit drinks may leave the item a bit sticky, but that will wash off with hot water.

Ian S C

Ian,

Are you also answering my concern regarding the lead solder i.e., will citric work for the tender with soft soldered beading?

Phil H

If you don't want to atack the brass use an alkali. As has already been mooted Horolene is designed to clean old and dirty brass clocks without damage so why not use the right product for the job.

regards Martin

De-zincification is common in old cartridge cases. Worse if they have been on the ocean. I have some Imperial Japanese Navy case, and a few British and Australian from WWI onwards.

De-zincification comes from exposure to the atmospheric oxygen - I guess. Not so good either if the case has been buried.

You can re-introduce the zinc again by electrolysis - think.

Western Australian Maritime Museum (in Fremantle) have had success in stabilising bronze cannons from Dutch wrecks recovered from shallow water on the coast. These ships ran aground in the 1600's. The Museum used a process of a controlled atmosphere rich in fuming zinc (so it was hot) and under pressure to force the zinc back into the metal structure.

About 30 years ago I attended a lecture by one of the Museum's curators. The lecture was about such things. They, the Museum, as world leaders in the process were also stabilsing a canon jetisoned (jetsum) from the First Fleet ship HMS Syrius after it ran aground on Norfolk Island - just after the First Fleet had landed at Botany Bay, N.S.W.

Not much help for your problem, but you may have to be satisfied with a "copper" finish - as they are very old.

Not knowing how much they have oxidised or the condition,

I had good results from using combinations of mixtures of washing liquid, clean pea shingle, stainless steel cream cleaner and white wine vinegar to remove the inside corrosion/staining of my Avon Jet engine starter cartridges-

More to do though.

The exterior, I used the old formula T cut and elbow grease-

These need more internal cleaning for when I'm ready to convert their use as fuel tanks, but the worst is sorted.

I use phosphoric acid on brass, it's also good as a flux when soft soldering stainless steel,the annual "yarm fair" is in soon & I usually repair stainless water carriers for some showman friends.

There's another option.

You could clean it, then put a thin layer off brass plate on top. Zinc and copper have the unusual property of being able to be plated simultaneously.

Take a look at this kit:

www.gaterosplating.co.uk/index.php?route=product/product&product_id=203

Neil

OK, so its some time since you all gave me your recommendations. I went with 1/2 cup of vinegar, teaspoon of salt and flour to stiffen into a paste. I have to admit, my wife was both sceptical and wondered as to where all this was leading. Anyway, a couple of coats of the paste, leaving each on for about 1/2 an hour and taking off with a fine ScotchBrite. A final polish with some Duraglit (other brands are available) and a final buffing up. The picture tells the story. (150mm german WW1 Howitzer 'cartridge).

Thanks for your help ladies and Gents

BobH

Has the process damaged the headstamps? I know Duraglit can, and I'd expect Scotchbrite could too - though it might be possible to minimise both.

No, they look good, even see the turning marks on the end of the cartridge.