Does NH4OH based brass cleaner really weaken brass?

[Maven]

There is a discussion on the BP Cartridge subforum, "Why did my brass turn rainbow colors?", specifically posts 2, 3, 5, 8, 9, 10, which raises an important question: Will a brass cleaner containing ammonia actually weaken cartridge brass? Thus far the posts have presented anecdotal/doesn't reports that it does not ("internet rumor," "bullspit"), but the question remains: Is there independently confirmed and repeatable evidence that brass cleaners containing ammonia do in fact weaken cartridge brass? Molly if you read this, perhaps you'd care to comment?

[geargnasher]

I really don't like to quote or refer to Wikipedea, but here's a cut-paste that sounds reasonable. I'm looking for the reference right now:

"Brass is susceptible to stress corrosion cracking, especially from ammonia or substances containing or releasing ammonia. The problem is sometimes known as season cracking after it was first discovered in brass cartridge cases used for rifle ammunition during the 1920s in the Indian Army. The problem was caused by high residual stresses from cold forming of the cases during manufacture, together with chemical attack from traces of ammonia in the atmosphere. The cartridges were stored in stables and the ammonia concentration rose during the hot summer months, so initiating brittle cracks. The problem was resolved by annealing the cases, and storing the cartridges elsewhere."

Gear

[303Guy]

Old 303 Brit cartridges used to split at the case necks. No atmospheric ammonia concentrations required. I thought is was simply age hardening causing the problem (with cold work stressed brass - all modern brass is neck and shoulder annealed. So much so the military specs require the annealing to be visible). If I was able to anneal the old brass before it cracked it was fine. Surely if it was ammonia attacking the stress zone causing the cracking, annealing them at this time would be too late? That does not mean that relatively fresh stressed brass was not being attacked by the stable ammonia, just that it might not be the only mechanism for the eventual cracking.

As for brass cleaners that contain ammonia? Well, I'm in the 'hasn't happened to me yet' camp. I'd hazard a guess that the exposure is way too short to have any effect. But trapping some ammonia gas inside the case might have a very different outcome!

[Mooseman]

Ask anyone who deals with ammonia...Brass fittings are not allowed because ammonia eats them. Here is a reference from Chemical & metallurgical Engineering , Vol.24.>http://books.google.com/books?id=znMfAQAAMAAJ&pg=PA979&lpg=PA979&dq=Ammonia+effect+on+brass&source=bl&ots=K8lOkkz6pm&sig=_lv3tgXBoOctZBvjbI-2Le9knpk&hl=en&ei=0irZTpuRKKebiAKC_eTcCg&sa=X&oi=book_result&ct=result&resnum=10&ved=0CHoQ6AEwCQ#v=onepage&q=Ammonia%20effect%20on%20brass&f=false
While a fast polish and wipeoff will remove the outer oxidation and may not weaken the brass much at all, putting it in a tumbler and exposing inside and outsides of cases to ammonia is something risky in my book.

[Mooseman]

Even Dillon Precision addresses this...http://www.dillonprecision.com/content/p/9/pid/23664/catid/8

[Rocky Raab]

I think the above sources take the answer well past mere anecdotal frippery.

If you use Brasso or any similar polish agent in your tumbler -- STOP!

Brasso does a beautiful job on your GI belt buckle, but how many psi does your belt buckle have to contain, hmmmmmm?

[geargnasher]

I dunno, Rocky, my belt buckle might need to be stronger than some!

The only thing I use ammonia on it glass. Citric acid for brass, stainless steel, etc.

Gear

[Maven]

All, Thanks for those replies as they are a wonderful antidote to the anecdotal nonsense I mentioned earlier. I suspected that ammonia was indeed bad for brass long before there was an internet as most reloading manuals mentioned its deleterious effects. It's also nice to learn that the concentration of it, as well as the amount of Zn in cartridge brass, and prevailing temperature are major players too. Btw, I think some got the wrong idea about cleaning or polishing brass because of my inquiry. To wit, I NEVER use or advocate the use of ammonia based brass cleaners, e.g., Brasso, Noxon, in a tumbler nor have I ever done so. I only use a Bon Ami-like cleaner in an orange (the fruit) oil carrier that Midway used to sell, in my tumbler and it works great.

[Mooseman]

There are many NON- ammonia polishes on the market that reloaders use.
Flitz , Blue Coral, NuFinish, Frankford Arsenal Polish, Cabelas , Lyman, Dillon, Berry's , etc.
So many safe choices that do a fantastic job.
Bon-Ami is one I havent tried... Thanks

Rich

[303Guy]

Interesting and informative thread. Ammonia containing bore cleaners are used because of the way ammonia attacks copper. I didn't suspect it played a major role in brass or copper embrittlement. Good thing I don't actually clean my cases much, if at all.

Does that mean that if there's been ammonia related stress corrosion but no actual fracturing, it is too late to anneal the cases?

[rintinglen]

I work in a natural gas fired electrical Generating station. We use 29% aqueous ammonia for NOx control. Once, during repair of a chemical feed pump, a mechanic mistakenly used a brass elbow as a replacement. It failed completely in less than 6 hours operation, being eaten away by the ammonia solution. One look at that elbow and I was convinced it didn't want my windex and brass in the same bucket.

[Maven]

rintinglen, Re brass + Windex in the same bucket suggests BP cartridges. Mike Venturino, who occasionally posts on the BP Cartridge subforum, recommends a solution of Windex with VINEGAR, something like 1qt. Windex : 1gal. water for soaking and cleaning BP encrusted cases. (It works!)

mooseman, Some have advocated adding Bon Ami or even Nu Finish car wax to their tumbling media, although I've never done so. The Midway USA brass polish contains a fine Bon Ami like abrasive in an orange oil carrier, which works very well and very quickly.

[Rocky Raab]

I long ago stopped adding ANYTHING to my tumbling media. That decision came when I tumbled a rather large batch of .223 brass in well-used media to which I had religiously added a capfull of polish to every previous batch.

The brass came out coated with hard gray patches of something that I had to manually rub off with a solvent rag -- and it didn't remove easily, either. I surmised that the hard gray stuff was the remains of accumulated polish. I tossed that media and have never used polish since. I've never had that horrible gray plaque again.

[tomf52]

I've been using Brasso in my media for forty years now and have yet to have a problem. The metalurgists at my father place of employment seemed to think the waxes in the Brasso did far more to protect the brass then the amonia did to harm it. At any rate I have yet to experience a problem with it's use.

[mpmarty]

In years past I could buy little bottles of red jewlers rouge in a liquid suspension that I added to my media. This worked great but it is no longer available. :(

[Mooseman]

I have regular tumbler media coated in rouge I use for some range brass that is very tarnished...Made by Lyman I think. It is a bit nastier to handle the brass after tumbling and rouge gets inside the cases.
But it works.
Thanks Maven for the heads up !

Rich

[jimkim]

Every manual I have says not to expose brass to ammonia. Seeing how ink isn't free and typesetters have to be paid, and everyone of the people with the testing facilities say it, I'd have to conclude that exposing brass to ammonia damages it. Corporations rarely spend money just for the heck of it.