Did I ruin this brass ?

I acquired some very corroded and tarnished brass, for free. It was so corroded that my Rockford tumbler would not get it clean.
    My wife suggested that I soak the brass in ammonia  overnight. Well, that worked kinda. But the clear ammonia turned blue in the process, so now I am wondering if some chemical process took place, leaching some necessary mineral out of the brass, causing the brass to be  unusable for reloading ? Any answers...?

Depends a lot on the concentration of the ammonia.  If it was a 1/4 cup household ammonia to a gallon of water, likely not.  So to give a solid answer I need a few more details.  Concentration of ammonia used, how long exactly, and anything else you might think is helpful.

I filled a plastic coffee can with corroded brass, then filled the can with straight ammonia. It was very corroded.

Well, this article says so.  It would be for architectural brass and decorative objects, but it is a way of removing tarnish… 

https://www.ehow.co.uk/how_2126150_use-ammonia-clean-tarnished-brass.html

My educated guess (engineer by profession) is that it is likely ok, at least for a few firings.  The usual failure method in the presence of ammonia is “Stress corrosion cracking”.  In ammunition this usually is found in loaded ammo stored in an ammonia (vapor) rich environment.  The brass cases crack where the bullet is seated.  In your case, the brass was fired and there is no applied stress from a seated bullet.  So stress corrosion is not likely to start….

There was some etching of the surface and that may be ok as chemical removal of tarnish is usually an etching process.  

So what all this means is.. I’d go ahead and use it and it will be safe (rifle cases with cracked necks are usually safe to fire). It may not last as long as store-bought Fresh brass but it was free!

Thanks for your input, and the link. Some ( 1K or more ) are so corroded that they are stuck together, and look like a bad battery post. I think they will be sold for scrap metal.
   The badly tarnished brass, ( about 1K ) that sat overnight in ammonia, I will use for practice only, and watch for cracks.
    Plus, I have some (about 1K ) that came out clean and shiny.....Thanks

Wobbley wrote:My educated guess (engineer by profession) is that it is likely ok, at least for a few firings.  The usual failure method in the presence of ammonia is “Stress corrosion cracking”.  In ammunition this usually is found in loaded ammo stored in an ammonia (vapor) rich environment.  The brass cases crack where the bullet is seated.  In your case, the brass was fired and there is no applied stress from a seated bullet.  So stress corrosion is not likely to start….

From an educated guess (metallurgical engineer), the above advice is BAD.  SCC occurs even without bullet seating, stress in the case is more than sufficient for the process to occur.

  How are cartridge cases made to resist the pressures from firing?  WORK HARDENING.

• Brass is drawn through dies until it cannot be drawn anymore without breaking;
  
• An annealing step softens the brass so more cold work can be performed.  NOTE:  in the quantities and speeds at which brass goes though the presses, it is far more economical (and faster) to induction heat casings so work hardening in critical locations can be retained.  Depending on coil dimensions (coil size, number of windings, and spacing between coil and brass), RF frequency used, and how well these two are matched to the brass, induction can be more precise than if a torch was used;
  
• Continue drawing and annealing as needed until the desired properties (hardness, ductility, elasticity) are reached in the cartridge case.
  

Annealing adds time to the manufacturing process, and it adds to the cost of making brass.  This is why manufacturers like to anneal as little as possible - it allows for larger volumes of product to be produced in a given amount of time.  Ever wonder why Winchester .308 cases weighing ~157 grains ("PALMA" headstamped cases from the mid-to late 90s) are not still being made?  I understand that a special set of dies, along with a rare five step draw and anneal process were used to make them.  Not sure if the successor to the then Olin brass company (the brass works and the ammo company were both owned by Olin-Matheson until sometime in the late 1990s or early 2000s) still has the dies, or if they do, if they would be willing to make more.  Anyone willing to front a buy (pay, in full) for a new run of 100,000 cartridge casings?  Do not know what quantity makes a minimum lot size for production, 100,000 casings may be insufficient.

BTW, SCC was discovered in early .303 British ammo, which was stored in horse barns in India.  This is the vapor form of ammonia that Ashley mentions.  SCC can also start from using liquid ammonia.  I did an experiment in college where a pre-stressed brass pipe was swabbed with liquid ammonia, placed inside a bronze ring, then heated to accelerate the reaction.  The damage was - significant.

Is pistol brass annealed after final draw?  Nope!  Might not even have an anneal after headforming.  Certainly not a “neck” anneal. (No neck to anneal).  While there’s some residual cold work certainly. I doubt if it’s enough to rise to SCC threshold.  So  I really don’t think the brass is destroyed from at least some usability.

Curious, why not use phosphoric acid to clean? Or Iasso?  I fell in love with it.

Here is one more engineer's opinion (Electrical), with the cost of primers/bullets/powder why do it at all. That brass that might give inconsistent bullet pull and short life, why not just turn it in for scrap and buy new brass or at least once fired clean brass?

Just a thought and my two cents, with inflation it is really only a 1/4 of that that!

Randy

Suggest you get something designed for cleaning brass, rather than something designed to keep your drink cold. 

Rockford tumbler

not to derail the thread, but what does it mean when you leave a bunch of brass in a lemi shine and squirt of dawn solution for 15 hours, and when you rinse them out they have really really pretty colors... blues some purples,, etc

It means you’ve etched out some zinc on the surface and that makes the cases look redder.  The blue is a surface tint.  Lod’emandshoot’em

Thank you everyone that offered advice. I think I've learned my lesson "DO NOT MESS WITH CHEMICALS I DO NOT UNDERSTAND ". Luckily I have enough good brass to last me for a long long time.....Jim

Next time, try vinegar. It leaves the brass a little pink but cleans it well. I keep the pink brass for lost brass matches.