Ruined Brass?

[Dannix]

I'm going to try tumbling BatchA, maybe it's just a surface tarnish, but is BatchB basically history?

Batch A (deprimed, in the bag) is the result of forgetting about brass in a vinegar bath too long, but not as long as Batch B.

Batch B is the result of a half-gallon of water bath with a maybe a 1/4 cup of baking soda and a tablespoon or so of dish detergent... forgot about it for a few days. Then rinsed and filled with a half-gallon of water and about 1 cup of vinegar and a tablespoon or so of dish detergent... forgot about it for again for a few days.

I learned two things out of this:
1. When you're crazy busy, don't decided to add non-necessities to your workload.
2. Sometimes it pays to not be cheap. I went out and bought some stainless steel media and a Thumber Model B after this.


If Batch B is toast. I'll just clean it up, anneal it, and use it as jacket material.

Dannix

[MtGun44]

So what's wrong with it? Looks like it needs a touch of tumbling for final polish.

Why is it 'toast'??

Bill

[warf73]

Run it threw a tumbler should be fine, if not like you said it will make good jacket material.

[Czech_too]

Surface discoloration, put it in the tumbler for a few hours. Don't forget to put in a used dryer sheet, it'll help keep your media cleaner longer.
It's not as though you used anything really corrosive in the wash.

[canebreaker]

It looks good to me, no holes in the sides that I see.
I have some brass tarnished so bad that you could call it black.
It gets brighter everytime I tumble it.

[Dannix]

Well I was concerned as I read somewhere how that pinkish hue seen inside some of those BatchB cases indicates zinc was leached out, resulting in weaker brass (I believe I recall that correctly).

Just keep them separated and go particularly conservative on the loads?


Edit: It's interesting the pinkish-white hue is only found on the inside of the cases. I wonder if it is sodium bicarbonate settled out of solution during drying. It could be scrapped off if so -- going to test that.

[Dannix]

Well here's the post-cleaning results:

What do you think? Batch B I didn't bother to deprime in case it was only good for jacket material. Load'em light and see how it goes?


(Thumbler Model B, High Speed, Stainless Steel Media, 3Hrs)

[sabot_round]

I say load away!! I frankly don't see any unsafe issues.

[RKJ]

If it really bothers you put them in a cherry koolaid bath overnight (or longer) I'd bet it will remove the spots. Then tumble as usual.

[Shiloh]

Try soaking briefly in warm water to cover with a tablespoon or two of muriatic acid. This will cut the heavy tarnish and corrosion. Rinse very well with clear water, let dry, or dry in a warm oven.
Polish as usual. You'll never know it was tarnished.

Corroded brass will be visible and should be scrapped.

Shiloh

[KYCaster]

Dannix is on the right track here. The "bullseye" spots are a dead give-away.

What you have is galvanic corrosion...essentially a reverse plating process. Some alloys (brass for instance), in an electrolyte (vinegar) will show a preferential corrosion of one of the alloying metals where the parts are in contact.

What you see is an area where the zinc is depleted from the alloy, leaving only copper. What you don't see is a much larger area where the same corrosion has begun, but hasn't advanced enough to be visible. The corrosion begins at the grain boundries and weakens the bond between individual grains.

Do a Google search for "Galvanic corrosion of brass" and you'll find enough material to keep you busy for a while.

Whether you choose to use the brass or not is entirely up to you...after all the earliest cartridge cases were formed from pure copper. Personally, I'd trash all of them.

Just my no-so-humble opinion. :roll:

Jerry

[1hole]

You don't have a problem. Tumble it all normally and use it.

The "pinkish" color is only the dark surface oxide/tarnish that's been converted by the weak acid in vinegar, it's NOT a problem.

Galvanic action requires two (or more) different metals to soaking in the same conductive solution. If the case soaking was in a glass or plastic container there was nothing to cause that effect.

[GP100man]

I`m a true scrounger (cheap is to harsh) but the ones with the spot at the mouth I`d be weary of & load the others .

Try the revolver rounds that have the spot at the mouth , Ive found deep split cases without damages to the cyl.

But the question is still there , is this batch of brass worth the risk????

Just my 2 cents.

[Tom_et]

Cast some and Blast some IMHO

But if any of those are 45 colt send them to me
I'll do something with them to save you any Problems :)

[AviatorTroy]

Load them up and SHOOT!!!

:redneck:

Seriously tho if you think that looks bad you should see some of the cases I have in circulation.......

[KYCaster]

You don't have a problem. Tumble it all normally and use it.

The "pinkish" color is only the dark surface oxide/tarnish that's been converted by the weak acid in vinegar, it's NOT a problem.

Galvanic action requires two (or more) different metals (Copper and Zinc?) to soaking in the same conductive solution (Acetic acid?). If the case soaking was in a glass or plastic container there was nothing to cause that effect.

OK, I must be missing something here and I'm willing to be educated. The reason I'm concerned is this appears the same as some corrosion I found on some 308 brass I stored in a cardboard box in a very humid basement. No ammount of tumbling in corncob or walnut hull would remove the "bullseye spots". When fired using a well proven load I had an unusual number of case failures, mostly splits near the neck/shoulder. A bit of research convinced me the problem was caused by "Galvanic action", but I could be wrong.

Dannix says he tumbled in stainless steel which is supposed to be prettty agressive media and it still shows the spots.

I just assumed that the "pinkish" color was due to Zinc depletion of the brass, leaving a Copper rich alloy, but again, I could be wrong. You said, "The "pinkish" color is only the dark surface oxide/tarnish that's been converted by the weak acid in vinegar, it's NOT a problem." Can you tell me what it has been "converted" to that's a different color than the oxide/tarnish or the original brass?

Why didn't tumbling in an agressive polishing media return the brass to it's natural yellow color? I just assumed that "pinkish" IS THE NATURAL COLOR of the alloy that remains after the Zinc is depleted, but again, I could be wrong.

So, help me out here. If I'm wrong I want to know.

Jerry