Corroded Brass???

[Josh Smith]

Hi Folks,

I just tossed 40 pieces of otherwise good 7.62x54r brass:


No idea what happened.

These had been loaded with Varget, backed by Federal primers and firing SST bullets.

Nothing unusual.

I had them stored in Plano ammo containers, which I also tossed. The brass stored next to these, only in surplus ammo pouches, were unaffected.

These were kept in my shop, which is of course climate-controlled.

They were fired and put up against the day I'd find more of the powder I like, and that was yesterday.

I've never seen this type of brass corrosion when it wasn't exposed to a cleaner with ammonia, and it was all kept away from chemicals.

Any thoughts, folks? The only common denominator seems to be the Plano plastic storage cases. Once-fired and not cleaned that was NOT stored in these were just fine.

Thanks,

Josh

[fguffey]

I've never seen this type of brass corrosion when it wasn't exposed to a cleaner with ammonia, and it was all kept away from chemicals.

I have, for the worst of cases I use vinegar once for the life of the case. I do not take short cuts when rinsing the cases, I do not load cases that have been cleaned in vinegar (acid) for long time storage.

If you are cleaning with stainless steel pins the additives to the solution could have an acid. I would not have thrown the cases out, again, I would have rinsed the cases to neutralized 'the what ever' caused the corrosion.

F. Guffey

[Josh Smith]

Man, I thought about it, but some were pitted. I also can't see the inside.

Now that you mention it, I have seen that with vinegar. I used vinegar to darken a brass blade on a muzzle loader I had once-upon-a-time.

I'm more concerned about figuring out what happened so it doesn't happen again, though!

Regards,

Josh

[ironhorse1]

PVC

I see that the copper in the cases is deteriorating back to copper sulphate.

I don't think that vinegar will do that to brass.

Exposure to salt or a chloride may cause corrosion.

You stated that you stored them in Plano boxes. and only had corrosion with those cases.

So are Plano boxes made with PVC/ poly vinyl chloride?

I'm not a chemist but do know that plastic can and will deteriorate over time, gassing out the chemicals which it is made from.

I find this interesting and a heads up about storage in plastic.

Feel free to look up PVC on wiki and form your own opinion.

Thank you for posting this as I have never seen this exact problem before.

As far as verde gris forming on brass this was a problem on tanned leather with plain brass cases. Yours are blue having the appearence of pure copper sulphate.

Are there any chemist Calgunners out there?

irh

BtW if I had cases where the copper was leaching out of the brass I would toss them too! Good call.

[3RDGEARGRNDRR]

Ive had this happen with simple green as a test wash medium. Pretty sure any detergent can cause this. Its worse with nickel plated cases