My brass turned purple

[egd]

OK, here's what I did. I tumbled a batch of brass (9mm) and when I took it out it had a lot of media (lizard bedding walnut stuff) all stuck in the inside of the cases. I couldn't just shake it out so I rinsed it with clear water to get it out. I rolled them on a towel to get most of the water out then put them on a baking sheet and put them in the oven at 300. after about 45-60 min. I just turned the oven off and left it overnight to cool down. When I got it out it was all discolored and kinda purple looking.
I did a search and found a couple of threads. one had heated his to 450 and people said to throw it away since it had gotten too hot. The other said the cause was too much lemon shine, but I didn't use anything other than water.
My questions are: can I still use the brass? I would think so, but... And is there an easy way to make it look like brass again?

 

[GooseGestapo]

Trace minerals in the water reacted with the alloys in the brass and tarnished it. Stain may be permanent, however. Tumble again.

 

[50 Shooter]

It's from the heat, you should use the lowest setting on your oven which is just under 200 degrees on most ovens. As far as tossing it, I don't think you'll have to but keep it seperated from your other brass.

Try seating a bullet and see what happens, if the brass collapses its to soft and needs to go to the recycler. Put a crimp on a bullet, if it won't hold the bullet then you're going to have to toss it all again. Just be safe, try a handful first and not all of them at once.

 

[Rule3]

To HOT for TOO long.

Tumble with CLEAN media and some type of additive like NU Finish or products sold for the purpose. If that doesn't work buy some Lyman Tuff Nut with the Red polishing compound, If that doesn't take it out not much will other hand polish with extra fine steel wool.

To long or too much acid (lem shine, vinegar) will do the same thing.

 

[Reloadron]

All you needed for a bake out, as mentioned, was about 200 degrees F. Consider also depending on the quality the average home kitchen oven will swing from 275 to 325 with a 300 degree set point. That assumes a true 300 F. set point and good temperature uniformity throughout the work zone in the oven.

The only time I have media that is difficult to remove is if the nu finish hasn't completely mixed with the media.

a picture or two would be nice so the degree of purple discoloration can be seen. I doubt the brass was damaged.

Changes start to occur in brass grain structure at 480 degrees fahrenheit. To properly anneal brass, the temperature needs to be at 650 degrees F. for several minutes--BUT this will transfer too-much heat to the lower case in that time. So we need more heat for a shorter time. We need to raise the neck temp to about 750 degrees F. only for a few seconds to anneal.

What you did amounts to heat treating the brass at around 300 F. The purple bothers me but your local water chemistry likely caused that. Then too, I am not sure. You don't mention how many pieces?

Ron

 

[egd]

Well, maybe not exactly purple, kinda depends on how the light hits it. It has a bluish discolored look is probably more accurate. Maybe a couple hundred total.
I loaded two bullets and I'll try them. They loaded fine and look ok.
I don't know why all that stuff stuck inside them in the first place. That was the second batch of brass I had ran through that media and the first batch came out fine. I've never added anything to my media. I'm not that concerned about having "perfect" looking brass, just clean and reasonably nice looking. I will throw out that batch though.

 

[cali_blues]

I don't know why all that stuff stuck inside them in the first place. That was the second batch of brass I had ran through that media and the first batch came out fine. I've never added anything to my media. I'm not that concerned about having "perfect" looking brass, just clean and reasonably nice looking. I will throw out that batch though.

Slightly off topic, I recently came across a batch of GFL (Fiocchi) range brass that had some kind of tar or something inside it, and a ton of media stuck to it. Trying to clean it out just made a bigger mess, I ended up tossing all of it. I've read that the tar might be to prevent setback.

 

[Nordeste]

Just tumble that brass again and it should be fine.

As for the GFL (Fiocchi) brass with the tar inside. As far as I know, yes, it is to prevent setback. And if you toss in the tumbler straight away, your media will get stuck inside. What I do with it is decap (without rezising), clean in the sonic cleaner, and when it's dry tumble it for the nice shiny finish we all like.

 

[rchery59]

I did the same with some 380 brass a few years ago. meant to just heat the oven to 300 and forgot to turn it down. sat in there for an hour. I've reloaded it and didn't cause any problems.

 

[Rule3]

Slightly off topic, I recently came across a batch of GFL (Fiocchi) range brass that had some kind of tar or something inside it, and a ton of media stuck to it. Trying to clean it out just made a bigger mess, I ended up tossing all of it. I've read that the tar might be to prevent setback.

"Tar" for waterproofing is easily removed with naphtha, mineral spirits, WD 40 or similar solvents.

 

[stompah]

Tumble some more brass, then rinse and put them in the oven for less time at the lowest setting. If the brass turns purple again it was the water and if the brass doesnt turn purple it was the heat that turned it purple.

Then you can at least make a better decision to keep or toss it.

 

[PJSprog]

Reinforcing my decision years ago to stop tumbling my brass. A couple pulls in my Lee Trimmer wrapped in steel wool is clean enough for me.

 

[egd]

I just read my last post and realized it might not have been clear. I plan to throw out that batch of media and re-run the brass through new media. That's IF the two bullets I made up shoot fine.

 

[Ironicaintit]

Egd,
Thats funny! I literally smacked myself in the forehead and said "d'oh!" When you said you threw out that batch!
So thanks for clarifying, now i feel better
Im a brass hoarder, and treat them like they're collectable coins or something.
They have to be structurally unsound for me to toss them out.
Actually, I kindof like brass with a nice patina!

After my dad passed, I found a bunch of 9mm luger brass in his yard. It was dirty, it was dark. I tumbled them for a little while to get the chunks off, inspected them and sized them all. (And inspected again) they were still darkened, and the sizing actually kindof burnished them. I think they look neat!

 

[egd]

I have an interesting followup to all this. Earlier I went out to throw out that batch of media and discovered something I'd forgotten. I had put another batch of brass in there and had ran it for a little while after I had taken out the brass that was filled with stuff. Well, this was filled with stuff too. But I thought what the heck, and turned the tumbler on and let it run for an hour or so. When I came back I checked it immediately after turning it off, and the brass was all clean, inside and out.
So maybe I've discovered something many of you already knew. Take your brass out right away after tumbling so media doesn't stick inside. Or maybe I just got lucky.???

 

[Catpop]

Another tarnished story. I'm a commercial diver and recently had to dive in a pond with minute amounts H2S. When I came out all my brass was black or severely tarnished. This has happened to me at least twice in my diving career of 25 years.
I did not throw myself out, but probably should have!
Haha catpop

 

[fguffey]

egd, my opinion, drying brass in the over is a bad habit.

F. Guffey

 

[egd]

fguffey, I doubt I'll ever do it again.