So I Baked My Brass at 425 For a Bit...

[RLinNH]

I like to dry my wet tumbled brass in the oven at 225 for 30 minutes, then let it cool in the oven overnight to to insure that it's dry. Long story short, I left the brass in the oven for a few days. Wife pre heated the oven to 425 for some nom nom nom onion rings, and lo and behold. When she went to place the onion rings into the oven, there sat my brass. The brass was in that environment for about 25 minutes. It now has a nice rainbow hue to it in the right light. What type of damage did I do to that brass?
It's no real loss as it's only range .223/5.56 brass. Only 100 pieces that I was part of a lot that I will be turning into .300 BO Brass. But I would like to know what damage I did to the brass? Why is it now a rainbow hue? Obviously due to the high heat at a prolonged time, but metallurgically speaking, what happened to the brass? Should I throw it away now as it may be unsafe to use?

 

[B y r o n]

I'd say it should be dry! If you haven't looked up the figures yet, to anneal brass you need to get it in the neighborhood of 700 degrees. So your 425 degree drying cycle was not hot enough to change it.

 

[jakelly]

It’s fine. BTDT, it’s fine.

 

[roostercogburn98]

Going into 300BO conversion so blast away

 

[Carlos Danger]

You say there's a "rainbow hue"? There it is.




Brass turns gay at 424°.

 

[JBoomhauer]

 

[Doom]

Unfortunately your brass may not be fine. Depending on the vicinity to the upper heating element the brass may have gotten a lot hotter than 425F. The preheat is like broiling. Take a piece or two and try crushing the brass with a pair of pliers towards the base but above the rim. If it crushes easily it trashed.

 

[jakelly]

It’s not going to heat soak the brass before ambient temps kick the preheat off. It’s been discussed here before. Smash as many pieces as you need to be confident, but the brass is fine.

 

[PKelley]

I had the same sort of thing happen with 1000 new 223. The temp regulator went out and it went straight to broil. It was all annealed. No good.

 

[Doom]

It’s not going to heat soak the brass before ambient temps kick the preheat off. It’s been discussed here before. Smash as many pieces as you need to be confident, but the brass is fine.

The brass will exchange heat with the heating element through a process called radiation heat transfer. It will get hotter than the air temperature while the radiant heating element is on. The brass may be fine but your assumption is wrong.

 

[Southernspeed]

I did the exact same thing with some 45-70 and 6.5cm brass. It was fine, still reloading it.

 

[jakelly]

The brass will exchange heat with the heating element through a process called radiation heat transfer. It will get hotter than the air temperature while the radiant heating element is on. The brass may be fine but your assumption is wrong.

No, I’m not assuming wrong. Radiation heat transfer requires a clear path, which you won’t have with brass on a tray from the bottom element. Unless the broil setting is used, the upper element won’t matter much, as they are barely used or not at all in the preheat or baking setting. Even with a convection oven, given the fact that the brass has to be viewed in a certain light to see the rainbow hue, you can pretty much rule out annealed brass.

I get what you’re saying, I agree that it could be the case in different instances. In this particular case, that brass is fine.

 

[Doom]

Preheat on most ranges uses the top element also. You are correct if the bottom element is the only one used for preheat. Sorry for the "assumption confusion".

I almost made this mistake back when I was ultrasonic cleaning pistol brass.

 

[918v]

If you shake out the water from the cases before leaving them to dry overnight they will be dry by the time you get around to charging them. No need for oven drying.

 

[msgriff]

I use an old Ronco 5 tray food dehydrator I picked up for $5 at a garage sale.

 

[Hecouldgoalltheway]

Bla bla bla, just close your eyes, grit your teeth and shoot it.

You'll probably be fine, and if not, you'll look badass with an eyepatch.

 

[Doom]

If you shake out the water from the cases before leaving them to dry overnight they will be dry by the time you get around to charging them. No need for oven drying.

I went solar before I went back to dry with walnut media.

 

[RLinNH]

Thanks to all for the great information. I'll crush a few pieces to see how it holds up.

 

[Barelstroker]

Thanks to all for the great information. I'll crush a few pieces to see how it holds up.

At 425 F for 25 mins, there's zero chance of the cases being annealed.
At low temps of around 220 C which is 425 F, 70-30 brass has been measured to increase slightly in hardness during lab testing of the annealing process.
As long as you're confident that the brass didn't get substantially hotter, don't worry about crushing any of them, tells you nothing as you probably couldn't feel any reliable difference with pliers anyhow.
Even at 525 F, 25 mins is too short a time frame.
Load it & go.

 

[just browsing]

Lol yeah it’s fine. Been there done that!