Cooked brass?

[Southernspeed]

Hi folks, new to the forum and seeking wisdom!

I sonic cleaned a bunch of brass from last range session (45-70, 44m, 45acp and 6.5cm), rinsed under hot water then put in the oven 150 for a spell to dry. It's always worked fine but this time ... I forgot to take it out. Next day I put the oven on to heat up for dinner at 425 degrees. Oven heated up then after about 10 mins at 425 I went to put the dinner in. Oh joy, a baking sheet full of slightly discolored brass!

So my question is, have I cooked it and need to scrap it? I've read that brass doesn't alter structurally until it passes 600 degrees but it all had that slight 'case hardened' look to it.

I don't want to scrap a load of good brass but also don't want to deal with split cases and head separation deals.

Any thoughts?

[JimB..]

I can’t find the graph showing time vs temp, but I think you’re fine. Maybe take a case and try to crush the mouth in your fingers. If it crushes easily and has no rebound then it’s been over annealed, but again I doubt that you got there.

[FLINTNFIRE]

Well never put brass on higher then 175-200 15 -20 minutes

[smithnframe]

Phil Sharpe used to cook off loaded cartridges in a paper bag but that’s a different story!

[uscra112]

Sources are all over the map on this. Best I can find with a quick search is that 475F is the not-to-exceed temperature.

Here's the rub, in your case: While the thermostat in your oven may have been set for 425, the temperature of that brass may have gone considerably higher if it was exposed to direct radiation from a heating element.

If it were me, I'd chuck it if it's discolored all the way to the base.

[Southernspeed]

I can’t find the graph showing time vs temp, but I think you’re fine. Maybe take a case and try to crush the mouth in your fingers. If it crushes easily and has no rebound then it’s been over annealed, but again I doubt that you got there.

Thanks, Jim. I was thinking that if I resize and they act normal with some spring back I'd be ok. Guess there's no way to know if I'll risk head separation 'til it happens!

[Southernspeed]

Sources are all over the map on this. Best I can find with a quick search is that 475F is the not-to-exceed temperature.

Here's the rub, in your case: While the thermostat in your oven may have been set for 425, the temperature of that brass may have gone considerably higher if it was exposed to direct radiation from a heating element.

If it were me, I'd chuck it if it's discolored all the way to the base.

The voice of reason is never the one we want to hear! This is what I had in the back of my mind (though hadn't considered the direct heat from the element) but was looking for an excuse to ignore it, it's quite a lot of brass, good, expensive, once fired brass ..... damn it!

[country gent]

The soak time worries me more than the temp. Also the whole case being exposed. annealing isnt just the temp its time also, a combination of the 2. The normal method of heating to 600-750* at the neck for just a few seconds allows the neck shoulder to soften before it gets to the base. A lower temp will do the same if a longer time but then the heat flows into the base.

Its hard to check with out some special equipment. As the base is thick and solid for a small distance crushing wont tell a lot there.

[uscra112]

Good point. I should have qualified that the 475F figure that I posted assumes soak time much longer than the few seconds that results from typical flame annealing.

[Southernspeed]

The soak time worries me more than the temp. Also the whole case being exposed. annealing isnt just the temp its time also, a combination of the 2. The normal method of heating to 600-750* at the neck for just a few seconds allows the neck shoulder to soften before it gets to the base. A lower temp will do the same if a longer time but then the heat flows into the base.

Its hard to check with out some special equipment. As the base is thick and solid for a small distance crushing wont tell a lot there.

Thanks, I think I'm convinced. I've done far more stupid things in my life but that doesn't make me feel any better!

[5Shot]

**Not relevent**

[JimB..]

According to this chart you are probably best to throw it out.

https://hosting.photobucket.com/albums/ab102/unclenickmod/Brass%20Annealing_zpsjo2qnwqc.gif

Make sure that you’re reading the Fahrenheit temp line, I still think it’s fine.

[ShooterAZ]

I have done the exact same thing with a batch of 30-06 brass. It was fired multiple times, so I didn't feel too awful bad about scrapping it. Better safe than sorry is what I say. If it was discolored, I would definitely scrap it. Just my $.02...

[5Shot]

Make sure that you’re reading the Fahrenheit temp line, I still think it’s fine.

You know, I misread the OP regarding the amount of time it was in the oven. If it had been an hour, I would say to toss it for sure, but 10 minutes probably isn't much of an issue.

[JimB..]

You know, I misread the OP regarding the amount of time it was in the oven. If it had been an hour, I would say to toss it for sure, but 10 minutes probably isn't much of an issue.
Agreed.

Honestly, if I had plenty I’d scrap it, but if it was dear I’d load it.

[ulav8r]

If the neck retains some spring, I would at least try a few with light loads.

[rayh]

Why not do a light to med load and check for head expansion between a cooked case and normal case. If the same, then work up to a higher load.

[243winxb]

As the oven heated up, brass became scrap.

[Southernspeed]

If the neck retains some spring, I would at least try a few with light loads.

As JimB originally suggested, I did just that and on the 45-70 cases I can squish them to quite an oval mouth then they spring right back. I'm going to recreate my mistake and take a temp reading on a few pieces of brass just to see what actual temp they got to. Going by the info above, if they stayed below 500 I think I'm ok, especially as they still seem to have a lot of spring back.

[243winxb]

6.5 CM @ 62,000 PSI. :coffeecom

[Southernspeed]

So I recreated the situation tonight with one piece each of 45-70, 44m, 45acp and 6.5cm. Exactly the same situation but with only 4 pieces of brass instead of around 120 so you could argue they would have heated up more this time (?), anyway, the hottest was the 45-70 by half a degree and that was 297.7 degrees. Looking at the info a couple of you guys have posted I reckon I'm safe. None of them are loaded full house and all in modern reproduction rifles (apart from the 45acp of course) and the 6.5cm is a bolt gun with triple locking lugs. I'm thinking the discoloration could have been enhanced by having just been sonic cleaned so the brass was as 'bare' as could be. Anyhow, thanks for all your input!

[gwpercle]

Keep your eye out for an old food de-hydrator ... the round ones with stacking plastic trays .
They dry things well and wont "over cook" the brass , you can leave it on a couple days .
I'm sure you'll catch some flack for drying those dangerous lead contaminated cases in the oven you cook human food in ... but not from me ... I have cast boolits on top the stove with an old pot my Mom gave me to melt the wheel weights in . None of us ever suffered from it !
Gary