Oven heat brass and annealing

Mas

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#1
I was trying to dry my brass by heating them in an oven at 350 Fahrenheit for 15 minutes. After that the some of the cases have this rainbow-like color on them. Is this a sign of annealing? Could this be dangerous because the cases are too soft? I don't think I'll oven dry my cases again, but I'm wondering if I can still use these cases.

I also found this great article about annealing. http://www.6mmbr.com/annealing.html

(the cases were put in a pot with the lid on, and the pot was put at the bottom of the oven)
 
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spife7980

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#2
Thats a good question. In response I first have a counter question, can you rub the rainbow off? Its not like a soap on the surface or something simple like that, right?

All of the more recent charts Ive seen have shown that annealing doesnt really start to take place until 500 degrees or so but thats all flash annealing. With more time they will change at lower temps.






At 300 I imagine that you are probably safe but I would try to find a case that wasnt in the oven and see if you can tell any difference in how easy they buckle with a pair of pliers. Its crude but its better than nothing.
 
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Mas

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#3
First of all thank you for replying sir!

Although my oven was set to be 350 F, I was stupid enough to put the pot that contains the brass so close to the heating element so I don't know how hot the brass actually got......

Before trying to rubbing the rainbow like color off, one of the cases looks like this following:
before.JPG



Aftering the rubbing the case looks like the following:
after.JPG

The bottom of the case after rubbing:
afterr.JPG

So even after then rubbing there's still some slight blueish color on the case.
 

mijp5

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May 7, 2009
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#4
Make yourself a dryer instead. You don’t need 350 for drying. If you must use the oven, just use less than 200
 
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pell1203

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#6
Get yourself a quarter or half sheet stamped metal baking tray (usually $3-5) and dump your brass on it after first washing it with clean water and gently roll it around on a dry cloth towel to do a quick dry on the outside of the brass.

Stick the tray in the oven at 170-200 degrees and dry for 15 minutes. Take tray out of oven and roll the brass around some on the tray and put back in oven for another 15 minutes.

Remove from oven, let brass cool. Process is simple, easy, and yields completely dry brass every time.
 
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Mas

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Get yourself a quarter or half sheet stamped metal baking tray (usually $3-5) and dump your brass on it after first washing it with clean water and gently roll it around on a dry cloth towel to do a quick dry on the outside of the brass.

Stick the tray in the oven at 170-200 degrees and dry for 15 minutes. Take tray out of oven and roll the brass around some on the tray and put back in oven for another 15 minutes.

Remove from oven, let brass cool. Process is simple, easy, and yields completely dry brass every time.
Thanks for the tip! Do you think the brass shown above is over-annealed or is it still good?
 

mijp5

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Will definitely do that next time. Do you think the case shown above is still usable?
I don’t see why not, but that’s me. If you are really feeling unsure, Take a pair of needle nose pliers and crush the neck of one of the cases and compare that pressure to a case you didn’t put in the oven. If the oven dried brass is super soft, maybe skip it. Obviously if it is bothering you that much, toss it.
 
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Mas

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#9
I don’t see why not, but that’s me. If you are really feeling unsure, Take a pair of needle nose pliers and crush the neck of one of the cases and compare that pressure to a case you didn’t put in the oven. If the oven dried brass is super soft, maybe skip it. Obviously if it is bothering you that much, toss it.
Thanks for the great tip, Now I understand what spife7980 was talking about!
 

mijp5

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#15
I have high doubts about it being annealed but I also don’t want to make you have a case head separation. If it’s just coming off, that’s not annealed
 
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pell1203

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#16
If you only set oven to 350 degrees and had them in there for less than an hour you probably got nowhere near the 500 degrees at which annealing begins to take effect even being inside a pot with a lid on. Are you even sure there is a heating element on the bottom of your oven?

If it were me, I'd just go ahead and use them normally. Load a few and shoot them... inspect them closely after that and decide. As soon as you shoot them again they will start getting work hardened again.
 

Mas

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#17
If you only set oven to 350 degrees and had them in there for less than an hour you probably got nowhere near the 500 degrees at which annealing begins to take effect even being inside a pot with a lid on. Are you even sure there is a heating element on the bottom of your oven?

If it were me, I'd just go ahead and use them normally. Load a few and shoot them... inspect them closely after that and decide. As soon as you shoot them again they will start getting work hardened again.
Thanks for replying pell1203. Yes I'm sure I put my pot near the heating element. Indeed after finding these rainbow-colored marks I google searched the images of heating elements for baking ovens and then I realized that the M shaped metal coil which I thought was the oven rack was actually the heating element. The good thing is that I didn't put the pot directly on the coil but only next to it.

I guess I'll do what you suggested here and hopefully the brass will still work well.

It's a good lesson learnt though.
 

Mas

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#18
I have high doubts about it being annealed but I also don’t want to make you have a case head separation. If it’s just coming off, that’s not annealed
Hi thank you for the input, what do you mean by "just coming off"? Did you mean the color came off after rubbing?
 

spife7980

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#20
While I don’t think any material changes took place the safest route is to scrap it. You won’t lose the side of your face for playing it safe.
 
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mijp5

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#21
Spife is probably right. I just got on the computer and I now see the case head. Federal brass isn't precious enough to try to salvage. It's soft brass and there are much better pieces to be had in 300WM
 

Mas

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#22
While I don’t think any material changes took place the safest route is to scrap it. You won’t lose the side of your face for playing it safe.
Thanks for the kind consideration! that sounds a bit scary... is there known cases where soft brass lead to explosions of the firearms?
 

Mas

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#23
Spife is probably right. I just got on the computer and I now see the case head. Federal brass isn't precious enough to try to salvage. It's soft brass and there are much better pieces to be had in 300WM
I definitely think safety should be of primary concerns, on the other hand, I've spent quite some time cleaning the brass. So I would be a bit upset if I have to throw them away...
 
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#24
You’re probably good, as long as the oven had been somewhat preheated before putting in the brass, you are definitely good. Ovens will go above the set temp while heating up. You don’t really have anything to worry about as far as the hour is concerned, as the annealing process doesn’t start til about 450. I would personally shoot that brass, without hesitation.
 
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#25
I have personally shot many pieces of brass like this and reloaded them many times, they didn’t behave a bit differently than their unbaked brethren. You aren’t going to blow your face off.
 
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Mas

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#26
I have personally shot many pieces of brass like this and reloaded them many times, they didn’t behave a bit differently than their unbaked brethren. You aren’t going to blow your face off.
Thanks for your opinion! It's good to know that I could keep the brass and my face at the same time!
 

Mas

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#27
After testing the oven baked cases with a pair of pliers, they do seem to be softer than the cases that haven't been baked... So I ended up discarding these baked cases for extra safety.... I thank everyone again!
 
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