annealing
- Thread starter AJoldfart
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I’m sure that there are calibrated IR thermometers that would work, but the calibration would likely be costly.
Could stick a long insulated probe inside the neck, but doing it by hand would be challenging.
Could stick a long insulated probe inside the neck, but doing it by hand would be challenging.
Supposedly, in a darkened room when you just see the faintest glow, that's the temperature. Certainly don't go by the color change of the brass.
The good news- it's better to under-heat than over heat it. You can cook the zinc out of it with too much heat. Then again, I watched a series of youtube videos where a guy completely overcooked his brass and couldn't tell a difference when he resized them.
I have an IR thermometer which goes up to 620F, so I just let it cook a second longer to get to 700. 308 takes about 2x the time in the flame as my 300BO for example.
The good news- it's better to under-heat than over heat it. You can cook the zinc out of it with too much heat. Then again, I watched a series of youtube videos where a guy completely overcooked his brass and couldn't tell a difference when he resized them.
I have an IR thermometer which goes up to 620F, so I just let it cook a second longer to get to 700. 308 takes about 2x the time in the flame as my 300BO for example.
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Could be wrong, but I don’t think you can cook the zinc out of brass, at least not at 700-900F. I mean, where would it go?
The brass gets soft, but I doubt that it’s a function of changing the alloy.
Where would it go? The air? Where does wood go when you burn it...? According to this, zinc evaporates at 900F, which is just over the temperature that you want to anneal. Zinc undergoes sublimation (solid to gas), without a liquid phase.
I'm no metallurgist, but over-cooked brass has a different color- something is gone, and I heard it was zinc, but reading, it could be tin cooked out as well. The cases look more pink when they've been cooked.
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Blackhawk44
Active Member
I do the darkened room thing with a drill and a socket. You've got to bring the temperature up quickly or the heat will travel too far down the brass. The neck and shoulder area is as far as you want to aneal. As soon as I see the faintest orange appear, I drop the case out of the socket.
One thing I've found that helps is prior to annealing I wet clean my brass with steel pins, dishwashing liquid, and a touch of lemishine.
You may not be able to go by the color change of the finished brass but if I see the faint orange glow when hot and my brass looks like new Lapua brass when I'm done, I don't think I'm very far from where I need to be.
Zinc can sublimate, it can also melt.
The chart you refer to is in degrees Celsius, not Fahrenheit. Zinc does not vaporize at 900F. In a very low pressure atmosphere it can be made to sublimate at around 1,000F.
As for the color change, I haven’t studied it, but why assume that something is gone, isn’t it as likely that something has been added?
Zinc would have to melt, otherwise how would they be able to cast those crappy wheel weights. 
One thing I like about induction annealing - 0.9 seconds is all that a 223 case requires in my annealer.
One thing I like about induction annealing - 0.9 seconds is all that a 223 case requires in my annealer.
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