Annealed Brass - TempilStik

[Josh Smith]

Hi All,

With all the conflicting information out there about annealing, I decided to experiment a bit.

I'd heard I needed a pan of water; that no, a air cooling was fine; to make the neck glow and to keep the neck from glowing and the flame from changing color, as either indicated a cooking-off of zinc from the copper (zinc melts at about 790°).

Structural changes begin in brass at 650°, so I used a TempilStik crayon that turns to liquid at that temperature.

I marked the case in three places: 1/4" below the shoulder, halfway down the case body, and at the head.

The TempilStik melted below the shoulder at 8 seconds. An additional 2 seconds did not melt the crayon halfway down the body, so it looks like for this particular setup, which is a 9/16" deep wall socket stuck in an electric screwdriver, 10 seconds per case, air cooled, gives adequate annealing without burning out the zinc.

Josh

 

[scap99]

Sweet! Thanks for that.
Just saved me from having to buy an annealing machine.

 

[Dawico]

I always thought you had to cool them rapidly to get the annealing to work properly. That is why people do it in water and knock them over once they are heated enough. I could be wrong though. I haven't actually researched it much.

 

[M. Sage]

I always thought you had to cool them rapidly to get the annealing to work properly. That is why people do it in water and knock them over once they are heated enough. I could be wrong though. I haven't actually researched it much.

If you cool metal quickly, you harden it. Annealing is a highish heat with a slow cool. In between the two, you wind up with tempering.

 

[grasshopperglock]

If you cool metal quickly, you harden it. Annealing is a highish heat with a slow cool. In between the two, you wind up with tempering.

Sage, thats steel. Not brass. Once you anneal it, you can dunk it in water, still pink hot. It still stays soft. Brass is an different animal then steel. Brass and copper don't temper. The only way to harden them back up is to work harden them.

 

[Deavis]

10 seconds per case, air cooled, gives adequate annealing without burning out the zinc.

Just want to point out that you don't know actually know that at all locations (i.e the case shoulder), which you only measured to 650 degrees. To completely validate that statement you would need to ensure that at 10 seconds the highest temperature was still less than 790°. If your temperature ramp were linear and you started out at room temperature you'd actually be pretty close at 10 seconds. Assuming you started in a 74 degree room, your ramp was 72 degrees per second (650-74)/8 = 72°/s thus in 10 seconds you would see 74+(10*72) = 794° if it is linear and assuming your mark melted at exactly 650°. That's only if you are concerned with that area, just wanted to point that out.

 

[scap99]

Just want to point out that you don't know actually know that at all locations (i.e the case shoulder), which you only measured to 650 degrees. To completely validate that statement you would need to ensure that at 10 seconds the highest temperature was still less than 790°. If your temperature ramp were linear and you started out at room temperature you'd actually be pretty close at 10 seconds. Assuming you started in a 74 degree room, your ramp was 72 degrees per second (650-74)/8 = 72°/s thus in 10 seconds you would see 74+(10*72) = 794° if it is linear and assuming your mark melted at exactly 650°. That's only if you are concerned with that area, just wanted to point that out.

I think my brain just did a BSOD on me...that hurt.

 

[Josh Smith]

Just want to point out that you don't know actually know that at all locations (i.e the case shoulder), which you only measured to 650 degrees. To completely validate that statement you would need to ensure that at 10 seconds the highest temperature was still less than 790°. If your temperature ramp were linear and you started out at room temperature you'd actually be pretty close at 10 seconds. Assuming you started in a 74 degree room, your ramp was 72 degrees per second (650-74)/8 = 72°/s thus in 10 seconds you would see 74+(10*72) = 794° if it is linear and assuming your mark melted at exactly 650°. That's only if you are concerned with that area, just wanted to point that out.

Hello,

I understand what you're saying. It's not an exact science.

Brass begins to anneal at 650°F. I don't want any critical areas to get that hot, so a 3000° torch is used locally for a few seconds along with a rotating heat sink.

Zinc will begin to cook off at 787.15°F, so if my flame turns red at all, the zinc is evaporating. This occurs at 12 to 15 seconds; I don't know how long for sure on this setup and will test that tonight with an old case.

I've taken some case necks back to copper, or pretty close, and they still shoot fine. Anyone who makes the necks glow a bright red has done the same. I do wonder how a case will shoot after all the copper is gone from the neck after multiple annealings.

Regards,

Josh

 

[shortround]

Any discussion of "annealing brass" without an explanation of why it may be necessary in the first place is useless.

Most brass, especially bottle-necked cases, will split from repeated reloading before anyone ever has to consider "annealing."

No one can authoritatively state how many times a case has to be fired and reloaded before "annealing" is called for.

Please enlighten me, as I am always open to new facts.

 

[scap99]

I think you answered your own question.
Assuming there was one. Lol

I've heard that after 4 or 5 times the hardcore BR guys anneal just so they don't waste expensive brass, don't have to prep new brass, and most importantly have consistent neck tension.

I'm sure each shooter, each load, each gun, each brand of brass, and superstition plays into the intervals.

 

[Josh Smith]

Hello,

I just ran a TempilStik-marked case up to 30 seconds. The neck was glowing red but the TempilStik remained halfway down the body.

This is after I got the steel socket good and hot by holding it in the flame.

I need to get some 750 degree TempilStik and see where everything's at heat-wise.

I probably should also do this without the socket to see how long it takes without the long heat sink. The socket comes up to about 1/4" below the case's shoulder.

Josh

 

[Vern1]

Here you go, everything you ever or never wanted to know about annealing:
The Art and Science of Annealing