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

 

[Win1917]

Just an observation, what you proved is that with annealing done properly, heat conduction to the case head isn't a problem. That's good. To refine the process a little bit, put the temp indicator inside the case neck. The neck is thinner material and has nowhere to conduct heat to so temps can rise more quickly than where you put the indicator below the shoulder.

FWIW, if you look at a phase diagram, cartridge brass doesn't start to become liquid until around 900F. Pure zinc melts at a much lower temperature. 750 tempilaq inside the case neck is pretty much the standard method for making sure cases get hot enough but not too hot.