This section has some of my thoughts about case annealing and conclusions I have drawn during the process. I’m sure others have formed different views so take this as my opinion.
- Get the case neck and shoulder hot enough to anneal and soften the brass but not so hot that it starts to outgas some of the alloying elements.
- Don’t get the case head anywhere near annealing temps
The temperature brass anneals at varies depending on how long it is exposed. Example is that you can anneal at 500°F if it is held there for hours. The hotter it gets the faster it anneals. Most cartridge annealing resources suggest that 700-750°F is the target temp to get the neck to for it to be called “annealed”.
My setup process:
I start by painting 650 or 700°F Tempilaq from the case neck down to well past the shoulder. Then apply the 450°F tempilaq from below the shoulder down to near the case head. I set the case height in the coil so that the shoulder is about halfway up into the coil. I’ve found that you want the case higher than you would first think because there is a lot of mass around the shoulder that needs heating and you don’t want to “cook” the case neck waiting for that to heat.
After setting the height, I choose a time that is shorter than what you expect (you will get a feel for it when you get some done) and press the anneal button. First time you should not have melted the 700°F tempilaq – that’s good, increase the time, let the case cool back to room temperature and run it again.
Once you get to a point where the tempilaq is melting, increase the time until it is just getting down past the shoulder and onto the body. I record this as my anneal time for now.
Next I remove all the tempilaq and reapply fresh stuff. Anneal the case and closely watch how the tempilaq melts. The goal is to have it melt simultaneously from case mouth to below the shoulder and then the case is dropped. Normally the case neck melts first and then it moves down over the shoulder onto the body. If this takes some time to happen, then I raise the height of the case and do it again. Keep repeating this until you can get it to melt simultaneously from case mouth to past the shoulder. I mark this height on the annealer for that cartridge.
After getting the height set, you can go back and check the anneal time. If the tempilaq is melting and then “cooking”, you can probably reduce the time a little. You may also need to increase it a little if raising the case height meant it now only just melts before dropping.
I have never had an issue with overheating towards the case head, in fact the 450°F tempilaq barely melts 1/3 of the way down as shown in the picture.
Yellow - 700°F, White - 450°F
Example of how high a 300WM case is set in the coil.