Very good read/study on annealing.

[MrBottleneck]

I have always heard when flame/torch annealing if the flame starts to turn orange you are burning off Zinc from the brass.
I then read this article or study done by the makers of AMP.
I must say I am very impressed with they extent to which they have gone to design an annealing machine.
https://www.ampannealing.com/articles/40/annealing-under-the-microscope/
According to what I read in the attached link Zinc will not burn off. The only point at which Zinc will be removed is at the boiling point which obviously we do not get too.
This is interesting and informative.
Then I see a many posts talk about people not liking Wet SS tumbling because they feel it work hardens the brass. Once again from what I take away from the studies and testing they (AMP) have done this just isnt the case. It appears as though it only hardens the skin (so to say) to some degree.
The reason I was reading the article or let alone on the site was I have great interest in purchasing an AMP.
I currently use a flame based annealling machine and even though it works its not as a precise system as the AMP.
Very innovative machine they have designed and even more impressive length to which they have studied the annealing process.
I hope my interpretations of the read/study in relation to my post where correct.
Just thought I would post up this link for anyone interested in reading.

 

[ImBIllT]

As someone who only anneals every 10-30 reloads, I was never concerned with zinc burn off anyway, but it is nice to know. Not that I truly knew the answer, but I pretty much figure that using propane for only a few seconds, I couldn't possibly burn off enough of anything to matter in just 1-3 annealing cycles over a case's life.

As far as tumbling something causing it to work harden, you must deform something beyond the eleastic region and into the plastic region. If you're not pulling cases out of the tumbler with dents in them, then you shouldn't be work hardening anything.