RegionRat
Gold $$ Contributor
The only point I was trying to make, was to try and prevent drift with respect to what low temps can do and the difference between some published information that represents bulk and that it is very different than a cartridge neck. I admit we went down a rabbit hole since it isn't applicable to home annealing. Without tensile testing, you can't detect it.The OP was asking for info on tempilaq and dull red case glow when annealing.
Tempilaq is useful to prevent case body damage. Damage to the body strength can occur as low as 530F, so use 400F Tempilaq to insure the body didn't get hot. That won't be hard to manage when you are properly flame or induction annealing.
It takes some practice to use it for the neck and unless you are correlating it to the glow point, it may be difficult to learn on your own. You end up needing the initial infrared glow point, so practice timing that in a dark room to hit it consistently and use that as a baseline.