Quote:
Originally Posted by flyrod
+1 on the annealing recommendation. If you still get cracks, try annealing "more" i.e. to a higher temperature. If the metal is glowing a visible dull red in low light, that is about the right temperature. This may be hard to observe when using a torch.
The use of water is to stop the process or limit it. You want the case head to stay hard, and the neck/shoulder to be soft. Some people stand the cases up in a tray of water and run a torch over them. This keeps the heads cool. Dropping a case in water keeps the heat in the neck from transferring to the head. In most situations water is not needed, because the head has enough mass that it will not get hot enough to anneal. The WSSM is one example of where annealing can be tricky, particularly with a torch, because the case is short and thick. I use induction to quickly apply enough heat do the job without heating the entire case.
Cracks are usually due to work hardening or defects/grain structure of the manufacturing process. Stress corrosion cracking, hydrogen embrittlement, neutron embrittlement, mercury inclusion, etc. are not generally a problem for hand loaders.
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+1 for induction, You can see the change very well and can repeat it, Not all cases will take the exact same time to heat, I have recovered a lot of old cases this way, If by an oddity in the case or lack of attention you get some a bit soft they will do just fine after a few firings, The smaller cases I now set in to a large screen kitchen strainer basket, a cold steel plate works great also except you don't have all that much time to stand them up perfectly before your fingers start smoking, I do wear a 100% cotton glove