I simply MUST get off my lazy duff and remember to take some pH paper home the next weekend I'm doing a big tumbling run with my tiny 3# A-R1 Thumler. I'm using a small amount of Great Value dish soap and 3 or 4 pinches of Lemishine with enough water to cover 150 pieces of 9mm and about 18 oz of pins. Run for 1.5 hours. I need to get some before and after pH readings of what is working, then vary the chemicals and check results.
Aside from the terrific discussion posted above, I return to my prior question:
Wondering if someone out there has experienced premature failure of pink brass?
Would the answer to this question not answer whether the pink brass is a concern? Is the pink discoloration just a surface issue or is it an indicator of a much more serious problem in the realm of the aforementioned bugbear of stress corrosion cracking?
(About a year ago, I saw some good samples of what appeared to be stress corrosion. Guy brought out a rebuilt German MG 34(?). All he had for testing was some old, old, did I mention OLD, South American import Mauser rounds. He kept having problems in full auto because the old cases were splitting apart.)