I'm not sure why I'm being told what I need or don't need - that part is non-negotiable. Stacy, your response echoes the response you gave me some years ago when I said I needed to develop a logo etching system capable of outputting 1 knife per 60 seconds. Instead of contributing toward a solution that satisfied the criteria, you suggested that I simply lower my expectations. I went on to develop a successful system. Advice that encourages the maker to lower expectations and abandon development efforts are a disservice to the craft - worse than no advice.
I need a heat-treating solution that gives me (a) a surface hardness within 2 points of the core hardness and (b) a surface finish that is free of pitting. I've tried ATP-641 and it was a failure on requirement A.
Foil works, obviously my initial interest in argon was based on the apparently incorrect assumption that it would be cheaper/easier than foil (taking into account the time it takes to fabricate the foil pouches).