I do remember a discussion here when Brownell's first marketed their case hardening kit. As I recall the main point Oscar made was that Brownell had the temperature schedule wrong. I do not know if they have changed it since then. Hopefully this will jog some one's memory.

As for the oil layer. I have read where several people claimed to use it. Never saw any of their work. I know of 1 commercial operation that does not use it.

Pete