Roger Shoaf wrote:

A friend of mine worked at a place that used hydrogen as their gas,

I don't think that you want H in an environment where steel is heat
treated of hours. Hydrogen will diffuse into the steel and will make it
brittle.

Nick
--
Motormodelle / Engine Models:
http://www.motor-manufaktur.de
Ellwe 2FB * VTM 87 * DLM-S3a * cubic
more to come ...