Thanks for all the info/opinions!
I have the bottom line to report.
A few local calls from gas suppliers got varied replies:
1) Naw, them tanks ain't rated for nuthin but air.
well, gas is gas unless there are some DOT regs, plus the good point that
you can't go back to air or O2 after other gasses.
2) You would spend as much on the proper valve as you would on a new
True, but a 66FT tank wouldn't require as many trips for gas and would
still be manageable as opposed to the real big tanks.
3) The national tech rep from Worthington Cylinder had the final say:
SCUBA tanks are tapped for NPT -national pipe thread and industrial gas
cylinders and valves have NGT - national gas thread.
Plus the local calls to gas suppliers revealed that they don't just let
you use the tank with a deposit - there is a $50/year rental on the
tank. Plus they only exchange tanks so if I can find a used tank for a
good price that makes more sense than turning in a nice new tank. In
the meantime I will stick with my flux core for the little bit of
welding I am currently doing.
Thanks again for your input. This list provides a wealth of knowlege!