Awl --

My latest realization is that you can compensate for low cfm with tank
volume, to some extent. Feel free to correct this.

What are some good (read: safe *and* free) options for makeup tanks?
Propane -- as in BBQ? Oxygen? Acetylene? Others? I see many
substantial-sized tanks in the dump that look neither Ox nor acet, thicker
than your 5-ft tallish Ox tanks. Iny idear what these are?

One problem I can foresee is finding/making adapters to these tanks, as I'm
pretty sure there are no standard plumbing threads, no adapters that I am
aware of. How does one attack this problem?

I hesitate to have welding done on a tank, altho I think with piddling 120
psi air in an oxy/acet rated in the 1,000s of psi, mebbe welding "welded
couplings" is not so dicey.
--
DT