On Tue, 19 May 2020 05:06:27 -0700 (PDT),
wrote:

On Sunday, January 24, 1999 at 2:00:00 AM UTC-6, James Hubbard wrote:
About ten years ago I wanted to make one of these air tanks out of a
freon jug. I bought a kit with a valve, hose and safety valve in it . My
dad had worked on air conditioners for 20some years, so I went and asked
him for an empty tank. He told me that about ten years before he was
asked by the company he worked for(a large chemical company that also
made freon) to try to find them some old freon tanks so they could test
them. He rounded up several and he was told to take them to the
company's safety research lab. He took them to the lab and while he was
there he asked why they wanted them. The man over the lab told him that a
person had made an air tank from one of their old freon jugs and went to
a gas station to fill the tank. He was holding the tank between his legs
when it split apart. He lived but without some of his vital parts, anyway
he decided to file a lawsuit against this company because the tank blew
up. I cant tell you to use your tank because there are thousands out
there that are ok, But I went out and bought a new portable air tank.
Jim Hubbard

I have a 50 lb R-22 tank that I've been using as my portable air tank for OVER 30 YEARS!! It's always been kept in the house which may have helped. I suppose though, I should go looking for a fresh one. T'care, Mike
At 30C R22 is about 160psi
Freon tanks have a "blowout disc" that ruptures at something
approaching 600PSI. A freon tank is likely safer than a lot of cheap
"air pigs" designed to operate at 120PSI . painting the interior to
protect against moisture MIGHT be a good idea (on the air pig too - -
- )