I had one recently that a friend used for air storage with a tiny compressor. He had robbed the pump off of it when new. I used it for auxiliary air too but eventually the system falls behind anyway, I also see them on marketplace on occasion with just the tank.
A friend had one under a workbench that had been re-called but he didn't know. When it let go it didn't escape the confines of the bench but did knock the back wall of the shop off of its foundation a couple inches. An erupting water heater can even leave the building but that's steam not air.
A friend had an old water well non bladder expansion tank he used for an air compressor tank in his barn. The pressure valve failed and it kept running until the tank let go. That tank had a domed top and a welded in bottom so that bottom blew out. It blew the siding off the barn and launched itself through the ceiling and up into the hay loft. He found all this stuff when he went out there one day, luckily nobody was around.
Another group of smart fellas made their own tank out of schedule 80 pipe with ends welded in by a "good" welder, one end blew out and did a bunch of damage and nearly severed the legs of a kid that was in the building when it blew out. All that jazz makes the new air compressors at Menards look pretty "cheap" really ;-).
A quality(even used,they last a Long time) ASME certified tank is best;they have large,threaded inspection ports on the sides of them.
A homemade tank.. or even a cheap-China tank(made way to thin out of cheap steel and welded by??? who..)after it's been in use for a couple years just isn't worth the danger.
Have a look at Grainger,etc. for a price.. but the small tanks(ASME)are almost impossible to find made in USA. Difficult to find 'new quality' anywhere,to a price-point.
A quality stationary compressor is best;if you have room for it to 'live'.
The quality and Thickness of the steel used & good welds,etc. gives me piece of mind;a good,long-term investment. You notice how thick the steel is(built to code)on an oxygen tank used for gas welding? Made heavy to last for a long time.
A product called Fluid Film is also very good(open-up the air ports in the tank & spray it in all over the bottom,then leave it open to the air & let it dry-up for a week,seal it back up and go)to use on a new(or used)tank;it will protect the steel inside there much longer than just oil.
A bit of searching around can yield a quality USA product(maybe some place has a collection of good quality vintage items:tanks,etc. laying around all dusty somewhere..)that's designed and manufactured to last for Years.
