There was a used Shoebox compressor for sale recently in the classifieds here. They are made and supported in the U.S.A. Very simple design and easy to service.You could find a used scba cylinder on ebay with a couple years of life for under $200 to around $80. I would recommend to hydrotest the cylinder for your safety and to return it if it fails hydro. Then you'll need a fill adapter. You can't build one cheaper than the one Joe B. sells at http://www.airtanksforsale.com/ in the same configuration. I've tried. You will need to remove as much moisture as you can before the compressor or you will overwhelm the high pressure molecular sieve filter.You could also use compressed nitrogen if it is convenient for you. Here are two threads I started that can give you a stareting point in your research:Shoebox https://www.gatewaytoairguns.org/GTA/index.php?topic=120744.0Nitrogen https://www.gatewaytoairguns.org/GTA/index.php?topic=130114.0I am sure more people will respond with suggestions.Taso
I’m curious...doesn’t the Shoebox require another compressor in order for it to work? That’s an additional cost if you don’t own one sufficient to support the Shoebox.
Also, aren’t scuba tanks limited to 3000 psi? Scba tanks are mostly 4500 psi except for the specialty tanks which could be as low as 2200 psi. That drastically reduces the number of refills.
Here's another one for $150 with 5 years left:https://www.ebay.com/itm/2007-MSA-4500psi-30min-Stealth-H-30-Carbon-SCBA-AirPack-Bottle-Cylinder-Tank/142523525314?hash=item212f1068c2:g:YZAAAOSwBdhZz6MIJust be patient and keep looking. Just verify the born on date on the label with the DOT number.Taso