Guide
What size compressor for sandblasting
The hungriest tool in the shop, and it never pauses.
Short answer
A small blast cabinet or pot blaster uses about 12 CFM at 90 PSI without a break, so the compressor needs to deliver about 15.6 SCFM with a margin: a 17.5 SCFM class machine, usually a two-stage 80 gallon or larger. Bigger nozzles use a lot more.
Why sandblasting outruns most compressors
A blaster draws its full air flow the whole time the trigger is held, and a blasting job holds it for minutes at a time. There is no duty cycle to average over, so the compressor has to deliver the full demand on its own. The tank only covers the first moments.
| Compressor | Delivers | Blasting before pressure drops |
|---|---|---|
| 30 gallon, single stage | 5.1 SCFM | 1.2 min |
| 60 gallon, single stage | 10.5 SCFM | 10.9 min |
| 17.5 SCFM class | 17.5 SCFM | continuous |
After the tank reaches cut-in, a compressor that is short on flow keeps losing pressure, and blasting slows down sharply below about 80 PSI. Stop-start blasting with a small compressor works for rust spots and small parts; it does not work for a panel or a frame.
Nozzle size sets the demand
A blaster’s air use depends almost entirely on the nozzle bore and the pressure. The 12 CFM figure is a small nozzle on a hobby cabinet or pot. Each step up in nozzle size uses substantially more air, and production blasting nozzles need 50 CFM and more from a tow-behind diesel compressor. Check the chart that comes with your nozzle, then size from that figure.
Dry air matters as much as flow
Moist air clumps the media and blocks the nozzle. Fit a water separator at the compressor and another at the blaster, and drain the tank every session.