James B,
Sandblasting demands a high volume of air. The "hole" in the end of the hose is huge. To do an effective job, you need lots of sand moving at a great speed.
A air compressor needs a large displacement to move a large volume of air..cubic feet of air!
Because there is no free lunch, the large displacement compressor needs a large source of power, whether it be a electric motor or diesel engine.
Take a straw and put a pea in it. Blow the pea across the room. How much lung power did it take?
Take that same pea and lay it in a empty toilet paper roll. Blow it across the room. Big difference. You need more CFM!
If you plugged the ends of the above examples and blew into them while recording the pressure, they would be identical..PSI, no big deal, CFM, big deal.
Stuart
