Stu is right on Woody, and you have it. Just picture a bucket of water vs a 55 gal barrel with the same size hole in the bottom the bigger the hole (cfm) the more fluid is flowing out. If the hole that goes in is the same size as the hole that goes out the container volume doesnt change. Now alter either the hole that goes in or the hole that goes out and you can see the relationship. The container is simply a buffer for short bursts of output. if you had a 10,000 gal air tank all that would mean is that you could probably run your air grinder for couple of hours before the pump kicked on again. Of course the pump would probably burn up refilling the tank unless it had a 100% duty cycle.
The cheaper compressors that most of us can afford are simply not designed to run continuous ly.
And from my point of view, if you could afford a compressor that put out 25cfm you probably wouldn't need much of a tank at all because it would keep up with just about any thing that you might add to your tool box.
Denny Graham
Sandwich, IL
