On Feb 14, 11:10*pm, "Mike Marlow"
wrote:

*Put in half as much air as you're suppose to - you'll run out of air twice as fast.

Good point. The increased pressure noted is the direct result of
"compressing" more air into that finite space.

Using the OP as an example, adding a second tank that would double the
volume of "tank capacity" at 40PSI (say) or doubling the pressure
(80PSI) to the existing tank, would have the same result vis a vis the
volume of air in the tank(s)

And, at an output PSI setting of 40psi, for instance, one would expect
twice the discharge rate or "run/use time" from the latter than the
former.