Will 4.9 scfm comp.at 40 psi operate 4.9 air consumption gravity fed spray gun

Question

lowes gravity fed spray gun,HVLP. 39.99

Answer 1

PSI is PSIG which is (PSIA +14.7). The above contributer is mistaken by adding the atmosphere the the 40 psi. It already has the atmosphere in it. Unless it specifically says PSIA it is PSIG.

His calculation adding the atmosphere in the denominator is incorrect.

Answer 2

IF the compressor is actually 4.9 Scfm, that is, STANDARD cubic feet per minute, AND the spray gun requires 4.9 actual cubic feet per minute at 40 psig, then no, it won't.

4.9 scfm assumes standard pressure of 1 atmosphere

at 40 psig, you have less volume

4.9*14.7/(40+14.7)=1.3 acfm

so, 4,9 scfm will only be 1.3 acfm after you pressurize it up to 40 psig

However, if your compressor is rated for 4.9 acfm at 40 psi, then of course it should deliver 4.9 at that pressure and that should be sufficient for the gun rated for that.