CFM v/s PSI For Nozzles

 

The following chart is a good reference to determine your nozzle/pressure v/s compressor requirements for sandblasting.  The larger the nozzle opening, the more air flow you will allow.  The higher the PSI pressure (Pounds per Square Inch) you plan to blast at, also increases your compressor requirements.  This chart provides a reference to determine the CFM capacity (Cubic Feet / Minute) of Free-Air flow that your compressor must be capable of in order to keep up with a sandblaster using a nozzle of a certain size at a certain pressure. 

Example: If you're planning on  blasting at 40PSI and your sandblaster has a 3/32" diameter nozzle, your compressor must be able of producing a minimum of 6.8CFM Free Air to keep up with your blasting. 

NOTE
This does not mean that if your compressor is not able to provide 6.8CFM at 40PSI that you can't use it, it simply means that your sandblaster will withdraw air from your tank faster than the compressor can refill it, and at certain intervals you'll have to stop blasting to allow the compressor to catch-up.  This means that your compressor will probably be running consistently and that at certain points you will most likely have to stop blasting to give the compressor a rest.  Another side effect of an undersized compressor that is running consistently is that the compressor will be hot, producing a hotter air output, that when cools in the tank and the lines will condense and produce more water in the lines.

CFM v/s PSI For Nozzles
CFM Free Air Flow @ Nozzle Diameter (inch)
PSI 1/64 1/32 3/64 1/16 3/32 1/8 3/16 1/4
1 0.03 0.11 0.2 0.4 1.0 1.7 3.9 6.8
5 0.03 0.24 0.5 1.0 2.2 3.9 8.7 15.4
10 0.06 0.34 0.8 1.4 3.1 5.4 12.3 21.8
15 0.10 .042 0.9 1.6 3.7 6.6 15.0 26.7
20 0.12 0.48 1.1 1.9 4.2 7.7 17.1 30.8
25 0.13 0.54 1.2 2.2 4.7 8.6 19.4 34.5
30 0.16 0.63 1.4 2.5 5.6 10.0 22.5 40.0
40 0.19 0.77 1.7 3.1 6.8 12.3 27.5 49.1
50 0.22 0.91 2.0 3.6 8.2 14.5 32.8 58.2
60 0.26 1.05 2.3 4.2 9.4 16.8 37.5 67.0
70 0.29 1.19 2.7 4.8 10.7 19.0 43.0 76.0
80 0.33 1.33 3.0 5.3 11.9 21.2 47.5 85.0
90 0.36 1.47 3.3 5.9 13.1 23.5 52.5 94.0
100 0.40 1.61 3.7 6.4 14.5 25.8 58.3 103.0
110 0.43 1.76 3.9 7.0 15.7 28.0 63.0 112.0
120 0.47 1.90 4.3 7.6 17.0 30.2 68.0 121.0
130 0.50 2.04 4.6 8.1 18.2 32.4 73.0 130.0
140 0.54 2.17 4.9 8.7 19.5 34.5 78.0 138.0
150 0.57 2.33 5.2 9.2 20.7 36.7 83.0 147.0
175 0.66 2.65 5.9 10.6 23.8 42.1 85.0 169.0
200 0.76 3.07 6.9 12.2 27.5 48.7 110.0 195.0