Pressure-blast nozzle CFM reference
| Nozzle bore | 80 PSI | 90 PSI | 100 PSI |
|---|---|---|---|
| No. 2 · 1/8 inch | 17 CFM | 18.5 CFM | 20 CFM |
| No. 3 · 3/16 inch | 38 CFM | 41 CFM | 45 CFM |
| No. 4 · 1/4 inch | 68 CFM | 74 CFM | 81 CFM |
| No. 5 · 5/16 inch | 113 CFM | 126 CFM | 137 CFM |
Only the listed pressure columns are selectable. The calculator does not interpolate the table or turn compressor horsepower into delivered air. Compare a documented delivery point, then separately allow for the pressure lost along the installed air path.
A 5/16-inch suction nozzle is not a No. 5 pressure-blast nozzle
The Clemco SG-300 manual gives an example combination of a 1/8-inch air jet and a 5/16-inch nozzle using about 22 CFM at 80 PSI. A pressure-blast No. 5 with a 5/16-inch bore uses 113 CFM at 80 PSI in the separate reference chart.
That difference is why the system selector matters. A suction gun’s internal air jet is part of its consumption specification. Applying the pressure-blast bore table to an arbitrary cabinet would answer the wrong equipment question. The SG-300 manual also distinguishes gun consumption from recommended total compressor capacity.
Worked example: why a bigger receiver will not close this gap
A No. 2 reference at 90 PSI needs 18.5 CFM. Against an entered 5.3 CFM delivery point at the same pressure, the numeric deficit is 13.2 CFM before other demands, reserve or duty limitations. A larger receiver stores more air over a given pressure interval, but the same pump still has that continuous-flow shortfall.
Switching the example to a No. 3 at 90 PSI raises the chart demand to 41 CFM. Nozzle selection therefore deserves attention before treating tank capacity as an upgrade. Review the tank storage explanation and recovery calculator for the separate storage question.
Nozzle wear and the rest of the air system
The Pro-Series Big Clem manual shows a No. 5 example at 90 PSI increasing from about 126 CFM new to 173 CFM worn. Its worn condition means a bore enlarged by 1/16 inch. These are approximate blasting-condition figures, not air-only flow measurements or a universal wear curve.
Add actual concurrent process demand from the system documentation. The reserve field starts at zero to make the unadded allowance visible; zero is not a recommendation for final design. The manufacturer’s separate system-sizing chart includes additional demand and reserve, demonstrating that nozzle CFM alone is incomplete.
The check also cannot qualify a compressor or particulate filter for supplied breathing air. Use the blaster and respirator instructions for that system. For energy planning once the air requirement is established, use the electricity cost calculator.
Questions before you decide
Can a 20- or 60-gallon compressor run a sandblaster?
The gallon label does not establish sustainable airflow. Identify the exact blast system and nozzle, then compare delivered air and manual limits. Larger storage does not remove a continuous supply deficit.
Can I use these presets for a siphon blast cabinet?
Use the suction/manual mode and the exact air-jet/nozzle specification from the cabinet or gun manufacturer. The pressure-blast chart is not a generic cabinet table.
Does a positive supply margin prove the setup will work continuously?
No. The figures still need compatible rating conditions, sufficient pressure under flow, adequate delivery hardware and the compressor’s duty/application limits.