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Pressure Sand Blasters | Grit and Sand Blasting Spares
Air Requirement
The largest electric motor available on single phase supply is normally 3 h.p. This will drive the pump of a l4 c.f.m. compressor, which will give l0 c.f.m. FAD (Free Air Delivery). l0 c.f.m. FAD will sustain a constant 72 psi. through a nozzle 3mm. diameter. A compressor of l0 c.f.m. FAD would give the best results with both the ACE and the CLASSIC gritblasters at the higher pressures. Of course, smaller compressors (5 c.f.m. upwards) will also work, but will not sustain the higher pressure indefinitely.
With a smaller compressor, you will either have to pause from time to time to allow the compressor to build up the pressure again, or let the gritblaster work continuously at the lower pressure (see chart below).
The following chart gives an indication of the pressure you can expect your compressor to sustain when blasting continuously through the 3mm, 3.5mm & 2.5mm tungsten carbide nozzles.
| Displacement | Free Air Delivered (FAD) | Pressure w/3mm nozzle | Pressure w/3.5mm nozzle | Pressure w/2.5mm nozzle |
|---|---|---|---|---|
| 19 cfm (540L/min) | 13 cfm (370L/min) | 95 psi (6.5 bars) | 72 psi (5 bars) | 130 psi (9 bars) (above max) |
| 14 cfm (400L/min) | 10cfm (300 L/min) | 72 psi (5 bars) | 55 psi (3.7 bars) | 100 psi (7 bars) |
| 10cfm (300L/min) | 7 cfm (200L/min) | 50 psi (3.5 bars) | 40 psi (2.75 bars) | 70 psi (5 bars) |
| 8 cfm (225 L/min) | 5 cfm (150 L/min) | 36/5 psi (2.5 bars) | 30 psi (2 bars) | 50 psi (3.5 bars) |
| 3.5 cfm (100 L/min) | 2.5 cfm (70 L/min) | 18 psi (1.25 bars) | 15 psi (1 bar) | 25 psi (1.7 bars) |
NOTE: this is where the top quality tungsten carbide pays dividends. Its low wear rate enables it to retain its bore diameter longer.
With cheaper nozzles (mild steel or ceramic) the high wear rate means your compressor cannot sustain its optimum working pressure. The larger nozzle bore means more air required.
TUNGSTEN CARBIDE NOZZLES (55mm long). All nozzles available please contact us for further details.
2.5mm bore for fine detailed work with grit under 500 microns.
3mm bore - gives concentrated blasting of rust & paint and for general use.
3.5 mm bore - only if you have larger compressor.