Washington Mills offers a surface finishing guide that provides a suggested grit size based on a specific workpiece, nozzle, PSI, and desired RA finish.
Simply follow steps 1-3 to yield a recommended grit size based on an RA value for your
Note: the data provided on these charts (both Suction and Direct Pressure units) were obtained under the following conditions, and it is recommended you interpolate the indicated readings for any changes in these given conditions. Conditions or equipment need not be identical to the chart below to achieve similar results. The data provided on this chart are averages but should give satisfactory results in most cases.
Blast Units: Pangborn
Nozzle Size: 1/2" and 1/4"
Nozzle to Workpiece: 6"
Blast Direction: Perpendicular
Blast Pressure: 40 to 100 psi