Typical peak-to-valley bands
| Mesh | Garnet | Steel grit G40/50 | Aluminium oxide |
|---|---|---|---|
| 16-20 | 100-125 micron | 125-150 micron | 110-140 micron |
| 30-40 | 75-90 micron | 90-110 micron | 80-100 micron |
| 30/60 | 50-75 micron | 60-85 micron | 55-80 micron |
| 60-80 | 35-50 micron | 40-60 micron | 30-55 micron |
| 100+ | 15-25 micron | n/a | 10-30 micron |
Mesh is not a promise of profile. Pressure, standoff, steel hardness and a worn nozzle all move peak-to-valley. A 30/60 garnet at 100 PSI on mild steel often lands in the 50-75 micron band used by many Indian epoxy specs. The same mesh at 60 PSI on hard plate can undershoot. Prove it with an ASTM D4417 style gauge or replica tape before you lock the coating system.
If the spec says 40-60 micron, do not throw 16-20 mesh at 120 PSI and hope the paint keys. You will over-profile, waste media and risk peak-cutting through a thin film. Change mesh or pressure, then measure again.