[Harleydad]

Characteristics of Abrasives: Most abrasives are graded as to Sieve Size. A sieve is a utensil of wire mesh or closely perforated metal used for straining or sifting, and can be used to separate coarser abrasive from finer abrasive. As the abrasive is poured through the sieve, the larger particles remain. The sieve is rated by the number of openings per square inch, so the higher the number, the finer the mesh. Also, the higher the number, the finer the abrasive. If an abrasive is graded 60-80, it means that it will pass through a grade 60 mesh sieve. Coarser abrasives (lower numbers) normally cut faster and create less dust within the cabinet, however the finish can be so coarse that the surface being blasted is extremely rough. If intending to paint or do further preparation on the metal, it is better to use a finer abrasive, to save prep time later. In summary: higher mesh numbers mean finer finishes and slower cutting action. Lower numbers mean coarse finishes and faster cutting action.