Choosing the proper grit size of media to get the desired finish is often a little bit of trial and error. Different medias at different pressures on different metals with different processes will result in different surface finishes.
These 304 stainless steel washers needed to be etched with Silicon Carbide Grit to achieve a lightly etched finish (Aluminum Oxide Grit was not allowed for this particular situation). Since the exact finish was not specified, a range of grit sizes were tested. Starting at the top and going clockwise, the discs were blasted with 36 Mesh, 60 Mesh, 100 Mesh and 220 Mesh Silicon Carbide Grit at the same blasting pressure.
While a little difficult to see the detail, it is clear that as the grit size gets finer, the finish get much smoother. This is typical of all types of blasting media. Larger grit will result in a heavier etch than finer grit. It’s just a question of what grit size gives the desired results for a specific application.