Just done a trial run with coarse salt using money as the media and I can say it works perfectly the powder is flour like within 2 minutes and so fine it floats. The good thing about rapid vibrations seems to be in how it seperates the large particles from the small allowing the media to grind them down. Leave it on for an hour and I am sure you will get powder that will pass 300 - 400 mesh.
Edited by pyrotechnist, 15 November 2008 - 05:00 PM.