Other than putting a nice even finish on the exterior crankcase surface, I don't see any advantage in bead blasting the case if other, more invasive methods do an effective job in cleaning the oil passages. You must close up every single opening, otherwise there's a good chance the glass beads will find their way into the oiling system. As pointed out by Snowman, that's bad news. Are many shops (or owners) accomplished enough to do this correctly? One can also remove paint with carb cleaner, paint remover or even brake fluid.
Sherwood
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