Sand/bead blasting is not a cure (or a preventive measure) against corrosion, but it does help prepare the sheet metal for treatment that will avoid the recurrence of corrosion. In layman's language, it uses tiny abrasive particles sprayed at high velocities to "grind" away surface impurities, paint, putty, rust, resin, and other excesses, to expose the bare sheet metal underneath. This sheet metal can then be dented to perfection, or be cut/welded to create a rust-free, smooth surface. By use of other anti-oxidants applied to the metal, you can minimise the possibility of rust returning.
It carries with it intrinsic physical and environmental hazards, and as with all things technical, one should take all necessary precautions with oneself and with the metal to be blasted/cured.
