when the shot falls down into the bottom of the cabinet, and is sucked back up to blow around again... anyone know how it's filtered out from the bits of rust etc.. ?
It's not, well the fine particles are drawn out in the dust extraction, but the larger bits get cycled around with the shot.
Or that's how the one I used to operate worked, but that was a proper industrial one, 5m x 4m, self loading using screw feeds in the floor, you didn't just put your hands in, you stood inside it !