need to pick up a sandblaster(and a rotisserie, but that can wait till another day) I just need to know what capacity I should get....I dont mind a bit of extra work if I can get away with a much cheaper price...I dont plan on using it for exterior panels anyway(at least not using sand, possibly with baking soda), just the undercairrage and interior, I want to strip it all down to bare metal and re-coat it with POR-15 underneath and repaint all the interior metal, will one of these 10lb capacity blasters do the trick? or am I going to need to buy a 40lb unit?