I worked in a machine shop with a real good bead blaster. I'd take my frames and other parts in there and blast them at lunch, then prime them right on the spot. That was 20 yrs. ago and not a speck of rust has returned under my paint jobs on any of my bikes. Here's a tip. Don't touch the blasted part with your hands. Use a glove or paper towel to handle it. I blew off the dust with the compressor as soon as I took it out, hung it with wire and primed it right on the spot without ever touching it. Gary