After blasting I would hit the metal with a metal prep/conditioner, something with phosphoric acid. I used to use ppg dx579 but can't seem to get it around here anymore so I picked up some of por-15's 'prep & ready' metal prep. I also wouldn't use por-15 itself on my lawnmower but I think their metal prep liquid should be okay. I think it's pretty close to what I was using before, seeing as it's phosphoric acid and zinc phosphate. The ppg dx579 neutralizes and rust that may have formed since prepping the metal and lightly etches the metal. You apply the stuff with a fine scotchbrite pad, let it sit on the metal and react for 5-10 minutes or so, then clean the metal with laquer thinner to get all the acid off. Then hose on your epoxy primer.