Personally I would stay away from the soda blasting. You will never get all the residue out of the bumper and have some serious adhesion issues. Wet sand it with 400 grit and feather out any areas the paint chipped. Fill any cracks with 3M DuraMax bumper repair and sand smooth. Prime with a reduced Epoxy Primer and top coat with your favorite base coat and clear coat.

Frank Cox
Cox Custom Cars