Instead of sand blasting get a D A sander with eighty grit paper. This will strip the old finish down to bare metal fast. then sand with fine sand paper and then prime with a primer for adhearing to bare metal. The primer I have been using is a new hybred primer. Good adheasion with a primer designed to build or spray on allowing a good heavy thick ( several coats ) coating. then after it is allowed to cure & dry it can sanded to a nice smooth finish. This process can be repeated several times if needed to fill in all the small pits and inprofections.
All this sounds simple but it can be a quite involed process. The D A sander requires a good size air compressor but would allow you to do your vehicle in smaller projects and elimate the sand blasting.
