On sandblasting, I think it depends...
I did portions of my chassis with an old school 'home gamer' sand blaster attached to my air compressor. The unit essentially consists of a suction type paint spray gun with a hard steel nozzle. Apart from the fairly regular and irritating material pick-up issues, it worked fine.
Now, if considering a commercial outfit, those are often powerful enough to put a sheet steel seat into low earth orbit, so yeah, too aggressive.