I assume you mean bumper cover. If you do, then FOR THE LOVE OF GOD DO NOT SANDBLAST IT! It's ABS plastic- chances are you'll create serious waviness, high spots/low spots, deep pits, and even holes. Best case scenario, you'll still end up sanding for days to smooth it out. Bulldog makes an aerosol stripper that is safe for plastic. I used it on my bumpers before I glassed them.
However, why are you stripping the paint off in the first place? If it is only going to be repainted, my suggestion would be to use a DA with 320+ grit paper, then wetsand up... However, based on your post, my assumption is that you've never painted anything before and that the suggestions I've just made will not be well understood.
Although it's more expensive, drop the bumper off as it is at a reputable body shop and let them do the work for you. You'll be happy you did. Otherwise, you have a lot of reading ahead of you and some serious practice in store before you're ready to paint something important.