sandblaster or wire brush + rust neutralizer?

I plan to clean up my floor pans and the floor of my trunk which have suffered from water leaks and I don't have access to the tools necessary to remove and replace the metal. I'm looking for a fix that will last a few years - at which time I'll find a way to put in new metal. I'd like to remove the rust and then repair the floor pans and trunk with fiberglass mat and an epoxy resin that I've purchased from a local marine supply store.

My question is- what's an acceptable way to prepare the metal for the repair? Would a sand-blaster do a good job or should I use a combination of a wire brush and a rust neutralizer? After removing loose rust, I intend to apply POR 15 to the metal before applying the epoxy resin.

I don't own a sand blaster but have been told I can purchase an inexpensive sandblaster that would work for the floors and trunk. I already have a 4 1/2 HP air compressor.

Am I wasting money with the sandblaster?

I'm totally open to suggestions.