I can't imagine that you could just do the back side without the paint running through to the front. I used this stuff on my frame and misc parts as well. If you are using a black top coat, make sure you get the gray POR-15. Black on black is really hard to tell what and what has not been painted. Also, follow the instructions, in the POR-15 cures all the way, it is slick as sh*t and nothing will stick to it. If you have them sand blasted, I would just get the powder coated. I had mine done for around $250 seams like a lot but well worth it.