I would like to coat the entire body of my old truck with rust seal before i paint it (white or gray). Would one color of rust seal be best for this? I am concerned about sanding smooth and body work before i top coat it. Also, any idea of how much rust seal I may need to spray the inside and outside of of all the body parts?

Silver is the best color of RustSeal for priming bodies of cars. Any of the other 9 colors will work as well. Apply a coat of KBS Fusion Self-Etching Primer after you have applied your minimum of two coats of RustSeal, and then apply all the sandable primer or body filler you want. You can do this the next day, next week, next month, next year. You can then sand that smooth. You will want to buy a gallon of RustSeal to cover the entire body of your car. Check out the complete directions for RustSeal here: http://www.kbs-coatings.com/rustseal-directions.html Check out the directions for Fusion Self-Etch Primer here: http://www.kbs-coatings.com/fusion-directions.html Please do not hesitate to contact us if you have additional questions.