So this is in response to Rustbelt Bob's post in the older thread on this subject. Figured I'd reply over here to keep things simple.
In the other thread I said I wouldn't get started until spring, what sucks is I actually have been working on this since spring as weather and time permits. I'm getting more OCD as I age. I decide on an order of operations and I have a problem changing. Character flaw, mental illness who knows. Anyway, I wanted to paint the bed while it was closer to the garage, but before I could paint it, I needed to prep it. This is a picture of the inside of the bed after I had scraped, by hand with different scrapers and putty knives, all of the old cheap bedliner paint the last owner had sprayed in there. It's a white bed, the inside of the box was black. In this shot I'm just about ready to start scraping the tail end. This is before I did any sanding. Whoever put in the old bedliner didn't degrease or scuff. It was peeling in places. I degreased, scuffed, primed, sanded with 120 by hand to remove dry spray and provide some tooth. So the bed was actually about 2 years of round 2-its. The reason I didn't just sand the hell out of it from the start was that white paint is like rust proofing from God. I wanted to save it as best as I could. The black streaks are where the paint had been worn through to the steel and the bedliner paint stuck. That was removed before I primed. In the end I did not apply the bedliner while the bed was near the garage.