I’m in the process of fixing up a rusty Duramax. I have replaced the rockers and cab corners. The truck is dark blue and I have gotten a door that is gold, a fender that is green and a white bed. I have 2 questions at the moment.
I’d like to change the color to white, since the panels are different colors and dark will this affect the outcome or will the primer solve that? I’d rather not strip them down to bare metal.
I’ve read a lot on this question and still don’t know what to do, should I paint the jams and under the hood then assemble and paint everything or paint the panels while there off the truck?
Thanks, I haven’t done bodywork in about 10 years so i’m basically relearning everything.

Not a pro, but here is my take on your project.

If you prime or seal everything the same color then the white BC will cover the same from part to part.

Solid colors can be sprayed with the parts off the car and still get a good match between panels. Best if you do them all at the same time to prevent environmental factors from effecting the color. Metallics and tri-coats need to be painted assembled.

You can do the undersides, jambs, firewall, etc… first, then assemble and spray the outside. There are tricks on how to minimize overspray and hard tape lines.

Hopefully others will chime in with more details.

Yeah I would say you are on the right track, I would prime and paint as much as I could off the truck, all the jambs, inside fenders etc. Then while dissasembled spray your sealer on the jams, paint and clear. Then assemble the whole thing as previously said, and do a really good job taping and make sure any hardline has rolled tape, that will prevent the paint from lifting when you unmask it. Spray sealer over the totally primed, blocked and cleaned surface and you will be all set for a good color match and even colored truck. Colors sand and buff if necessary.

GOOD advice above, and yes you should be ok doing individual parts with the white. sealing or priming all the parts the same color will be a benefit. so here is what I like to do with a project like this.
I like to remove the box this depends on if you want to paint between the cab and box. i'll set the box outside pull the doors, fenders, hood, and any other parts that are going to be painted. now I prep and paint the cab, jams and all. now if you have the room move the cab out of the way or outside. now do the box when your done with it assemble to the truck. now do the doors when dry put them on the cab, do the same with the fenders and hood. doing it this way you have some place to put the parts after they have been sprayed and they are out of your way.
Jay D.