body prep sanding advice
 

my roof and sail panels on my 74 were just replaced/fabricated a couple weeks ago, so now i need to get them painted. only thing is the area's not ready for paint, so i want to do the prep work myself before taking it to maaco for a single stage job...i'm on a budget lol


only concern i have is i dont know what grit sandpaper i should start and finish with.


right now the roof has its original paint with a couple rust bubbles and surface rust along the front & rear windows, and the sail panels are covered with Polyprimer. i was about to start the roof with 180, treat the rusted spots with metal conditioner, the sails at 80, finish everything at 320, spot putty when needed and sand that down with more 320. but i wasn't sure if i'm supposed to use a finer grit after 320. i've heard that using 400+ can actually decrease bonding to the next layer of paint/primer. is that true?

also, if it makes a difference, maaco said they would use sealer primer, then paint the car with their single stage paint. i wanted them to use some Polyprimer i bought but they said they can only use their own primer lol


so again my main concern is with what maaco plans on using for primer & paint, i dont know what my final grade sandpaper should be, and if smoothness was important vs. good abrasion to promote adhesion...i dont wanna ask maaco cuz of the driving distance & it would be a hassle to ask over the phone...the most i've done was practice sanding on some el camino gas cap panels lol, so any good advice is appreciated, thanks =]

Hey Ryan!

How have you been?

Glad to hear it's coming together well!

Which Maaco is going to shoot it for you? Had a friend at one of those but not sure which location and if he's still working there. PM me and maybe you can contact him to get some inside assistance...

I would suggest you try to get the same product Maaco is using and if you can prime it yourself then block it down afterwards. Usually, 400 grit is the final sanding of the primer before color.