The car was repainted once by the previous owner and it's some ugly stuff...so what grit sand paper to use to sand off the paint?

TIA

 

id start with a low ## grit, then primer then sand again with a higher grit, and then after that many many step process i would wetsand and final primer then paint

 

75% Wrong.

If the car has been repainted ONLY ONCE, then you are safe to just wetsand with 500-600 grit paper until its all smooth then repaint. If it has imperfections like peeling paint, then you can use a paint stripper, or sand it with 40 grit paper in the problem area. Then finish sand with finer than 40 grit and work up to 180 and your're ready for primer in the repair area. wetsand the primer, and you're ready for paint.

Again, if the paint is in okay condition and not peeling, then you Don't have to sand all the way down to bare metal.

 

How far should you strip/sand the factory paint, if it has spots, mainly all over the hood, roof and hatch deck, that have been damaged by tree sap? Will the car turn out alright if only those problem areas are stripped down to bare metal, while the sides of the car, where the paint just has some scratches, only have the top layer of clear coat removed? The body shop proposing this would then seal all over with polyurethane primer before re-spraying and clear coating.

 

sand the flaked, rusted areas to bare metel he said basicly

 

Paint/Paint 320 or finer (600 the best). if u just go on paint on paint u dont need to prime but if u get cut throughs use vari prime/uro prime or whatever products your into. If u have it primered go no less than 600 with a flat block or a scuff pad to make sure its level. After that just put a nice BC/CC on it and the bitch is a work of art.