Need Help prepping car for paint or not?

Question

I've taken a few class's on body repair and know the basics. the hatch on my car was white and had holes from a spoiler, I filled them in and painted it flat black.

My problem: When wet sanding the paint just seemed to come right off.

Im woundering if i didnt prep the surface good enough? I started with 80 Grit, went 180 then 320 ,a fter the 320 i primed, I sanded by hand and kept it random, no major scratchs were showing in the paint.

I did use spray cans, so Im woundering if I just didnt get enough paint on the surface? any help is appricated. thanks

Sorry I should of mentioned that I only wetsanded with 320, and it was Dupli Color - Automotive paint ;), No paint gun available at the moment

Answer 1

thats some wickedly heavy grit sandpaper. Usually when you wetsand paint you use way higher grit sandpaper.

and spray cans are NOT automotive paint. its not even close. spray paint is essentially worthless on any high durability project. you need auto paint.

Answer 2

sand it all back off and resand with the 320 grit. if you have bondo or fiberglass exposed, you need to spray those areas and areas where bare metal is showing with a automotive primer. after the primer has fully dried, scuff it with the 320git paper, tape off areas that you don't want paint at. get a wax and grease remover and tack cloth from a auto paint and body supply store.also get you a couple cans of quality automotive spray cans while your there. this paint will be expensive but worth it. after doing all that. wipe the area down with the wax,grease remover and dry with another clean cloth. was dried go over the area to be painted with the tack cloth. its a sticky cloth that removes dust,dirt,lint etc from the car surface giving a much cleaner paint job. then shake the paint as stated to do so and spray paint the area.

Answer 3

Add A Couple Coats, And You Should Be Fine.