paint

[6T9PONY]

"Prepping" a body for paint doesn't just mean wetsanding and spraying the paint. This was posted in the classic forum, so I'm guessing it's a classic car. That would mean that unless the body was already recently restored (doubtful) it's going to need a healthy amount of work that's going to take a long time, especially for an amateur. This isn't a brand new, perfectly straight Mustang we're talking about here.

If it's an old Mustang, there are going to be hundreds of dings, waves, rust spots, etc. that will take a lot of time to fix, if you do it right. Wet sanding over a ding doesn't get rid of the ding. If you do it right, it'll take at least three passes of puttying and block sanding to fix it (putty/sand/putty/sand/putty/sand). That could take over an hour in itself, just to fix one little ding on one little body panel.

You only spent a few minutes per panel wetsanding? Either your paint is probably already peeling or you don't know what you're talking about.

There's no need to soak the sand paper over night. All you need to do is make sure that the surface you're sanding is wet, the paper is wet, and BOTH SURFACES ARE CLEAN! Don't let a bunch of sanding residue build up on the panel while you're sanding. Even if you're using very fine grit paper, the residue will gouge the surface. This means that you constantly need to be rinsing off your paper and the surface that you're sanding.

Another good thing to keep in mind when you reach the block sanding stage (one of the last before spraying) is that the point isn't to sand off primer, the point is to level the surface. You have to use a very consistent, very light touch.