you only need to wait till it's done flashing (solvents have dried) about 15min at 70 degrees.to apply another coat.
wait about 3-4 hrs(depending on the coats and outside temps) to start wet sanding the primer. I personally wait at least 24 hrs before I wet sand the primer. then dry it off really well. and it's ready for color
that's how we do it a the body shop. but I only use automotive grade paints on bodywork.
if you are painting a engine or something, just let it flash off for an hour or two and spray your color.
Last edited by serpentracer; 03-18-2010 at 12:59 PM.