Originally Posted by ernie22golf
A few on the roof and others on bottom of doors. I have bought some touch up paint, clear coat & primer and plan to sand the spots - then prime - then touch up and finally - clear coat. I'm wondering how I can sand small area'* without harming the areas that have not problem nearby.
Hmm. I'm not a big fan of spray can paints. Yes, for convienience I'll use them on engine parts (I go through a lot of silver and black) and in the engine bay or hidden areas. But for body work, there'* no substitute for the urethane paint used on the car originally.
On a touch-up job the drill goes something like this. Block sand the rust and surrounding area to bare metal. Don't wory about sanding on areas outside the damage. In fact, the goal is to feather the sanding further away from the spot...the bigger the feathered out area, the harder it will be to spot the transition from old paint to new (The human eye gets faked out by the contours of the car and the subtle change of color isn't noticed when it'* spread out over a large area.)
Wipe the bare metal and sanded down paint clean with acetone. Do this alot to clean out any grease, oils, etc. Prime the spot with a good etching primer, block it again, wipe it down again, and again, and again, mask off to the nearest seam or panel and shoot you base and clear over that. Let it cure for a day or two, then wet sand the paint and buff it out to about 1500 grit. Like the others said, let the paint cure for a few days before doing any waxing.
On a solid color car, there'* usually no problem blending the panels in (provided the paint dealer got a good match to the actual color of paint on your car.) Though, figuring out where to mask the car off to hide the paint seams can be tricky. The roof is always a b*tch, since it'* such a large, visible area with no natural breaks in the panels to hide a paint seam. Doors are pretty easy. Use the natural breaks created by the mouldings.
I'll be doing a white '90 LE here pretty soon. I've still got a panel that got customized last year by a putz who rear-ended me, plus a little rust in the trailing edges of the rear doors to clean up.