Please forgive my ignorance...is it possible to shoot clear over a faded section...
 

...of the original paint? I have a guards red 911 and the paint on the roof is dead/dying. The color coat is fine...in fact it can be waxed to a nice sheen. I'm just trying to temporarily halt further deterioration until I have a window out respray in the late spring. I'm currently doing a mechanical restoration and wanted to do the paint last.

Forgive me as I am totally ignorant when it comes to automotive paint.

If you are going to paint the car in the spring then it will not be worth the trouble to clear coat. If you can get a shine with wax, you can probably bring the color back up with 1500 then 3000 wet sandpaper and buff it with Maguires diamond cut compound. I would try that before messing with clear.

Sorry Jim for jumping in. I have a panel with exact same color and problem. I don't think I am going to restore the car any time soon so I was thinking of the same solution. I know the proper way is primer, color, and clear coats, but can I sand the original paint with 2500 grit to sough it up then spray several clear coats and sand buff it? Will it stick? Will it last?
Thanks.

it not worth the truoble and cause much bigger headaches down the road . insted of sanding it with an ultra fine sand paper and clearing . try sanding with a 4 , 5 or 600 grit paper and use single stage color . by sanding with an ultra fine and clearing it will delaminate the clear in no time . your thinking why ? becouse most or the dead and dieing color will still be left on the panel and continue to die even with clear over the top . sanding it with a 400 , 500 or 600 grit you willl be taking all the dead paint off the panel and giving a good substright for the new sealer and single stage color to bite into . so with only about a 20% increase in cost over just clearing the panel you will get a permanent fix . the labor time is the same becouse you still have to sand , mask , spray , color sand and buff .

got it. Thanks for a very clear answer. Also, I assume sanding it with 600 grit, then proceed with primer/color/clear is also a good approach, and last long?
Thanks

there would be no need for a primer unless you are doing plastic work (body filler) or you have alot of bare metal spots . all you need is a good sealer and top coat . a 400 to 600 grit cut from the sand paper is to fine for most primers to bite into for a proper adhesion . a sealer is not a primer .

ok, let me make sure I got it right.
If the surface is perfect, not need of body work, I can just:
1- sand with 400-600 grit.
2- body sealer (No idea what it is, will ask the paint shop)
3- color coats.
4- clear coats.
Am I ok here?
Thanks.

yes i think you got it ? but its not called body sealer ! just sealer . a sealer is a product that you spray on for a few reasons . it give a uniform smooth surface for your top coats . it aids in achieving better adhesion and holding down sand scratchs from 400 and some 500 grit cuts . most base colors will scrink in a little to a 400 and 500 grit sand scratch . if you don't opt for a sealer when using a 400 or 500 grit papers . in most cases you will spend more time color sanding them out or over time you may start to see some fine scratches . but they will sand out . if its a tintable sealer you will need less top coats (color coats) to achieve coverage .

got it. Thank you much.

I just pop up another related question. What if the old paint has clear coat. Do I have to sand away all the old clear or it's ok to stay, just need to rough it up?
Thanks.

Just to chime in another concurring viewpoint, I have seen a few folks try the re-clearcoat thing over the years. The results always end up badly - peeling or just plain looking crappy. And then you don't have the option of buffing out the original finish, so you have to totally repaint.

This is why I love old cars with single-stage paints. It's just the same substance down to the primer. When it gives out, it gives out. IMHO, clearcoat was the industry's way of cheaping out on paint while giving a deep shine with less work. Now you get finishes like the embarassing orange peel on new BMWs.