http://vettenet.org/touchup.htmlHere's what I do to touch up scratches (even deep ones down to the glass), if you're patient you'll find that on a scale of 1-100 (100 being the best) you'll get a 90-95 quality touchup.
Standard colors (red, black, white, etc.) are the easiest to do. Keep in mind though that metallics are challenging to even the pros, so don't be too much of a perfectionist on your results. Take pictures of the scratches or stone chips before you start. As you're polishing and start to feel you could've done better, refer to the original photos, you'll find you probably did okay.
I use the 5-foot rule on metallics. If I can't see the touchup from 5-foot, then the job is acceptable. You'll find that basically you have three choices;
touchup with a brush and try to conceal the spot
area-spray and try to feather (a good job is marginal at best)
Spray the entire panel (sometimes this IS easier)
You can do options 1 & 2 yourself. Option 3 requires someone competent in mixing paint and operating the sprayer.
For stone chips and deep scratches, I recommend option 1. I follow these steps when I do them:
Clean area of all dirt, wax, etc.
Wet sand with 1500 paper.
Using GM Touchup paint (color code matched) and an artists paint brush, paint a minimum of 12 coats of paint into the scratch (the number of coats is relative to the depth of the scratch), letting the paint dry at least 30 minutes between each coat (you're using the paint as filler, don't worry if the paint in the scratch seem higher than the paint on the body).
After you have enough paint in the scratch, wet sand first with 600 grit, then 1000 grit, and finally with 1500 grit. Sand until you cannot feel any surface deviations where the scratch is (don't panic, you will still be able to see where the scratch was, we're not done.)
Wait 2 hours and then paint 3 coats of touchup clear coat (again using the artist's brush). After dry, wet sand with 1000 and 1500. Sand until you cannot feel any surface deviations where the scratch is (don't panic, you can still see it, we're still not done.) When finished, there should be just the slightest hint of a `mound' over the length of the scratch.
Leave it alone for 48 hours.
Now, wet sand with 1500 until you can no longer see any hint of the scratch. Then finish with a 2000 grit wet sand. Wash well...
Compound with Meguiar's #2, using a clean buffer wheel. Do this twice, then use Meguiar's #9 (swirl remover). Be sure to wash the area with soapy water and rinse it between each change of buffing. Change to a clean buffer wheel and use a good Foam Cut. Then glaze by hand with Meguiar's #3.
Practice on an out-of-the-way area before you do this project in earnest. With a little bit of patience and some practice you'll find you can get pretty good with this.
