John,
What process can you suggest for color sanding and polishing. I've color sanded up to 2000 grit but still have scratches and swirls that i can't get rid of. Any suggestions would be helpful/
Thanks,
Sal
Sal,
2000 grit for color sanding will be sufficient to get you there. I regularly go no further than 2000, and I get excellent results. I quit using compound several years ago and now just use a polish after the color sanding. It is a little more work, but it does not leave swirl marks. I use 3M Finess-it on a wool pad at less than 1000 RPM.
The key to using this polish it to start out with very high pressure and decrease to very light pressure as it dries up.
I stay on very small areas, and I don't move on until all scratches are gone, even if it takes more than one application. Finess-it will leave a glass-like finish which is totally devoid of swirl and scratches. I only use a foam pad for my final polish after the car is completely done. It quite often takes 2 or 3 applications of polish on an area before I find it acceptable. You will also find a small 3" buffer to be invaluable for the edges and tight corners. I don't know how we ever got urethane cars buffed witout them! On lacquer cars, you can always just hand rub those areas, but with urethane, it is almost impossible to hand rub. use a wool pad on the 3" buffer as well for good results. I always tape the edges and body lines with masking tape to avoid buffing through on them, and then come back with the small buffer to get the edges, as I can control it better.
I have a waterbug sander, and sand large panels with 4000 before polishing, but it is not necessary, it just makes the polish step go faster. The finess-it will remove all scratches that are 2000 or finer if you use sufficient pressure at the start of the each pass.
The only other thing that I can reccomend it to use more water when sanding to keep the paper flushed and avoid any grit getting under the paper and scratching the finished surface. I always color sand with a medium/soft sanding block to maintain a uniform scratch pattern, and avoid using my fingers in all but the tightest corners. You don't say if you sanded with a more agressive paper prior to 2000, but I normally try and avoid doing so unless I have an area of bad runs or the like. The problem with starting with , say 600 and moving up to 2000, is you never know for sure when you have the 600 grit scratches out, and the polish will not take out 600 grit scratches, no matter what!
If I ever have to use a more agressive paper, I sand more than normal with the 2000 to assure that the 600 grit scratches are gone.
Regards, John McGraw
