When buffing paint, one of this biggest challenges is to get the grainy look out of the clear coat. The clear coat may appear smooth and fully glossy, but if you look close with a fluorescent type light tube, you will more than likely see a slight texture that looks like grain.
This is mostly from the sandpaper, and a small amount from the wool buffing pad. Here’s what to do about it.
- Spend a lot of time with a wool pad and compound. By far, the most time consuming, and important part of buffing is using a wool pad.
- Adding 2,500 grit to your wet sanding steps helps tremendously.
- Buff against the grain.
- For the most part, the buffing pad should be flat on the panel. You can tip it just slightly to control what direction the pad is buffing.
- This grain is the most difficult to correct along edges and body lines, because it’s harder to get the buffer to change directions, and buff against the grain.
The yellow lines in the image above represent the genera direction of the sand scratches. To start, we need to buff against these. 
In order to get the majority of the buffing completed, it’s very important to have the buffer running off of edge, as shown with the arrows. This also cuts across the sand scratches. 
More than likely, there will be a small amount of texture remaining from sanding. In addition, but far more subtle, there will probably be some slight grain from the wool buffing pad, especially up to edges and body lines. The buffing must now be adjusted to buff against the first buffing direction, being very careful of the edges. 
The image above shows all the directions of the different grains. Every time you adjust, you will eliminate more of this grain. When getting towards completion, use less and less pressure, and make sure the wool buffing pad is clean.