Finish sanding is done with sanding films, or other fine grit sand papers. You can go as far as you would like, but I like to get it to where there is a nice smooth edge, that has a small sheen to it. There may still be some fine scratches as you can see in the 2x picture above, but to the naked eye it looks very well finished.

Before you start sanding, always be sure to cover anything you don't want scratched, like the outside of the holster or sheath, and any hardware you have attached , like chicago screws. The surface of the kydex is meant to be textured, and you don't want to remove any of that, because it will be visible. Therefore, everything but the edges should be covered.

The rough edge shown in the first photo is after the belt sander using a 120 grit belt. After this I touch up any areas that the belt sander can't get to with a dremel and small sanding wheel, and then it is on to the finish sanding process.

The pack of sanding films from the hobby shop comes with 5 grit levels, all different colors. They go in the following order

1. Black - 150 Grit - Use this to get out the bigger scratches, don't stay too long with this paper if you've already done 120 grit
2. Orange - 280 Grit - This reduces those big scratches from the other sandpapers even further, This is where I spend a bulk of the time sanding
3. Grey - 320 Grit - We further reduce the scratches, and begin to polish.
4. Tan - 400 Grit - This begins the polishing, and you can really tell now if you have areas that you need to go back and work on with a tougher grit.
5. Red - 600 Grit - This is the final polishing stage, and by now you should have a nice finish.

This process can take as long as you want. Typically I spend about 5 to 10 minutes on finish sanding, moving through the different grit papers as necissary until the edges of the kydex are to my liking. These minutes you spend here will probably be the difference in a the feel and presentation of your finished project.