Notice that the P1000 paper is 18 microns.
P2500 is 8.5 microns.
WEPS 1000 grit diamonds are listed at 7 microns.
I used to use sandpaper before I got stones to cover my progressions. I too noticed that the p2500 and eveb the p1000 paper would give me a much better polish and less tooth than the diamonds. I also noticed that the paper wore down much faster than I liked. I tend to think that Clay has to be right on this. The abrasive on the paper is breaking down to finer sizes. It is another example of how it is hard to choose a sharpening material simply based on the abrasive size. In fact I would go down to 0.3 micron 3M lapping paper taped to my 1000 diamonds. I never could get the level of polish nor edge refinement doing that as what I can do with the CHosera 10K which has abrasives sized at about 1.7 microns.
Yep, 18 degrees each side for 36 inclusive
Sandpaper taped to the 1000 grit diamond stone:
I've read more often that people use sandpaper. Any idea how the 1000 grit sandpaper compares to the 1000 grit diamond stones?
Where I live I can get sandpaper up to 2500 grit. However, thats the (FEPA) P-scale, which is different from the ANSI scale that Wicked Edge use for their stones. You can compare the scales here.