One more thought from the "Shapton Glass 500 is the perfect razor repair stone" side of the house: it's not talked about much, but these stones do glaze. The reason it's not talked about much is that they still cut really well when they glaze. I view this as a positive characteristic, mostly. I could shave of an SG 500 edge, and have shaved off of an SG 1000 edge, by using very light pressure for enough time that the stone starts burnishing more than cutting. But for repairs, you may want to refresh the surface a couple of times, especially if you are not using pressure sufficient to expose more of that superfast cutting surface.