Most of the places I have seen recommend Windex for hand sanding a blade. I used Windex on a HHH Damascus 254mm gyuto I made (Also a S Grind) and it worked pretty well to go up to an 800 grit finish before etching and then 1200 after etching. I made up a sanding block about 3/8" thick and one edge flat and the other edge has a radius to match my radius platen. I have a 210mm Magnacut K tip S Grind blade I had to hand sand. Started at 120 and worked my way up to 800. Partway through the process, I decided to try some tapping fluid (Tapmatic IIRC??) instead of Windex and I was shocked at how much better it worked! Sandpaper stayed cutting a LOT longer; I used maybe a 2" section per grit instead of 6-8" per grit and it seemed to give a cleaner, more even finish. Anyone else try tapping/cutting fluid instead of Windex for hand rubbing blades??