Originally Posted by
Marshal
I doubt you're doing any damage since you're using one side for slurry, and the other for polish. In fact, that's what I do with my Welsh slates. One side is roughed up and used for slurry/fast (er) cutting. The other is polished and burnished for finishing and used water only.
On topic - as others have said, slurry is more to speed up the cutting action and typically you'll dilute it and finish with just water. You don't 'need' slurry - but depending on your progression/hone it may make things infinitely quicker. My question is, what are you using before you move to the Jnat? If a 10 or 12k synthetic, I can't imagine you would need much slurry if any at all before moving to your finishing stone. If it's a lower grit, slurry will be a must, and how thick will depend on what grit synthetic you're employing.