I have medium and ultra-fine Spyderco stones. Unlike the experience of others, both came in quite flat.
With considerable doubts, I have so far used them dry. And, so far, they both cut very well. And, following the company line, I wash them periodically with a powdered kitchen cleanser. The one I use is a non-abrasive, oxalic acid based cleanser (Bar Keeper's Friend). Works a charm, and has so far dispelled my doubts about dry sharpening and polishing.
The UF stone turns a burr quickly without starting on the coarser stone many times, usually 15-20 sharpenings, so it gets most of the usage. (I remove the burr with green compound on mdf in a few passes and get back to my project.) So far, when it's clean, my eye can't tell it's been used at all. It looks to my eyes -- which are not young, but still pretty decent -- just as it did when new. My edges can't tell it's not new either. My medium has so much less use it may not be timely to evaluate it's durability, but so far, it still performs like new. It gets washed far less often than the UF. It has thus far remained quite flat.
My use isn't all that long term yet, but so far it has been the most convenient, the most rapid, the cleanest sharpening approach I have ever used and my edges are as sharp as any I have ever been able to attain. I'm not going back to my diamonds, my Arks, or any of the other possibilities our there. Maybe we can all look forward to someone making really fine grit CBN stones one of these days, and they may be better than the ceramics, but until then, I'm sticking with my Spyderco.
Last edited by James Waldron; 08-24-2016 at 5:25 PM.
Fair winds and following seas,
Jim Waldron