Any downsides to the ceramics?

[termiteslayer]

I'm quite impressed with what the Spyderco sharpmaster does and I'm considering getting the ceramic bench stones.
The cleanliness of the ceramic system appeals to me.
I have Arkansas stones and have used them for over a decade but I'm not a fan of the oil or wetness in general when I have to put my plane or chisel blades immediately into wood after I sharpen 'em. A smidge of oil left on the irons and getting into the wood is not desirable when I have to do a glue-up.
Pros and Cons of ceramics?
Any cons?

 

[Jason B.]

I wouldn't use them for those tool blades. Sandpaper on glass or waterstones would be my choice.

Cons:
not always as flat as they seem
work best with stainless steels
can cause edge chipping with high Rc carbon steels and ZDP-189
excessive burring
can burnish if enough pressure is used
limited grit range


Pro's:
Nice finish
sharp edges
not very expensive

 

[Obsessed with Edges]

I have a couple of the Spyderco Double Stuff two-sided (M/F) pocket stones. I've found them to be most handy for relatively light touch-ups on blades with burrs or small dings/chips, after which I strop on leather. Specifically, I use a stropping (edge trailing) motion with the stone to remove the burrs. For heavier sharpening or reprofiling, I think diamonds are the way to go. The ceramics are pretty nice, but also relatively high grit, so removing a lot of metal will take a while.

As knifenut mentioned, the ceramics are sometimes not flat. I've noticed a slight concavity with my Double Stuff stone. When sharpening, it betrays itself in the presence of the metal fines at the edges of the stone, and not as much in the central portion of the stone. Being that it's ceramic, it'd be much more difficult to sand/lap it flat too. I also have been using a Lansky system for reprofiling, and the fine/ultrafine ceramic stones in that kit weren't flat either. They were slightly warped (bowed) right from the factory. I actually used an old DMT Diafold M/F diamond sharpener to flatten them, but it took a long time and a LOT of elbow grease. Took a good portion of the diamonds off of the sharpener too (but I wasn't using it for much else anyway, so I was willing to try it).