Ceramic Blades

[Robson Valley]

I'm just a little tired of buying new ones. While they are extraordinarily sharp out of the box, they are brittle. Have decided to buy a monocrystalline diamond plate to clean up all the chipped = serrated edges. What say you for grit size?
Personally, I like steel. Ceramic blades have been around here for decades in lumber planer mills, as they last 3X - 4X old steel blades. Should stay there.

[Bernoulli]

It depends. An ultra-fine to maintain an edge. If you wait too long you'll have to have something to bring the edge back for finishing on the ultra-fine.

[Robson Valley]

Thanks Bernoulli:
Looked over the Lee Valley DMT plates.
Would you suggest 600X and 1200X? I see that they could do double duty
to flatten the water stones that I use for wood carving edges.
I can see no point in the 8000X, nobody will notice the edge quality in the guts of a tomato. And, the blades (white) only have a dull sheen to them.

[Bernoulli]

The suggestion I made is based on steel knife sharpening experience. I've just read up on sharpening ceramic blades. Everything I've found says send it back to the factory. I imagine some have been successful, but diamonds leave tiny grooves that lead to fractures. Diamond paste perhaps - but why even fool with it? If you're going to purchase diamond stones anyway, I prefer Eze-Lap, but I have both Eze-Lap and DMT. You may find that diamond stones will sharpen your wood carving tools as well as water stones and will do it a lot faster. I'd get an equivalent grit to the water stones you're already using.

[Robson Valley]

Thanks. I get my share of knife sharpening experiences in my kitchen. Initially, Porsche would not reveal either the bevel angle nor the stone grit size for their 301 series of knives. If that isn't the height of arrogance, I don't know what is.
Anyway, somebody knocked them back: the King water stone is 4,000 grit and the total, included, bevel angle is 20 degrees. I get a good result.
While chrome green (0.5 micron) may not be as fine as some of the diamond pastes, I need the simple hardness of the diamond to get anything done on those ceramic edges. They are HARD, not like my Pfeil wood carving tools. And, what comes with hard is sometimes also very brittle.
Sharpening & honing compounds all scratch the surface, be it steel or ceramic. While a honed edge may look all bright and shiny to your buck-naked eyeball, I suggest a 20X magnifier for a dose of discouragement.
Since all of the ceramic blades belong to my GF, she can deal with them. Right now, her strategy is just to buy another one. I'm a steel sort of a guy.

The magnetic properties of the iron oxides don't become obvious until the particles are less than 100nm (1000nm = 1 micrometer). It would be fun to run my big old reel-to-reel tape deck on Fast Foward and see what that tape could do for honing!

[fenderbelly]

I was given a ceramic knife as a present and as someone said sharp as out of the box. as it started to lose its edge i bought a sharpener.
It was a cheap one but all i read made it look good. I was ever so gentle with it and took a 4mm lump out of the cutting edge which resulted
in it being binned. I then treated myself to a stainless global G2 which i am more than happy with.