12-03-2017, 09:40 AM
Thank you, Mr Rupert. And, that is a good question.
To the best of my understanding, stones like Spyderco's are pure ceramic- no abrasive. Same with "ceramic rods". There are no abrasive particles like there are on diamond stones or diamond rods, only a semi- rough surface.
I don't know how they produce such an accurate, consistent surface texture, but it must be formed before the material is hardened/fired... whatever. There is no texturing after hardening. It would actually wear diamonds down, so I can't sharpen my sintered ceramic blade without a "disposable" $75 diamond belt. I think it would be possible to affect the edge with a TAS diamond wheel, but you'd probably hate the result on the knife and the wheel.
This form of ceramic is hard enough that the surface texture just doesn't wear out. Need proof? Have you ever heard of anyone lapping their Spyderco stone? No, because they don't wear. To clean them, you let the oxalic acid in Bar Keeper's Friend dissolve the "stuck on" steel for you, and you just rinse it off with water.
Well, Everyone laps "ceramic" Shaptons and Naniwas. Not only to keep them flat, but because it exposes new aluminum oxide abrasive, which Does leave a scratch pattern.
Anyway, the texture of ceramic is rough enough to remove steel, but the steel removed from the blade just sticks to the high spots of the stone. Since those spots are not sharp at all, you get virtually no scratch pattern from ceramic stones or rods. To make matters worse, as soon as you have steel stuck to the high spots, you're just rubbing steel against steel, galling the edge.
I've determined for myself that ceramic rods are pretty worthless (recently, I may add). No scratch pattern means no tooth, which means smooth edge, which means forgettaboutit. Sure, a ceramic rod in the kitchen isn't a sin, but I would not be able to upgrade to a diamond rod quickly enough. Once you boys get around to edge retention testing, you will figure this out immediately.
To the best of my understanding, stones like Spyderco's are pure ceramic- no abrasive. Same with "ceramic rods". There are no abrasive particles like there are on diamond stones or diamond rods, only a semi- rough surface.
I don't know how they produce such an accurate, consistent surface texture, but it must be formed before the material is hardened/fired... whatever. There is no texturing after hardening. It would actually wear diamonds down, so I can't sharpen my sintered ceramic blade without a "disposable" $75 diamond belt. I think it would be possible to affect the edge with a TAS diamond wheel, but you'd probably hate the result on the knife and the wheel.
This form of ceramic is hard enough that the surface texture just doesn't wear out. Need proof? Have you ever heard of anyone lapping their Spyderco stone? No, because they don't wear. To clean them, you let the oxalic acid in Bar Keeper's Friend dissolve the "stuck on" steel for you, and you just rinse it off with water.
Well, Everyone laps "ceramic" Shaptons and Naniwas. Not only to keep them flat, but because it exposes new aluminum oxide abrasive, which Does leave a scratch pattern.
Anyway, the texture of ceramic is rough enough to remove steel, but the steel removed from the blade just sticks to the high spots of the stone. Since those spots are not sharp at all, you get virtually no scratch pattern from ceramic stones or rods. To make matters worse, as soon as you have steel stuck to the high spots, you're just rubbing steel against steel, galling the edge.
I've determined for myself that ceramic rods are pretty worthless (recently, I may add). No scratch pattern means no tooth, which means smooth edge, which means forgettaboutit. Sure, a ceramic rod in the kitchen isn't a sin, but I would not be able to upgrade to a diamond rod quickly enough. Once you boys get around to edge retention testing, you will figure this out immediately.