What angles are you using for ceramic knives?

[Darin Dickinson]

Hi all.

I am trying to sharpen my wife’s Kitchenaid ceramic knives from Costco. I am curious, what angle should I be using? I am trying 20 right now, as she is, um, a tad less careful about beating the knives up than I am. I thought she would be less likely to chip the edge at 20, but working one over with 1um lapping film on a glass blank doesn’t leave it feeling very sharp…. I did try searching, but gee, run a search for “angle” and “ceramic” and you will hit a ton of stuff about the ceramic paddles… 🙂 So if the answer is on the boards and I just couldn’t find it, sorry!

Thanks!

Darin

[Mark76]

I have never sharpened a ceramic knife, so I have no personal experience with this. But Tom, who made a video of shaving his head with a ceramic knife, used 10-15 degrees per side. You can read about his endeavour here: http://jendeindustries.wordpress.com/2012/08/03/worlds-first-ceramic-knife-shave-video/

The reason you get so many hits you don’t like when searching is that if you enter multiple words, the engine searches for word1 OR word2 OR word3 OR … That’s as flexible as it gets 😉 .

I’ve put an improved search function on the request list for the new forum.

Molecule Polishing: my blog about sharpening with the Wicked Edge

[Mark76]

Oh, and by the way: welcome! :cheer:

Molecule Polishing: my blog about sharpening with the Wicked Edge

[Leo Barr]

The angle sounds practical but you need to check that you have reached the edge with a loupe one thing similar to steel the lower the angle the more sharp it will seem but it will chip more easily . In my mind since you should not peel or chop in a sloppy manner they are only good for slicing something like lettuce or slicing fruit . They chip very easily and the chances are the micro chips will end up as part of your meal.

[Darin Dickinson]

Yeah, the reason I was thinking 20 was because of the micro chips. My wife doesn’t chop, she mainly slices fruits and veggies, but she doesn’t pay attention to applying sideways force on the knife when it is against, and maybe a bit in, the cutting board for example.

I am using a loupe to look at the edge, and thought I was there. I am hesitant to use a sharpie to see if I am there as I am afraid it will soak in the ceramic. Any experience on that? I would use it in a heartbeat if I thought it would just stay on top. Then sharpen until the sharpie is gone and I should be there!

Thanks again!

Darin

[tcmeyer]

I tried sharpening an inexpensive ceramic chef’s knife. It was a white blade and I did use the Sharpie method with no problems. Unfortunately, there was a fairly deep chip. When I was making no appreciable progress with my 400’s, (actually, I think it ruined one of my 400 stones) I tried moving things along with my 200-grit stones. Big mistake. In one stroke, I had multiplied the chip by about 200 times. I immediately tossed the knife into the trash. Won’t do that again.

My lesson? With material as hard as ceramic, progress is really, really slow. Unless your knife only needs a touch-up, you’d probably be better off with a diamond wheel. Maybe a Tormek?

[wickededge]

It really helps to keep the diamond plates wet while sharpening ceramic. It’s important to keep flushing them out because the ceramic material turns to fine powder and really loads up the spaces between the diamonds.

-Clay

[tcmeyer]

Thanks Clay:

That’s great information. I have a black ceramic blade I bought from WoodCraft to make into a custom knife. I’ll give the water trick a try for sure!

Maybe I should have kept that chipped blade and just called it serrated!

Tom

[Leo Barr]

Tormek do not do a diamond wheel . They do take about 10X longer to do & i would not suggest using anything less than 1K -been essentially glass the ceramic is not porous on any I have sharpened. Expect about 100 passes per side with 1K+ to get to the edge if you are keeping the same bevel angle longer if not flushing the plates regually is definitely the thing to do as wickededge says.
Try to be as smooth as possible with the paddles otherwise you will chip the blade.
Since you already sharpen knives it is proof enough that you have the patience to get a good result.

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