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!
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.
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.
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!
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?
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.
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.
So if the answer is on the boards and I just couldn’t find it, sorry!
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