Ceramic Knife - Sharpening?

[FuzzyBunny]

Ceramic knives huh? Are these the same kinda knives that go right through metal detectors? You know, just like the plaxtic glocks do?

Kidding aside, I have thought of getting one and I did not know they made folders. Only downside I see in a folder is I would use it alot. Of course during use I do drop knoves and that would be the end of it.

Question, what were ceramic knives designed for? Do they make a serrated one too?

 

[hmphargh]

My understanding is that they were designed because they can be sharper, hold an edge better than steel but at the cost of brittleness. I understand they're popular with scuba divers since they don't have the same rusting issues as steel knives.

As far as serrated ones, I've seen serrated ceramic kitchen knives like bread knives and tomato knives, but they have different serrations than steel knives, the serrations aren't pointed, they are rounded or flat with slots in them. I haven't used a serrated ceramic knife, but I would imagine they cut more like an edged knife than a serrated steel knife does because of the shape of the serrations.

 

[FuzzyBunny]

Thanks thats what I was wondering

 

[CWL]

My understanding is that they were designed because they can be sharper, hold an edge better than steel but at the cost of brittleness. I understand they're popular with scuba divers since they don't have the same rusting issues as steel knives.

Nah, the ceramics first came out commercially because they are inert so will not impart a taste to your food, will not rust nor pass germs from food to food. They are harder than steel so "theoretically" will cut better and hold an edge longer than most kitchen knives. Also, they first came out in Japan for the sake of novelty.

Remember that most kitchen knives are pretty dull since few knife users have the level of fanaticism that we do about sharpening knives. Compared to a dull knife, ceramics are a wonder.

I wouldn't recommend using one as a diving knife, unless it is a special ceramic made by Mad Dog knives specifically as a dive knife/pry bar, you are looking at a very brittle piece of material. It'd be as useful carrying a shard of pottery for a knife.

There is a dive knife that incorporates a ceramic insert, but that is specifically to help cut monofiliment lines, the actual knife is ss steel.

 

[Gordon]

Actually I think the first ceramic commercial knives were Bokers about 25 years ago followed by Kyocera kitchen knives.

 

[CWL]

Actually I think the first ceramic commercial knives were Bokers about 25 years ago followed by Kyocera kitchen knives.

This may be true regarding first introduction to the West, but I think Boker sourced the blades from Kyocera originally, (but now may be buying from China). I'm pretty sure that they do not have the equipment to mill, cast and form high grade ceramics.

Kyocera is the largest manufacturer of high-grade ceramics in the world, and has spend hundreds of millions in R&D and equipment to manufacture ceramic compositions for manufacturing, micro electronics, anti-conduction, automotive, etc. Ceramic knives are almost a by-product of their investigations into wear & corrosion-resistant cutting materials for industrial applications.

Here's some quick info about how ceramic knives are made:
http://global.kyocera.com/fcworld/first/process2.html

 

[philip8]

Ceramic knife is a knife that is very useful. I have a ceramic knife in my house i used in the kitchen to slice and also i have a
throwing knife

 

[pictoblu]

It's my understanding that kyocera makes all the ceramic blades and the other companies, boker included buys from them.

My son in law just had to have one of those ceramic folders after he saw some show on tv about the kyocera factory. He got one and said he loved it. I tried one and it was ok for a while, but heck, it's ceramic and it had to be treated as such.

Also had gotten a ceramic bladed boker fixed blade for the kitchen. Was totally NOT impressed. Blade chipped after a couple weeks and I just threw the thing in the trash can.

Will take a steel blade over a ceramic blade EVERY day of the week.

Good thread, BTW.

 

[sfc_mark]

It is also my understanding that Kyocera makes the Boker blades. I ordered a Boker for a coworker from my wholesale catalog a few years ago. The edge seemed unimpressive at first, but it would actually shave hair from the back of your wrist. They are delicate (brittle), though. They are for vegetables only, no meat as they will chip on bone.

I recently saw the ceramic kitchen knives at Harbor Freight and bought the middle size for $20. It is sharper than the Boker, which was $96 wholesale. Everyone in the family loves it.

 

[John C]

My understanding is the ceramic knives work like saws rather than a conventional knife. The diamond chips are embedded in a soft ceramic carrier (~40 Rc). The diamond chips do the cutting, but eventually abrade away. So in using a ceramic knife, it's important to saw back and forth with little downward pressure, letting the knife dig in, rather than force the knife downwards. I find I get the best cuts when I use this method.

-John

 

[sfc_mark]

My understanding is the ceramic knives work like saws rather than a conventional knife. The diamond chips are embedded in a soft ceramic carrier (~40 Rc).

Um....no.

 

[ArfinGreebly]

Mohs Scale

The ceramic used in knives is up around 8.5 on the Mohs scale, while steel knives run around 6.5 or so. Diamonds are 10 on this scale.

Rockwell isn't used for ceramic, as it's basically stone, not metal.


(Worth noting BTW, ceramics are typically quite a bit harder than marble and other counter top materials. If you're going to use a ceramic knife in the kitchen, a cutting board is more than just "a good idea." It will keep the ceramic blade from scratching hell out of the counter.)

 

[Gordon]

I cut a Gentleman Jack bottle in half with a Mad Dog ceramic after my two sons and I killed it one cold night last year! You have to keep the knife exactly 90 degrees to the surface with moderate pressure and it kinda just deeply scores it so a light tap against a table separates the two halves. Worth the dough, well you should have seen my kids' faces!