Scrap Yard Discussion Forums

Previous Thread
Next Thread
Print Thread
Page 1 of 4 1 2 3 4
ceramic knives? #285510 04/29/09 04:56 PM
Joined: Apr 2009
Posts: 70
M
Midtown Offline OP
Pooch
OP Offline
Pooch
M
Joined: Apr 2009
Posts: 70
Just wondering if anyone has had any experience with ceramic kitchen knives? I took a bit of a gamble and ordered one of these: Ceramic Santoku just to see what they're like.

From what I gather, they're sharp as hell, nonmagnetic, easy to clean and light weight. That's the good part. The not-so-good part is that they're brittle, and can't be sharpened without a DMT stone or equivalent. I'll post some photos and observations when I have any of either, but meanwhile I thought I'd ask, since there are so many friendly, helpful, well-informed folks here <img src="/ubbthreads/images/graemlins/smile.gif" alt="" />

Re: ceramic knives? [Re: Midtown] #285511 04/29/09 05:03 PM
Joined: Apr 2008
Posts: 1,120
Jon C Offline
Junk Yard Dog
Offline
Junk Yard Dog
Joined: Apr 2008
Posts: 1,120
I've never used them, but everything you stated is exactly what I've heard. Let us know how it works out for you, I've been curious about them.



Just one thing, though... there is no "Riddle of Ceramic!" <img src="/ubbthreads/images/graemlins/laugh.gif" alt="" />


JYD #94
Re: ceramic knives? [Re: Jon C] #285512 04/29/09 05:17 PM
Joined: Apr 2009
Posts: 70
M
Midtown Offline OP
Pooch
OP Offline
Pooch
M
Joined: Apr 2009
Posts: 70
what's up, atomic tattoo brother <img src="/ubbthreads/images/graemlins/smile.gif" alt="" />

[Linked Image from img98.imageshack.us]

Re: ceramic knives? [Re: Midtown] #285513 04/29/09 06:25 PM
Joined: Apr 2008
Posts: 1,120
Jon C Offline
Junk Yard Dog
Offline
Junk Yard Dog
Joined: Apr 2008
Posts: 1,120
Sweet! That's awesome.


JYD #94
Re: ceramic knives? [Re: Jon C] #285514 04/29/09 08:56 PM
Joined: Dec 2008
Posts: 1,407
ThePitbullofLove Offline
Junk Yard Dog
Offline
Junk Yard Dog
Joined: Dec 2008
Posts: 1,407
I've got a Boker ceramic.

My brother does too.

Pros-
-Scary sharp
-They stay scary sharp for a long time
-They're easy to clean and don't stain
-Light

Cons-
-Brittle
-Expensive (or they were last time I checked)

My brother took one of his Boker ceramics to work with him one day, and knocked it off the counter. The tip of the blade fractured and came off. It is still usable, but missing the tip, so don't bang them around or drop them...and no battoning!!!

Again, a reminder: These are likely to be the sharpest out of the box cutting instruments you've ever seen (scalpel sharp, razor sharp, broad head arrow sharp), so BE CAREFUL.


[color:"red"]Hey man! There's a beverage involved here...


JYD#92[/color]
Re: ceramic knives? [Re: ThePitbullofLove] #285515 04/29/09 10:08 PM
Joined: Apr 2009
Posts: 120
rmc85 Offline
Mutt
Offline
Mutt
Joined: Apr 2009
Posts: 120
IIRC Boker says it takes special equipment to sharpen ceramic knives.

EDIT: Boker forum on Bladeforums

Last post, last line.

"you cannot sharpen it yourself, it takes special grinding equipment.

Thanks, Terry "

Last edited by rmc85; 04/29/09 10:10 PM.
Re: ceramic knives? [Re: rmc85] #285516 04/29/09 10:12 PM
Joined: Dec 2008
Posts: 1,407
ThePitbullofLove Offline
Junk Yard Dog
Offline
Junk Yard Dog
Joined: Dec 2008
Posts: 1,407
Quote
IIRC Boker says it takes special equipment to sharpen ceramic knives.

EDIT: Boker forum on Bladeforums

Last post, last line.

"you cannot sharpen it yourself, it takes special grinding equipment.

Thanks, Terry "

Yup, industrial grade diamond sharpening wheels...

A ceramic knife is a knife made out of very hard ceramic, often zirconium oxide (ZrO2). These knives are generally produced by compacting Zirconia powder using high pressure presses which apply a pressure of around 300 tons to produce blade shaped blanks. These blanks are very brittle and fragile which can be shattered by a slight blow and special binders are used to retain the shape of the blank until the firing process. Like all ceramics these are consolidated into a dense and strong ceramic by solid state sintering at approximately 1400 degree Celsius for 5-12 hours in a high temperature furnace. The result is a very tough and blunt blade which needs to be sharpened to get the desired cutting edge. The blades are sharpened by grinding the edges with a diamond dust coated grinding wheel.

Zirconia is very hard; it ranks 8.5 on the Mohs scale of mineral hardness, compared to 6 to 6.5 for hardened steel, and 10 for diamond, giving a very hard edge that rarely needs sharpening. However, when sharpening is needed, they cannot be resharpened the same way as steel blades, which are often sharpened with a ceramic whetstone. To sharpen the edge of a blade a material harder than the one that is being sharpened is required, and ceramic knives are usually sharpened with industrial grade diamond sharpeners.

Pure zirconium oxide on the other hand is restricted from broad industrial use due to its polymorphism. This means from room temperature to high temperatures it goes through three phases: monoclinic, tetragonal, and cubic. The volume change on cooling to the monoclinic phase is associated with a large volume change, which often causes failure of the component. To alleviate this effect, additives are utilized to stabilize the high temperature phases to eliminate this volume change. Magnesium, calcium and yttrium are often used to stabilize the zirconium oxide for which yttrium provides the best mechanical properties yielding the charactersitic mother of pearl appearance. The highest strength and more importantly toughest zirconia is produced with 3 mol% yttrium oxide yielding partially stabilized zirconia. This material consists of a mixture of tetragonal and cubic phase with a bending strength of nearly 1200MPa.

Ceramic knives will not rust, leading to their use by SCUBA divers. They are also nonconductive and nonmagnetic, which can be useful for bomb disposal operations. Their chemical inertness to both acids and alkalis and their ability to retain a cutting edge far longer than forged metal knives, makes them a very good culinary tool for slicing and cutting through boneless meat, vegetables and fruits. Since they are very rigid they cannot be used for chopping, cutting bones or frozen foods or prying open things, which may cause the cutting edge to chip off or the blade to break free from the handle. The tips of these knives are resistant to rolling and pitting but may break when dropped to the ground.

Several brands also offer a black blade made by an extra firing or sintering via hot isostatic pressing (HIP). This process turns the ZrO2 into zirconium carbide (ZrC). The transformation to zirconium carbide improves the toughness of the blade, the key limitation to using ceramics in knife blades.

Ceramic knives present a conceptual problem to the security industry since ceramics are not picked up by metal detectors. To solve this problem, many manufacturers of non-military knives include a quantity of metal in each knife to ensure they are detectable with standard equipment. Ceramic knives can be detected by extremely high frequency scanners (i.e. Millimeter wave scanner), although (as of 2006) these scanners are not yet in widespread use.

Last edited by ThePitbullofLove; 04/29/09 10:12 PM.

[color:"red"]Hey man! There's a beverage involved here...


JYD#92[/color]
Re: ceramic knives? [Re: Jon C] #285517 04/29/09 10:53 PM
Joined: Feb 2007
Posts: 8,297
Rainwalker Offline
Junk Yard Dog
Offline
Junk Yard Dog
Joined: Feb 2007
Posts: 8,297
Quote
Just one thing, though... there is no "Riddle of Ceramic!" <img src="/ubbthreads/images/graemlins/laugh.gif" alt="" />
<img src="/ubbthreads/images/graemlins/confused.gif" alt="" /> <img src="/ubbthreads/images/graemlins/confused.gif" alt="" /> <img src="/ubbthreads/images/graemlins/confused.gif" alt="" /> <img src="/ubbthreads/images/graemlins/grin.gif" alt="" /> <img src="/ubbthreads/images/graemlins/grin.gif" alt="" />





I've been tempted to get one more than once, but I'm really afraid I'd break it in no time. <img src="/ubbthreads/images/graemlins/blush.gif" alt="" />


JYD#35 Dog Walkin in the Rain
Re: ceramic knives? [Re: Rainwalker] #285518 04/29/09 10:58 PM
Joined: Feb 2007
Posts: 14,586
Horn Dog Offline
Junk Yard Dog
Offline
Junk Yard Dog
Joined: Feb 2007
Posts: 14,586
Some of the first knives were ceramic or at least not metallic. Obsidian is sort of glass-like or ceramic-like. I would think that they would be great for skinning and such. Maybe not so good for chopping maple.


Horned, dangerous, and off my medication.
Re: ceramic knives? [Re: Rainwalker] #285519 04/29/09 10:58 PM
Joined: Dec 2008
Posts: 1,407
ThePitbullofLove Offline
Junk Yard Dog
Offline
Junk Yard Dog
Joined: Dec 2008
Posts: 1,407
Quote
Quote
Just one thing, though... there is no "Riddle of Ceramic!" <img src="/ubbthreads/images/graemlins/laugh.gif" alt="" />
<img src="/ubbthreads/images/graemlins/confused.gif" alt="" /> <img src="/ubbthreads/images/graemlins/confused.gif" alt="" /> <img src="/ubbthreads/images/graemlins/confused.gif" alt="" /> <img src="/ubbthreads/images/graemlins/grin.gif" alt="" /> <img src="/ubbthreads/images/graemlins/grin.gif" alt="" />





I've been tempted to get one more than once, but I'm really afraid I'd break it in no time. <img src="/ubbthreads/images/graemlins/blush.gif" alt="" />

Ceramic isn't strong: flesh is stronger...
What is the power of Ceramic compared to the hand that wields it?

Contemplate this on the Tree of Woe...[/Doom]


[color:"red"]Hey man! There's a beverage involved here...


JYD#92[/color]
Re: ceramic knives? [Re: Horn Dog] #285520 04/29/09 11:02 PM
Joined: Dec 2008
Posts: 1,407
ThePitbullofLove Offline
Junk Yard Dog
Offline
Junk Yard Dog
Joined: Dec 2008
Posts: 1,407
Quote
Some of the first knives were ceramic or at least not metallic. Obsidian is sort of glass-like or ceramic-like. I would think that they would be great for skinning and such. Maybe not so good for chopping maple.

Obsidian is a glass-like volcanic rock that can be knapped into blades that are wickedly sharp. The Aztecs used obsidian knives, and a particularly nasty club embedded with obsidian blades.

Today Obsidian is used in cardiac scalpels, since the structure allows for a sharper and thinner blade than is possible with steel.

It's some cool stuff.


[color:"red"]Hey man! There's a beverage involved here...


JYD#92[/color]
Re: ceramic knives? [Re: ThePitbullofLove] #285521 04/29/09 11:54 PM
Joined: Apr 2009
Posts: 70
M
Midtown Offline OP
Pooch
OP Offline
Pooch
M
Joined: Apr 2009
Posts: 70
hot [censored], this forum can't be beat for information and personality <img src="/ubbthreads/images/graemlins/smile.gif" alt="" />

Page 1 of 4 1 2 3 4

Powered by UBB.threads™ PHP Forum Software 7.7.3