Ceramic Sharpening Stones for Wood Carving Knives
Years ago, I wrote an article about using diamond plates for sharpening.
Afterward, I heard from quite a few people asking the same question:
Why do you like diamond stones better than ceramic stones?
The truth is, I don't.
I like anything that gives me a smooth, sharp edge without making sharpening more complicated than it needs to be.
My preference for diamond stones at the time came down to something much less scientific.
I'm a clutz.
I dropped a ceramic stone on the concrete shop floor.
That didn't go particularly well.
I suddenly had two ceramic stones—and neither one was very useful.
I learned three things that day:
-
Diamond plates are tougher.
-
Maybe I need a rubber floor.
-
I need to stop being a clutz.
None of that means ceramic sharpening stones aren't good.
In fact, a good ceramic stone can put an excellent edge on a carving knife.
You just have to understand where it fits into the sharpening process.
What Is a Ceramic Sharpening Stone?
A ceramic sharpening stone is an abrasive stone used to remove small amounts of steel from the cutting edge of a knife.
As the blade passes across the stone, abrasive particles cut into the steel and gradually reshape and refine the edge.
That's really all sharpening stones do.
Different stones simply accomplish the job in different ways.
Ceramic sharpening stones are commonly made with hard abrasive materials such as aluminum oxide, silicon carbide, zirconia, or other engineered ceramic abrasives.
The exact composition varies considerably from one manufacturer and stone to another.
For a woodcarver, the chemistry isn't nearly as important as understanding how the stone behaves.
A good ceramic stone is hard, stays relatively flat, and can produce a very refined cutting edge.
And that's exactly what we're looking for on a carving knife.
Why Ceramic Works Well for Carving Knives
Wood carving puts different demands on a knife than many other kinds of cutting.
We're not trying to chop through rope or break down cardboard boxes.
A carving knife needs to make clean, controlled slicing cuts through wood fibers.
That means I want a fine, smooth edge.
A ceramic stone can be very good at producing that kind of edge.
Fine ceramic stones remove relatively small amounts of steel while refining the scratches left by coarser sharpening.
That makes them particularly useful toward the end of the sharpening process.
Once the edge is established, I can move to the strop and finish the job.
The Stone Creates the Edge. The Strop Refines It.
This is probably the most important thing to understand about ceramic stones—or any sharpening stone.
A sharpening stone and a strop don't do the same job.
The stone creates or restores the cutting edge by removing steel.
The strop maintains and refines that edge.
If your carving knife is still cutting reasonably well but has lost a little of that effortless slicing feel, don't automatically reach for the ceramic stone.
Try the strop first.
If stropping restores the edge, you're done.
Keep carving.
If repeated stropping doesn't bring the knife back, then it's probably time for a sharpening stone.
That's when the ceramic stone comes out.
Deepwoods Tip
I don't sharpen a carving knife simply because I've been using it for a certain number of hours.
I sharpen it when the knife tells me it needs sharpening.
If the edge still slices cleanly, I strop it and keep carving.
If the strop can no longer restore that clean slicing action, then I know it's time to remove some steel and re-establish the edge.
The less unnecessary steel I remove, the longer the knife keeps the geometry I originally put into it.
Fine Ceramic Stones vs. Coarse Stones
One thing worth knowing about ceramic stones is that many of them are better suited to fine sharpening and edge refinement than heavy repair work.
That's not a disadvantage if you understand what the stone is meant to do.
If you have a badly damaged edge, a chip in the blade, or a bevel that needs significant reshaping, starting with a very fine ceramic stone can turn into a long afternoon.
For that kind of work, I want something more aggressive.
Once the basic edge has been established, a finer ceramic stone makes much more sense.
Think of it like sanding wood.
You wouldn't normally remove saw marks with your finest sandpaper.
You start coarse enough to do the work efficiently and then move progressively finer.
Sharpening isn't much different.
Ceramic vs. Diamond Sharpening Stones
This brings us back to the question that started the original article.
Which is better—ceramic or diamond?
I don't think that's the right question.
Both can sharpen a carving knife extremely well.
Diamond plates tend to cut aggressively, stay flat, and tolerate life in a working shop pretty well.
And, as I learned, they're considerably more forgiving when somebody drops one on a concrete floor.
Ceramic stones can provide a wonderfully refined edge and are especially useful in the finer stages of sharpening.
I don't see one as replacing the other.
They're simply different ways of accomplishing the same job.
If you already own a good ceramic stone and know how to use it, there's no reason to buy something else just because another carver uses diamond.
Learn the sharpening system you have.
Consistency matters far more than chasing the newest stone.
Can You Use a Ceramic Sharpening Stone Dry?
Many ceramic stones are designed to be used dry.
That's one of the things people like about them.
There's no oil bottle to keep nearby and no water stone to soak before you start sharpening.
You can pick up the stone, touch up the edge, clean the stone when you're finished, and go back to carving.
However, ceramic stones aren't all manufactured the same way.
If the manufacturer of your particular stone recommends water, oil, or another sharpening method, follow those instructions.
The goal isn't to prove that one method is right.
The goal is to maintain the knife without damaging either the edge or the stone.
Why Does a Ceramic Stone Turn Dark?
If you've used a ceramic sharpening stone for a while, you've probably noticed gray or black streaks appearing on the surface.
That's normal.
What you're seeing is steel and sharpening residue collecting on the stone as the abrasive removes material from the blade.
Eventually that buildup can reduce how efficiently the stone cuts.
When that happens, the stone needs to be cleaned.
Many ceramic stones can be cleaned with dish soap, water, and a non-aggressive scrubber, although you should always follow the stone manufacturer's recommendations.
A clean stone cuts better than one loaded with metal.
Do Ceramic Stones Stay Flat?
One of the advantages of a hard ceramic stone is that it can stay flat for a long time.
That's useful when sharpening carving knives because the sharpening surface influences the geometry you're putting onto the blade.
A stone that dishes badly can gradually change that geometry.
Hard ceramic stones resist wear better than many softer traditional stones.
That doesn't mean they'll remain perfectly flat forever.
Pay attention to the surface.
Your sharpening equipment needs maintenance just like your knives do.
Ceramic Stones Are Hard—But They're Also Brittle
Here's the lesson I learned the expensive way.
Ceramic is hard.
Hard and tough aren't the same thing.
A quality ceramic stone can resist abrasion extremely well and still break if you drop it on concrete.
Treat it more like a piece of glass than a steel sharpening plate.
Don't toss it loose into a toolbox.
Don't leave it sitting on the edge of the bench.
And if you're anything like me, don't assume you'll catch it before it reaches the floor.
You probably won't.
The Coffee Mug Sharpening Trick
At some point you've probably seen somebody sharpen a knife on the unglazed ring on the bottom of a ceramic coffee mug.
I've seen it too.
Naturally, I had to try it.
It actually worked reasonably well on a utility knife.
Although next time I'll probably empty the coffee out first.
The unglazed ceramic surface on the bottom of some mugs can act as a fine abrasive and touch up an edge.
It's an interesting demonstration of how ceramic can abrade steel.
But for my carving knives, I'd rather use an actual sharpening stone with a known, flat surface.
The coffee mug can go back to doing what it does best.
Holding coffee.
Advantages of Ceramic Sharpening Stones
There are several reasons a woodcarver might like ceramic stones.
They can produce a very fine edge.
Fine ceramic abrasives are well suited to refining a carving knife before stropping.
Many can be used dry.
That makes sharpening simple and convenient.
They stay flat for a long time.
Hard ceramic surfaces resist wear and dishing.
They're relatively easy to clean.
Depending on the stone, accumulated steel can usually be removed with ordinary cleaning.
A quality stone can last for years.
Take care of it and there's very little to wear out.
Disadvantages of Ceramic Sharpening Stones
They aren't perfect.
Fine stones remove steel slowly.
That's good for refinement but not necessarily for repairing a badly damaged edge.
The surface can load with steel.
As the stone becomes dirty, its cutting action may slow until it's cleaned.
They're brittle.
Drop one on a hard shop floor and you may learn the same lesson I did.
You may still need another sharpening surface.
If your ceramic stone is very fine, you'll probably want a coarser stone or plate available for edge repair and reshaping.
None of these are reasons to avoid ceramic.
They're simply things worth knowing before you choose a sharpening system.
How I Would Use a Ceramic Stone on a Carving Knife
For routine carving knife maintenance, my approach is pretty simple.
First, I strop.
If the knife comes back to the edge I want, I stop there.
If stropping doesn't restore it, I move to the sharpening stone.
I use only enough sharpening to re-establish the edge.
Once I've done that, I return to the leather strop.
I don't keep grinding simply because the stone is already sitting on the bench.
Every pass removes steel.
Once the edge is restored, the stone has done its job.
Don't Chase a Perfect Sharpening System
Carvers can spend an incredible amount of time discussing sharpening equipment.
Oil stones.
Water stones.
Diamond plates.
Ceramic stones.
Sandpaper.
Powered systems.
Everyone has a favorite.
I've used enough different sharpening methods over the years to come to a pretty simple conclusion:
Use a system that gives you a clean edge and that you understand well enough to use consistently.
If that's ceramic, use ceramic.
If it's diamond, use diamond.
If you're getting the edge you want with another system, there's no need to change just because somebody tells you their way is better.
The knife doesn't care what you sharpened it on.
The wood only cares about the edge you leave behind.
How Do You Know When the Edge Is Ready?
I don't think you need a complicated test.
Put the knife into wood.
A properly sharpened carving knife should enter the wood without excessive pressure and produce a smooth shaving.
The cut should feel controlled.
The surface left behind should be clean rather than torn or fuzzy.
If the knife does that, the sharpening worked.
That's the test that matters to me.
My Advice
If you already have a ceramic sharpening stone, learn to use it before deciding you need another sharpening system.
A good ceramic stone can put an excellent edge on a carving knife.
Just remember where it fits.
Use the stone when the edge actually needs to be restored.
Use the strop to maintain that edge between sharpenings.
And don't remove more steel than necessary.
Most importantly, don't spend so much time worrying about sharpening equipment that you forget why you're sharpening the knife in the first place.
We're trying to get back to carving.
And if you do decide ceramic is the sharpening system for you, I have one last piece of advice.
Don't drop it.
Trust me on that one.
Frequently Asked Questions
Are ceramic sharpening stones good for wood carving knives?
Yes. Ceramic sharpening stones can produce the fine, refined edge that works particularly well on wood carving knives. Fine ceramic stones are especially useful during the later stages of sharpening before finishing the edge on a strop.
Should I use a ceramic stone or a strop?
Use them for different jobs. A sharpening stone removes steel to restore or reshape the cutting edge. A strop maintains, deburrs, and refines an existing edge. If stropping still restores your knife, there's usually no reason to sharpen it on a stone.
Are ceramic stones better than diamond stones?
Neither is automatically better. Diamond plates generally cut aggressively and are very durable, while fine ceramic stones are excellent for refining an edge. Either can be part of an effective carving knife sharpening system.
Can ceramic sharpening stones be used dry?
Many ceramic stones are designed for dry use, but not every ceramic stone is the same. Follow the manufacturer's instructions for your particular stone.
Why does my ceramic sharpening stone turn black?
The dark marks are primarily sharpening residue and steel removed from the knife. As this material accumulates, the stone may cut less efficiently and should be cleaned according to the manufacturer's instructions.
How do you clean a ceramic sharpening stone?
Many ceramic stones can be cleaned with water, dish soap, and a non-aggressive scrubber. Because ceramic stones vary in composition, follow the cleaning recommendations supplied by the manufacturer.
Do ceramic sharpening stones wear out?
Hard ceramic stones can last a very long time and tend to resist dishing. They still need to be kept clean and protected from impact. Their biggest weakness isn't usually wearing out—it's being dropped and broken.
Do I still need to strop after using a ceramic stone?
Yes. I finish sharpening by returning to the strop. The stone establishes the edge, while the strop removes the remaining burr and refines the cutting edge before the knife goes back into the wood.
Continue Reading
Continue exploring The Deepwoods Handbook:
