Making my own ceramic hone

Razor hones were usually a shellac bond if I'm remembering right.

There's a lot that goes into making a good abrasive stone, but the biggest factors you'll be dealing with are your bond type, bond to grit ratio, and press force when molding them.
 
Oh wow, I didn't even know that.

I thought one of these could be made simply by firing up some clay. I had thought of extremely fine powdered glass as an abrasive. I don't have access to a press.

Meh. Another daydream bites the dust. Thanks for the heads up, anyway.
 
Knife2Grind said:
Oh wow, I didn't even know that.

I thought one of these could be made simply by firing up some clay. I had thought of extremely fine powdered glass as an abrasive. I don't have access to a press.

Meh. Another daydream bites the dust. Thanks for the heads up, anyway.
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Hi,
What exactly was the dream?
Save money?
Save time?
Get something thats not available?
Have you tried your glass powder on a piece of flat wood to see how it works ?
 
Glass dust likely wouldn't do so well anyway, as a hone used to remove much metal. A burnishing effect would be more likely. Silica isn't much harder than simple, basic steels, and might actually be less hard than many more modern steels. If it's ground fine enough (really fine), it may be worth a shot trying it on a strop for finishing edges in simpler steels. Even then, I wouldn't expect it to do more than help remove weakened bits of burrs, as with a bare leather strop.

Other issues come to mind as well. The hazards of working with silica/glass dust are well-known, if it gets into the lungs (or eyes, etc).


David
 
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Yeah you wouldn't want to use glass powder as your abrasive. It's really not hard enough to work well. You'd still be wanting to buy bulk aluminum oxide or silicon carbide, and then you'd need to decide on the grade you were using. Then getting the bond strength calculated right for the particular abrasive and application.
 
Pressing would be the single limiting factor, I would think. I believe these hones are pressed to shape under many, many hundreds of tons of pressure. I don't know a single person with a 2000+ TON press in thier hobby shop.;)
 
DavidHoback said:
Pressing would be the single limiting factor, I would think. I believe these hones are pressed to shape under many, many hundreds of tons of pressure. I don't know a single person with a 2000+ TON press in thier hobby shop.;)
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Hi,
barber hone sizes are ~3inch x 5inch
a bench top shop press provides 6 tons or 12000lbs of force
12000 lbs / ( 3inch * 5inch ) = 800 PSI
or if you use a tall/skinny mold
12000 lbs / (3"*1") = 4000PSI

And grinding wheels are made using 100-5000 psi
and 100psi can be achieved by the weight of two average weight adults :)
 
bucketstove said:
Hi,
What exactly was the dream?
Save money?
Save time?
Get something thats not available?
Have you tried your glass powder on a piece of flat wood to see how it works ?
Click to expand...

My dream was to just take some clay, from a creek, and form it to a flat rectangular shape, and heat it up in a furnace until it was ceramic (like an unglazed coffee mug). Without even adding an abrasive.

I have seen, for example, this guy (Cliff Stamp) sharpen a knife to the point where it would make cross-grain push cuts on thin paper, using a simple brick. I figured my little clay hone, which would be much smoother and heated far beyond brick temperatures, might do.


I was not even aware these old vintage razor hones were made with presses, I always thought they were just clay fired in a furnace.
 
Knife2Grind said:
My dream was to just take some clay, from a creek, and form it to a flat rectangular shape, and heat it up in a furnace until it was ceramic (like an unglazed coffee mug). Without even adding an abrasive.

I have seen, for example, this guy (Cliff Stamp) sharpen a knife to the point where it would make cross-grain push cuts on thin paper, using a simple brick. I figured my little clay hone, which would be much smoother and heated far beyond brick temperatures, might do.


I was not even aware these old vintage razor hones were made with presses, I always thought they were just clay fired in a furnace.
Click to expand...


If you go to the right creek, you can get a stone for sharpening that will work very well without having to fire it. It will need to be flattened. Super fine ones are not common in my area, but fine siltstones are not too difficult to find that produce an edge in the 600 grit range. Look for sandstone type formations. The abrasive is quartz, so it won't work great on modern high carbide steels, but on low carbide stainless and carbon steels they work very well. I use one for backpacking and it puts an edge on my hatchet that cleanly shaves arm hair. A little homework should point you to where you can find likely stone deposits in your locality.

The technology behind the old barbers hones is pretty involved...

Here's some more info re how the old timer's used to do it:
https://bosq.home.xs4all.nl/info 20m/grinding_and_honing_part_1.pdf

Some interesting info on "knife boards" starting on chapt 3
 
Cliff mentions in the video, about sharpening on a clay brick, that many manufactured bricks also contain about 20% alumina (aluminum oxide). In doing some of my own reading on bricks (driven by the same curiosity towards sharpening), I seem to recall alumina is added for brick applications exposed to high heat (fireplace/furnace brick, for example). For extreme heat applications, some will have an even higher percentage of alumina added. If it's in there, that'll have a much bigger impact on how successfully one might be able to cleanly abrade the steel in a knife blade. Aluminum oxide is about 3X as hard as most simple knife steels, and harder than some carbides (chromium carbide, tungsten carbide, for example) as found in some higher-alloyed steels. It's less likely you'll find much alumina in simple clay from a creek, if any at all. It occurs in nature and is mined in specific areas of the world, but I don't think it's all that easy to find otherwise.

If it were just silica, a.k.a. silicon dioxide, as he also mentions as a component, it's kind of a toss-up as to how well that'll work. With some steels, maybe so; with others, likely not so good. And bricks seem to vary all over the place in their composition. I've tried one red brick on simple pocketknives in simple steel (like 420HC, or even 1095 or CV), and it didn't abrade even those steels very well at all. A lot comes down to a combination of the hardness and the particular shape of the grains in the brick, some of which the grains will be too round/blocky to cut well; especially if they're also not much harder than the steel being worked. This is the same variation I've seen in trying different rocks/stones found on the ground. Sometimes you get lucky and find one that can work with a given blade. More often than not, though, they often just beat up the edge, rather than cleanly shaping it.



David
 
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Do they really add alumina to the clay before firing it??? I thought alumina was just a natural constituent of most clays.
 
Ah my apologies Dave I see what you were on about. Perhaps the clay in my neighborhood doesn't have much alumina, I have no way of knowing. Thanks for the help, guys.
 
Knife2Grind said:
Do they really add alumina to the clay before firing it??? I thought alumina was just a natural constituent of most clays.
Click to expand...

Based on what I've read, alumina (Al2O3) is generally added in amounts according to the application for the brick's use. Of the bricks I've tried, if it's been there at all, it's likely an insignificant amount (very small).

And of the natural 'clays' I've read about, it's generally a material called 'kaolin' or 'kaolinite', which isn't very hard. It contains aluminum, and is referred to as an 'aluminum silicate'; but it's only ranked at Mohs 2-2.5 in hardness, as compared to most hardened steels at Mohs 5-7, most of the time.


David
 
Yeah as a general rule of thumb you won't find any aluminum oxide in common rocks, but you'll probably find siltstones or sandstones with a good amount of silicon dioxide.
 
Knife2Grind said:
My dream was to just take some clay, from a creek, and form it to a flat rectangular shape, and heat it up in a furnace until it was ceramic (like an unglazed coffee mug). Without even adding an abrasive.

I have seen, for example, this guy (Cliff Stamp) sharpen a knife to the point where it would make cross-grain push cuts on thin paper, using a simple brick. I figured my little clay hone, which would be much smoother and heated far beyond brick temperatures, might do.

I was not even aware these old vintage razor hones were made with presses, I always thought they were just clay fired in a furnace.
Click to expand...
Hi,
If you like that kind of fun you can do that, no need to dream about it, its low-tech
ClayPotFilter_final_web.pdf (bake it with/on dry cow poop)
How to Find, process, and fire clay without a kiln

You can also spike the mix with aluminum oxide or silicon carbide
from $1 sandpaper or a dollar tree sharpening stone,
soak and scrape the "dry" paper,
cook or burn the wet-dry,
crush the stone , not difficult, break into pieces, rub corner into dust against a flat
... dont forget to laugh about this part :D
 
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