Thread: How much slurry on a coticule?

How much slurry should you keep on a yellow coticule when honing?

Presently, I get a good slurry on the stone with a slurry stone before honing. But after a few passes, teh slurry begins to run off the sides of the stone or build up on the blade. Should I stop then and use the slurry stone again until I see slurry floating on the stone or does sufficient slurry remain to maintain its effectiveness so long as the stone is moist?

I don't have that problem with slurry on stones. If it runs off the sides, you may be using too much water and if it all seems to scoop up into the hollows like a shovel, you may need a bit more water. Can you experiment a bit more with the water and slurry consistency and report back if that makes a difference for you?

Chris L

I'll give it a shot this evening.

You can use the yellow coticule in three different ways, depending what you're trying to achieve

• With slurry
• With water only
• Without water

Each one will give you a different degree of cut (grit)

I use the slurry after establishing a bevel with a DMT-8E
Then I move on to water only

Instead of using it withou water I move to a 3M 1 micron abrasive film and finish with 0.5 chromium oxide.

Now the secret is out

Many ways to skin a cat.

With slurry, a coticule cuts very fast. The result is very smooth, but the free floating garnets in the slurry also affect the very tip of the edge, by "micro-rounding" it. This effect is more severe with a very dense slurry, than with a thiner slurry. Normally the slurry needs to have the consistency of coffee milk. But do note, that the resulting edge will only shave marginally.

With water, a coticule cuts very slow. It excels in polishing grit marks of another hone, but once it hits the bottom of a given scratch pattern, it is much to slow to do any further refining of the edge.

For this reason, a coticule with water cannot improve much on the edge formed by a coticule with slurry. The slurry edge is already smooth, and the water-honing really is way to slow.
To put this differently: if you take the sharpest edge you can get of any synthetic brand 4K hone and you polish that on a coticule with water, you'll end up with a much sharper razor than when you would include a slurry session before the water session.

Conclusion: if you want to use the coticule as a finisher after a progression on coarser hones, then use it only with water.

There's a method for circumventing the slurry-water problem, which allows for honing a razor on nothing else but one coticule, but that requires a secondary bevel, which is a more advanced technique.

Best regards,
Bart.

I have had a bit of luck setting a bevel on 1200 grit wet'n'dry sandpaper (untill I get a DMT1200 thingy), then onto a Belgian blue whetstone, Coticule with water only and finaly metal polish on 3 layers of newspaper taped to a flat surface.
I have also found that a coticule with slurry makes for a blunt edge.
I would love to try and sharpen a knife that has an edge setting spine (ala razor) on a coticule with a good slurry, fast and sharp enough too

Originally Posted by littlesilverbladefromwale

I would love to try and sharpen a knife that has an edge setting spine (ala razor) on a coticule with a good slurry, fast and sharp enough too

Ahhh... you have just decribed a Scandinavian Sloyd knife (Mora of Sweden is a common brand). It's actually more like a wedge blade as both bevels are very wide and flat. The steel however is laminated, softer steel on the sides and a narrow layer of high carbon steel in the center.

With all that metal to remove, it takes some time to get a dull knife honed up..... could be why I hollow ground the bevels on mine with a 12" diameter honing wheel!


Kaptain "Herring for lunch, why not!?!?" Zero

Hi Zero. Some porn or links please?
I like the sound of these knifes

Well, its hardly worth getting excited about..... they are rather crude knives actually, meant for traditional woodworking (whittling) and the like.... here' a couple of pictures, hard plastic sheaths and all... I remember when they came with a leather sheath though... They are handy in the shop, inexpensive enough to not have to worry about and there's no way you can break them unless you really go out of your way to try! Lee Valley sells the ones pictured here, I got mine while I lived in Norway.





Regards

Kaptain " I grew up on whale meat in the 60s......<sigh>" Zero

wow those are cool i like the wide bevels