Thread: Slurry when?

Is there a general rule for when to let slurry build up and when to not? I see some guys with a puddle of black mud on their stone, and some guys who hone under running water, so there's gotta be some difference I'm missing right?

I am far from the world's foremost authority but in broad brush strokes slurry is used to speed the honing process and minimize the amount of strokes. The more strokes the more wear. Slurry is used at the beginning of the process for that particular stone and in general early in the progression. However, you may slurry a finishing stone also then dilute to plain water. Honing under running water comes at the very end in the polishing stage to remove slurry and swarf so it is just stone and steel.
I'm sure others will chime in with more complete information.

I think Paul has managed to summarize the basic idea of using slurry quite well.

There is a kind of magic to using slurry with natural stones that you learn as you work with the stone. Japanese natural stones (JNats) can take a long time to learn even with hand holding provided by experts like our own Euclid and coticules take patience and practice that reveal the characteristics of each particular stone you have. The principals are the same as Paul outlined:
•. thicker slurry to start with (like milk, not heavy cream) to reduce the natural grit of the stone and remove more metal
•. thin the slurry incrementally with water to gradually refine the edge
•. finish on plain water (or dry) to polish the final edge

I’m not sure that building a starting slurry is as important when you are working through a full progression of synthetic stone grits. Gssixgun, I think, would advise taking advantage of the slurry that forms as you hone, but in my opinion, working through a progression of grits accomplishes what diluting the slurry with single stone honing with a natural stone does.

Of course, many of us use a combination of synthetic and natural hones, so we create our own hybrid slurry progressions. If I have a really beat up blade (nicks, rust on the edge, terrible bevel), I’ll start with a diamond plate to reshape the bevel; move to a 1K Shapton to continue that process; move to 4k/8k Norton to refine the bevel and then finish with slurry on a coticule or Oozuku. Final polish will be on a high grit natural like a Vermio or la Lune followed by chromium oxide on a paddle strop.

That’s me. Others have their preferred progressions. You figure it our for yourself with the stones you acquire and the blades on which you are working. And, you read all about how the honemeisters here do it and refine your strategies accordingly. No simple, single answer, but that’s what makes this a fun hobby.

Yep. As one member's signature says, "there are many roads to sharp." Each stone, razor and honer is different. I would say that one is best advised to listen to others, consider what multiple people say then find your own personal way based on the best available information.

My advice for whatever that is worth is to finish a razor on your highest synthetic. Then make a small slurry about the size of a quarter. And work that. Try to maintain the sharpness at first. Once you get that down you can experiment with different amount etc. From what I've seen at various meets we have had in NY over the years is newer guys tend to make a huge slurry. And slurry dulling is a thing. not saying that large slurries are bad. But take it little by little. Once you master a small slurry you can work that up. I'm no expert admittedly. But I'm just telling you what I've seen and done. Good luck.

Slurry is loose grit, it can increase the cutting power of a stone, but effects can be very stone dependent. Synthetic slurry does not break down, 1k slurry remains 1k and can damage an edge as it hones the bevels. Some Natural slurry does not break down and can have the same effect. Some natural slurry does breakdown finer and is not as aggressive but can still edge damage.

As a rule with a synthetic progression, you can use slurry at the early stages of setting a bevel or removing the previous grit’s stria, but once removed clean the razor and stone and hone on a clean stone to set a new even stria pattern and make a straighter edge.

For naturals it depends on the stone and what you are trying to achieve. If you are trying a one stone honing, heavy slurry can help make the stone more aggressive, thin once the bevels are flat and meeting and you want to polish the bevels and straighten the edge.

If you are finishing on a natural, from say an 8k synthetic where the bevels are flat, meeting, and polished, you may not need slurry or a very thin slurry. If using a Jnat, where you can have a progression of nagura, (slurry stones), you can use them in progression to further refine the bevels and edge, but the same edge impact rules apply.

Edge impact damage is not that critical, because there are easy workarounds, one of which is simply Joint the edge and make a straight edge, then reset the edge to get the already flat bevels to meet, then finish on a clean stone. Or just hone the edge straight on a clean or minimal slurry. Here technique plays a large part.

The best thing for new honers is to get good magnification 60-100x and look at your bevels and edges at various stages of the honing process and become aware of what effect you are having on the bevel and edge. The better you understand the cause and effect you have in you stroke, pressure and slurry/stone combination the better and more repeatable your edges will become.

The goal is a straight edge, but we must polish the bevels to polish the edge. The rub is, you can polish the bevels to a mirror finish and still not have a straight edge.

Originally Posted by PaulFLUS

Yep. As one member's signature says, "there are many roads to sharp." Each stone, razor and honer is different. I would say that one is best advised to listen to others, consider what multiple people say then find your own personal way based on the best available information.

Remember this Paul?



I just test shaved it this morning.

1K Naniwa SS to set the bevel, 3K Naniwa SS, 8K Naniwa SS and then Welsh Lyn Melynym. 60 on cotton, 100 on leather.

Started the slate with slurry and thinned it after roughly every ten laps until it was water, I didn't use running water or dry. I decided to treat it like a coticle basically and had a really good shave with it.

It passes the HHT, treetops and all that good stuff, but more importantly, I am looking forward to my next shave with it.

When I started honing I took everyone's opinions and made my own way from there. I feel this did help me to understand, but you soon learn there are a lot of different ways about it. What really helped fine-tune my honing was to listen to just "one person". Stick with the way that person does it until you can do it over and over. Then try to do different stuff. Slowly adding different ways I got from others to fine-tune MY way of honing. It's like when learning to shave with a straight. Stick with one razor and soap until you learn that equipment. Then change ONE THING and learn again.

Listen to what everyone says as I don't think any of us would steer you wrong on purpose. But I'd pay closer attention to what Marty/Euclid says. He is one of our best teachers. He love to help with pictures and diagrams.

Now in my opinion... You said Black Mud!
Mud is not Slurry! The Black Mud is swarf.
Swarf is microscopic bits of metal. This is something you don't want to hone on for long.
You clean the black stuff off when you can. The slurry is ground bits of your hone.

The slurry is good. Black is not.

BTW, Be sure to get your name in on this month's Giveaway. You have just enough days to be eligible to win. Just take a moment to read the rules of the giveaway and while your at it, check out the rules of the forum. It's not a lot but its best to be informed.

The Art of Slurry

Simply put, the use of slurries is a tool that can be used multiple ways, it isn't just about upping the cutting power..

It takes time and practice with multiple razors and stones to really get the most out of them, the biggest problem is that there are really no set rules. it isn't science, it is an art..