Thread: Jnats... best guide for getting started?

My Karasu arrived and I'd did maybe 200-250 laps with just water on my Morris sculptor edge. Was interesting. Took about 100-150 laps before I got any noticeable "slurry" off it. Water just started to look slightly carbonated. A glance at 100 and I saw that it was tiny silica? particles. Another 100 or so laps and the water looked clear, but the particles were still visible under magnification (the reduction of size with use that everyone talks about I suppose). The thing cuts super slow. I had some 4k scratches left in it and it basically just misted them up. No idea what grit it is, but it's finer than my swaty at least.

What's the best place to read about technique using this. I just toyed around with it really, but a few questions immediately:

1. Once I get a slurry going should I let it dry completely, or just reduce the amount of water I add and keep it just barely moistened, or something else?

2. When finished if the stone is close to dry (maybe 30sec-1min away) should I wipe it off or let it air dry?

Thanks in advance.

See my album for pics Or my thread in show and tell.

If you figure the stone to be finer than a Swaty its obviously in the finishing class.
Should be used after 8k not 4k. You may just be trying to do too much with it. 250 laps seems excessive. My finisher is an Asagi & stays pretty wet during the final polish but that's only 30 or so strokes so not likely to dry out. I usually just wipe it off when finished. Also as a rule with J-Nats its wise to coat the base & sides with some kind of laquer if it isn't already ~ some stones tend to crack. I use an Atoma 1200 diamond plate to generate a light slurry ~ keeps the particle size uniform rather than using a Nagura stone which could mix coarser grit in with the slurry of a finishing stone.

Nice looking stone, Ian. Good luck with it!

Originally Posted by onimaru55

If you figure the stone to be finer than a Swaty its obviously in the finishing class.
Should be used after 8k not 4k. You may just be trying to do too much with it. 250 laps seems excessive. My finisher is an Asagi & stays pretty wet during the final polish but that's only 30 or so strokes so not likely to dry out. I usually just wipe it off when finished. Also as a rule with J-Nats its wise to coat the base & sides with some kind of laquer if it isn't already ~ some stones tend to crack. I use an Atoma 1200 diamond plate to generate a light slurry ~ keeps the particle size uniform rather than using a Nagura stone which could mix coarser grit in with the slurry of a finishing stone.

Oz, I'm certainly no expert in the subject, but ercently I've been talking to several people about the lacquering issue because the stones I got from my barber weren't lacquered, and he used them for decades with no apparent ill effects.

Apparently, the advice about lacquer is for carpenters, who tend to work and sharpen outside--so if they leave their stones out in winter, the water that's seeped into the seams in the rock might freeze and crack the stones. All of the people here I've talked to have said there is no need to lacquer indoor stones, like barbers (and we) use.

Just something I've been picking up.

It's a 4k king so it is 8k. I go back and forth with what to call it. I'm gonna just start saying 4k JIS or 8k mesh whenever I refer to it to avoid confusion.

I've got a 1200 DMT I'll use once I've gotten a better feel for the stone to slurry it.

I'm pretty sure it has been laquered although it does appear bits have chipped off exposing unlaquered rock. I'll repair that as soon as I get a chance.

Yeah, I know 250 is a lot. I was using zero pressure and just wanted to see what the thing would act like at its least aggressive. It was like honing on greased glass most of the time, until the surface got just short of dry (when the water becomes really tacky for that minute or so), then the friction went through the roof. Not so much I wasn't comfortable honing with one hand, but you know how you can feel almost like there's a patch of something sticky on the stone and it grips at parts of the spine every once in awhile? That was happening.Then as soon as it's dry (Or I add more water) it becomes like glass again.

Thanks for the advice.

Originally Posted by JimR

Apparently, the advice about lacquer is for carpenters, who tend to work and sharpen outside--so if they leave their stones out in winter, the water that's seeped into the seams in the rock might freeze and crack the stones. All of the people here I've talked to have said there is no need to lacquer indoor stones, like barbers (and we) use.

Cheers Jim. I was generalising. Extremes of temp. are a concern with most stones. Not sure about the others but IIRC Suita stones can tend to crack & I've got some Narutaki & Uchigomori koppa that break up easily but that's useful in some applications

Personally, I don't generate a slurry on my finishers. By the time I get to higher grit hones (coticule, Asagi, C12k, whatever), I'm just doing some final polishing/smoothing, so there is no reason for slurry. I'm not looking to remove much metal so I don't need the cutting speed (well, the speed would be nice on the C12k I guess), and I don't want to cut into the edge much. Furthermore, some finishers (and I believe this is true of Japanese naturals, but please correct me if I'm mistaken) break down with use to become progressivly finer, and it seems that creating a slurry would counteract that effect.

If I was going to slurry, I don't think I would use a DMT 1200, because I think that would leave scratches in the hone. I try to stick to using a slurry stone of whatever hone I'm using (bbw for bbw, coti for coti, appropriate nagura for Japanese natural, etc).

I'm not really sure what you are asking in question 1. When using a slurry, I typcially create a mild slurry and then slowly dilute as I go along (the rate depends on what stone I'm using). If I want to maintain a level of slurry, I usually completely rinse off the hone and re-create the slurry as needed. From the way you worded your question, it sounds like you want to increase the concentration of the slurry - but I don't know why one would do that, so I must be misreading.

To answer your second question, I keep the sides of my Asagi dry at all times and I always dry off the hone after using her. My understaning of finishers is that you only want the thinnest glazing of water on the hone; this only takes a couple of drops. This means that I don't have water running down the sides of the hone. While I do think that there would have to be substantial water absorption and temp change to damage the hone, it's certainly not something I'm going to risk. It's a great hone, an expensive hone, and a gift - I'm not going to mess about.

With my Aoto I'm not nearly as concerned. That thing drinks in a fair bit of water during use so I do have water running down the sides. All I do is take care to dry her off after use, and I don't soak her for any length of time - I just keep the top nice and wet.

Originally Posted by IanS

It's a 4k king so it is 8k. I go back and forth with what to call it. I'm gonna just start saying 4k JIS or 8k mesh whenever I refer to it to avoid confusion.

I've got a 1200 DMT I'll use once I've gotten a better feel for the stone to slurry it.

I'm pretty sure it has been laquered although it does appear bits have chipped off exposing unlaquered rock. I'll repair that as soon as I get a chance.

Yeah, I know 250 is a lot. I was using zero pressure and just wanted to see what the thing would act like at its least aggressive. It was like honing on greased glass most of the time, until the surface got just short of dry (when the water becomes really tacky for that minute or so), then the friction went through the roof. Not so much I wasn't comfortable honing with one hand, but you know how you can feel almost like there's a patch of something sticky on the stone and it grips at parts of the spine every once in awhile? That was happening.Then as soon as it's dry (Or I add more water) it becomes like glass again.

Thanks for the advice.

S'ok, I 'm not confused I used to use King's & sometimes still do. I would still recommend something like a King 8k before the Karasu. It just really saves a lot of time. If you do that you'll get to that greasy sticky point on a J-Nat polisher with just water in a very few strokes & the blade will be ready. Much beyond that & you can over hone but of course your stone may be as slow as you say. It's all about learning your individual stone. You've tried the 250 pass madness . Now maybe try see what 5 or 10 does to a nearly shave ready blade.
And I wouldn't worry about re-laquering a few exposed chips.

YMMV

With my finisher with slurry I am able to get a razor from 5k stone all the way.
For slurry you can use a 1.2k DMT plate or nagura. As far as I know nagura is not recommended for Suita stones.

Originally Posted by holli4pirating

Personally, I don't generate a slurry on my finishers. By the time I get to higher grit hones (coticule, Asagi, C12k, whatever), I'm just doing some final polishing/smoothing, so there is no reason for slurry. I'm not looking to remove much metal so I don't need the cutting speed (well, the speed would be nice on the C12k I guess), and I don't want to cut into the edge much. Furthermore, some finishers (and I believe this is true of Japanese naturals, but please correct me if I'm mistaken) break down with use to become progressivly finer, and it seems that creating a slurry would counteract that effect.

I thought it was the slurry that breaks down

If I was going to slurry, I don't think I would use a DMT 1200, because I think that would leave scratches in the hone. I try to stick to using a slurry stone of whatever hone I'm using (bbw for bbw, coti for coti, appropriate nagura for Japanese natural, etc).

Can't speak for the DMT as I use an Atoma but the Asagi is so hard I need a loupe to see any scratches. Still looks glassy to the naked eye. I think a well worn diamond plate is pretty safe. It's an idea that So uses to prevent Nagura scratches. Some stones like Suita can have small holes or pits in the surface that trap the larger Nagura particles scratching the finish. Of course not as big a risk on an Asagi as they have no Su (holes) but it does give you a slurry of equal size to the stone. YMMV

Oz, it is my understanding as well that the slurry is what breaks down...

Also, thanks for the info on your stones...I'd never thought about softer finishers breaking down like that. Good call.