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Wabisabi-Ken

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Hi guys, so I just joined the jnat club. Took a gamble on yahoo and now here I am wondering what it is that I may actually have and in need of some advice regarding sealing it and wondering about filling in a stray cut.

The only info I had on the stone was Kyoto mizukihara, any insight on it at all would be cool. The stone seems to be somewhat hard, getting a slurry going seems to take a fair bit of effort, it isn't very thick and is a light yellowish brown I guess. I was hoping for something that would give me a nice kasumi finish (I'm dreaming of not spending a fortune for a jnat that can do so 🤣) but this little guy seems too hard and doesn't really give much contrast between the core and cladding. Maybe I need to refine technique, or play with nagura? Who knows.. but if it's too hard maybe I still have hope for it being good for razor sharpening, I think I'll get into using straight razors so not all hope is lost 🤣


IMG_20220612_230142.jpg
IMG_20220612_230057.jpg

There you can see the stray cut, I was wondering if there's any way I can fill it in so it won't become a hole in the future. Assuming it would become a problem once it's exposed?

I am also wondering about what is the cheapest method for sealing the stone?

Any help appreciated, thanks guys!
 
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I don't know anything about the use of that particular sort of jnat I'm afraid. But in answer to some other q.s...

No you don't need to fill the cut mark, that will be fine. (The stone has been cut on all of the main sides too after all!)

The cheapest ways to seal a stone are: clear oil-based wood varnish or stone sealant (kind of thing people put on slate flooring for example). Or I believe you can do it also with kinda spray on waterproofing stuff. All should be easily available in a hardware store and $10 US worth will last for dozens of stones. You'll want a few coats.
 
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Maybe try getting some slurry worked up with a diamond plate. If you don't have any naguras on hand that works just fine. It should help with contrast. Technique is also huge though.
 
If you’re in Japan the local hardware stores sell “Cashew” lacquer. It’s spelled in English so it’s easy to spot. Yellow is good if you want the classic yellow tint and you’ll need a little bit of thinner.

There is also now a spray clear urushi (うるし) . Very small spray can and costs about ¥1000. This is great stuff IMHO. Find the Cashew and you’ll find this nearby in the same section.
 
Hi guys, so I just joined the jnat club. Took a gamble on yahoo and now here I am wondering what it is that I may actually have and in need of some advice regarding sealing it and wondering about filling in a stray cut.

The only info I had on the stone was Kyoto mizukihara, any insight on it at all would be cool. The stone seems to be somewhat hard, getting a slurry going seems to take a fair bit of effort, it isn't very thick and is a light yellowish brown I guess. I was hoping for something that would give me a nice kasumi finish (I'm dreaming of not spending a fortune for a jnat that can do so 🤣) but this little guy seems too hard and doesn't really give much contrast between the core and cladding. Maybe I need to refine technique, or play with nagura? Who knows.. but if it's too hard maybe I still have hope for it being good for razor sharpening, I think I'll get into using straight razors so not all hope is lost 🤣


View attachment 183934View attachment 183935
There you can see the stray cut, I was wondering if there's any way I can fill it in so it won't become a hole in the future. Assuming it would become a problem once it's exposed?

I am also wondering about what is the cheapest method for sealing the stone?

Any help appreciated, thanks guys!
I'd like the measurements in millimeters and the weight in grams so I can give you an approximate hardness number. Length, width, thickness, weight.
 
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It's a level 4.5 in hardness. Should work well as a razor stone.
Could you elaborate on how you determine the hardness by dimensions and weight? It seems like it has something to do with density I guess.
I am new to Jnats and your calculation seems pretty interesting to me.
 
@Grayswandir you’re awesome, calculating the hardness for others :). I remember that great recent discussion, probably @cotedupy has something to do with it, about density and hardness.

@Wabisabi-Ken the cut should be no problem, but if it starts catching on stuff I’d chamfer it with a file or diamond plate. Same goes for the rest of the edges hard corners, I like a bit of wiggle room when polishing.

I used Home Depot random brand spray lacquer, it’s cheap and seems to work well. There’s better options I’m sure but I have no problems with it. I hate the offgassing period when The jnat smell is covered tho.

Re: kasumi finish - mud mud mud, and then technique x1000. Diamond plate, nagura, hell even synthetic nagura (although this may not show the true finish the stone is capable of). It’s possible it’s too hard to be an easy polisher, in which case I think there’s a couple small uchigumori floating around.. but if you’re looking for big contrast something in the 2.5-3.5 hardness range might give you a less stressful time. Welcome to the rabbit hole 😁
 
Could you elaborate on how you determine the hardness by dimensions and weight? It seems like it has something to do with density I guess.
I am new to Jnats and your calculation seems pretty interesting to me.
Hello,

A friend of mine named Greg runs a website called naturalwhetstones.com and all the credit goes to him. He figured out the math (quite simple to carry out on a calculator) and it was designed specifically for Japanese natural stones. If you want to figure out the hardness of other stones, you have to figure out a few different, specific things about the makeup of the stones.

This is the scale:

Jnat Hardness Scale.jpg


Cotedupy knows quite a bit about natural stones, he's a great resource and he's helped me out for sure.

-gray.
 
@Grayswandir you’re awesome, calculating the hardness for others :). I remember that great recent discussion, probably @cotedupy has something to do with it, about density and hardness.

@Wabisabi-Ken the cut should be no problem, but if it starts catching on stuff I’d chamfer it with a file or diamond plate. Same goes for the rest of the edges hard corners, I like a bit of wiggle room when polishing.

I used Home Depot random brand spray lacquer, it’s cheap and seems to work well. There’s better options I’m sure but I have no problems with it. I hate the offgassing period when The jnat smell is covered tho.

Re: kasumi finish - mud mud mud, and then technique x1000. Diamond plate, nagura, hell even synthetic nagura (although this may not show the true finish the stone is capable of). It’s possible it’s too hard to be an easy polisher, in which case I think there’s a couple small uchigumori floating around.. but if you’re looking for big contrast something in the 2.5-3.5 hardness range might give you a less stressful time. Welcome to the rabbit hole 😁
I didn't realize Home Depot carried a spray lacquer. Is it in the same aisle as the denatured alcohol and the poly/shellac finishes?

Thanks,

-gray.
 
I didn't realize Home Depot carried a spray lacquer. Is it in the same aisle as the denatured alcohol and the poly/shellac finishes?

Thanks,

-gray.
I use the minwax brand spray lacquer, purchased at lowes. Worked well on the three stones I sealed. Did about 6 coats with 30 minutes between coats then 24 hours to dry.
 
I didn't realize Home Depot carried a spray lacquer. Is it in the same aisle as the denatured alcohol and the poly/shellac finishes?

Thanks,

-gray.
At my local store it’s the isle adjacent to the paint counter - drop cloths, brushes etc and paint cans. There’s a bunch of lacquer near the end, a few different kinds. I can’t remember what exactly it was, but works well. I haven’t used it with a thirsty stone yet.. the day will come.
 
At my local store it’s the isle adjacent to the paint counter - drop cloths, brushes etc and paint cans. There’s a bunch of lacquer near the end, a few different kinds. I can’t remember what exactly it was, but works well. I haven’t used it with a thirsty stone yet.. the day will come.

I have a Sigma Power 1K and 2K (not the Select II series) which are super thirsty stones. Water goes in one side and straight out the bottom. I intended to seal the sides and bottom to retain the water. I used some generic spray lacquer and even with several sprayings it was completely absorbed into the stone. Later I used thick Cashew lacquer which worked and water consumption is notably reduced.

Later I pondered, if I sprayed enough lacquer into the Sigma Power, could it theoretically be turned into a splash and go? By extension I wonder if there is an effective technique for turning soaking stones into splash and go’s?
 
@Grayswandir you’re awesome, calculating the hardness for others :). I remember that great recent discussion, probably @cotedupy has something to do with it, about density and hardness.

@Wabisabi-Ken the cut should be no problem, but if it starts catching on stuff I’d chamfer it with a file or diamond plate. Same goes for the rest of the edges hard corners, I like a bit of wiggle room when polishing.

I used Home Depot random brand spray lacquer, it’s cheap and seems to work well. There’s better options I’m sure but I have no problems with it. I hate the offgassing period when The jnat smell is covered tho.

Re: kasumi finish - mud mud mud, and then technique x1000. Diamond plate, nagura, hell even synthetic nagura (although this may not show the true finish the stone is capable of). It’s possible it’s too hard to be an easy polisher, in which case I think there’s a couple small uchigumori floating around.. but if you’re looking for big contrast something in the 2.5-3.5 hardness range might give you a less stressful time. Welcome to the rabbit hole 😁


Could you elaborate on how you determine the hardness by dimensions and weight?


Specific Gravity of stones is an interesting subject, and is often misunderstood somewhat, or used incorrectly. I'll do a post about it sometime, including explaining how to measure it accurately and easily.

Though just to be clear - @Grayswandir isn't misunderstanding it here. The scale he posted is for exactly the kind of stone that OP has, and so should give a good estimation of hardness. It's an interesting and useful resource I think; I hadn't seen SG used like this for jnats until he sent to me that scale a few weeks back.
 
@Wabisabi-Ken

@Grayswandir gave you a good perspective. That said... numerical scales are a pet peeve of mine. I think it gives beginners the impression that it is easy to quantify how a stone will work without actually using them!! It is worth being aware that these scales are completely arbitrary. I dont mean to imply they are useless (or poo-poo anybody's scale)....they are useful tools for vendors and customers. For example note that JSN, Aframes and Watanabe each have their own system/scale. No doubt, they will be correlated but there is no exact conversion from one to the other.. So just be aware that these numbers are not some absolute standard...

Indeed, as far as I understand it, the Japanese dont think about stones so numerically... they are less exact (which in some ways might be more precise!!). Instead they think about broad categories, coarse (arado), medium (nakado) and finishing (awasedo). These grades will have correlated physical and geological attributes... but in the end you just have to try a stone... this is why the forum recommends buying from reputable vendors. But... for what it is worth... I think making low stakes gambles on yahoo is an equally valid approach if you dont mind a harder learning curve and suffering the inevitable duds...


If you’re in Japan the local hardware stores sell “Cashew” lacquer.

@Wabisabi-Ken, do some due diligence. There is antecedal evidence the real-deal cashew can cause allergic reactions. Even if it is not a bother to your health, it is more fiddly... you'll have to thin it and apply it. So unless you are dedicated to being traditional, don't use cashew!!! That said... modern "cashew" lacquer might be "cashew lacquer" in name only... and may have been reformulated to be less toxic and faster drying.

As others have said... if you aren't determined to be traditional, you may as well go to a hardware store and buy some marine/exterior clear coat spray. It will probably be a modern and (relatively) safe formulation of polyurethane.

A final note on sealing the stone... this is one of those ambiguous territories. Some people swear their stones behave better when they are sealed. Others are more ambivalent. This only really matters for more porous stones. For performance, if your stone doesn't slurp up water like a sponge, there is less reason to seal the stone. It seems hard... so I doubt it will be thirsty. The other reason is to prevent the stone from cracking. You only need to do this if you can see really obvious sedimentary boundaries in your stone... which I cannot?? Another vain reason might be to preserve stamps ;)

So I say... just start using it an experimenting!!


As for the cut in the side stone.... wabi-sabi man! Leave it be. The Japanese are happy to use irregularly shaped stones (koppa)... even for the geometrically cut ones, it is common for edges to be rough or have chips knocked out the corners....



I was hoping for something that would give me a nice kasumi finish (I'm dreaming of not spending a fortune for a jnat that can do so 🤣)

For your next yahoo 'bet'... buy from sellers who are posting pictures of the slurry. Look for a slurry that is quite muddy. If the slurry is almost entirely black swarf, the stone is hard. You want to see a creamy mud paste with dillusted black metal swarf. See if they are describing the stone as 'fine' or 'finishing'. They might even include words like hazy... Do your best with what images they provide to see if the stone is uniform and has a fine grit. This will take you a step in the right direction... but a fine kasumi finish is a whole skill (and equipment) level to build up!

Surely you can find a toishi seller in Osaka!!! You could even make a trip south to Sakai and make the rest of us jealous...
 
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@Wabisabi-Ken

@Grayswandir gave you a good perspective. That said... numerical scales are a pet peeve of mine. I think it gives beginners the impression that it is easy to quantify how a stone will work without actually using them!! It is worth being aware that these scales are completely arbitrary. I dont mean to imply they are useless (or poo-poo anybody's scale)....they are useful tools for vendors and customers. For example note that JSN, Aframes and Watanabe each have their own system/scale. No doubt, they will be correlated but there is no exact conversion from one to the other.. So just be aware that these numbers are not some absolute standard...

Indeed, as far as I understand it, the Japanese dont think about stones so numerically... they are less exact (which in some ways might be more precise!!). Instead they think about broad categories, coarse (arado), medium (nakado) and finishing (awasedo). These grades will have correlated physical and geological attributes... but in the end you just have to try a stone... this is why the forum recommends buying from reputable vendors. But... for what it is worth... I think making low stakes gambles on yahoo is an equally valid approach if you dont mind a harder learning curve and suffering the inevitable duds...




@Wabisabi-Ken, do some due diligence. There is antecedal evidence the real-deal cashew can cause allergic reactions. Even if it is not a bother to your health, it is more fiddly... you'll have to thin it and apply it. So unless you are dedicated to being traditional, don't use cashew!!! That said... modern "cashew" lacquer might be "cashew lacquer" in name only... and may have been reformulated to be less toxic and faster drying.

As others have said... if you aren't determined to be traditional, you may as well go to a hardware store and buy some marine/exterior clear coat spray. It will probably be a modern and (relatively) safe formulation of polyurethane.

A final note on sealing the stone... this is one of those ambiguous territories. Some people swear their stones behave better when they are sealed. Others are more ambivalent. This only really matters for more porous stones. For performance, if your stone doesn't slurp up water like a sponge, there is less reason to seal the stone. It seems hard... so I doubt it will be thirsty. The other reason is to prevent the stone from cracking. You only need to do this if you can see really obvious sedimentary boundaries in your stone... which I cannot?? Another vain reason might be to preserve stamps ;)

So I say... just start using it an experimenting!!


As for the cut in the side stone.... wabi-sabi man! Leave it be. The Japanese are happy to use irregularly shaped stones (koppa)... even for the geometrically cut ones, it is common for edges to be rough or have chips knocked out the corners....





For your next yahoo 'bet'... buy from sellers who are posting pictures of the slurry. Look for a slurry that is quite muddy. If the slurry is almost entirely black swarf, the stone is hard. You want to see a creamy mud paste with dillusted black metal swarf. See if they are describing the stone as 'fine' or 'finishing'. They might even include words like hazy... Do your best with what images they provide to see if the stone is uniform and has a fine grit. This will take you a step in the right direction... but a fine kasumi finish is a whole skill (and equipment) level to build up!

Surely you can find a toishi seller in Osaka!!! You could even make a trip south to Sakai and make the rest of us jealous...
The point of the scale is so people can run the numbers themselves, before they buy from a stone vendor. A lot of sellers are grossly misrepresenting the hardness of their stones, and this scale is accurate, as long as the stone in question is close to being a rectangle, which most stones for knives tend to be. This scale is very helpful and very accurate for determining specific hardness of Jnats. I've ran the numbers for all my stones and it works well. More importantly, Greg has ran the numbers on hundreds of stones, so his tests are statistically meaningful.

Of course there are other attributes that are very important, like fineness and particle size. Though most hard stones tend to be fine, there are plenty of softer stones out there that are fine, so it's not a hard, fast rule that all hard stones will be finer stones, or that softer stones will be coarser then harder stones, there are always exceptions.

I think it's important for people to be able to run this equation on stones before they buy them, so they'll have a fairly accurate way of determing how hard the stone they are buying truly is.
 
:)

@Grayswandir; like I say... I am not trying to poo-poo anybody's efforts. It is pretty cool that Greg as taken the time to make categories based on an objective measurement.

I hope you can appreciate, for beginners, it might not be clear that various vendors use their own scales. There isn't a ratified standard. Saying 5+ hardness or 9.3/10 hardness is fairly abstract for a beginner. I am not sure it communicates much more than saying 'this stone is hard'... or this stone is 'very hard'.

I don't mean to imply scales have no use! They are good for enthusiasts and they allow vendors to grade their stock. Unless a scale is adopted by all vendors, beginners should just keep in mind that each scale is only really consistent for a specific vendor (assuming the vendor applies the scale objectively every single time). Of course... all scales will be correlated. That is the point! They will communicate the same idea, yet they will not necessarily map cleanly from one to another.

The most objective measurement of hardness might be something like a shore or rockwell hardness test. This is what Watanabe reports... But I have my reservations that an HS or HR test is sensible for stones... these tests rely on plastic deformation... which stones don't do very well!! This measure of 'hardness' isnt quite the same as the way we talk about stone 'hardness' (really wear/dish resistance).

Some vendors base their judgments on a subjective 'vibe' after using or seeing the stone. If the vendor has enough experience, this is fine... particularly if you can have a discussion with them! But this sort of grading clearly isnt something that an independent party can repeat objectively!

Since Greg has opened a store, it is great that he has taken the time to devise a semi-objective method for doing it 👍. A benefit of the method is that everybody can measure density without fancy equipment - so people can compare their own stones to what Greg offers. Like he says, you could even measure density accurately by calculating the volume using water displacement. It would be pretty awesome if he did that for every stone he listed!


Again... I'm not trying to be mean... there is enough mystery around natural stones. I think it is worth being explicit to help beginners navigate the jargon!
 
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@Wabisabi-Ken

@Grayswandir gave you a good perspective. That said... numerical scales are a pet peeve of mine. I think it gives beginners the impression that it is easy to quantify how a stone will work without actually using them!! It is worth being aware that these scales are completely arbitrary. I dont mean to imply they are useless (or poo-poo anybody's scale)....they are useful tools for vendors and customers. For example note that JSN, Aframes and Watanabe each have their own system/scale. No doubt, they will be correlated but there is no exact conversion from one to the other.. So just be aware that these numbers are not some absolute standard...

Indeed, as far as I understand it, the Japanese dont think about stones so numerically... they are less exact (which in some ways might be more precise!!). Instead they think about broad categories, coarse (arado), medium (nakado) and finishing (awasedo). These grades will have correlated physical and geological attributes... but in the end you just have to try a stone... this is why the forum recommends buying from reputable vendors. But... for what it is worth... I think making low stakes gambles on yahoo is an equally valid approach if you dont mind a harder learning curve and suffering the inevitable duds...




@Wabisabi-Ken, do some due diligence. There is antecedal evidence the real-deal cashew can cause allergic reactions. Even if it is not a bother to your health, it is more fiddly... you'll have to thin it and apply it. So unless you are dedicated to being traditional, don't use cashew!!! That said... modern "cashew" lacquer might be "cashew lacquer" in name only... and may have been reformulated to be less toxic and faster drying.

As others have said... if you aren't determined to be traditional, you may as well go to a hardware store and buy some marine/exterior clear coat spray. It will probably be a modern and (relatively) safe formulation of polyurethane.

A final note on sealing the stone... this is one of those ambiguous territories. Some people swear their stones behave better when they are sealed. Others are more ambivalent. This only really matters for more porous stones. For performance, if your stone doesn't slurp up water like a sponge, there is less reason to seal the stone. It seems hard... so I doubt it will be thirsty. The other reason is to prevent the stone from cracking. You only need to do this if you can see really obvious sedimentary boundaries in your stone... which I cannot?? Another vain reason might be to preserve stamps ;)

So I say... just start using it an experimenting!!


As for the cut in the side stone.... wabi-sabi man! Leave it be. The Japanese are happy to use irregularly shaped stones (koppa)... even for the geometrically cut ones, it is common for edges to be rough or have chips knocked out the corners....





For your next yahoo 'bet'... buy from sellers who are posting pictures of the slurry. Look for a slurry that is quite muddy. If the slurry is almost entirely black swarf, the stone is hard. You want to see a creamy mud paste with dillusted black metal swarf. See if they are describing the stone as 'fine' or 'finishing'. They might even include words like hazy... Do your best with what images they provide to see if the stone is uniform and has a fine grit. This will take you a step in the right direction... but a fine kasumi finish is a whole skill (and equipment) level to build up!

Surely you can find a toishi seller in Osaka!!! You could even make a trip south to Sakai and make the rest of us jealous...

The current Cashew lacquer takes a full week to dry to be usable. During that time it has a strong urine and ammonia smell. I can’t confirm toxicity but the stuff is messy. I got it all over my hands and it is hard to get off.
 
The current Cashew lacquer takes a full week to dry to be usable. During that time it has a strong urine and ammonia smell. I can’t confirm toxicity but the stuff is messy. I got it all over my hands and it is hard to get off.

Thanks! Wow... yuck! Sounds messy!

Marine/exterior clear coat polyurethane I say!!
 
:)

@Grayswandir; like I say... I am not trying to poo-poo anybody's efforts. It is pretty cool that Greg as taken the time to make categories based on an objective measurement.

I hope you can appreciate, for beginners, it might not be clear that various vendors use their own scales. There isn't a ratified standard. Saying 5+ hardness or 9.3/10 hardness is fairly abstract for a beginner. I am not sure it communicates much more than saying 'this stone is hard'... or this stone is 'very hard'.

I don't mean to imply scales have no use! They are good for enthusiasts and they allow vendors to grade their stock. Unless a scale is adopted by all vendors, beginners should just keep in mind that each scale is only really consistent for a specific vendor (assuming the vendor applies the scale objectively every single time). Of course... all scales will be correlated. That is the point! They will communicate the same idea, yet they will not necessarily map cleanly from one to another.

The most objective measurement of hardness might be something like a shore or rockwell hardness test. This is what Watanabe reports... But I have my reservations that an HS or HR test is sensible for stones... these tests rely on plastic deformation... which stones don't do very well!! This measure of 'hardness' isnt quite the same as the way we talk about stone 'hardness' (really wear/dish resistance).

Some vendors base their judgments on a subjective 'vibe' after using or seeing the stone. If the vendor has enough experience, this is fine... particularly if you can have a discussion with them! But this sort of grading clearly isnt something that an independent party can repeat objectively!

Since Greg has opened a store, it is great that he has taken the time to devise a semi-objective method for doing it 👍. A benefit of the method is that everybody can measure density without fancy equipment - so people can compare their own stones to what Greg offers. Like he says, you could even measure density accurately by calculating the volume using water displacement. It would be pretty awesome if he did that for every stone he listed!


Again... I'm not trying to be mean... there is enough mystery around natural stones. I think it is worth being explicit to help beginners navigate the jargon!
Hey Luftmensch,

I hope you can appreciate, for beginners, it might not be clear that various vendors use their own scales. There isn't a ratified standard. Saying 5+ hardness or 9.3/10 hardness is fairly abstract for a beginner. I am not sure it communicates much more than saying 'this stone is hard'... or this stone is 'very hard'.
That's the beauty of Greg's little equation, it cuts through all of that minutia, and they can get a pretty accurate hardness or density rating by running the equation themselves. They don't have to take a seller's word on how hard the stone is, because they can run the numbers and find out for themselves. Often times, the seller gets the information on a stone from the wholesaler, so they're not trying to deceive anyone, they're just going off of what their wholesaler told them, and often those rating are off by an entire level.

Most vendors use their experience, and give a subjective rating, just as you said. I personally don't care for subjective opinions, I'd rather have a solid number to rely on, or as close as I can get. I know this is more of a western mindset, and the Japanese do things a little differently from us. Keith Johnson once said (paraphrasing) that the ratings are all over the place, and you really have to judge the stone for yourself.

Greg's site is geared more towards sharing knowledge with the community, though he does sell a few items on ebay now and then. His site is a great place for a beginner to dip their toes into the world of Japanese natural stones. He also has a trusted vendors list, and I'm sure you'd be familiar with many of the vendors on that list.

I took no offense at your post, and I understand where you're coming from. My response was about clarifying how I choose to use Greg's information. I think it's valuable, but there is a margin of error, like anything else, but it's pretty tight. It's hard enough to trust that you're actually buying an Ozuku or a Nakayama, as stamps can be faked, and not all people selling stones are trustworthy.

Sometimes it's a good practice to pick up a stone for less money. and see if you think it's worth getting into Jnats, as a lot of stones are grossly overpriced, and don't come from the mine as advertised. I've found some modestly priced stones to perform very well, but people will spend more for the provenance (stamped vintage stones). If you're going to spend hundreds of dollars for a stone, it really pays to learn all you can about them, and experiment with some less pricey stones.

On the other hand, there are people out there who can afford a $700 dollar stone, and don't mind paying that amount, as long as the stone is what the vendor promised.
 
First of all thanks to everyone for the replies and great advice, chamfering the edges of the cut in the stone hadnt crossed my mind but that definitely seems the way to go, I guess I was worried about the blade dipping in there and causing uneven spots. I will also see what I can find at my hardware store for sealing the stone. although I dont think Ill be in a rush because it seems structurally sound for now.

@Grayswandir thanks for giving me that rough hardness number and the chart for calculating, that is a handy resource and definitely something worth keeping in mind. As for the hardness that seems about right, in my mind when I was using it, the stone definitely seems to be quite fine and takes a lot to get any kind of slurry going, I am not too disheartened as I should have some old Japanese straight razors showing up soon (yet another hole to dive into haha) so lets see how the stone does with that. On my shopping list is an atoma diamond plate and nagura so it will be fun to see how those work with the stone.

@Luftmensch I definitely get what you are saying about the numerical scales being able to lead people astray, I think it is still a handy tool but to be honest I never really would look at that when all I have is pictures anyway, the sellers on yahoo definitely arent very descriptive and it seems a lot of them apply minimal effort in descriptions on purpose so they can just say "it is what it is"... Basically If there werent any photos of the slurry or a blade sharpened by the stone then I wouldnt even consider it... Actually I only had any interest in stones that had pictures of a blade polished by said stone, because I really had no clue on slurry colour or stone types etc. The photo of the kiridashi used on my stone seemed to have a nice contrast on it so that made me hopeful. The stone when I am using it seems kinda tacky or gummy sometimes, like it sometimes grabs the surface of the bevel on high spots or something like that. I am yet to take a really nice flat blade road to it yet, I was considering buying a kiridashi as a kind of a benchmark tester for stones since it is a nice small surface area and should be easier to get consistent results/readings. Seems like a logical approach to me.

I have visited Sakai a couple of times now, it is what got me to take the plunge into knives! Got my first knife there and now im hooked. It is funny though, I am having trouble finding anywhere that more specifically specialises in whetstones here in osaka, on my next visit to sakai I will ask around for leads on where to have a look at stones. Hopefully I will have some luck with that!

Oh and here is a picture from the auction that I kinda based my gamble off of haha. Think its dangerous to assume that the finish he got there may translate into a finish that it could give a knife?

stone.jpg
 
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@Wabisabi-Ken
Nice thread. I am looking what I can get out out of my first not so expensive nats.

Some Mizuhikara are available in Europe. Described to offer good kitchen edges and nice contrast.

@Luftmensch and @Grayswandir
I liked to check the density of my stone. 2.7 indicates a finisher, what I looked for. This stone might be mangable for a beginner. And of course this is only another hint.
 
I took no offense at your post, and I understand where you're coming from. My response was about clarifying how I choose to use Greg's information. I think it's valuable, but there is a margin of error, like anything else, but it's pretty tight. It's hard enough to trust that you're actually buying an Ozuku or a Nakayama, as stamps can be faked, and not all people selling stones are trustworthy.
😍

Thanks for being cool! It is easy to offend (and be offended) on the internet. It is really great that people like Greg take the time to freely share knowledge they have accumulated.

Sometimes it's a good practice to pick up a stone for less money. and see if you think it's worth getting into Jnats, as a lot of stones are grossly overpriced, and don't come from the mine as advertised. I've found some modestly priced stones to perform very well, but people will spend more for the provenance (stamped vintage stones). If you're going to spend hundreds of dollars for a stone, it really pays to learn all you can about them, and experiment with some less pricey stones

Yeah... 100% agree. Experimenting on cheaper stones is probably more wasteful. There will the inevitable dud... or stone that did match your expectations... But that experimentation is a natural education. You learn faster by trying a bunch of different stones.



Actually I only had any interest in stones that had pictures of a blade polished by said stone, because I really had no clue on slurry colour or stone types etc. The photo of the kiridashi used on my stone seemed to have a nice contrast on it so that made me hopeful. The stone when I am using it seems kinda tacky or gummy sometimes, like it sometimes grabs the surface of the bevel on high spots or something like that. I am yet to take a really nice flat blade road to it yet, I was considering buying a kiridashi as a kind of a benchmark tester for stones since it is a nice small surface area and should be easier to get consistent results/readings. Seems like a logical approach to me.

That is a smart approach!

If you want to do a really nice and even kasumi you do need a knife with a flat blade road. If you don't, the low spots will haze differently. A thicker mud can help with this... but it doesn't sound like your stone is conducive to producing lots of mud? It might be really difficult to chase the kind of kasumi you are imagining?

A note on 'razor stones'.... I think beginners read this and dont put much thought into what it means. For a start... as you can imagine, your stone wont explode if you use non-razors on it. Clearly you can use any tool on any stone 😉. You might also wonder... what is a 'hard' stone?? It is a combination of things. For me, it is largely a coded way of saying 'slow to release grit'... which also means slow to generate a slurry. But it can also literally mean that the particles are hard. Often it means both.

Stones that are slow to release grit will cut slowly - the exposed abrasives wear out and are not quickly refreshed by new sharp particles. Conditioning the surface with a nagura can help abrade away the dull abrasives... and... you can generate a surrogate slurry from the nagura to help lubricate and catalyze honing process. You can get a nice gradient where the stone will cut faster when the surface is fresh; as the particles dull and break down, the stone cuts slower and finer. These qualities are useful for razor and tool users. For tools with uras, you want a surface that stays very flat. For tools with uras, it is also advantageous (albeit tedious) to have a slow stone - you want to remove as little steel as possible. Mistakes happen more slowly and you have more time to control the outcome.

Back to stones that (literally) have 'hard' particles. It is possible for particles to abrade hardened steel but not the cladding in an aesthetically pleasing way. If the cladding is soft relative to the stone abrasives... instead of shattering into smaller particles, the abrasives just plough through (scratch) the cladding. Tool users don't care. Tools have a pretty hard life... they would probably get scratched by something anyway! Tools also often have a greater surface area of hardened steel to polish.

Hopefully you can imagine how geological processes correlate some relevant qualities? Fine particles tend to fall to the bottom of a volume. Particles at the bottom will get ground finer and be subject to higher pressures. High pressure will pack the particles closely together by squeezing out water and collapsing any voids. Because small particles are packed together tightly, it may mean less mass per volume is occupied by softer/lighter cementing agents (not 100% sure about this). Anyway... deeper geological layers tend to produce hard and fine stones!

Since kitchen knives won't explode if you use them on a really hard stone... 😉 you can try to get an aesthetic polish by using lots of slurry, very light pressure and patience. More water or slurry might also help with the stickiness you are feeling. On these stones, I think nagura or other tomo-stones are better for generating slurry than diamond plates. I think diamond plates have a higher risk of suspending larger 'scratchier' particles in the slurry. Success in this process can be maddening... you might be doing really well for five minutes and then something scratches the cladding. Doh!!!
 
Here's a little post explaining more about specific gravity (density) of a stone, including how to measure it accurately and easily, potential pitfalls in trying to use it to discern character, and some broad SG ranges for different types of stone:

https://www.kitchenknifeforums.com/threads/specific-gravity-of-whetstones.59567/
The big takeaway (as has been mentioned by others above) is that trying to divine how a stone will act based on SG is often confusing and unreliable; at best it's only going to give an approximation, and at worst can be completely misleading. You need to know what you're looking at, both in terms of chemistry and composition / geology, as well as having a broad frame of reference in comparing the exact same types of stone to get much from it.
 
For sealing stones the thing I like best it this product intended for sealing slate floors. It is clear, and super durable, as you would expect from something designed to be walked on for years. I was lucky enough to find a sample sized tin, which would do dozens of hones.

2A430D66-E82B-4F7A-9B6B-773ED7F0092C.jpeg
 

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So today was a good day!
I had a couple of vintage Japanese straight razors off yahoo show up today.
razor.jpg
razor3.jpg


So naturally I was eager to get into it and see just how sharp I could get them with my limited equipment. Unfortunately one of them had a warped blade which upon closer inspection I could see quite easily given the bevel was thicker at the heel on one side and thicker at the tip on the other side. Blueing of the steel was the first sign that something was up actually. I figure someone must have tried to heat the blade up in some kind of straightening attempt. Oh well they came as a pair and were pretty cheap.

So I was going to use this dud to just get stuck in and get a feel for using stones on them. Considering I didnt have a very good flattening stone I could tell any sharpening wasnt going to be ideal.... Notice how I said that I didnt have a good flattening stone, thankfully I was awaiting on another package and later in the afternoon my atoma 400 plate showed up aaaand wow. First of all using these straight razors on the stones pre atoma I could tell that the stones werent perfectly flat even though I tried as best I could with my flattening stone and pencil. makes sense given the flattening stone is smaller than my whetstones. But yeah getting the razors on the stones was a great insight into the precision of work required to get a truly sharp edge... Anyway wow, flattening my stones with the atoma is a great feeling!

Now I felt hopeful that with the atoma 400, my king 800/6000 and my mystery jnat that maybe, just maybe I now had the minimum requirement of equipment to be able to get an acceptably sharp edge for shaving. Ideally I would like a 3000 stone but hey I wasnt gonna let that stop me. Started on the 800 then 6000 and man working on properly flat stones is damn satisfying!

Moment of truth comes around as it is time to take the atoma to the jnat. flattening and building a slurry was a breeze and also really satisfying as I couldnt achieve that just by working it with a knife, with the slurry my hopes for still being able to use this stone on my knives are much higher than before, so I look forward to giving it a try again soon. Taking the razor to the stone felt really satisfying I must say. I think I am lucky enough that so far this jnat seems to be good enough for the job. After the stone I went at it with a leather strop and is now at the point of tree topping leg hairs.. It isnt consistently passing the hanging hair test but I think with what I have and some practice I can get it there.

I am both stoked and excited. This process of intrigue, learning, purchasing, hoping, experimenting and learning more is a great time. All the better having other people talk with about it and share in the fun. Thanks to everyone!
 

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Be careful trying to "correct" bad geometry on a razor. Often times grinding away more steel can lead to other problems. Just slap some tape on the spine and see if the razor will take an edge (make contact from heel to toe). If it does, you're good to go.
 
Be careful trying to "correct" bad geometry on a razor. Often times grinding away more steel can lead to other problems. Just slap some tape on the spine and see if the razor will take an edge (make contact from heel to toe). If it does, you're good to go.
Yeah I'm not trying to correct anything really, just using it as a practice tool, but it does seem that I can get it contacting so I'll just sharpen it as best I can and see what happens..
 
We've all got our ways of honing a razor, but I prefer Jnats and nagura stones. they're very versatile. You can set a bevel with a King 1000, but it's not what I would call a razor stone. Many people will point you to the Naniwa Green Super stone (1k), but I keep hearing about the crazing and cracking problems with that stone, so I'm not sure it's the best stone for setting a bevel anymore. A good bevel setter is the Shapton Kuromaku 1.5k stone, and it's economic and you'll get good results with it. I personally use that stone, but only if I really need to create a brand new bevel. A lot of razors really just need a little bevel refreshing, and a botan nagura does a great job at refreshing a bevel.

How many stones do you have, and what is your finest stone?

-gray.
 
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