Sealing Japanese Natural Stones with Cashew Lacquer - Tools, Technique, Steps, and Examples

[@jessefiorinif6057]

Again thanks for taking the time to make these videos. Possible suggestion for αn upcoming video would your process for attaching stones to α wooden base. So far I’ve haven’t seen any of your attached but if you wanted to do that thin stone featured in this video I’d love to see it.

[@naturalwhetstones]

Good suggestion Jesse, and the Koma I sealed up here is probably a prime candidate! Thanks for your comment.

[@desiredonekhl]

I’d second this

[@naturalwhetstones]

Thanks for chiming in as well!

[@morehn]

What is the difference between a stone that's good or bad for a razor vs knife?

[@nikobobich9726]

I heard a lot of people have been using the mountain cashew laquer they sell now is just as good as the japanese cashew look into it if you havent already

[@naturalwhetstones]

I have heard of it, yes.

[@nikobobich9726]

@@naturalwhetstones I figured out that I just need a 400 and 1200 tsuboman atoma and to use the 400 for flattening and 1200 for the fine stones and natural stones for slurry I can even use the 1200 on a 1000 soaking stone.. I think this is the best way to do it because the 140 is just way to aggressive. The 400 with the handle is perfect for post lacquer too with the mountain cashew

[@TotemoGaijin]

As someone who just tried to do all this (as wood finish, not stone), I would highly advise people to stay away from plastic cups. I'm not sure what kind yours was, but the plastic cup I used, I mixed everything, put on my first coat, came back a few hours later to check, and the cup was melted and lacquer was everywhere. If I were to do it again, I'd just find some kind of glass jar.

[@naturalwhetstones]

I think you have to make sure it is PET plastic. I'm also sure the type of lacquer you use matters too. Good tip though, I've never personally ran into issues.

[@nikobobich9726]

Im a huge fan dude keep up the good work you are very very informative!!! I have a few questions for you if you don't mind? I bought an ohira tomae Jnat from a friend that works at a cutlery out here in LA called Yoshihiro. He Had a rare red one that has red streaks on the top, bottom and sides he said it was the rarest one he had. I trust him ive done a lot of business with him. Im new to naturals as you can tell. I have 2 atoma tsuboman's with handles the 140 and 400. First question is which of the 2 would you use for flattening and leveling this stone? Second question is I bought some watco laquer they have 3 brands in spray a satin and 2 other ones for sale. I bought the satin one is that safe to spray on this stone in 3 coats? Last question is after I seal up this stone is it safe to soak it like my cerax stones until the bubbles or a bad idea to get better performance out of it. I just do not want to mess this stone up I love it already. Please let me know

[@nikobobich9726]

actually it was the clear wood brand not the satin my mistake*

[@nikobobich9726]

They have rustoleum clear gloss maybe that one might be better

[@msremer1]

I'm using transparent alkyd paint for boats. It is cheap, very durable, complete transparent. Tested 10+ years on my stones. UV light don't change transparency. Laquer can be stored very long time 5+ years. If you buy odorless thinner you can paint stones inside (good ventilation still required). Laquer is marked Lazurol S1119 in my country.

[@naturalwhetstones]

Great alternative! Thanks for bringing it up.

[@SeaDragonGod]

Very informative as always, thank you!

[@judgetoogood1033]

Excellent presentation. I have a large Nakayama, it has not treated with Cashew Lacquer. I bought the stone from a reputable dealer. None of his stones are lacquered, jus wondering why.

[@dedosdigital]

In Japan there is a lot of packaging and preparation for the retail consumer . But it is expected the artisan should know how take care of his tools himself .

[@lunfardo]

Curious - are the fully dried and hardened cashew lacquer clumps salvageable at all, if you soak them long enough in turpentine oil?

[@naturalwhetstones]

You can get all the lacquer off of the stones for sure, even with alcohol. But you would have to reseal it. The small clumps really don't matter.

[@judgetoogood1033]

I have a Naniwa 2000 green brick of joy. Do I use it on a stone. When do you not use Cashew lacquer. How about Japanese whetstones that say to soak them. If you do seal them will it do manage. Thank You……

[@naturalwhetstones]

Cashew or not os up to you. Synths don't need it for sure. Naturals it's always good to seal them up honestly. In so far as soaking naturals it depends on the stone. Always a risk for a crack, especially if it has lines in it or previous cracks. It can really improve the performance of some stones though

[@lofotenknifeworks2278]

Love your videos and your website. Do you have any suggestions for books on natural stones? Or do we have to make you make one? 😅

[@naturalwhetstones]

Thanks for your comment! I don't know any to be honest and many good ones I think are Japan stones only and in Japanese. Sorry! Maybe someday I will make one myself ;)

[@lofotenknifeworks2278]

@@naturalwhetstones I will be the first to buy it :)

[@naturalwhetstones]

Thanks I appreciate it. I can see doing it at some point but I would feel the need to travel and really get hands on photos and testimonials. Right now a world tour isn't in the cards but maybe someday!

[@lofotenknifeworks2278]

@@naturalwhetstones i have a standing invitation from my supplier in Japan, and I do plan to take the trip someday. Im all synthetics atm, but I really want to expand my selection to naturals as well. I just dont have the knowhow yet. I love to work on them though 😁

[@msremer1]

​@@naturalwhetstones I will be second who will buy yours book. 🙂

[@buckbeans1]

How often does the stone have to be resealed after the initial process is done?

[@naturalwhetstones]

Unless you damage it somehow by a drop or something you should never need to seal it again. Maybe a few generations after you will need to do it again if it is a hard handheld Nagura with a lot of abuse.

[@judgetoogood1033]

Where did you get the ATOMA plate holder and brand. Thank You.

[@naturalwhetstones]

I think I got it off eBay, been a long while! You can find them googling atoma handle.

[@morehn]

Do you have any opinion or knowledge of Indonesian sharpening stones?

[@naturalwhetstones]

Ive never used them first hand but I know people who I trust who have. They seem worth skipping.

[@morehn]

@@naturalwhetstones okay, thank you. I guess I'll skip that one. Can you please advise me if you would recommend anything else in my inventory? For a Victorinox high carbon steel knife Rockwell 56, these are the stones I have: Arkansas soft, hard, black Belgian Blue 611 and 910 Belgian Coticule 212 Green and Black Shadow Aoto Tanaka Toishi hard Shohonyama Nakayama Ohiro Uchegomori Nakayama nagura I'm very new to jnats and natural stones, so there's a lot that I'm trying to learn. Am I missing any steps of what you would recommend in terms of a good sharpening progression for a knife? My goal is to get a perfectly smooth finish, and I like a polished finish but it really just needs to be perfectly smooth to the touch when I run it along my fingernail such that I shouldn't feel any bumps.

[@judgetoogood1033]

I noticed that some of the edges of your big stones had sharp edges. I use a ATOMA diamond plate to chamfer all edged. Edges can be brittle…..

[@naturalwhetstones]

Ah never caused me issues before! Some I found others I don't.

[@Doodle-.Snoozel]

If I seal it is it okay if it’s in sunlight ?

[@naturalwhetstones]

Yeah shouldn't be an issue.

[@neutronshiva2498]

Could you use cyanoacryllic glue (super glue) for this?

[@naturalwhetstones]

I'm sure it is possible but I would not as it likes to crack. Something like epoxy if you wanted to use glue would make more sense. In the end though a form of clear sealer or varnish will work best.

[@Doodle-.Snoozel]

What is a good finger nail polish to use to lacquer the stone?

[@naturalwhetstones]

I can honestly say I have no idea! The one time I tried it I just went and grabbed whatever was the least expensive. Sorry I can't help more.

[@Doodle-.Snoozel]

@@naturalwhetstones okay thanks for the help

[@Doodle-.Snoozel]

If it’s water based can you still use it?

[@naturalwhetstones]

There are water based sealants that work yes

[@sryslyuguys]

Would this work with synthetic stones? I hsve a gesshin 400 XL i love but unfortunately it is really thirsty.

[@naturalwhetstones]

The sealing doesn't particularly stop them from being thirsty, it is more meant to avoid cracking by limiting water ingress from anywhere but one direction (the sharpening face). It would work for a synth but I'm not sure what value it would add for you.

[@sryslyuguys]

@@naturalwhetstones ah I understand thank you. I thought that by waterproofing the sides and only having the top surface exposed, water would not drain out from the stone as quickly, thus would require less water replenishment (less thirsty). My main goal is to make the stone less thirsty and require less water. As it stands it needs to be splashed every 20-30 seconds or it dries up. Hoping to maybe only require a splash every few minutes. Is there anything else that would work for this? I think the stone is really porous so the water just goes straight through

[@naturalwhetstones]

Only thing would be to soak the stone or get a different one. No other real options!

[@Doodle-.Snoozel]

Hey what was that black stone ?

[@naturalwhetstones]

Water of Ayr stone from Scotland

[@Doodle-.Snoozel]

What other options that can be used to lacquer

[@naturalwhetstones]

Many options. You can use fingernail polish, Winsor and Newton Artists Gloss Varnish (I have used this to good effect), others have brought up alkyd paint for boats or clear acrylic as well. Lacquer will be amongst the most durable finishes though when cured which has some benefits for stone use.

[@Doodle-.Snoozel]

How long do you have to. Wait until the Winsor and Newton artists gloss take to dry up?

[@naturalwhetstones]

@@Doodle-.Snoozel It highly depends upon how many coats you put. One coat is dry to the touch in maybe 15 minutes, but can be marked if pressed. It takes maybe 24 hours to fully cure. I tend to put a few coats on about 1-2 hours apart, and let it sit for a week. I'm not really sure if it takes the full week, but I have always just played it safe.

[@Doodle-.Snoozel]

@@naturalwhetstones how many coats should i do? if i use the windsor and newton artist gloss?

[@user-pm7pw1tl3t]

So people develop allergies against tree sap...but not the cashews?!

[@dedosdigital]

If you are in Japan you can get Cashew Varnish everywhere , inexpensive and fresh . It requires no straining and is easily thinned with mineral spirits or tupentine . If you are not in Japan you cannot get Japanese Cashew Varnish , because Cashew Co does not export it .

[@naturalwhetstones]

Yep! If only they did. And of course fresh cans do not need any straining. The straining is only needed if you have old stuff laying around - as I did.

[@dedosdigital]

@@naturalwhetstones I am in Japan , and I use Cashew Varnish , about 700 yen per can retail ; I find a can lasts a long time unopened , fresh from the store . Once opened , a different story , lasts for about a month . In case of your interest , I found pure cashew resin sold as a paint/varnish , sold by an American company . They told me they could ship internationally , retail/ sample sizes . I think it was called Earth Paint . Cashew Nut Shell Liquid , CNSL , and distilled Cardanol , Cardol , are not volatile . Cashew Varnish as sold in Japan is a mixture of alkyd and cashew resin in oil base , volatile , shipping prohibited .

[@naturalwhetstones]

@@dedosdigital Yep! I brought the Earth Paint up in the video I believe.

[@celestialogian1183]

@@naturalwhetstones Hello! I'm interested in the Earth Paint, since I don't have a workshop and live in a rainy place. I could not find where you spoke about it, but what I found in google search yields an "Earth Paint Natural Varnish". Is this what you are referring to? Do you recommend it? Their FAQ says that it's alcohol-based, and that the alcohol "penetrates deeply" on the first coat. Is this okay for a JNAT? Thank you for your time, sir.

[@naturalwhetstones]

I've never used it before only heard of it! I am sure it works fine though, I have friends that say it works well

[@danhip2442]

not a very good solvent, it seems to me, my cashew lacquer did not curdle like that

[@naturalwhetstones]

Hey Dan, you are talking about the my old lacquer I tried to strain out? It was about 3 months old. I find that it tends to do that once exposed to air a few times over uses.

[@danhip2442]

@@naturalwhetstones Hello. Sorry, I didn't quite get it. I've been keeping mine in its original jar for several years now, occasionally opening it up and pouring a little. He is OK.

[@danhip2442]

@@naturalwhetstones By the way, did you have the varnish delivered to the United States by plane normally?

[@naturalwhetstones]

@@danhip2442 Hey Dan! That would certainly keep it better for longer. I could also have let the turpentine sit in the cup for a while and a lot more would have revived. I tend to do a lot of stones at once, so a lot more of the lacquer gets exposed to air than probably your method. When it is exposed, a small amount dries each time no matter what, so it can get clumpy (hence the straining). I have to get it via seamail to the US none of the delivery services will take something explosive/flammable on the planes. It is a real pain!