Cashew lacquer comes from yes, the cashew fruit, the same tree that gives us the nuts. Along with hon urushi, it is a traditional lacquer in Japan. Cashew is easier to use and cure than hon urushi, and safer as hon urushi is the sap of the kiurushi tree, and is basically poison ivy sap. Anyway, the first image is my set up to apply cashew lacquer on these stones. BTW, the Japanese do not lacquer Mikawa nagura because they aren’t layered stones, but it is popular to lacquer them in the west to preserve the stamps or keep them clean of hand grime. First image top row, two Mikawa nagura, a small can of amber cashew lacquer distilled turpentine. Bottom row, a good quality non-shedding brush, a disposable scoopage spoon, two barber size stones, and a large spice bowl lined with aluminum foil for easy cleanup. I dilute the cashew with turpentine until it’s about like maple syrup. Applying it takes some learning but it isn’t difficult, too thick and it could run or sag before it sets, and it will wrinkle if it’s too thick.
They look nice and I’m wondering why lacquer is applied in the first place - is it strictly aesthetics?
No, it’s usually applied to seal layer cracks on the side of the stone to prevent water from getting into the cracks. Historically these stones were used in shops or sheds that weren’t conditioned, so if water got into the cracks and froze at night, over time the stone could split apart. If you’re buying a stone these days and it has lacquer on the sides, you should look carefully for cracks. Hon urushi is expensive and difficult to cure properly, so they usually didn’t just slap this stuff on every stone. But by the same token, if you see hon urushi on a vintage stone, the stone is usually good, because they didn’t go to the expense and trouble for a junk stone. A variation was using mulberry paper and hon urushi (the poison ivy sap) to reinforce the sides, and hon urushi was also used a a glue.Mulberry paper or washi, has long, thin strands, or at least some of it does depending on the manufacturing, and together with well cured hon urishi that made a material very similar to carbon fiber. They made armor out of this combination.
Yes, but I only have one hone with hon urushi on it, and it’s thin, only one coat. When it’s properly done, it’s gloss black just like the cashew lacquer, so visibly it isn’t different. Hon urushi comes in many colors, and it’s used for expensive fountain pens ($1000 and up), katana sheaths/scabbards, and the like. It has to have a certain temperature and humidity to cure, and most people who use it have a curing ‘box’ to control the temperature and humidity. I don’t have one, but there is a good stretch in summer here when I can do it. The problem is that it cures slowly, so bugs and such are a problem. Alex Gilmore gave me a tube of hon urushi, it’s tan when it’s raw but cures black. As I said, it’s basically poison ivy sap, so gloves and long sleeved shirts are a requirement, yoh simply cannot get any on you. Alex watched the seller in Japan put it in the metal tube. The seller had something like a e0-gal drum of it, and a little ladle. He ladled it out, no gloves, and filled the tube without getting any lacquer on the outside of the tube, then sealed it. Real skill..
I'm so allergic to poison ivy, that I would be hospitalized trying to use that stuff. I hear some people have similar reactions to the cashew lacquer.
I think that’s true of many lacquers Scott, and I’ve heard the same thing about cashew lacquer, but don’t know of any actual examples and I’ve gotten it on me several times with no adverse affect. I’m allergic to poison ivy too, but if I know that I’ve been exposed to it, like clearing brush, and I wash up with plenty of soap and water within 15 minutes or so of exposure, I don’t break out. If I do break out, it takes at least a week for the rash to go away. There’s also reportedly a natural remedy, at least in summer, jewel weed. It grows wild here in very wet and sunny bottom lands, and there’s some in my local park about a mile from me. I haven’t tried it.
Finished up the cashew lacquer (2nd coat on the sides of the big iro) and it’s cured well enough to handle. I always seem to get a smudge of lacquer on the face, so these are ready for a light lapping. The Shapton DGLP did the heavy work, then a very mellow 600 Atoma did the surfacing, followed by a Mikawa nagura and a well-worn Japanese near wedge. And they will be ready to go, gloriously flat. Mizuochi San (he makes the Iwasaki razors, forge to honing) knows best!
OK Scott, here’s a stone with one thin coat of hon urushi on it. I’ll probably finish it this summer if my urushi is still good. After two more coats I would expect it to be jet black.
Here’s a short video of the master at work, making the razor from scratch to finish, something I doubt the Europeans masters ever did.
Hi. I'm new. Where can I purchase some of this amber cashew lacquer. I live in California USA Thanks in advance.
There is a place in CA that carries it, but they’ve been out of stock since covid, no idea why, hyper-cafe. You might give them a call. There’s a seller on Etsy that carries it, just search for it. It will come sea mail, so be prepared to wait a while.
I only found one seller on Etsy. TeaDogu. He however, only stocks clear, red and black. Hyper-Cafe.com does not take special orders. : ( I might have to try to find someone in Japan to get me some and send it to me.
That’s the cheapest way, cashew is very cheap in Japan. Order about 6 cans at a time. I use the amber, black, and translucent red.
