Thread: Ozuku JNat: problem using shellac

Originally Posted by heirkb

Wow, thanks for all that great info. I'll have to try to get this current coat of shellac off and see what I can do. The weird thing is that the current coat has actually started to look a lot better and isn't getting prints on it anymore. I'll keep it for a few more days and see if the issue was the heat/quantity of water that it was in contact with during the lapping.

It's looking better and holding up better now because it's cured.

Without seeing it, I'd still be thinking that what's on there is compromised. You can see how long it lasts but it might not be sealing properly and then, when some moisture seeps into your stone, it might hold more of that moisture in and for longer- the exact opposite of the purpose of sealing it.

Were I you I'd be tempted to soak a good lint-free cloth or non-shedding brush in denatured alcohol and neatly "slop" as much onto the shellac as I could, over the course of 10-15 mins or so- however long it takes to re-soften it. This will re-activate the shellac that's on there, allowing it to then cure moisture free, in a more even coating, and therefore make a newer and better and more durable seal. May as well slap a few 50/50 (equal parts can solution and denatured alcohol) while you're at it.

A quart of denatured alcohol should be a few bucks at any hardware store.

Anyway, good luck with it. It's always fun to experiment with something new!

Originally Posted by Rubicon

It's looking better and holding up better now because it's cured.

Without seeing it, I'd still be thinking that what's on there is compromised. You can see how long it lasts but it might not be sealing properly and then, when some moisture seeps into your stone, it might hold more of that moisture in and for longer- the exact opposite of the purpose of sealing it.

Were I you I'd be tempted to soak a good lint-free cloth or non-shedding brush in denatured alcohol and neatly "slop" as much onto the shellac as I could, over the course of 10-15 mins or so- however long it takes to re-soften it. This will re-activate the shellac that's on there, allowing it to then cure moisture free, in a more even coating, and therefore make a newer and better and more durable seal. May as well slap a few 50/50 (equal parts can solution and denatured alcohol) while you're at it.

A quart of denatured alcohol should be a few bucks at any hardware store.

Anyway, good luck with it. It's always fun to experiment with something new!

Yup, I'm gonna start on that work tomorrow. Gonna try my best to get all the shellac off. Do you think running a little hot water on it would work for that?

I think if I can get the shellac off, I'm gonna stick to something like polycrylic (waterbased polyurethane, right?). I've used that before and it gave me no problems at all. Just have to get through the 19 inches of snow outside to get to the one Home Depot in Manhattan

Wish I could get my hands on some cashew lacquer. That would be pretty cool...

Originally Posted by heirkb

Yup, I'm gonna start on that work tomorrow. Gonna try my best to get all the shellac off. Do you think running a little hot water on it would work for that?

I think if I can get the shellac off, I'm gonna stick to something like polycrylic (waterbased polyurethane, right?). I've used that before and it gave me no problems at all. Just have to get through the 19 inches of snow outside to get to the one Home Depot in Manhattan

Wish I could get my hands on some cashew lacquer. That would be pretty cool...

Water won't help. Just solvent.

I haven't used poly on stones, and I pretty much don't touch the stuff- to me it's a Mach 3. If I ever do use a synthetic varnish it's marine spar varnish- tough, longer-lasting, and relatively bulletproof.

If it were my stone I wouldn't put anything fake on it. I don't trust poly's seal on a molecular level, I don't know how those chemicals react with the stone, and at the end of the day it's just artificial garbage.

Plus, it does not age gracefully and to get it off you need stripper, a whole new can of worms.

So, without trying to tell you what to do, I'd stick with the shellac because you're 75% done already. It got complicated because you were unaware of its peculiarities, but now you know.

I'll let others with more experience chime in with what's best to seal a stone and what to avoid and defer to them. No matter what, take your time, do some research, and reach your decision in the fullness of time. There's no rush and you don't want to bung your stone with a permanent mistake.

Good luck and enjoy!

edit: come to think of it, Tung Oil may be the best thing- it's natural, durable, water-resistant, and commonly used on stone in pretty tough applications. Might just be the next best thing to urushi and cashew. In fact, this will be my next experiment. Opinions, anyone?

I guess I was thinking of abandoning the shellac because of what you were saying about how it doesn't hold up well to water. Also, I don't really want to take the risk of messing something up and having it trap even more water in my stone. I'll look into spar varnish as a solution as well, but I first need to get this shellac off...do you know if spar varnish would work for a stone?

Originally Posted by heirkb

I guess I was thinking of abandoning the shellac because of what you were saying about how it doesn't hold up well to water. Also, I don't really want to take the risk of messing something up and having it trap even more water in my stone. I'll look into spar varnish as a solution as well, but I first need to get this shellac off...do you know if spar varnish would work for a stone?

Spar varnish will work, but it's artificial and will be very tough to touch up and remove down the road. Same as poly, but tougher. Unnessarily tougher. I'd never put it in my house, let alone on my precious stones. In a few years it's garbage and will kill the natural grace of your stone.

Here it is 1AM and I'm researching what to seal a stone with, even tho my Jnat seems happy as is. YOU started it!

The more I read the more sure I become that Tung Oil is the way to go. It polymerizes as it cures, just like urushi, and comes from a nut, just like cashew. It's waterproof, tough, and natural. It's long-lasting and touches up easily. To me the biggest criteria are natural, water-resistant, and easily removable. Plus, it's indigenous to Asia. I really think Tung Oil is the ticket.

The trick is to only use pure Tung Oil- alot of it has poly hidden in it. Check local availability both at hardware stores and a real woodworking store- Manhattan or Bklyn MUST have at least one. If not:

Pure Tung Oil Finish - Wood Finishing - All Natural Finish - China Wood Oil - Real Milk Paint ®

The small size + some solvent will be enough. The first few coats should be thinned for better penetration, the later coats not thinned for better body. It's slow drying and slower to cure so do your cleaning and lapping and honing and then sealing so everything can properly cure for a few weeks. Not sure this is any different from urushi or cashew, but I don't know for sure.

Anyway, I really think Tung Oil is the ticket BUT I've never used it to seal a hone. I really think you're safe, but if you do yours before I do mine then YOU are the guinea pig, so proceed at your own risk. But at the end of the day, the risk seems negligible because it's natural and removable and certainly safer than poly...

Let us know what you decide and how things work out. I think this Tung Oil idea just might be a genuine breakthrough and a milestone in the history of HAD!

Isn't oil bad for these stones, though? I remember reading that I should try to find something that will not penetrate the stone too deeply. I'm not sure...at this point, I might just buy some urushi...

Originally Posted by heirkb

Isn't oil bad for these stones, though? I remember reading that I should try to find something that will not penetrate the stone too deeply. I'm not sure...at this point, I might just buy some urushi...

I think you are getting way too involved in a simple process of sealing stone.
Shellac works just fine, all my stones are sealed with it and have been fine for a year now.
As far as urushi, I doubt you will be able to get it unless there is a vendor in US (have not been able to find onein US). Importing from Japan will probably be impossible, because urushi presents health hasard, it causes severe allergic reactions and it take weeks to cure.