I spent the last 24 hours sealing, lapping, and chamfering my Ozuku.
For sealing, I used Minwax Polycrylic Clear Gloss, painted on with a paint brush. 3 coats, 2 hours apart, 24 hours of drying time. Note: Don't set the stone directly on a flat surface like newspaper while doing this. The gloss drips down, dries, and then you have little bits of newspaper bonded to your edges. I set my stone on a stack of post-it notes.
I liked the finish, and now I see why folks recommend it. My stone is fairly solid 'round back, but does have some flakes, etc. With three coats of this stuff those delicates parts are now well bonded to the rest of the stone. You can see in some of the pictures below where the gloss is acting more like a glue in the corners.
The finish also augments the stone's colors, I think, and provides a less slippery surface to grip the stone when wet.
Lapping was a chore. It took me a good hour+ as this stone was HARD. Used my "chisel-mellowed" DMT 325 followed by BBW followed by my tomonagura. Chamfered the edges, and was good to go.
Now for some aftershots:
If my JNAT looked like that...I'd be obsessed too.
Honing & Restorations