Folks,

I've had a Naniwa Snow White 8k that I usually do not use, preferring my Shapton Pros and HC Glass 8ks instead, but two of my friends have had these stones, two each actually, and all 4 stones cracked to the point that they no longer will use them on razors. The stone is similar to the Choseras which have sometimes also experienced cracking.

Mine has not cracked at all, but I used three coats of undiluted brushing lacquer applied with a foam brush to seal the sides and back, and after each use I wrap it loosely in a dish towel to slow the drying. Even under magnification there are no cracks. Yet, the experiment continues.

During my initial tests I noted that the stone is extremely thirsty, and it also absorbed that first coat of out-of-the-can lacquer like it was nothing. So I believe that the cracking is being caused by the stone absorbing a lot of water then the outer layers drying too fast and shrinking, resulting in the observed cracks.

There's some anecdotal evidence of such behavior, the most prominent are those ventilated boxes Shapton uses on the Pro line to control the drying rate. Those boxes cannot be cheap and they would not use them if there was not an understood reason for it. They also appear to have sealed the sides on the current series and the sides and back on the previous series with the graphics on the back. BTW the Snow White will not fit in a Shapton Pro box, it's too thick.

Anyway, the lacquer and towel were meant to mimic what Shapton did and I've had success so far, so I thought I would post in case the information might help others. I also note that Max at JNS now recommends sealing synthetics.

Cheers, Steve