Shapton’s Glass Stone 7 series was announced in 2018. The ‘7’ refers to the 7 mm thick layer of abrasive on the glass substrate. The significance of this dimension is related to the 5 mm layer of alundum charged ceramic found on the original Glass Stones.
Each 7 series stone measures 6.25” in length, and just a hair less than 1.5” in width. The overall thickness, including the glass substrate, is 7/16”.
The particle sizes of the 7 series stones are different than those of the original Glass Stones. The coarsest is 25 µm, and the rest, in order are: 11.5 µm, 6.7 µm, 4.0 µm, 3.0 µm, 2.0 µm, 1.2 µm, .85 µm, .44 µm . It’s important to note that there is no reference to ‘X’ or ‘K’ on the packaging; these stones are qualified exclusively by particle size.
In comparison, the particle sizes of the originals Glass Stones are: 122.5 µm (120x), 66.82 µm (220x), 45.94 µm (320x), 29.4 µm (500x), 14.7 µm (1k), 7.35 µm (2k), 4.9 µm (3k), 3.68 µm (4k), 2.45 µm (6k), 1.84 µm (8k), 1.47 µm (10k), 0.92 µm (16k), 0.49 µm (30k).
So, you can see that the finest 7 stone is slightly finer than the top dog in the Glass Stone series. I also note that each of the original Glass Stones are ‘full size’, and that there is a wider range of ‘grits’ available too.
This particular Glass Stone 7 is the ‘finest’ synthetic stone available presently. It is super-fast, and extremely consistent and it leaves a very ‘mirrored’ polish. This is a high-end finisher only, and I would suggest keeping touch-ups to no more than 4-5 passes. Every time I pushed the edge past 20 laps, the edge was harsh. Keeping the lap count low allowed me to control that somewhat. I still feel that the edges were a little bit harsh though, which is – IMO – a typical edge signature of all high grit synthetic water stones. I suspect that buffering the edge with lather might help, but I am not a fan of putting soap on porous synthetics. I may try that eventually, but for now I am just going to use this stone with water only.
It’s small enough to store anywhere. It’s light, and easy to lap. This is a splash and go stone, so there is no soaking required and it dries off very quickly. All of these factors add up to the finest Glass Stone 7 being an excellent option as a modern-day barber hone, travel hone, or quick touch up hone to keep in the bathroom.
