musicman980
Senior Member
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PA Whetstones
For the past few years I have been searching my native Pennsylvania for a suitable whetstone material. We have rocky soil, boulders strewn about the landscape, and plenty of shale and slate outcroppings, and almost all of it is too hard and scratchy. Eventually I discovered a type of stone that performs extremely well as a polisher and sharpener once you know its intricacies. It’s an elusive and sensitive stone.
I’ve been wrestling with these stones for a while trying to figure out how they work. Sometimes they gave amazing finishes, other times they were too scratchy. These aren’t the types of stones that just hand you amazing finishes without due diligence. There are certain stipulations that make these stones a little more sensitive than your average stone, but the rewards are clear as day. As a polisher, the contrast is untouchable by any Japanese stone I have ever used. Cores that are deep mirrors, and claddings that are perfectly opaque. Streaks are completely eliminated with ease, and spot treatments blend in instantly.
These pieces have an unusual characteristic with regards to their hardness. Slurry pours out of them under a diamond plate, making them seem extremely soft. But under a knife blade, they hardly release anything at all. They act hard or soft depending on what you rub on them. Anything with a grit, like the micro protrusions of a diamond plate or sandpaper engages with the stone’s surface and releases a ton of slurry, but anything that is smooth like the bevel of a knife or razor doesn’t catch the surface in the same way and the stone’s particles stay locked in place.
There are a few extremely useful characteristics of these stones. The first is that they give the same level of polish with or without slurry. So, if you accidentally scratch your bevel on water only, you can raise a slurry and take out the scratches without taking any steps backwards. This works quicker on cladding scratches, as the stone is much gentler on the hard core. The second is that they completely eliminate any streaking. No matter where I focused my pressure, or where I did any spot treatments on the finish, the work blends in instantly with the surrounding area. It really is unbelievable.
Some stipulations to keep in mind: (1) They are sensitive to diamond plates. If your plate is too fresh or too aggressive they tend to release larger chunks of grit that can scratch your bevel. I use a PA nagura or the worn out part of my atoma 400 and the slurry is much cleaner. (2) They are really thirsty stones. (3) Most scratches visible on the hagane before you use the PA stone may still be there after, just more mirror and in heavy contrast with an opaque cladding. I used a Nakayama with slurry before going to the PA stone just to clean up lower grit scratches, and this helped a lot with the final finish.
I don’t know how these perform on honyaki, but I would love to find out.
For the past few years I have been searching my native Pennsylvania for a suitable whetstone material. We have rocky soil, boulders strewn about the landscape, and plenty of shale and slate outcroppings, and almost all of it is too hard and scratchy. Eventually I discovered a type of stone that performs extremely well as a polisher and sharpener once you know its intricacies. It’s an elusive and sensitive stone.
I’ve been wrestling with these stones for a while trying to figure out how they work. Sometimes they gave amazing finishes, other times they were too scratchy. These aren’t the types of stones that just hand you amazing finishes without due diligence. There are certain stipulations that make these stones a little more sensitive than your average stone, but the rewards are clear as day. As a polisher, the contrast is untouchable by any Japanese stone I have ever used. Cores that are deep mirrors, and claddings that are perfectly opaque. Streaks are completely eliminated with ease, and spot treatments blend in instantly.
These pieces have an unusual characteristic with regards to their hardness. Slurry pours out of them under a diamond plate, making them seem extremely soft. But under a knife blade, they hardly release anything at all. They act hard or soft depending on what you rub on them. Anything with a grit, like the micro protrusions of a diamond plate or sandpaper engages with the stone’s surface and releases a ton of slurry, but anything that is smooth like the bevel of a knife or razor doesn’t catch the surface in the same way and the stone’s particles stay locked in place.
There are a few extremely useful characteristics of these stones. The first is that they give the same level of polish with or without slurry. So, if you accidentally scratch your bevel on water only, you can raise a slurry and take out the scratches without taking any steps backwards. This works quicker on cladding scratches, as the stone is much gentler on the hard core. The second is that they completely eliminate any streaking. No matter where I focused my pressure, or where I did any spot treatments on the finish, the work blends in instantly with the surrounding area. It really is unbelievable.
Some stipulations to keep in mind: (1) They are sensitive to diamond plates. If your plate is too fresh or too aggressive they tend to release larger chunks of grit that can scratch your bevel. I use a PA nagura or the worn out part of my atoma 400 and the slurry is much cleaner. (2) They are really thirsty stones. (3) Most scratches visible on the hagane before you use the PA stone may still be there after, just more mirror and in heavy contrast with an opaque cladding. I used a Nakayama with slurry before going to the PA stone just to clean up lower grit scratches, and this helped a lot with the final finish.
I don’t know how these perform on honyaki, but I would love to find out.
