Yellow Lake Oilstones

[cotedupy]

Hot take for y'all... I suspect that the Yellow Lake Idwal (at least this one) and the the Penrhiw Hone are one and the same thing.

In Idwal terms these are relatively soft and very quick, with a distinctive light green slurry and high-ish SGs. Not at all your typical hard n fine razor type LI.

I'm actually pretty near certain on that. I thought it was probably the case after I first flattened a couple of the Penrhiw Hones, but didn't have my YL on me for a direct comparison until yesterday.

Along with Grecians this is my favourite type of 'Llyn Idwal'.

 

[Legion]

Hot take for y'all... I suspect that the Yellow Lake Idwal (at least this one) and the the Penrhiw Hone are one and the same thing.

In Idwal terms these are relatively soft and very quick, with a distinctive light green slurry and high-ish SGs. Not at all your typical hard n fine razor type LI.

View attachment 1615649

View attachment 1615651

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I'm actually pretty near certain on that. I thought it was probably the case after I first flattened a couple of the Penrhiw Hones, but didn't have my YL on me for a direct comparison until yesterday.

Along with Grecians this is my favourite type of 'Llyn Idwal'.

So is Penrhiw actually on the Idwal lake, or a different spot? Are LI stones all mined near the lake?

 

[cotedupy]

So is Penrhiw actually on the Idwal lake, or a different spot? Are LI stones all mined near the lake?

It isn't, nope. There is certainly a quarry at lake Idwal with that kind of novaculite stone, but it's also found elsewhere around the place. As the crow flies Penrhiw is probably about 8 or 10 miles from Llyn Idwal.

1 - Llyn Idwal (novaculite)
2- Penrhiw (novaculite)
3 - Glanrafon (slate)
4 - Dorothea (slate)
5 -Cwt i Bugail (slate)

 

[cotedupy]

Coupla vids showing the speed and edges of the YL Idwal and Penrhiw Hone. These stones are to 'normal' Llyn Idwals what Washitas are to Translucent Arkansas... and I like them very much indeed!

 

[cotedupy]

Something has been niggling in the back of my mind for a little while now in relation to this quote below (my bold):

'it is almost black (or a very, very dark grey) and instead of being a siliceous slate it is a calcareous siltstone and gives results much like a Silkstone, superior to the rest of the Yellow Lake family of honing slates.'


Now Neil Miller knew an awful lot about UK sharpening stones, there's the occasional old post of his that isn't entirely correct but they're rare. And this seems a very specific thing to say if you weren't completely sure about it, because one would not normally associate calcareous stones with sharpening. The Mohs hardness of Calcium Carbonate is 3, it wouldn't even scratch mild steel let alone hard steel. Though of course one can get stones that contain both Calcium Carbonate and Silica, which would be suitable as a whetstone, and it's something like this that he's referring to.

And luckily for us it’s a relatively easy test to do, because carbonates react with acid in a way that an awful lot of other things don't, so let's have a look...

I'm not using some industrial strength HCl here, just a couple of drops of normal white wine vinegar from the supermarket on the bottom of the stones, coarsely lapped with a 140 Atoma to make sure the surface is exposed. And TBH I wasn't expecting to see a reaction on any of them.

---

Stone 1 is the very fine, grey type of Yellow Lake Oilstone. See the bubbles in the liquid here? This stone has carbonate in it.

I don't actually have a wooden box Salmen stone on me atm, but I'm relatively sure that Stone 2 is the same kind of rock. No reaction.

Stone 3 is a very dark, very fine stone, one of the best finishers I own, and I believe is Enterkine Water of Ayr. This is also reacting.

Stone 4 is Aberllefenni Slate, i.e. the 'normal' type of Yellow Lake Oilstone, and the modern Dragon's Tongue stone.

Stone 5 is a YG Thuringian. No reaction.

After cleaning them off and drying down; you can clearly see the marks on stones 1 & 3, where they reacted in a way the others didn't.

---

So there you go.

Obviously Stone 3 which I think / thought is WoA would match the initial description too, and if anything it's a darker colour than Stone 1.

But actually my suspicion is that the very fine, grey type of Yellow Lake Oilstone that @Wid and I have is the one that Neil M was referring to. It's a YL, it's dark grey, it's extremely fine-grained, and it is, as he said... calcareous.

 

[Legion]

Something has been niggling in the back of my mind for a little while now in relation to this quote below (my bold):

'it is almost black (or a very, very dark grey) and instead of being a siliceous slate it is a calcareous siltstone and gives results much like a Silkstone, superior to the rest of the Yellow Lake family of honing slates.'


Now Neil Miller knew an awful lot about UK sharpening stones, there's the occasional old post of his that isn't entirely correct but they're rare. And this seems a very specific thing to say if you weren't completely sure about it, because one would not normally associate calcareous stones with sharpening. The Mohs hardness of Calcium Carbonate is 3, it wouldn't even scratch mild steel let alone hard steel. Though of course one can get stones that contain both Calcium Carbonate and Silica, which would be suitable as a whetstone, and it's something like this that he's referring to.

And luckily for us it’s a relatively easy test to do, because carbonates react with acid in a way that an awful lot of other things don't, so let's have a look...

I'm not using some industrial strength HCl here, just a couple of drops of normal white wine vinegar from the supermarket on the bottom of the stones, coarsely lapped with a 140 Atoma to make sure the surface is exposed. And TBH I wasn't expecting to see a reaction on any of them.

---

Stone 1 is the very fine, grey type of Yellow Lake Oilstone. See the bubbles in the liquid here? This stone has carbonate in it.

View attachment 1623458


I don't actually have a wooden box Salmen stone on me atm, but I'm relatively sure that Stone 2 is the same kind of rock. No reaction.

View attachment 1623457


Stone 3 is a very dark, very fine stone, one of the best finishers I own, and I believe is Enterkine Water of Ayr. This is also reacting.

View attachment 1623456


Stone 4 is Aberllefenni Slate, i.e. the 'normal' type of Yellow Lake Oilstone, and the modern Dragon's Tongue stone.

View attachment 1623455


Stone 5 is a YG Thuringian. No reaction.

View attachment 1623453


After cleaning them off and drying down; you can clearly see the marks on stones 1 & 3, where they reacted in a way the others didn't.

View attachment 1623454


---

So there you go.

Obviously Stone 3 which I think / thought is WoA would match the initial description too, and if anything it's a darker colour than Stone 1.

But actually my suspicion is that the very fine, grey type of Yellow Lake Oilstone that @Wid and I have is the one that Neil M was referring to. It's a YL, it's dark grey, it's extremely fine-grained, and it is, as he said... calcareous.

I tried my wood box Salmen and got no reaction. The caveat to that is I did not degrease it first, but I still would have expected some reaction if it was going to.

 

[Empire straights]

I tried my wood box Salmen and got no reaction. The caveat to that is I did not degrease it first, but I still would have expected some reaction if it was going to.

Considering that vinegar is a decent degreaser I'd think you would have got some reaction as well.

 

[cotedupy]

I tried my wood box Salmen and got no reaction. The caveat to that is I did not degrease it first, but I still would have expected some reaction if it was going to.

Cheers for confirming.

I obviously shouldn't have doubted what Neil said, but I was slightly surprised that those two stones did react. Because to all intents and purposes they look and feel like regular slates, but clearly something else going on. And tbf they do both also have lower SGs than you might expect for dark slate hones, 2.72 - 2.74 from memory.

 

[rideon66]

@cotedupy So my labeled DB Water of Ayr from the Enterkine quarry 2.72 SG did the exact same as yours with white vinegar after roughing up with a new 400Atoma plate.

 

[Wid]

I gave my stones a go with this test. Here are the results. The Water of A-no reaction. Dragon’s tongue-no reaction. The wood boxed Salmen-no reaction. The fine grey Yellow Lake-reaction. The for the heck of it the Black shadow-no reaction.

You can clearly see the grey YL stone has marks left on it.

 

[cotedupy]

@cotedupy So my labeled DB Water of Ayr from the Enterkine quarry 2.72 SG did the exact same as yours with white vinegar after roughing up with a new 400Atoma plate.

Thank you again for testing that for me mate.

As you know - I was pretty confident before that my unlabelled stone was the same thing as your DB Enterkine WoA. But then when I saw those little bubbles I thought: That's peculiar, maybe mine is something different, better check with Tom...

Good to know though that we were right all along!

 

[cotedupy]

I gave my stones a go with this test. Here are the results. The Water of A-no reaction. Dragon’s tongue-no reaction. The wood boxed Salmen-no reaction. The fine grey Yellow Lake-reaction. The for the heck of it the Black shadow-no reaction.

View attachment 1623933


You can clearly see the grey YL stone has marks left on it.

There we are then. I think we have a pretty certain answer for Neil's superior calcereous siltstone.

Interesting that your WoA didn't react, sounds like there might perhaps be a testable Meikledale / Enterkine difference in composition here...

 

[Wid]

There we are then. I think we have a pretty certain answer for Neil's superior calcereous siltstone.

Interesting that your WoA didn't react, sounds like there might perhaps be a testable Meikledale / Enterkine difference in composition here...

My slate I found locally did not react either. Only the YL stone had a reaction.

 

[cotedupy]

My slate I found locally did not react either. Only the YL stone had a reaction.

Yep, the very large majority of whetstones won't show an acid reaction in this way. That was why I was slightly surprised by my results.

TBH before doing the tests - I suspected that Neil M had probably got it wrong about it being calcareous, cos it just seemed like a 'normal' slate. Shows what I know eh!

 

[Empire straights]

I gave my stones a go with this test. Here are the results. The Water of A-no reaction. Dragon’s tongue-no reaction. The wood boxed Salmen-no reaction. The fine grey Yellow Lake-reaction. The for the heck of it the Black shadow-no reaction.

View attachment 1623933


You can clearly see the grey YL stone has marks left on it.

As I've read this thread I've started to question if one of my mystery slates is one of these. I've used it briefly, once, to see what it does.. seemed to polish and shear any tooth away but I need to test some more. I thought it was a big thuringian but im not so sure. It's like between 3/4"- 1" thick and 2x8". The box is really nice, the stone was very well cared for. I wish I knew what type of wood the lid is. @Bowmaker What do you think? @cotedupy I'd like your opinion and everyone else's on the wood and stone as well.

 

[Wid]

As I've read this thread I've started to question if one of my mystery slates is one of these. I've used it briefly, once, to see what it does.. seemed to polish and shear any tooth away but I need to test some more. I thought it was a big thuringian but im not so sure. It's like between 3/4"- 1" thick and 2x8". The box is really nice, the stone was very well cared for. I wish I knew what type of wood the lid is. @Bowmaker What do you think? @cotedupy I'd like your opinion and everyone else's on the wood and stone as well.


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Did you try the vinegar test?

 

[cotedupy]

As I've read this thread I've started to question if one of my mystery slates is one of these. I've used it briefly, once, to see what it does.. seemed to polish and shear any tooth away but I need to test some more. I thought it was a big thuringian but im not so sure. It's like between 3/4"- 1" thick and 2x8". The box is really nice, the stone was very well cared for. I wish I knew what type of wood the lid is. @Bowmaker What do you think? @cotedupy I'd like your opinion and everyone else's on the wood and stone as well.


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It looks quite like a dark blue Aberllefenni type YL, but then so does a lot of slate.

Did it come from the UK? If so - it's probably a YL. If not - probably not.

 

[Bowmaker]

As I've read this thread I've started to question if one of my mystery slates is one of these. I've used it briefly, once, to see what it does.. seemed to polish and shear any tooth away but I need to test some more. I thought it was a big thuringian but im not so sure. It's like between 3/4"- 1" thick and 2x8". The box is really nice, the stone was very well cared for. I wish I knew what type of wood the lid is. @Bowmaker What do you think? @cotedupy I'd like your opinion and everyone else's on the wood and stone as well.


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Pretty cool RH went to the trouble of checkering the feet. I couldn't say for sure what type of wood but the rays remind me of English Oak.

English Oak | The Wood Database (Hardwood)

www.wood-database.com

 

[Empire straights]

Did you try the vinegar test?

Not yet. Give me a few.

 

[Empire straights]

It looks quite like a dark blue Aberllefenni type YL, but then so does a lot of slate.

Did it come from the UK? If so - it's probably a YL. If not - probably not.

I did. It came from a seller I've purchased lots of charnwoods and llyn Idwals from. A couple Grecians.