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Synthetic coticule. WIP

David was nice enough to send me one of the white slate-backed vintage stones that people often assume are reform coticules. I'm going to be doing significant testing on it and posting findings here. Tonight's the very beginning.

Slurry tests.

Coti
This stone
This stone (thinned so larger particles are move evident)

Draw your own conclusions here, but as for my opinion. Garnet size varies quite a bit in coticules. Some of my nicer vintages garnets are very small compared to some other coticules I've owned, but the particles in this stone on average, are in my opinion, far too small to be coticule garnets. Now, there are larger particles which could be, but they comprise an insignificant amount of the stone, AND (this is important) these particles are found in almost any synthetic. It's not at all uncommon to find particles as large or larger than coti garnets populating even modern synthetic stones slurries... they simply don't tend to comprise a large portion of the slurry. As for an assumption, I would say we can conclude that IF this stone contains coticule dust, it is either a very small portion of the make-up, or the dust is lower in garnet concentration than we would expect based on the concentration in whole coticule stones. I would further say, that this test offers no proof that there are garnets in the stones, it only fails to fully disprove this.


More testing will come, honing, attempts at dilucot, and shaves.
 

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David

The Fur Burglar!
Very interesting Ian. The particles are definitely smaller than the coti slurry. Looking forward to further observations.
 
Ok first and foremost: I just shaved with this. Here's before and after honing shots. Before is a quick, no frills LV coticule finish. I then went to this stone for a few dozen passes, hence the after shot.

The feedback is Really, REALLY nice. Like a good quality high grit synthetic meets a Thuri. It's smooth as silk, feels moderately fine, (not ultra fine), but very low abrasive... but that's just how it FEELS, I'll do some testing to see how fast it is later. In general, I liked the feel, but was unsure how it would affect the edge.
 

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The shave... now this is where things get weird.

I did the first pass, and actually thought I wasn't going to complete the shave. I can't put it any other way, the razor struggled during the first pass. It didn't actually hang up, or miss any hair, but take the way coticule edges require a little force behind the blade and amplify that several times, and that's what I experienced. It felt like a Washita finish, or some other coarse finish that can shave WTG, but will fail utterly XTG or ATG. I started thinking that David had sent me this stone just to see if I could even shave off it, and was already planning to try a shave off the slate side just to see if it were any better.

Then I did my second pass. It hesitated a bit in the typical places (primarily under my chin), but no worse than the middle-range barbers synths I've been using... but the odd thing was the shave was very obviously already closer than off those stones. After my third pass (which went easy as a Jnat finish), the shave was close. REALLY close... high end modern synthetic close. Right now I couldn't tell my shave from a shave off my 10k or 13k SP. It's that close. Tomorrow or the next day, I'll get an hours count and be able to more accurately say how it stacks up... but the razor was really sharp... which makes the struggling on the WTG pass very odd. After shave comfort? Actually quite good. More a/s burn than with a coticule, but given that this shave was significantly closer, that's to be expected; and no real irritation to speak of.

I'm very intrigued by this stone and will be shaving off it several more times in the next few days. My next shave will be using it directly after a mid-range synthetic to force it to do more actual sharpening, and less just overwriting an already shave-ready finish.
 
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Similar to the white and red stone im testing I thought was a coti.

Turns out mine will actually absorb water after a minute, so who knows what it is...
 
Yeah, this stone is ULTRA-porous. It drinks water like a king 4k. Definitely not a natural coticule for that reason alone.
 
Stone removes very little steel, but seems plenty fast. Appears to refine a DMT 8k edge in well under a minute, no problem... yet leaves no visible swarf. Shave tomorrow will tell if it's really doing what the scope says it is. This is after around 30 passes off a DMT 8k.
 

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Here is a minute honing on the backside (following 8k DMT), which I'm assuming for the time being to be some generic slate backing.

The back side removes far, far, far more steel than the front. I'll shave off this maybe in two days; but just from the scope, I'm gonna be honest, this surface appears superior to most of the modern slates I've tried.

Definitely shaping up to be an interesting little hone.
 

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That stone I mentioned is faster than you would think. It leaves no swarf but a new scratch pattern is evident.

Maybe i'll post pics tomorrow. It even has black inclusions, kind of funny.

I haven't shaved off of it but the HHT results were similar to what I get off my faster less fine coti.
 
Very cool tests. Has anyone been able to find any kind of advertising or writing for stones that even look like these? There have been more than one or two around but never any information on their history.
 

David

The Fur Burglar!
If you google man made coticule you can find some info on stones that look similar... not sure if they're the same stones. Scott has one but he said his is really hard....The stone Ian has is pretty soft. I've told Ian this but I'll say it here, when I got this stone the yellow side was pretty flat but the slate side was badly dished.
Great information Ian. That's strange about the shave, but interesting.
 
Very cool tests. Has anyone been able to find any kind of advertising or writing for stones that even look like these? There have been more than one or two around but never any information on their history.

I have been keeping an eye open for one in a box for the last 2 years without seeing one. There are plenty of these stones around someone should have a box. Hell I have one of these stones even though I never use it. Its hard as hell and I think the black is the finisher after the last time I played around with it but still don't know.
 

David

The Fur Burglar!
Does your stone drink, Scott? This one is on the softer side and tends to soak up quite a bit of water
 
I have been keeping an eye open for one in a box for the last 2 years without seeing one. There are plenty of these stones around someone should have a box. Hell I have one of these stones even though I never use it. Its hard as hell and I think the black is the finisher after the last time I played around with it but still don't know.

Definitely interested to know their history, who manufactured them, what the abrasive really is etc. They sound really interesting.
 
Mine doesn't drink water really but it does absorb it quite slowly. I didn't think mine was porous til I put a couple drops of oil on it and it soaked in.
 
I have been keeping an eye open for one in a box for the last 2 years without seeing one. There are plenty of these stones around someone should have a box. Hell I have one of these stones even though I never use it. Its hard as hell and I think the black is the finisher after the last time I played around with it but still don't know.

There was a big labeled one on eBay a few months ago, I'm almost positive... maybe I imagined the label. Either way it was good size, like 8 or 9" and clearly not a natural, but the same thing as this, big soft-looking white top and thin slate underneath. Went for a good amount, pretty much coticule (in that size range) price, and I wasn't willing to go that high. Wish I had now, this stone is looking really promising, and I may be more active in bidding on these in the future.
 
The red/white thing i've been playing with is hard on the white side(almost laughs at the DMT), and the red side is soft enough to get a slurry from with a regular coti slurry stone.
 
Yeah, I've always suspected the red/white stones were some form of two sided barber hone, not necessarily related to the "fake cotis" which always looked to me as quite soft (and this stone is definitely not hard).
 

David

The Fur Burglar!
That makes me wonder if there are different types of these because Scott's is hard and glassy. This one is soft and velvety.
 
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