Grit Range Of Slates?

[mjclark]

As part of an ongoing low-end honing solutions project, I bought a broken slate paving slab in B&Q today for 50p.
It's a soft stone and lapping very well so far with w/d - I'm starting with P40 and can then work through 80, 100, 150, 240, 800 and 1200 grits for the lapping.
And I'm randomly hoping the stones gonna come out somewhere between 2k and 5k to slot into the progression.
But realistically what grit could be expected?
I know slates can get up to 12k+, but this ain't one of those
I think it's a "Bradstone Charcoal Slate Stepping Stone" if that's any help

 

[Brooksie967]

Do you have a pic?

 

[mjclark]

Do you have a pic?

Well this is as far as I've got - thought I'd get a slurry stone by sawing off the end too. The slurry generates quickly and is dove grey.
The striations are from the 40 w/d, not actually in the stone itself which is uniformly "smooth" (a term which, like "sharp", I'm learning doesn't actually mean anything in this game).
It's 10.30pm here and the sound of all that sawing and lapping has irritated my girlfriend to such an extent that it's time to stop for the night, but I'll keep you posted

I want to use this in my microtome-to-near-wedge project which is also ongoing and also taking much much longer than I'd expected.
Ha ha- nobody told me it was going to be like this!

 

[Proinsias]

I've no idea on grit estimate, use it, lick it, rub a spoon on it, compare scratch pattens to other media etc.

I think you'll be lucky if you get something which performs as a sharpening stone at any grit level but then again many of the purple Welsh slates appearing recently had a similar past life.

Good luck!

 

[SliceOfLife]

Honestly, slates more often than not aren't poor quality for honing because they are too coarse. In my experience most slates that don't make good hones don't because they just cut far, far, far too slow to be worthwhile as a hone. It can be barely more effective than honing on glass.

My advice, take a finished razor, give it a good hundred passes on that slate with a small amount of pressure, and see what happens to the edge.

 

[mjclark]

Honestly, slates more often than not aren't poor quality for honing because they are too coarse. In my experience most slates that don't make good hones don't because they just cut far, far, far too slow to be worthwhile as a hone. It can be barely more effective than honing on glass.

My advice, take a finished razor, give it a good hundred passes on that slate with a small amount of pressure, and see what happens to the edge.

Yes I see what you mean - the result was a bit of a surprise, but in a good way.
Even 300 laps made not the tiniest bit of difference to that near-wedge which had just come off 1.2k.
But 300 laps for an A1 stainless steel blade which had come off 10k noticeably refined the edge and got it where I wanted.
So it's not the intermediate stone I was looking for, but seems like it could be a good finisher.
Ha ha- this broken slab was 50p but complete I think they're about £3.00 so maybe I should buy a load of them, lap them and sell them on ebay

 

[Brooksie967]

Just make sure you put them in beat up mahogany boxes to make them look vintage.

 

[Disburden]

The best way to test a grit of a stone is to hone up to 8K on a 8K level stone and examine the EDGE under a microscope (the edge is not the bevel, btw).
Learn what this looks like.
Do the same for other stones, 4K, etc and learn what the edge looks like.

Then when you test your new stones or natural stones you can see how they shave and compare under the microscope.
Hope this helps.

 

[Gamma]

Ha ha- this broken slab was 50p but complete I think they're about £3.00 so maybe I should buy a load of them, lap them and sell them on ebay

Call them something with 'Welsh' in the name - and you'll probably do very well...

 

[mjclark]

The best way to test a grit of a stone is to hone up to 8K on a 8K level stone and examine the EDGE under a microscope (the edge is not the bevel, btw).
Learn what this looks like.
Do the same for other stones, 4K, etc and learn what the edge looks like.

Then when you test your new stones or natural stones you can see how they shave and compare under the microscope.
Hope this helps.

Yeah that makes sense- I got a loupe so I suppose I'd better actually use it! After what it's done to that stainless edge, for sure this is >10k

Call them something with 'Welsh' in the name - and you'll probably do very well...

Well it's from a B&Q in Devon so maybe "Devonshire water stone"...

 

[ADRSPACH]

Or use oil instead and you will have another mysterious hone Devonshire oilstone.

 

[PapaFish]

I got a piece of slate from a hardware store here in the US. I cut a corner off and used it. It self-slurried a deep brown color, and quickly removed scratches from a 200 grit stone, and then (working under running water) would leave the edge at about a 6K level. I was very pleased since at the time I had no stones in this range. I gave that stone away to another member that didn't have a stone in the mid-ranges since I had the whole rest of the tile. I recently cut up the tile for hones, and found out that the tile is not at all consistent. That one corner was great, the rest of the stone has large particles in it that make it unfit for sharpening a razor. Oh well...
Good luck with your slate. Play around with it and see what you can get it to do.

 

[mjclark]

Update: I gave my stainless A1 about 400 laps on the paving slate with just water, stropped and shaved and it's put a great finish on it! Much better than the same blade coming off CrOx
Ha ha - I couldn't decide whether to ask my kids for an R41 or a set of those ebay welsh slates for my birthday.
I opted for the R41, and now I've got a nice slate finisher too!

But obviously lapping a paving slab is a real gamble.
I was hoping for a 4k-6k but have ended up with an excellent >10k

 

[mjclark]

Just as an update, I'm finding that if I put the B&Q paving slab with some light slurry into my progression between the barber hone and the Welsh oilstone then I get some really nice edges.
Guess that would put it in the 8k to 10k range.

 

[BakerAndBadger]

Could be the new B&Q Thuri!

 

[SliceOfLife]

It's dangerous to compare any other slates with thuri's.

Thuris are fast, consistent, reliable, easy to use, and perform excellently with slurry.

Pretty much all other slates are slow, inconsistent, a crap shoot, far more difficult to use, and slurry is very hit or miss. If you pick one up for a dollar and it fills a hole in your progression, that's great. If you buy a Yellow Lake and find it's a functional oilstone for $20, hey great. If you spend $200 on some grey, or brown, or blue piece of paving slate some one figured they could shove off on gullible forum members by creating a brief hubbub over them, claiming they are the next Thuri, or as good as a Thuri, or Finer than a Thuri, etc, it's substantially less great.

And I've seen that last thing happen probably a half dozen times in the few short years I've been around. Honestly with the amount of money I've seen wasted on stones that are no better than this 50p slate, I could retire. The worst part is seeing people who KNOW they got bilked but refuse to admit it even to themselves describe the stones later. They almost never say they're bad... yet almost every one of them with any experience or any other options has gotten rid of them... for some reason... but definitely not because they were bad.

 

[mjclark]

Yeah this B&Q slate works really well as part of my low end honing solutions with a progression made up of stones acquired from antique shops, boot fairs etc. and a reconditioned vintage strop.
The best find is what looks to be a Yellow Lake oilstone from a boot fair for 50p.
The other breakthrough was finding out (from this forum) that green Chromium Oxide acrylic paint on balsa does as good or better a job as the proprietary pastes.
Of course the problem with this is that you have to do a lot of experimentation to get the progression right and it's hard to discuss all these indeterminate grits.
But it's lots of fun and a very good way of learning. Even with my undeveloped techniques I can already get nice smooth HHT3/4 edges from this progression.
I read about a guy who tried using pieces of a Victorian blackboard to hone and reckoned it was about 6k, and it had crossed my mind that I could chop these paving slabs up and sell them on ebay, but that would be naughty

What's the consensus on those £9.99 Welsh slates available on ebay UK?
I'm tempted to get one.

 

[R Yates]

I actually have 3 "Welsh Slate Hones" they were from a friend in the UK he said they were in the range of 8K , 12k and 15 K they were labeled on the paper they were wrapped in when I received them and I found they are different grits .However not as labeled though they are much finer then we both thought .

( All three are Yellowlake slate )

The 10k being the "Purple Dragons Tongue" Very sweet Hone

Purple LLYN Melynllyn = grit range is around 12k to 15k and works very good under a loop one can see the difference when working with this stone it has awesome feedback on Knives and razors alike . (this is a Extremely Hard Stone)

Dark Green Gray Slate = This stone is in the 15k to 30K range ( not sure about this yet though I am leaning towards the 30k range as of now) this stone is also a very Hard stone the slurry is milky and provides a nice slip to the knives and razors that I have hones on it . the most odd thing so far that I have found is with the progression through the stones and slate trio of slate hones is the lack of /No need to hit a strop ! Really they provide such an keen edge and fine edge I did not have to strop my razors at all they finished out shave ready.

 

[Brooksie967]

I actually have 3 "Welsh Slate Hones" they were from a friend in the UK he said they were in the range of 8K , 12k and 15 K they were labeled on the paper they were wrapped in when I received them and I found they are different grits .However not as labeled though they are much finer then we both thought .

( All three are Yellowlake slate )

The 10k being the "Purple Dragons Tongue" Very sweet Hone

Purple LLYN Melynllyn = grit range is around 12k to 15k and works very good under a loop one can see the difference when working with this stone it has awesome feedback on Knives and razors alike . (this is a Extremely Hard Stone)

Dark Green Gray Slate = This stone is in the 15k to 30K range ( not sure about this yet though I am leaning towards the 30k range as of now) this stone is also a very Hard stone the slurry is milky and provides a nice slip to the knives and razors that I have hones on it . the most odd thing so far that I have found is with the progression through the stones and slate trio of slate hones is the lack of /No need to hit a strop ! Really they provide such an keen edge and fine edge I did not have to strop my razors at all they finished out shave ready.

If you look into these hones, they have been tested extensively and the 30k number you're throwing out there is waaaaaaaaaaaay above and beyond what other people found.

These were my first hones and the "Llyn Melynllyn", which isn't really one, is by far the best finisher out of my 3.

Do you have anything in the 30K mark to compare these claims to? Like a shapton glass 30k?

My intentions are not to discourage you but base on your post I'd say you were fairly new at this? If these stones are working for you then GREAT! They worked for me for a a number of months before I ventured into the Japanese stone world.

 

[R Yates]

If you look into these hones, they have been tested extensively and the 30k number you're throwing out there is waaaaaaaaaaaay above and beyond what other people found.

These were my first hones and the "Llyn Melynllyn", which isn't really one, is by far the best finisher out of my 3.

Do you have anything in the 30K mark to compare these claims to? Like a shapton glass 30k?

My intentions are not to discourage you but base on your post I'd say you were fairly new at this? If these stones are working for you then GREAT! They worked for me for a a number of months before I ventured into the Japanese stone world.

Yes I do have The Shapton Pro Set of Stones Here is what I have http://www.sharpeningsupplies.com/S...serID=78128803&SessionID=Mpp3MQVnxKuazOSrbSnZ

I also have a Vast amount of Japanese Water Stones that I ordered from My good Friend Dave Martell http://www.japaneseknifesharpeningstore.com/Sharpening-Stones-s/22.htm

I am Far from a Newbie when it comes to "Forging knives and razors" as well to the Sharpening them . I may be new to this site .However I am not to the Razor and Knife Community .

Best Regards