the correlation between stone's surface polishing degree and the honing it offers

Well, I have noticed some hones like the charnley forest, LLyn Idwal and turkey oilstone have to be lapped to a very fine, glass like finish to offer their finest finish for a blade. Other hones, like the Chinese 12k, yellow lake and many other usually harder stones, after used they tend to get glossy. do their honing abilities change according to the luster they have? It happens quite often on my hones, they do get slower but I'm not sure if they get finer. What is your opinion on this matter? Should I lap them to get them a bit coarser or not? Thank you

I have read it makes a big difference with some naturals, but do not care for it. The reason that I never lap beyond 325DMT is that I use slurry on my naturals, which is constantly refreshing the surface.

Thanks for the quick answer. It also depends from what someone uses to produce slurry. A diamond plate is usually preferred for its speed, and don't allow a highly polished surface to be formed, but with a slurry stone of the same stone used for honing, this glass like surface will be formed on many hones. And when this happens, polishing becomes quite difficult, because of surface tension (I think this is the name of the term), especially if they are flat, and used with water.

Many of my naturals do not have a slurry stone and I do not wish to use a DMT for the scratches it leaves, neither did I wish to cut a piece off leaving it smaller. What I have is a small piece of Lyn Idwall. (CF works also). It is harder than any other hone I have and works wonderfully as a slurry stone, as slurry is only generated from the hone itself, not the Lyn Idwall being so much harder. The piece of Lyn Idwall is like glass. It works nicely on coticules, Thurinigans, Silkstones and Yellow lake.

Yes it makes difference, on CF, and Jntas. I in general like to have all my stones as smooth as they can be.
I do not agree that when used with slurry scratches do not matter, but to each his own.

I have recently purchased one Llyn idwal, it was freshly lapped around 1k but when I used it, it scratched my blade. After that, I lapped the stone with 15k lapping film with 5k sandpaper between, and it became much more gentle on my blades. This stone was one of the reasons I opened this thread. I think it has much to do with the hardness of the stone. For the softer ones, I don't think it means something, and even less difference it makes when used with slurry. Don't you have problems with the surface tension between the razors and the blade(when they stick together like two pieces of glass with water between them)? For me, it turns the happy honing time into a nightmare.

Your stone may have been lapped to 1k grit by the seller but he could have rushed it. It's also possible dirt from the box got on the stone's surface. Some of those UK stone boxes are awefully dirty. 15k seems a bit excessive but kudos for trying :)

I agree that hard stones seem to benefit from a finer finish. Instead of fine sandpaper or lapping film you can also finish by rubbing it against another hone. I recently did this with a suspected Llyn Idwal and a 1k waterstone, it worked quite nicely.

I cleaned the stone, and lapped it with a 1k stone again, it was clean. And I used it with WD40. Yes, it's true that you can rub it with another stone, for finer hones, I use Chinese 12k pieces. It seems to me, under clear water its faster than with slurry for lapping stones but I might be mistaken.

i lapped my c12k out to 800wet or dry and now i use it almost exclusively with .5micron diamond slurry..... the stone has taken on a almost "mirror" like smoothness and altho it is slower than christmas it produces very very fine edges......

Do you use the stone without the 0.5μm diamond slurry? If yes, do you think it's finer than before? I usually lap my C12k with 600 grit diamond plate, and regardless how fine it gets after with honing, I don't see noticeable difference.

I use one of my phig's to lap most of my stones. Leaves them nice and smooth.

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Originally Posted by Vasilis

Do you use the stone without the 0.5μm diamond slurry? If yes, do you think it's finer than before? I usually lap my C12k with 600 grit diamond plate, and regardless how fine it gets after with honing, I don't see noticeable difference.

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i used it before with plain water... i tried it with the little slurry stone but it always seemed to leave debris that a. scratched the stone... or b. assed up the edge of the razor.....

now i will make ~20ish passes with water... then i put 3 or 4 drops of the diamond slurry and make ~50-100 passes or till the edge looks polished sufficiently... i honestly believe the diamond slurry is the reason the stone looks so polished now..... i was looking at it a minute ago and you can see a very good reflection in it....

I used the C12k with a C12k slurry stone, with or without slurry it still gives a polished marvel like reflection. But it becomes even slower.

Just some points to ponder, any media with use will get polished and shiny. A strop will develop a shine over use but I don't think that affects the job it does. In theory a rock has a certain hardness and whether it is polished or not will not change that hardness. I know with my hones I lap them to a shine and they work better in the sense that they seem to almost have a lubed surface but I have never noticed them to work differently as in a better edge whether they are polished or not. Now when I say polished as opposed to not polished I don't mean a hone that comes from the factory with a really rough surface I mean a good working surface and a truly polished one.

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Originally Posted by thebigspendur

Just some points to ponder, any media with use will get polished and shiny. A strop will develop a shine over use but I don't think that affects the job it does. In theory a rock has a certain hardness and whether it is polished or not will not change that hardness. I know with my hones I lap them to a shine and they work better in the sense that they seem to almost have a lubed surface but I have never noticed them to work differently as in a better edge whether they are polished or not. Now when I say polished as opposed to not polished I don't mean a hone that comes from the factory with a really rough surface I mean a good working surface and a truly polished one.

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but a polished surface is much less abrasive.... therefore... as the stone becomes shinier it slows its cutting and is able to polish the steel leaving less scratches.....

There's more to it than the surface. The abrasive grit is usually suspended in a media, and it is how easily this media releases the abrasive particles, and what those particles do when released, that determines things like cutting speed and polishing ability. Sure, if you are talking about a tightly bound grit, then surface texture can play a role, but in my experience most stones release grit into the water.

James.

I've given this some thought in the realm of eschers particularly. I've always used a 325 diamond plate to lap all of my hones. Actually on some real tough synthetics I've also used a DMTXX which ,IIRC, is 120 but I always finish up with the 325. I have one honing friend and mentor, Randy, who likes to lap to 1k with wet and dry sandpaper. Speaking of finishers, I don't recall if he does so with a 4k/8k. TBH I'm just too lazy to go to that extreme. Oddly enough I know another really good razor honer who likes a rough surface on his hones and prefers a Norton lapping plate from the old days. I'm told they were rougher than the current one.

I asked Lynn and Tim Zowada if they used slurry on their eschers. They both said no. Tim said he didn't see any point in dragging his edge "through mud." He added a smiley when he said it BTW. I, OTOH, do like to use a slurry on my eschers. The escher label has instructions on it which specify using the rubbing stone to create a 'lather' and that is why I kept with it. I do dilute as I go and I seem to get better results that way. Not better than if Lynn or Tim honed it, but better when I hone with slurry than with out it.

I prefer the feedback (or lack thereof) of a glassy smooth surface. I get that from lapping with a softer stone.
IME it doesn't make a difference to the cutting ability.

From the photos I have seen under a microscope for the escher stone specifically, the polishing it offers doesn't change weather it's used with or without slurry. From what I know, a stone without slurry gives a finer finish, so, it's use depends on how dull a razor is.
The way I'm thinking, about the polishing degree the surface of a stone has is, when the stone is been lapped with a low grit sandpaper or lapping stone, the surface of the stone appears to have "mountains and valleys" in a micro-scale. For the softer stones, I imagine that it doesn't really worsen their polishing abilities, but for the harder ones like novaculite, where quartz particles are bonded together by quartz, this type of surface might act as a different grit stone, scratching the steel. From my experience, the coarser I leave my hones (around 600grit) the faster they are. The glassy surface seems to work slower, but minimizes the chance of a scratch.
I'm not sure, Llyn Idwal and Charnley forest stones are a slate type of stone or novaculite? I have the impression they re the later.

I've used an Escher for years. For the longest time, I used it with just water, I have a few, and I did rub two of them together to create a slurry. I remember not being too impressed with the results. A few of my Escher's have instructions, some say use water to create a "Slime" and others say to use a rubbing stone. Now, the y/g I use now does benefit from a slurry. I use it, and make two dilutions, the last lap is plain water, and I always get great results. It's never disappointed me. Kind of my go to hone. Short of bevel setting, it's all I use these days.

Stones can glaze over causing a shiny surface and imparing your results. I had a J nat, a Nakayama Maruichi Asagi. (I think it has a few other titles, can't remember) oh yeah, "Nihon Kamisori" I think...TBH, these J nats drive me crazy. Anyway, it's surface had become glazed, A good lapping was all it needed to become a good finisher again. Now, I don't think that's what the op is talking about. I have a few stones w/ shiny surfaces that do fine the way they are. YMMV.

arkansas, charnley forests, and rozsutecs are examples of hones that will provide a finer edge/bevel polish when the surface is lapped smoother, or worn and broken in.

I will add another vote to "it makes a difference". I would rather burnish the surface of my stones with use than lapping with something else, but I suppose lapping with something else can get you close.

The C12, as a stone that isn't that aggressive and with a particle size that's bigger than 12k would suggest (at least in my experience with the WC version) is very sensitive to whether or not there's a slurry. Mine with a slurry is no stunner - at all - the edge is abraded and cloudy (and the shaving ability commensurately reduced). Without the slurry and with the surface able to be burnished for a while, the scratches are shallower and the edge polished and you can shave straight off of it very nicely.

Same with my japanese natural barber hone - it is finer than the C12, but with a fresh slurry on it, it is more aggressive on an edge than you'd expect.

There's a good picture on the web somewhere of a C12 with slurry and one without - I can't remember where it is. Someone brought it up on a woodworking forum a while ago.

I'm 3 months into my coti honing and feel off the DMT325 is too rough to manage polishing a razor and swarfs up quickly. After lapping it with my BBW, it becomes a slow finisher with mellow edges and loads up roughly 5 times slower.