# Quick question on stone flattening...



## luis j (Jan 19, 2011)

Hi guys...

As you know, I just got my new stone. An "Oishi" 1000-6000 grit. I didn't get the flattening plate, and I haven't found the suggested "Drywall screen", the only thing that I have now is sand paper. And my question is: To flatten my stone, what kind of grit do I need? Fine, medium or harsh ? Should I use the same kind of grit to flatten the 1000 and the 6000 side? How often should I flatten?

All your input will be very appreciated. I'll order the flattening plate as soon as possible but that may take weeks, I'm going to try to find the plywood at home depot, but that store is kinda far from this side of the city and now I'm particulary busy... But I'm plenty of sandpaper,  and I'll like to start flattening before I get the stone messed up.

Best regards.

Luis


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## boar_d_laze (Feb 13, 2008)

I don't know much about Oishi, other than the word means "delicious." It's almost certainly made by one of the larger companies.

If you're going to flatten on sandpaper, you MUST use WET/DRY, and not regular. Water stones can ONLY be flattened when well soaked and WET or they will chip and crumble. In the case of your stone that probably means about 30 minutes in the bucket. Since I don't know whether the stone is clay or resin, I can't give you better information than that.

The "when it stops bubbling, it's ready" school of thought is repeated endlessly but is also wrong. Most stones will stop noticeable bubbling after about five minutes, but few of them are wet enough to flatten without significantly more time. Clay stones take longer than most resins (yours is probably clay), and 20 - 30 minutes is fairly standard for less expensive clay stones, so you should be fine.

Drywall screen works better than paper, is significantly less messy (as long as you keep rinsing), and you'll get more uses out of it. IMO, drywall screen is second only to (expensive) fast diamond plates.

Flatten both sides of the stone on relatively coarse paper (or screen). You're looking for a grit level of about 150. Flatten both sides, and ALWAYS CHAMFER the edges and corners. 

If you're using paper or screen, you need to rinse it and the stone frequently during the flattening process or you'll clog the paper.

You'll want some finer paper to lap the fine side. If you have multiple stones, it's easy to lap the finer stones with the coarse -- but you don't have multiple stones. A nagura would be best for lapping, but paper in the high 200s to mid 300s will be okay.

BDL


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## luis j (Jan 19, 2011)

Hi BDL...

Thanks for your quick and accurate reply./img/vbsmilies/smilies/thumb.gif Based on your comments, I tried hard to find the drywall screen (I wrote "plywood" in my original post, I don't know why, but you got me, I meant drywall) but I could't, all I have is my 240 and 350 grit sandpaper.

Definetely, I'm going to order a flattening plate, I've seen two different choices from CKTG and the Epicurean edge, and I'll like to have your input, and from anybody with experience with those plates. One is the DMT http://www.chefknivestogo.com/dmtextracoarse.html and the other is the ceramic flattener http://www.epicedge.com/shopexd.asp?id=80253

Your comments will be very appreciated.

And I almost forget, you say that I need to "Lap the fine side" Can you explain a bit more?, remember that I'm a Mexican jumping bean and my english is not very good looking /img/vbsmilies/smilies/biggrin.gif

Best regards!

Luis


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## boar_d_laze (Feb 13, 2008)

Anything coarse enough to rapidly flatten will leave a coarse surface on a fine stone -- that is, a mirror image of itself. But the stone's surface must be fine for the stone to cut and polish smoothly. Consequently, it needs to be smoothed. Smoothing hard surfaces like stones called "lapping."

People who sell Japanese water stones, often sell a special stone called a "nagura." The nagura is a small, chalky stone, which is rubbed on the flat surface of medium and fine grit sharpening stone to lap it (doesn't do a great job though) and to begin the process of "raising mud."

The reason water stones are "water stones," is because water softens the substrate (clay, ceramic resin, magnesia, etc.), which breaks free of the stone from the action of the knife, and brings up a constant supply of fresh abrasives with it. "Mud" (a wet mix of loose substrate and abrasive) is important, because with most water stones, the mud does and should do a lot more work than the surface of the stone itself. This is especially true with higher grit stones, as those actually polish finer as the abrasives within the mud break down and become smaller and finer themselves .

I use a DMT XXC and recommend it above any ceramic flattener. There are other diamond stones better than the DMT, like the Atoma for instance, but they're quite a bit more expensive and nowhere near worth the money -- at least not for _flattening_. SiC sand on a flat "reference" plate (metal, stone or glass) also works very well.  But, if money is scarce to the point where you're compromising on stones and/or knives, drywall screen is the best option. Flattening is important, but a diamond flattening plate should be well down your list of priorities.

How did I know you meant "drywall screen" when you wrote "plywood?" Not my first fiesta, amigo. You should be able to find it at any paint or well-stocked hardware store where they sell plaster. It doesn't have to be Home Depot.

BDL


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## luis j (Jan 19, 2011)

I flattened my stone... The results according with the "Drawing an x with a pencil along the stone method" were fine, I erased the whole thing. I used only the 240 grit for both sides of my stone. When I started flattening the 1000 grit side, I could feel how the sandpaper was getting degraded very fast. I placed it on my marble stone (the one that I use for chocolate) and started scrubing the stone against the sandpaper that was on the marble. The 1000 side took a while to get the x totally erased, and when I saw that it was ready, I started flattening the sides, wich were much faster, and I discovered that you have to be much more smooth with those parts because the stone gets quickly degraded.

I was about to change the 240 sandpaper to get to the 6000 side, but I decided to check if the used paper was good enough and I started to grind. To my surprise, that was much softer and inmediately I saw that some yellow mud was forming on my black sandpaper, I rinsed it everytime that I was seing too much of it ,and within 2-3 minutes, the 6000 side was ready to go. I was much more carefull with the sides and the job was done in less than 5 minutes on the second side.

The sandpaper doesn't got too damaged aparently, but I will know next time I have to flatten the stone.

Best regards


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## luis j (Jan 19, 2011)

boar_d_laze said:


> Anything coarse enough to rapidly flatten will leave a coarse surface on a fine stone -- that is, a mirror image of itself. But the stone's surface must be fine for the stone to cut and polish smoothly. Consequently, it needs to be smoothed. Smoothing hard surfaces like stones called "lapping."


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## wagstaff (May 30, 2011)

There is quite likely a terminology issue. This from answers.com as various things people call drywall in Spanish:

1) pared de yeso,
2) tabla roca,
3) drywall (...mainly in Puerto Rico, and we definitely roll the 'r')

SOURCE: http://answers.yahoo.com/question/index?qid=20070605185858AAppkQ3


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## boar_d_laze (Feb 13, 2008)

Not drywall, but _drywall (sanding) screen_. It's a kind of tough plastic screen, like an abrasive cleaning cloth. I'm bi-lingual pretty much, but don't know the specialty jargon words except in a few areas. This was brought to my attention the last time we called Maderos, our usual electrical service to put up a LOT of fixtures each with some specialty BS, and they sent a guy who spoke almost no English. It seems like we both thought my Spanish is better than it actually is. Quite an adventure.

Anyway, I think "drywall sheets" are either _paredes_ or _yesos_, sanding screens are called _mallas para lijados_, and the 3M package reads PAREDES -- Mallas para Lijados. I think. In any case, I'll walk around the brand label and technical term with something a little more general: _Mallas abrasivas adecuada para yeseros en el lijado de emplastos de yeso_. If that's not right, it's probably close enough.

Use the nagura before sharpening. You'll find the process very interesting. What usually happens is that the nagura is softer than the stone, and starts breaking up leaving soft, chalky, nagura-mud on the sharpening surface, and filling the scratches left by the flattener. Then, when you take knife to stone, the nagura mud helps get the stone's mud protection going sooner.

BDL


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## wagstaff (May 30, 2011)

boar_d_laze said:


> Use the nagura before sharpening. You'll find the process very interesting. What usually happens is that the nagura is softer than the stone, and starts breaking up leaving soft, chalky, nagura-mud on the sharpening surface, and filling the scratches left by the flattener. Then, when you take knife to stone, the nagura mud helps get the stone's mud protection going sooner.


So a nagura is better than using one of the small DMT or Diaface ski- and snowboard- sharpening plates? I've been using those, never tried a real nagura. I didn't consider the nagura's own mud as the big advantage. Innarestin'.


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## luis j (Jan 19, 2011)

Hi guys...

Actually the literal translation of dry wall is indeed "Tabla roca" wich is ono of those thin walls made of yeso (Wich reminds me big time the consistancy of a Nagura stone). Since I actually know what a drywall is (the one that we're talking about) I told the guy on the little hardware store to give me a "Malla para lijar" , when he gave me a WTF look, I told him that it was some kind of mesh used by the "tablaroqueros" (The drywall installers) to sand, he kept looking at me as if I were a lunatic and thinking that what I was talking about didn't exist. When I told him that it was manufactured by 3M he just said....Ooooooohhh I see... We don't have it /img/vbsmilies/smilies/rolleyes.gif .

I'm going to ask to the handymand that I hire from the restaurant and he'll know, I'll keep u posted.

And Thanks for the advice on the Nagura, I'll try it soon.

Best regards.


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## fish boy (Aug 31, 2011)

Having used Japanese water stones and Japanese chisels for the past 30 odd years I would suggest checking out some reputable Fine Woodworking supply stores for your stones and lapping supplies. Woodworkers Supply is one, Woodcraft is another and Lee Valley & Veritas (very expensive) is a third. They may or may not have better prices than chef's supply houses.

I have always used my nagura stone BEFORE every sharpening and never as a stone flattening tool per se. The nagura creates a slurry (mud) quickly, with just 10 or 20 seconds of working the entire stone evenly; and as stated by BDL above, it's the slurry that does most of the cutting. For keeping my stones true I have always used "wet-dry" silicon carbide sanding sheets (the black paper) on a piece of glass about 3/16 inch thick or thicker if you can find a scrap somewhere. Stop into some glass supply or picture framing shop and ask if they could cut you an 8 1/2 by 11 inch piece from scrap...you may get it for nothing. They break custom cut glass all the time, they'll have scrap. Use the whole sheet of sandpaper and cover the whole sheet evenly with the stone.

I have to take exception with the abrasive grits for the screens and sandpaper being discussed here. I've never used them so I don't speak from actual experience, but I've never used anything coarser than 400 grit, and that's for the 800 grit stone (my most aggressive) and then finished it off with 600 grit. The yellow 6000 grit stone is so soft that I start with 600 and go up to 1200 grit to finish it off.

I know, I know.......a little excessive but hey, I've been making my living as a furniture maker and antiques conservator for over 30 years...so sue me, I'm a fanatic for perfect tools and edges.

Also, I never take my stones our of the water tray, they're constantly submerged. If you use them less than once a week though, I wouldn't bother with keeping them in the water constantly.

*Here's the big time saver:* since my stones get heavy use and wear much more unevenly sharpening relatively narrow chisels (as well as my knives) I give them 10-15 seconds of flattening every single time I use them before putting them away in the water tray. This is the way to spend the least amount of time having to flatten them and you only remove a tiny bit of material every time so they're always flat.

Sorry for the very long post.

MB


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## wagstaff (May 30, 2011)

Seems it wasn't a translation problem at all, then, Luis.  I was just thinking maybe... But that's all academic since you're ordering the DMT plate.


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## luis j (Jan 19, 2011)

Hi fish boy, nothing to apologize about a long post, actually it was very informative and a joy to read, I didn't know that chisels had to be THAT sharp /img/vbsmilies/smilies/eek.gif and seems like as chefs we share some of the same passions with woodworkes, just like keep our tools as sharp as possible and always looking for "the perfect edge". Nice!

And Wag, your comment is very accurate, the translation was at first very problematic, but when I saw an image of the 3M Drywall I knew that a literal translation was not helping and I started being more descriptive than literal. And you're right, I'll get the DMT, I think that it's going to be a good investment since my likes for sharpening and buying the knives and stones is getting serious. I still have a lot to learn, but I want to do it as best as I can.

Best regards to everybody.

Luis


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## fish boy (Aug 31, 2011)

BTW, this has probably occurred to you, but just in case......There are DMT (and other brand) diamond "stones" that are all different sizes. I have two, one is very aggressive, for very quickly removing metal when my chisel hits a buried nail or a screw fragment and puts a big divet in the edge.  Another fine plate for a very quick hone  to touch up a dull edge quickly for a task that doesn't call for a 3 grit sharpening session.  They're 3" x 8" and you might consider one to have in a drawer in the event that your "assistant" or noobie line cook knocks your knife to the floor and puts a huge nick in the blade.  I'm going to assume you already have a serrated knive and don't need to make one ;-)

I'm not suggesting you use these in lieu of sending them out for a regrinding from time to time......just an alternative to  spending half a day trying to get that edge even on your water stones. This way you don't have to wait for your favorite knives to come back from the sharpening service.

Apologies if this is just seducing the obvious.

MB


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## luis j (Jan 19, 2011)

I have zero experience with the diamond plates, but I'll consider all your advice by the time I get it. But seein the videos of the plate working on the stones, I guess that it has to be almost painfull to see and listen it grinding a chipped knife...Ouch!

I've seen many newbies turning a chef's knife into a serrated one/img/vbsmilies/smilies/biggrin.gif. LOL, by dropping it, opening cans/img/vbsmilies/smilies/mad.gif and slaming it on big fish, poultry and meat with bones /img/vbsmilies/smilies/eek.gif. Lucky me, I don't have guys like that in my staff... Or at least they don't do it anymore, but I'm sure that every cook has messed up at least one knife in his career -I did- , name it accident or ignorance. Good to know that given the case I'll be able to fix it myself with the DMT.

Thanks for your advice /img/vbsmilies/smilies/thumb.gif


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