Waterstones: How To Maintain Japanese Waterstones With Lapping

by Richard on January 10, 2012



Waterstones from Japan are the rage in the sharpening world today. In the store that I manage I sell waterstones from Japan by the truck load. I sell many different types of Japanese waterstones. Some of the waterstones are single stones and many of the waterstones are consumer based double sided waterstones that come at a value price.

Japanese waterstones come in many varieties. Some waterstones are clay bases ceramic and some are resin based ceramic. There are some waterstones made domestically by Shapton and they are some of the best waterstones on the market and even though Shapton says  the waterstones they produce are resin based they actually rubber based stones and they work very well.

If you are one of those people that are into using Japanese waterstones or you are one of those people that want to get into Japanese waterstones then you will need to do some research on waterstones to decide which one’s will work best for you. The other thing you have to look forward to is the fact that if you get into using Japanese waterstones or domestic made waterstones you will need to be prepared to spend some money on good quality waterstones and you will need to explore the kinds of grits that you will need to perform the sharpening chore. Remember: Some waterstones work well with carbon blades but maybe not stainless blades and then there are the waterstones that work well with stainless blade but maybe not so well with carbon blades.

If you have decided to buy Japanese waterstones for your sharpening arsenal then you will also need to be prepared to learn how to properly sharpen your knives on them AND you will also need to learn how to properly maintain your waterstones in order to keep the surface of the waterstones flat and as level as possible. This is done through a process call “lapping.”

Oh yes! Japanese waterstones need to have a maintenance schedule just as your knives need to have a maintenance schedule. So even though there is a learning curve when it comes to learning how to sharpen your knives to keep them at peak performance there is also a learning curve when it comes to keeping your waterstones at peak performance as well. Lapping waterstones in a labor of love to say the least.

So first thing is first: Lapping a waterstone is a relatively easy thing to do. I generally suggest that the sharpener lap their waterstones after each use. This prevents the waterstones from getting gullied or dished. When you see that your waterstones have a lot of black buildup on the surface of the waterstone that buildup is called “glazing.” This glazing is the buildup of steel from knives that have been sharpened over and over again on a stone that has not been lapped. This glazing will prevent proper contact of your knife blade to the waterstone and therefore you will not get your knives sharpened correctly because the abrasive is not making contact with the blade, the glazing is.

Lapping your waterstones is the process of removing the glazing and truing or leveling your waterstone so that your knife makes proper contact with the abrasive nature of the waterstone and therefore has even metal removal taking place so that your blade is consistent and contiguous.

There are a couple of ways of removing glazing from your waterstones. In the bad old days I used a piece of wet/dry sandpaper at 220 grit and wrapped it around a piece of 2×4 and stapled it into the wood and I would lay my waterstone on a flat surface and do my scrubbing back and forth until the glazing was all gone. This worked for a while until I found that the surface of the 2×4 that I was using was not exactly flat enough so in turn my waterstone was not getting leveled to a high degree of satisfaction.

So later in the process of me learning to do quality lapping of my waterstones I bought a DMT diamond diasharp at 220 grit  and a DMT diamond diasharp at 600 grit. I would then wrap a piece of 2×4 in thin cloth and wet it and then put a waterstone that has been soaking for 30mins minimum on top of the 2×4 and then use the diamond plate to lap my stones back to level.

Now after your waterstones have been lapped back to level there is a process you perform on your waterstones called radiusing the edges. This is where you take off the sharp edges of your waterstones to allow the blade even more consistent contact with the abrasive for a better sharpening experience. You radius the edges of the waterstones because sometimes the edges can raise the knife off of the center mass of the stone and only be lifted by the edges and this makes for poor contact with the abrasive.

All of this is covered in the video so please watch this video and leave a comment. If there are any questions please feel free to contact me and I will get back to you ASAP!

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{ 2 comments… read them below or add one }

Sushi Las_Vegas January 21, 2012 at 10:49 am

That’s the way you maintain Japanese waterstones !! Cheers


Richard January 21, 2012 at 6:30 pm

Thank you very much for stopping by and checking out this blog post and most of all for the kind compliment! Cheers to you!


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