If you’ve sharpened knives on a stone for any length of time or maybe inherited an old stone from someone, no doubt you’ve come across a worn stone with a concave surface. A lot of times the edges of the stone will have gotten rounded off as well. In fact, last fall a friend of mine was moving out of town and dumped off a box of ‘stuff’ for me. It included a nice older 6″ combination stone in the box that was absolutely loaded with old metal and oil and cupped in the middle. I scrubbed it up and used the following method to bring it back to true…..just like new.
An easy way to determine if you’re stone needs ‘leveling’ is to simply hold a flat surface along the top of the stone and see if any light shines through.
Edge Pro has a Leveling Kit that works really slick to take care of this. It’s simply a round piece of glass about 12″ in diameter with a round tube encircling the edge of the glass and comes with a bag of silica carbide.
Pay attention to the fact I’ve laid some newspaper under it to make sure none of the silica ends up on the formica countertop. You very quickly get an appreciation for that rubber ‘rim’ as it helps contain everything on the glass rather than letting it run off the edge. The silica carbide is meant to ‘cut’. It will take a formica or polished granite countertop and scratch the surface faster than you can say whoops. NOT an easy thing to explain as you’re sitting down to supper.
I pour about a tablespoon of the silica carbide on the surface of the glass…..
and just stir it with my finger a bit to make a slurry. It doesn’t take of lot of the carbide to get the job done.
Now, simply rub the surface of the stone on the glass in a circular motion to start leveling it.
When you start rubbing it, you’ll notice the carbide doesn’t spread out evenly as the void created by the uneven surface of the stone isn’t contacting the glass.
As you get down to level, you’ll see the silica spreading out evenly and you’re done!
You end up with a nice level and clean surface on your stone.
The second big benefit is the glass works perfectly to set up your sharpener on any type of surface and keeps any water from lubricating the water stones contained.
This whole process took maybe 5 minutes start to finish. If you’re really thrifty, you can let the water dry out and recover the compound for later use. You old timers have no doubt used a concrete block or maybe a piece of coarse carborundum sand paper to level things. This setup is so much more convenient to setup on the kitchen counter or my wood workbench in the shop (particularly in the winter). Most important, I know the piece of glass is about as true and flat as you can get.