Home Forums Gear Knives and Blades dumb sharpening stone questions

I inherited a few dark gray sharpening stones from my uncle (finish carpenter) and grandpa (black smith) and I'm ignorant how to tell if they are... oil stones or wet stones (water).

These are probably the hardware store or Norton abrasives.

So..

Use oil or water or does it matter?

Or is it... use oil for industrial stuff and use water for kitchen & food prep stuff?

And dont intermix water or oil use?

If it is impregnated with oil then that is what you use, if it is dry then use soapy water.

Wash the blade after sharpening...and no, do not mix

Me too... good question.

They are run of the mill cheap stones that almost certainly were used with oil and just as probably with water and dry.

If the stones are fairly clean and flat they are probably useful. Most are not, at least for decent knives anyway.

if the stones are soft, I use oil. With the hard Arkansas stones, I use water.

If you're really interested in sharpening knives using a stone this is they way to get started:

You need a medium coarse diamond stone say 400-600 grit and a combination ceramic stone, one side of 1000 grit and the other of 3000 grit.

The diamond stone will be a metal substrate impregnated with diamonds mounted on plastic. The ceramic stone will be two colors, one for each grit and may or may not come with a rubber "holder".

You set the knife at the angle to be sharpened on the diamond stone. A drop of dish detergent on the diamond stone with a teaspoon of water will wet the stonproperly. With the knfe at the proper angle slide the knife like you are trying to shave a very thin slice off the top of the stone. Keep slicing until you raise a burr on the edge away from the stone. Flip the knife repeat on the opposite side. Once you have set the angle like this you can start with the finer ceramic stone.

Soak the ceramic stone in water until it absorbs no more. On the 1000 grit side gently remove the burr from the blade and lightly polish the edge. You will be able to feel and hear when the edge is at the right angle. Go to the 3000 grit side and repeat. At this time if you did good work the knife is razor sharp. If it isn't, then you probably did not maintain the same angle during the process and will now have to go back to the diamond stone and start over again.

If you never let a knife go completely dull, you will not need to start with the diamond stone.

Once you have learned to feel the cutting edge as you sharpen you can go to a 1000 grit or finer ceramic rod (crock stick(s) either on a handle or mounted in a V on a piece of 1x2. A light stroke or two on the crock stick will maintain an edge for a very long time between sharpenings.

You can do the same thing with the grey stones you have, but the grey stones are nowhere near as durable and dish out pretty rapidly. Then you have to bring it back to flat with a diamond stone and that's hard on the diamond stone. The grey stone can be used with water and detergent or about any kind of oil.

Thanks guys.

The stones appear to have never been used in oil because they dont feel oily.

Saturate them with some water with a little dish soap in it for sharpening.
When done with a knife, use the soapy water and an old toothbrush to float the crud out of the stone.

Stones can be reflattened with a sheet of course sand paper and a flat surface.

I usually finish off with a leather strop laced with semi chrome. You can lace the strop with the crud
you clean off of the finest stone you use.
jmho
Tim

One trick I learned for hard stones like an India or Arkansas stone is to occasionally lap the stone with loose silicon carbide powder like people use in rock polishing machines or for sand blasting. This is not flattening but really only "scuffing" the surface of an already flat stone to break the glaze that builds up as you use them. What happens is that over time the stone becomes worn smooth in use and does not cut as aggressively as when it was new. People refer to this as "breaking in" sometimes, but eventually the stone gets smoother and smoother and then people will say that their stones "cut so slow".

If the stone is oily, blast the crud off of it with brake cleaner. Then, I will take a little 100 grit SIC powder and put it on a piece of scrap glass or a flat piece of steel. I then lap the stone using a figure 8 pattern for about 30 seconds or a minute using the weight of the stone only. If you bear down on it, you will only crush the grit up and make it less effective. You can use sandpaper or even a flat section of your drive way or a cinder block to flatten a stone like this but having two fixed abrasives rubbing against one another tends to 'polish" both surfaces whereas the loose SIC powder does a better job for lapping.

Incidentally, this is why people say water stones cut faster than oil stones. Most water stones have a loose bond and constantly break down in use, always releasing fresh abrasive. Many oil stones are the hard type and get clogged and glazed because people do not know how to maintain them. I sure didn't.

You can get SIC powder off of ebay which is where I got mine. A pound of it will last forever.

If you have the type of stone that releases slurry in use, you don't need to do this process as it is always releasing fresh abrasive. That is the advantage of this type of stone, the disadvantage being they dish and wear out fast. You can just flatten them and they will be good to go.

Often the reason users are having trouble with sharpening is because they don't clean the stones
and the blade is just gliding over the crud loaded up in the stones.
Usually WD40 will float the crud out of oil stones.
Soapy water for the water stones.
A used toothbrush can help with the clean up along with a paper towel.
When using any abrasives, bits, saws, cutting wheel, etc.....fresh cutting edges count big time.

Thanks for the stone maintenance tips.

time to do some cleaning...