Silica carbide for stone flattening

[LokiDK]

Good morning everyone! Reading around about stones and sharpening, I came across an important procedure for stones, which is flattening/lapping. It is suggested to use Silica carbide powder to flatten hard stones, as it should be the fastest and cheapest way to do it. Does anyone have experience with this product? It seems I cannot find it online in Greek stores.

[ntinos60]

My knowledge is that the carbides which are from 60 to 4000 grit are used for artificial stones only. A natural stone that has come out of the construction site with an optimal sharpening surface is best leveled with another same natural stone .

[LokiDK]

@ntinos60 I saw a lot of people especially in Italy using Silica carbide to flatten hard natural stones like ardesia nera to have an easier job to do, flattening it perfectly in a matter of minutes with a big effort. I have also a couple of videos at hand as well but only in italian.

Added in 2 hours 52 minutes 42 seconds:
I will leave one video here, in case someone is interested in this technique. I will translate the important concepts.



The stone in the video is a japnat Ozuko, which is said to be pretty hard.
Around minutes 2:20, Mauro (this is his name) shows Silica Carbide grit 400 and 800. He proceeds to put about a teaspoon on a piece of glass (about 6mm) and hydrates it lightly with some drops of water. You will see that he starts from 400 grit and then proceeds with the 800 grit that polishes the stone like it would be a mirror. After that, he uses another chemical with a superhigh grit but it's not suggested for all stones so I will avoid talking about it for now (if anyone is interested, I will translate that part as well), the process in this case is called dressing. Hope it will be interesting for someone.

[ntinos60]

Yes, this is what the surface of a natural stone from 1000 grit and above looks like.... when it is wet. When it dries, then the lines are visible ! That is why in this particular video and in the three stages the surface of the stone always looks like a mirror.

[LokiDK]

Obviously, when the stone is dry it won't be so shiny, but polishing is not the objective here. It's to make the stone as flat as possible, the second treatment is something additional that is not required for most stones.

[ntinos60]

@LokiDK The stone in the photos is 12k and was cleaned with sandpaper 2000. When the surface is wet it looks like a mirror (photo 2), while when it dries the lines are revealed (photo 1). On the other
side , the surface was cleaned with the slurry stone and the difference is obvious (photo 3).
I believe that when the sharpening is in the last stage where we press the blade against the stone while the water is running until the blade starts to stick back to the stone then these imperfections come out again on the blade.

[LokiDK]

The whole point of this process is not to have a shiny stone, is to flatten a hard stone in the fastest and easiest way. Even if the stone is shiny and the guy shows it with a smile, that is not the point. Hope it is clear now.

[ntinos60]

The whole point of this process is not to have a shiny stone, is to flatten a hard stone in the fastest and easiest way. Even if the stone is shiny and the guy shows it with a smile, that is not the point. Hope it is clear now.

Yes , In this case, I prefer straightening the stone with 350 grit sandpaper or coarser as the case may be and I upgrade to 2000 grit which I place back on glass and wet it until it sticks. But we do this once at the beginning and then we clean the surface only with the stone. I'm always talking about natural stones. With the technicians we clean everything with sandpaper.

Προστέθηκε μετά από 39 λεπτά 35 δευτερόλεπτα:

The whole point of this process is not to have a shiny stone, is to flatten a hard stone in the fastest and easiest way. Even if the stone is shiny and the guy shows it with a smile, that is not the point. Hope it is clear now.

Thank you for showing me Mauros, his videos are very interesting and I will watch them!

[LokiDK]

@ntinos60 let me know if you need help with the translation!