Question about new sharpening stones preparation for first use

[mike59]

Hey folks,

I'm about to start my hand sharpening journey and have a couple newbie questions that I have not
found an answer to.

Generally, do new whetstones need to be flattened before first use when new?

Specifically I have the following stones.

Shapton Glass 500 (Double Thick)
Suehiro Cerax 1000
Suehiro Rika 5000

I have no idea about the SG 500 or Rika 5000.

I do know that in a previous short go with a Cerax 1000 that it seemed like it had some sort outer layer that until it was removed yielded basically no sharpening results. Since then I've seen this outer layer mentioned a time or 2 by others so I suspect it will need to be flattened just to remove that outer layer. I haven't actually taken it out of the box yet. Thoughts?

Regarding the Cerax 1000 and Rika 5000 soaking times? I've seen recommendations ranging from 5-15 minutes up to 30-45 minutes and know that generally it's ready when it stops giving off bubbles and taking in water. I will say that with my previous Cerax 1000 I never saw a single bubble when I soaked it which is part of why I got rid of it at the time but have since wondered if that might have been due to the "outer layer". Any experiences with soaking times for these stones would be greatly appreciated.

Last question - I have well water and I was wondering if that would have an affect on the stones or sharpening performance or if it's not anything to worry about. It's pretty good as well water goes and we also have a whole house water filter. I do not plan to permasoak anything at this time.

Much thanks in advance to all!

Mike

 

[Blank Blades.]

When I use the rika I will let it soak about 10 to 15 minutes, but I think 30 minutes would be a good time too.

Some stones do need some surface conditioning from the manufacturer, not so much flattening usually. You can usually just use whatever you would normally use to flatten, to remove this top layer.

Do you have a way to flatten stones? I feel like that would be good to know. For the rika, you may want to use a nagura, after using some flattening stones, depending how course they are.

And I really dont think using well water should give you any issues.

 

[mike59]

Thanks jwthaparc!

Re a way to flatten - yes, I have an Atoma 140 diamond plate for flattening.

 

[M1k3]

Definitely flatten the Glass 500. The top layer is almost waxy like and kind of sucks. When water no longer wants to bead on the surface, then you're good to go. Can't say about the other ones but I'd just go ahead anyway.

 

[mike59]

@M1k3 - I had not heard this about the SG 500 - good to know and much thanks!

 

[M1k3]

@M1k3 - I had not heard this about the SG 500 - good to know and much thanks!

Every Glass stone I've used was like this. Not the Pro/Kuromaku though.

 

[Blank Blades.]

Yeah. You may want to follow the atoma with a nagura for the rika. If you don't have a nagura, you can just use your shapton glass to smooth the surface a bit. Just make sure to give it a quick rinse afterwards.

 

[ITKKF]

- Flattening before first use cannot do any harm, so I always do it. And don't forget to take care of the edges, this you should always do, the whole procedure is demonstrated in this JKI video:
- For my Rika I follow the bubbles rule and never had a problem.

 

[mike59]

Thanks again guys for the responses and @ITKKF thanks for the link. I've watched a few vids on how to flatten but that one is actually the best I've seen ... the most comprehensive for sure. Also, Jon mentions the harder exterior layer the manufacturers put on the stones .... that's it! That's what I previously noticed on my Cerax 1000! Note to self - if I want to learn something look first for a @JBroida video! I want to be like Jon when I grow up

 

[mengwong]

If you own a double SG500, you've noticed that it looks from the side like two single stones bonded together. That's exactly what it is. You can only assemble a stone like that to a certain depth without expensive technologies. Just putting the oxide into a press and heating and pressing it addresses the outer 1-2 mm almost immediately and does little for the middle. If you have reason to use a stone like the SG500 heavily, you may notice that it starts out hard, slow, and non-slurrying, almost as if it were glazed, and once you've reduced the thickness it picks up a lot of speed and slurries much faster. The quality of the grind is unchanged because it's still the same size grit, but the quality of the stone manufacture has changed a few millimeters in. If you take a double SG500 and work all the way through to the midpoint, you'll find a point where it again becomes slower and harder to sharpen on; then it eases up as you go into the next layer of the stone.

The original post is worth reading in full.

 

[Kawa]

I would always flatten a new stone.
Just draw a pencil grid on the stone and flatten. Is the stone flat, the pencil dissapears very quickly and you are done. If not, you continue till its gone.
You also remove the bad outer layer, if there is one, this way.


Soaking time on the rika: I put it in water for about an hour. Longer doesnt seem to change the sharpening feeling.
15 is minutes is too short for me, the feeling is quite different when sharpening.
Try it for yourself. Compare a 10 minute soak with an overnight soak (wont harm this stone) and see what you like better.