Shapton Rockstar 3k stone is magnesia binder

[Knife2meatu]

Correct?

 

[nopomo]

Resinoid?

 

[rickbern]

The type is listed as wa. That’s all I can see they actually say


It indicates the type of abrasive contained in the sharpening stone.
HA: Mono-crystalline fused alumina
PA: Pink alumina
WA: White alumina
A: Regular (brown) alumina
CA: Calcined alumina
HPA: High purity alumina

 

[Jovidah]

We can all take guesses but maybe just ask them? They have an actual website...

https://shapton.co.jp/en/contact_private/

 

[nopomo]

We can all take guesses but maybe just ask them? They have an actual website...

https://shapton.co.jp/en/contact_private/

Not a guess, I was going off of this post.

 

[Knife2meatu]

So. What do we have here, answer-wise:

Somebody talking about abrasive (WA), not binder;
Somebody saying resinoid, from referencing my own post. (mea culpa and all that, but still...)

As for contacting Shapton... I will not waste my time; they will not give a straight answer to this pointed of a question regarding their manufacturing process.

Anyhow. It feels harder than any resinoid I have, but sounds duller than any magnesia stone I own, including Shapton Kuromaku.

Anyway, this post is meant as a disclaimer for my above referenced low-effort guess-post:

Don't assume Shapton Rockstar stones are resinoid based on my aforementioned surmise.

 

[M1k3]

Use a blow torch on a corner. If it burns, it's resinoid.

 

[Knife2meatu]

Use a blow torch on a corner. If it burns, it's resinoid.

Doesn't start aflame. There appears to be a slight combustion, which I think is mold-release burning. Heated corner feels a bit more crumbly, but not melty, if you see what I mean.

I habitually try to avoid taking blowtorches to stones. But, okay, science.

edit: a lot more crumbly, on closer inspection...

 

[nopomo]

So. What do we have here, answer-wise:

Somebody talking about abrasive (WA), not binder;
Somebody saying resinoid, from referencing my own post. (mea culpa and all that, but still...)

As for contacting Shapton... I will not waste my time; they will not give a straight answer to this pointed of a question regarding their manufacturing process.

Anyhow. It feels harder than any resinoid I have, but sounds duller than any magnesia stone I own, including Shapton Kuromaku.

Anyway, this post is meant as a disclaimer for my above referenced low-effort guess-post:

Don't assume Shapton Rockstar stones are resinoid based on my aforementioned surmise.

I was quoting the message above yours.

Shapton got back to me. To summarize:
RockStar and GlassStone are the same; RockStar is thicker and does not have backing.
Japanese retail RS product has printed graphics, overseas/US retail models will not. RockStar series available from US retailers est. 1-2 months. It's Splash-n-Go, white alumina. Fancy option comes with a stainless case.

So it would seem that contacting the manufacturer would be worthwhile if you really want the question settled.

 

[Mr.Wizard]

Stones can have fills and treatments in addition to the bond. A vitrified stone that has a combustible fill will show a flame even while the stone itself does not burn.

 

[Knife2meatu]

Stones can have fills and treatments in addition to the bond. A vitrified stone that has a combustible fill will show a flame even while the stone itself does not burn.

We talking Gokumyo process? Otherwise, I cannot think of any stone I have heard of which would fit what you describe. Or perhaps you mean like pre-filled Norton stones and the like.

 

[Knife2meatu]

I was quoting the message above yours.

So it would seem that contacting the manufacturer would be worthwhile if you really want the question settled.

I was assuming about Rockstars being resinoid based on what information I could find on Glass Stones.

If the exact make-up of Glass Stones is still this unclear from the manufacturer's mouth several years after their introduction, I'm not at all optimistic about getting a straight answer out of Shapton from asking them...

Case in point, the person you were quoting...

 

[Mr.Wizard]

We talking Gokumyo process? Otherwise, I cannot think of any stone I have heard of which would fit what you describe. Or perhaps you mean like pre-filled Norton stones and the like.

I am not familiar with the "Gokumyo process" so if you have information on that please direct me to it.

I am referring to fills of resin, sulfur, wax, etc. that are injected into some industrial alumina and possibly silicon carbide stones to modify their behavior, for example to:

• Reduce porosity
• Decrease rate of wear and increase integrity
• Finish more finely
• Resist loading

 

[nopomo]

I was assuming about Rockstars being resinoid based on what information I could find on Glass Stones.

If the exact make-up of Glass Stones is still this unclear from the manufacturer's mouth several years after their introduction, I'm not at all optimistic about getting a straight answer out of Shapton from asking them...

Case in point, the person you were quoting...

Another secondary source: What is a Shapton glass stone made out of?

Shapton acknowledge that there is something in the stone besides abrasive and binder, “filler” seems a reasonable name for it. I remember Cliff Stamp saying the coarse Shapton Pros have some kind of waxlike substance in the pores that was visible under a microscope.

 

[Knife2meatu]

I am not familiar with the "Gokumyo process" so if you have information on that please direct me to it.

I am referring to fills of resin, sulfur, wax, etc. that are injected into some industrial alumina and possibly silicon carbide stones to modify their behavior, for example to:

• Reduce porosity
• Decrease rate of wear and increase integrity
• Finish more finely
• Resist loading

Ah. Very interesting re: the industrial processes. Thanks for the taking the time!

Gokumyo is Suehiro's trademark name for at least 3 of its higher-end, higher-grit stones (Suehiro's marketing is confusing, so maybe they have other "Gokumyo" stones besides those I am thinking of; 10k, 15k, 20k.

My wild surmise regarding the Gokumyo series is that they are an abrasive-rich, binder-reduced vitrified process (for abrasive performance), which is then resin-filled for structural integrity and to make it splash-&-go. As I say, this is all wild conjecture on my part.

 

[Knife2meatu]

I remember Cliff Stamp saying the coarse Shapton Pros have some kind of waxlike substance in the pores that was visible under a microscope.

RIP. I remember Cliff Stamp once saying in one video, the King Deluxe 1k was resinoid.

Does this machine convey irony? Who among us... I mean.

Wax-like filler in Shapton Pro would begin to explain the hydrophobia both they and the Rockstars have, when new. I've noticed the Rockstars regenerate some hydrophobic layer over a much briefer period of disuse, than do the Pros. Then again, the Pros are more worn and nearly 5 years old.

 

[Mr.Wizard]

My wild surmise regarding the Gokumyo series is that they are an abrasive-rich, binder-reduced vitrified process (for abrasive performance), which is then resin-filled for structural integrity and to make it splash-&-go. As I say, this is all wild conjecture on my part.

That sounds entirely plausible.