Thread: What grind have a chromium oxide paste??

Before i start sorry for my English. The question is what grind have a chromium oxiden paste its something about 600 grind or less. I`m thinking about a finishing paste.

Thanks for response

CrO is in the 60k grit range.

I good understand its 60 000 grint??

yes 60000 grit

Generally, chromium oxide is in the 0.5 micron range, stating it in different units.

And what Paste Of chromium oxiden will be The best. A homemad from pigment 44200, 44210 or buy a ready paste a Puma chromium? I know its that question may by stupid but now when i use my homemade strop i dom't fill any diffrences betwen that strop and dovo premim lether. If a sama be onest whit You guys i prefer my stop becuse its larger and more funn when use it

thanks for response Cube

Originally Posted by mainaman

CrO is in the 60k grit range.

CrOx is .5 Micron. So that means it's roughly the equivalent of a 30,000 shapton (.49m), or 8000 JIS Sandpaper...

I'm not sure where you got 60,000.

And, just for the record, the JIS only goes up to 8000, so anything after than is non-standard as far as Japanese stones are concerned...

let´s not go through this again.
Chromium Oxide is a crystalline product that could technically have ANY grit size.

The chromium oxide commonly used and availiable has a rough particle size of 0.5µm.
The pigment PG17 produced by Kremer Pigmente in Deutschland has made some REM analysis and the average particle size of their Cr2O3 is 0.3µm

0.5µm can be translated into certain grit systems.
So we should make clear wich one he wants to hear.

The number 60k (60.000) referrs to the MESH system,
that has been commonly used for diamond sharpening compunds.
It is standartized to 100.000 I think,
unless JIS wich stops at 8.000 (as far as we know).
Still JIS can be extrapolated to any grit size!

Another commonly used number in Mesh for 0.5µ particles is 50k.
Shapton says it uses the Mesh system as well, wich up to the 30k is correct,
but fails at 30k. Idk why the shapton with 0.49 is called 30k.
But it doesn´t make any difference.

Not only will a shapton 30k cut different than chromium oxide at roughly the same grit size, but are in any term incompareable.

I would say in these high grit ranges it would be best to talk about actually micron sizes. But this might be my personal preference

the interesting part for cube:


What I wonder about is why the thread starter thinks a finishing paste would be around 600 grit. Are you talking about AINSI sandpaper?


btw: the Pigment 44200 or PG17 is exactly the Chromiumoxide Pigment that I use.
It comes from Kremer in germany and has an average particle size of 0.3µm
and has a round shape. It is perfectly suited for our purposes.
You can mix a little bit of the poweder with oil and apply to your strop

Your razor or blade should be sharpened on waterstones up to ~8.000 (standart waterstone grit)
before you can go to the chromium oxide.

Originally Posted by Lesslemming

unless JIS wich stops at 8.000 (as far as we know).

And as far as Naniwa Kenma knows.

Every Japanese stone above 8K is based on in-house determinations, not on any external standard. This is straight from a representative of a Japanese waterstone manufacturer.

Every Japanese stone above 8K is based on in-house determinations, not on any external standard

You´re right. The only uncertainity that remained for me was,
that I did not see the official JIS list, that costs money to have a look at.

That´s why I said I personally prefer the actual micron size,
because it has the most information (but certainly not all. I wish to know the tolerances: 0.5µm +/- 0.3 or 10% above and 90% below) about the particle.
Still not about the sharpening power and action... but something to work with.

( I just saw a typo, I meant "unLIKE JIS wich stops at 8k (as far as we know) but can be extrapolated to any grit size")