This is part of a series of blog posts – looking into the appearance and composition of commercially available sharpening stones. If you are interested in the previous episodes, check out the archive for them.

If you have some suggestion on what I should look at next, or want to share your super secret DIY stones, I could be persuaded to open the bag of analytical devices… hit me up on Instagram under @marvgro for that.

Disclaimer: I’m not for sale. Every review you see on this blog is bought with my own money. I have no affiliation to any manufacturer.

Review

Today’s a very short, SEM heavy study. After taking a closer look at the Stroppy Stuff in Part 8 – leather and stropping compound (1 micron), I ordered some more. Let’s take a look at the 0.5 µm and 0.25 µm suspensions, which are very fine ones.

Stroppy Stuff 0.5 µm Emulsion

SEM micrographs of the 0.5 µm Stroppy Stuff Diamond Emulsion. Instrument: Zeiss GeminiSEM 560.

This was once again 1 drop of the emulsion, dried on a silicon wafer piece. The statement “high concentration” definitely holds true here – this is a surprising and high amount of leftover diamond grains! The grain is angular, and the distribution looks to be on the upper side of 0.5 µm – just like with the 1 µm Stroppy Stuff, particle size is constantly over the stated size, but in itself relatively homogenous. It is definitely much smaller on average than the 1 µm suspension – which is pretty much the only thing that is important. Absolute particle size doesn’t really matter, as long as you stay within one manfacturer’s system.

SEM micrographs of the 0.5 µm Stroppy Stuff Diamond Emulsion with some measured grains. Instrument: Zeiss GeminiSEM 560.

Stroppy Stuff 0.25 µm Emulsion

Because of the smaller size, the following gallery also contains some higher magnifications. In the overview at 2kx magnification, some outliers are visible. The emulsion was applied and dried in a laminar flow box, so I would imagine these larger particles were already in it.

SEM micrographs of the 0.25 µm Stroppy Stuff Diamond Emulsion. Instrument: Zeiss GeminiSEM 560.

The grain distribution appears to be, once again, on the larger side, but also, once again, smaller than the 0.5 µm compound. Overall, this is about what I would expect of a high quality 0.25-0.75 µm mix. The grains are monocrystalline and angular in their appearance, which makes them more aggressive than blocky grains in their material removal. I would consider this a very fine compound. Like all other Stroppy Stuff emulsions, after drying, no smearing film is left on the leather.

SEM micrographs of the 0.25 µm Stroppy Stuff Diamond Emulsion with some measured grains. Instrument: Zeiss GeminiSEM 560.