Couple questions about the ceramics

I’ve never heard it said on this forum that you’d use the micro-fines before the super-fines. I can’t imagine what the rationale would be for that.

As for me, I didn’t lap my ceramics until they were pretty heavily loaded with steel and I’d worn a low spot at the middle of the super-fines after more than three years. I don’t think lapping them when they’re new is necessary unless there is some anomaly, like a small bump sticking out. Or if you can see or feel a nasty roughness as you move them along an edge. But the 1200/1600’s always felt a little rough to me.

I use an EZE-Lap plate, but any diamond plate would work, except that I wouldn’t recommend one of the very coarse grits, like 100 to 200. My EZE-Lap is 400/1200.

If you think you need to lap them, and you don’t have a diamond plate, you can use one of your WE diamond stones, like the 800s or 1000s. Lay them on a flat surface on their sides, facing each other. Press the faces together and scrub them back and forth, applying not much more pressure than you’d apply at the sharpening contact point. I would thing that about 10 strokes is about all you’d need with new stones.

I should point out that these stones don’t need to be absolutely flat, but the thickness of the stones shouldn’t vary by more than about 0.010″ end to end. When they get visibly worn, that’s when you think serious lapping.

The progression I use – if I use both sets of stones – is: 1.4 mu, 1200, 1600, 0.6 mu. You can read here why: https://moleculepolishing.wordpress.com/2012/08/12/more-on-the-wicked-edge-micro-fine-ceramic-stones/%5B/quote%5D

I do also

Now that Mark says it, I recall him saying so earlier, but my 1.4’s don’t behave like that. 1200 grit should be the equivalent of 12 to 15 micron – so if a stone which is sold as a 1.4 micron leaves scratches coarser than a 12 micron, there’s something amiss. My micro-fines polish. My 1200’s scratch. I’ve never noticed that the micro-fines weren’t doing anything out of the norm.

This is interesting because I just lapped my super-fines and micro-fines but haven’t yet used the micro-fines. Later this week, I’m going to do a comprehensive series of scratch photos, alternating directions so that new scratches can be positively identified.

If the micro-fines perform differently after being lapped, that could be a flag for all to be aware of. I lapped them using a 1200-grit diamond plate. If necessary, I’ll re-lap ’em with a finer diamond film on a granite base or a 3/8″ glass plate to see if it changes properties. I have some samples of non-adhesive-backed diamond abrasive on non-woven fabric. I’ll have to snoop around and see if I can tell where they came from.

Bingo! I think I’ve nailed the reason for the confusion. As I said in my post just above this, I had recently lapped my super-fine ceramics – not so much because they needed it as because everybody here seemed to think it was the thing to do. Well, it wasn’t. Count one pair of super-fines as trashed! I tried them on my old Buck 110 and sure enough, the 1.4’s are now about 1200 grit. The 1.4 fineness lies only at the surface. Underneath that, it’s just crummy old ceramic, like my gray-brown Spyderco triangles.

On looking closely at them, you can see that I hadn’t lapped the entire surface, so I was able to get a photo of the difference.

Note to those who haven’t yet lapped their super-fine ceramics: If you get the urge, cut off a finger instead.

Also, if you simply use them for a bit then they should glaze back over… at least, that’s how water stones work. 😉

Of course guys, where I referred to “super-fines” I actually meant “micro-fines.”

Sorry, but I don’t believe the surface will ever regress back to its original grit.. And I don’t believe in some transition zone which is causing the 1200-grit scratch patterns.

When I lapped my super-fines (the 1200/1600 stones) it really did clean up the surfaces and the ceramic kept its characteristics – cutting at the original 1200/1600 grits. If you look closely at the photo of the area where I lapped the 1.4 micro-fine, you can see that where the super-smooth surface has been entirely removed, the individual nodules of ceramic are exposed. Even if there was a slurry, there ain’t no pores to fill. Here I zoomed in on the part of the photo that was clearest. Hope you can see what I’m talking about.

I think the super-smooth surfaces were produced by some clever work in the kiln firing process. Maybe even with a painted-on glaze. Like the diamond stones, once you remove ’em, they’re gone forever. That said, I’d sure like someone to prove me wrong. I wouldn’t have to buy a new set.

What grit did you use to lap your micro fine you are showing in the picture?

What I plan on doing removing that glaze with my fine dmt bench stone and make it nice and flat. Then use 1.3u diamond lapping film stuck to a marble flat surface to “polish” the ceramic back to what it is supposed to be grit wise. There were comments in the other thread that this ceramic is very hard and can take on the grit of what you sharpen it with.. It got me very curious and it is why I picked up a set of the micro fine.

I just need some time to get 4 utility blades sharpened to a really good mirror edge. Then I can hit each one with the ceramics and post some usb microscope pictures of the results. I have not lapped mine yet. So I guess I can do a 5th utility blade so I can see the difference before and after.