Monday, November 11, 2013

Siletz river canyon shale

Testing all of these beach stones made me think that I need to get to the source, as it were. Deciding to take advantage of the sunny weather, Ellie and I took a drive up the canyon. I was looking for sharpening stones (surprise!), Ellie was looking for amphibians. Success was found in one search, the other remains to be seen...Ellie found lots of salamanders. We forgot the camera, of course.


Lots of layering, I lapped numerous areas to test.

Very green stone. I need more homogeneous samples.

This layer was interesting, faintly purple and very smooth.

Interesting.... Definitely some polishing going on here.

What are those weird looking things? Bet you thought that I never used artificials, did you. 5000 grit. Hazy mirror finish.

Yep, definitely polishing. The stone makes a bit of slurry, but wanted a nagura so I used the ODC. It feels like my ink/sharpening stone, kind of sticky but you can feel it working. I sharpened on the long axis. All of the scratches that I can see are from the artificials. I will lap these samples to make a larger sharpening surface..... interesting!

I will go back and get more samples. These are too layered. The stones are very attractive but the layers add too much uncertainty, too much opportunity for very coarse scratching. You will have a layer of nice smooth green shale followed by a layer of what looks like sand. It doesn't seem to BE sand but....I passed on some bright green, thin stuff that in retrospect may be perfect. I wanted to try this stone cross grain, so I got thick pieces. The greener stuff is softer, too. That would be just fine.

As often happens, after using the man made stones I question the whole endeavor. For about 5 minutes. That's about how long it takes to erase the deep scratches and clean up the mess. I pretty much only use them outside where I have a hose and the funny colored grit won't hurt anything. They are pretty fast, though. As I may have mentioned, the naturals are splash and go and don't really make much of a mess. It feels a bit like searching for the holy grail, sometimes. For whatever reason, the naturals just FEEL right.

OK, after a sleepless night (well, I'm not THAT obsessed), I lapped a larger surface to make for a more thorough test...... but first, the man made stones, even the 5000 grit left too many scratches. To be as certain as possible about the origin of any scratches that may occur, I polished the edge using 2500 grit wet/dry paper to get a nice mirrored surface. That left pretty impressive marks too, but it's the best that I've got. Really easy though. The stones did all of the heavy lifting. Why not just use paper for the finish? It IS more consistent, gritwise. P2500 is the equivalent of about JIS 2300, so this is a step back in grit, but the paper leaves a very even pattern that appears more polished.

Nice dark slurry ( need to finish lapping the stone, though)! If you zoom in, you'll see the camera lens reflected in the steel.

The stone definitely polished out the P2500 grit scratches. For reference, I made the P2500 scratch pattern 90 degrees to the cutting edge. The stone did leave a few new scratches. They are pretty much the only marks left and you can see them if you zoom in. There must be a few sharp bits in the stone, or MAYBE some diamond grit got shed and imbedded. More on that later. This is looking VERY promising..... Not particularly fast, but finer than the other stones that I've got. 

The edge LOOKS sharp, but if you look very closely, you'll see that the P2500 marks are still present at the very edge. THAT'S why I don't use paper for sharpening tools. I can't get a truly flat bevel using paper. Or a strop. PSA backed abrasive..... maybe, but I haven't used it. Micro bevels and PSA film.... that would be my plan C (plan B would be India/hard Ark/wood strop). This edge would be fine for most tools, but won't cut it for Japanese planes. Not if you want thin shavings. For that you NEED the back flat. If you can't get the bevel flat, you can't get the back flat either.

While I was frantically trying to remove scratches from metal, Ellie made a fish trap and caught some fish.....

Here fishy fishy fishy..

A wonderful day!

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Like all of us, I am figuring this out as I go, so when you see something that is incorrect or flat out wrong (and you will!), let me know. This is a learning process. Real people and names, please. Constructive comments and questions are very welcome, but hate speak/politics are not! Life (get one!) is too short.

Thanks, Jason