środa, 28 stycznia 2015

Removing toxic line from Red Oohira


Hello there!!

I brought my Red Oohira stone from last JNS gathering in November. There is toxic line or inclusion which goes through half length of the stone and almost through whole deepness of ite. It splits it in half. Of course you can cut this stone and make tomo nagura's, small traveling size stones or fingerstones, but I wanted to save it.

I have postponed that project for a while, but now I found some time to remove it. I have never removed toxic line before so this is more like a experiment.

Let's start from ''the toxic line'' or ''inclusion''. What is that? The quote below comes from Easternsmooth.com blog:

http://easternsmooth.com/blog/jim-rion/2011/10/24/703-buying-japanese-hone-guide-beginners

''There are two basic types of inclusions: lines (called Suji?) and specks, called "hari" or "ishi" or sometimes "Suna-me" or sand eyes. Basically, these are accretions of minerals that are harder or of a different coarseness from the rest of the stone. If they are in areas that can hit your edge, they are called "living" and are best avoided if possible. If they don't hit the blade, they are called "dead" and, of course, aren't a problem. Both cases, however, can cause a drop in the price of the stone.''

So here it is. My Red Oohira:




So here you can see my line going through the whole depth of my stone.

 And here line is going through the lenght of the stone.


Let's look at it in the 60x magnification. Please note that I took those pictures with phone camera and some kind of magnifier so colours might be little bit different.




So my today's tool of choice was my girlfriend's manicure set...
 and diamond covered bit.
 I was gently removing the lines.

 It was going ok, but then I hit the first dangerous place. It's on the rounde corner. Later on I will show you all dangerous spots.

 Look at it under magnification. You can clearly see that there are different coloured minerals. My diamond bit felt slippery on those spots. I felt like bit was jumping over that place. It was too hard to remove. Almost dulling my diamond bit.


 Here you can see all spots.










 I couldn't remove them so I've decided to soak stone in water for few minutes to soften it.
 And after a little bit of soaking and working with my girlfriend's rotary tool I found this:
 You can see some kind of yellow crystal or something. This can easily chip your edge.

 This is how it looks after the job was done.

 Then I used my Atoma 140 and very hard worn DMT xcoarse (which is ultra fine now) to flatten the stone.

Of course I have rounded the sided as well.
 And then with help of Tenjou nagura I have rounded the gap corners.



 Looks scary big, right?



 But gaps are clean now and this is important:





It was time to test it. I used my Suisin Densyo White#1 270mm yanagiba. This is how it looks before:




And after Red Oohira. 

 This stone scratched my yanagiba. I left it for a day...
 and next day I started from the very beginning. I have polished my blade with JNS 800, White binsui and Red aoto so I was sure that there are no deep scratches.
This is Red aoto finished blade with uniform scratch pattern:





Short movie. Unfortunately memory in my phone was gone seconds before end of the movie:




 And after
 As you can see, I could use whole stone and it left uniform scratch patter.






That's it. Now I know that toxic line are not that scary and I have a great stone . Thanks for watching and take care...

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