tat2Ralfy said:
Very Interesting Jim Thank you.
So I assume they work because the abrasive splits and wears as you work the slurry, almost like wet/dry paper that feels finer as it wears out with use? a nice fresh slurry cuts the bevel into a sharp edge, and as the slurry wears, it starts to refine and polish the edge as its abrasive propery lessens, so I again assume the skill lies in maintaining a balancing act and keeping the edge keen as the stone turns from keen cutting to finishing?
Fascinating!
Also if my assumption is correct? how many laps are we talking here from fresh slurry to polished edge? is it a fast break down or a slow one, I saw your Barber did spend a lot of time raising slurry, so I assume it has to be heavy to cut that bevel initially? which leads me to think the slurry breaks down quite fast, there being no need to do 300-400 laps as I can with dilocut?
Ralfy, your assumption sounds spot on--that's just what I think happens. And you pose some VERY well timed questions.
I went in to see Kawaguchi-sensei today, to drop off a bottle of Bourbon I picked up for him in the States, and of course to get a haircut (the man is a barber, after all). I also took along my new Tamahagane to get the edge assessed.
The edge assessment went well--he gave it 80-90/100, so a solid B. Seeing as how I started out from 0, that felt very good. The edge on that razor, by the way, is undoubtedly the best I have ever honed myself. Smooth as silk--if I can get it to 100, then it will be a dream shaver, no doubt.
But of course, how to get it to 100 was on my mind, and apparently in his opinion my final challenge is exactly what you described here, Ralfy--getting that perfect balance in the slurry.
The slurry on my stone breaks down pretty quickly, within 2-3 minutes of honing. As it darkens, and thickens, you can feel the razor start to stick, and the edge starts to polish more than hone. Now, I have only recently been learning about refreshing the slurry--and of course, today he gave me some insights into it. When the slurry starts to get "sticky", turning into a paste rather than a liquid, it's time to add water and refresh with the nagura. According to him, you have to do that at least three times to get a good edge on a razor, depending on the hardness of the steel and the quality of the edge to start with. In honing my Tamahagane, I think I was refreshing the slurry too late, and it took me at least 5 rounds to get my 80-90% score.
When I started working with the slurry he told me to make, I would hone until the slurry had turned into a thick, pasty film on the hone--almost like glue. If the edge wasn't there, I would start over. Looking back with what I've learned recently, I think I can say it's not a BAD way, it will get you there, but it adds unnecessary time and effort (i.e. I was polishing when I wasn't done honing).
Now that I have a better idea of when to refresh, I think it will go more smoothly.
Now, I don't like talking about lap numbers, for a couple of reasons. One, my stones are very likely of very different dimensions than yours, and that effects the laps. Two, it's not just the slurry breaking down that effects the polishing, but the water level--the thicker/drier the slurry gets, the more the polishing effect (yes, that sounds counterintuitive, but I'll get to that soon). And three, it's just way too analytical. I overanalyze anyway, but perhaps the best thing that Kawaguchi-sensei has taught me is to just shut up and hone. Counting laps and analyzing scratch patterns gets in the way. The razor and the hone will tell you when they're ready, when you learn to listen...and I'm slowly learning to listen.
But, if it helps you, I reckon the only time I have gone over 200 laps on these hones was honing out a huge chip. That took literally hours. The regular honings, if I had to guess, would be...120 laps? Probably, yeah. It was taking me longer at first, but I can't imagine doing 400 laps...I'm a slow honer, and that would take me a week!
Now, to address Ray's question about slurry stones.
I have been looking at and researching Nagura for a while. The reason it has taken me a while is, the information has been scattered, and really only one man has written anything meaningful about them--Kousuke Iwasaki, father of Shigeyoshi Iwasaki and the man who put the name on the map, as it were. He's also, in a real way, the father of modern Tamahagane...but that's probably putting it a bit strongly.
Anyway, Iwasaki-shi was a researcher and a blacksmith, and he was utterly dedicated to making as perfect an edge as he could. To that end, he not only researched metallurgy, but stones as well. He found that Nagura, which were small, chalky stones used to make a slurry on Japanese hones for hundreds of years, had different types, and indeed the best didn't come from the "Nagura" mine at all. The best Nagura come from a place called Mikawa, and the Mikawa Nagura have 4 essential types. (The following is a brief rundown taken from Kousuke Iwasaki's book "How to hone kamisori and razors".)
First, is Botan. This stone, when used on a hone, makes a fast, coarse slurry. It is best for removing chips and straightening an uneven bevel.
Then come the Tenjou and Mejiro. These are finer and slower than the Botan, and suitable for les drastic work, like honing out a slightly rounded edge.
Then comes Koma, which is both very fine, and very fast--it's suitable both for polishing AND for repair, and thus is more expensive and hard to find.
HOWEVER, for the final edge, for getting the best you can get, you need what he called "Small form Honyama", i.e. a small piece of Nakayama Maruka stone, about the size of a matchbox. When used as a nagura, this stone will raise a slurry of the finest particles, which still cut quickly but then break down even finer to polish the edge.
This final stone is the key to getting a good edge, and this is what I have from my barber. When used properly, the small form honyama is able to put an exquisite edge on a razor. It is a bit slow for real repair work (I can attest to this form personal experience), which is why the other Nagura are also recommended, but for the final polish it can't be beat.
Now, in the book he wrote on how to hone razors, the only hone mentioned is the Honyama Maruka. No coarse or rough stone is necessary--just one finishing hone, and the different Nagura. For the care and honing of razors, this is all that is necessary--according to Kousuke Iwasaki, metallurgist, researcher and expert blacksmith.
Thus, using one VERY HARD (this is important) very fine grit stone, and different slurry stones, you can have a full specturm honing experience. Of course, if we're talking extreme damage, then maybe you should get an Aoto or arato...but then, Barbers rarely bought razors off of eBay in 1964.
