Newbie question on blade coating....

S

SharpEdge

Joined
Jul 7, 2000
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140
Hi, Im new to this, so plez bear with me.

I checked out some CASiberia and Bugei swords, they all have a thick film of coating close to the edge. Can anyone tell me what exactly are these?? Are they just for preventing rust?? Would i destory the hamon if i rub off the coating??
Thanks a lot.
 
I don't recall my cas iberia Chen having a coating.Basically you wipe it down with a nice soft rag with a quality oil.I cleaned mine up with some flitz polish to remove the dark acid etching on the hamon, leaving the natural look of the hamon.I polished fairly thoroughly and did not present any problems.I don't think you could destroy a hamon since it goes through the whole blade,but you might be able to over polish it.good luck,Ralph
 
From my understanding, the hamon does not go all the way through the blade. But it does take a significant amount of surface material to "remove it"

However, the effects of polishing compounds like flitz or simichrome will burnish the surface of the material, which is what you do not want. That effect smears over the steel and *will* mask the hamon. You don't polish these kinds of blades with a wheel and polishing compound...unless the blade has nothing interesting to look at anyway.

Just use enough flitz/simichrome to remove the oxides from the surface and restore a moderately reasonable finish. From edge-to-ridgeline (in that order), you should have yakiba being lighter colored, the habuchi/hamon should be brightest, but not overwhelming...and then the ji to the shinogi (ridgeline) should be darkest. If you want to use the simichrome/flitz to burnish the shinogi-ji (sides of blade from ridgeline to spine) and mune (spine), you can, but I wouldn't really suggest it giving the quality of the finish in the first place.

All ya really need to do is take those oxides off and restore some of the real beauty of yakiire, even if it's a hideous togari
biggrin.gif


Shinryû.
 
I'm confused,and granted my sword knowledge is very minimal.However; If a blade is differentially hardened using the clay process,the whole edge is hard,giving the line dividing the softer metal.How could this possibly be surface only and not hardened throughout the blade.I mean to say,it doesn't make sense that the hamon could be removed and unable to restore not being all the through the blade.So I'm curious as to why this might be.Thanks,Ralph
 
Okie...here's a synopsis of what I wrote...

I cannot be absolutely sure on this because I'm not a metallurgist or anything like that, but this is what I've noticed.

Anyone who's seen some Japanese swords will realize that usually the sides are not absolutely symmetrical, and sometimes a completely different style altogether.

The steels used for doing traditional yakiire are simple steels that don't have a very high hardenability, or rather they don't harden deeply. This lack of hardenability is what makes the hamon appear without blending out.

Anyways, it is not just surface-hardening, but it isn't through-hardened from this one spot all the way up to where the clay transition comes, and when polished down enough over time, you will eventually thin down the hardened steel. It's not immediate or anything, and they likely harden almost halfway depth on each side, so there's some yakiba (hardened edge) that will be hardened all the way through, since the steel thickness allows shallow hardening to go all the way through...but it doesn't go all the way through all the way to the hamon.

Doesn't make much difference either way, you probably will not grind down a chen to the point where you'll tire out the blade. But you can still mask the hamon by burnishing, because that covers up all the steel surface, including the effects in the steel.


[This message has been edited by Robert Marotz (edited 10-16-2000).]
 
Let me get this straight.
Does the smith coat the edge w/ clay or the spine w/ clay? They coat it before tempering or before quenching??

Thanks for all the replies.
 
the tsuchi is applied in a few different ways...but here's one of the common ones...

Clay is applied to the entire blade, then a spatula/scraper tool of sorts is used to scrape the clay off the edge portion. The edge itself is sometimes exposed or covered just lightly.

The idea is that there is less refractory on the yakiba/edge than the rest of the blade.

After the clay cures, the coated blade is brought to the fire and quenched in water for the hardening process. The additional clay on the body retard the cooling while the edge, with much less clay, will cool faster. The quench is also where the curvature, or at least a good share of the curvature of a blade is developed.

crazy stuff.
Shinryû.
 
Thanks for the reply, here's another question:
What's the main difference between a laminated blade from a folded blade. And what's the advantage of a folded blade? I understand the concept of laminating blade so you get edge holding and toughness, but what about folded?
Thanks
 
Good question, can be the source of confusion among a lot of people.

"folding" is a fashion of forge-welding that is designed to help squeeze impurities out of the steel and to sort of "mix" around all the little trace elements and everything. This is because of course billets of steel did not just come out of the ground, they had to acquire their own tamahagane, smelt it into billets of varying amounts of carbon (hagane/kawagane/shingane - high/medium/low carbon content). You would not want to directly weld even amounts of low carbon with medium carbon to get a blade, migration will cause the overall carbon content to be low, but I am assuming you understand that stuff. Anyways...Since the steel is made from a relatively crude starting point, purification is necessary. This is where folding comes into play. Impurities are squeezed out in the folds with the flux and scale. Sometimes welds won't be perfect, and you'll wind up with flaws. That's why you want to avoid overdoing weld cycles. Usually 6-14 "folds" are done to give you an idea. This is of course all done before actually forging the sword, as I'm sure you've gathered.

Lamination tends to refer to the styles of lamination constructions used to create swords. Some people and I have come to believe that this was not really a necessary thing to do, but it was done because you would not always get your kawagane and hagane, and there had to be a way of utilizing the shingane in a sword without it intruding on the ability of the edge. I believe, along with some others, that if tamahagane had a higher level of consistency in carbon levels, they would likely not have taken the laminate constructions.

Let's look at a simple style of lamination like kobuse, which is one of the most common. Core is the shingane, the low carbon stuff that won't harden worth dink. Hagane is jacketed over, forming the edge and sides. There are other styles that are more elaborate, having defined sides, edge, core, and spine...but it went under the principle that they were trying to use all the material they had in an effective manner, and it, in their opinion is much better off bending than breaking. Of course, over time with polishing, that hard jacket of the edge and sides in kobuse will be removed a bit and expose some of the core. This is a standard reason for blades being "tired" if you ever hear that term.

It's not uncommon for swords with cored lamination construction to bend almost like taffy. Some were quite sturdy but of course "great" blades were very outnumbered.

It was generally just a tradeoff some people had to learn to live with, and technique in swordsmanship was paramount to making an extremely effective cut while keeping the sword from twisting or bending. An art of precision that still doesn't fail to amaze me.

I love tamahagane and "folded" blades, but can live without the laminations...I don't really mind them if they're done well though.

Hope I was able to answer your question decently.

Shinryû.
 
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