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Iron Patina (sabitsuke)

Jim Kelso

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Debbie has enquired about how I developed the patina on the recent iron tsuba.


Iron work is significantly different from kinko (soft-metal) work in the approach to finish and patina. The kinko work generally has a much more polished and refined look whereas a large motive of doing a work in iron is to develop a surface finish and patina that looks unselfconsciously organic, wabi and sabi. (sabi literally means rust). The surface look is a combination of the surface finish and the sabitsuke (rust making). It may appear to a casual or even somewhat trained eye that the texture of iron tsuba is mostly created by the rusting patina. This is actually not the case in the Natsuo and similarly finished works, where the texture is largely developed by controlled chasing, in combination with a controlled rust patina. This can be verified by looking closely at work. There are several Natsuo tsuba in the Kiyomizu-Sannenzaka Museum that I was fortunate to be able to handle and photograph. In one piece in particular it is clear that a fairly dramatic finish texture was chased, as it is present except in very specific areas where, because of the design it was clearly a choice to moderate it or not have it at all.


Once one is convinced of how these textures were produced largely by chasing, every other iron work makes sense in that context. This is not to suggest that the controlled rusting (sabitsuke) patina is never part of the texturing process. Iron finishes can vary from very textured to quite smooth. I suggest that the finish is always a combination of chasing and rusting, in different proportions, according to what the craftsman/artist is aiming for. Iron mokume (pattern welded wood-grain) pieces indicate that acid etching was also employed, but I have no information on this practically, in the Japanese tradition, only my experience with modern pattern-welded blades.


This organic look should not be thought of as any less demanding than the polished, refined look of the soft-metal work. In fact I think it's more demanding in a way to achieve in that it must look "natural" and uncontrived, whereas part of the charm of the kinko (non-ferrous) work is the almost super-human finish.


Anyway, I need a break and will return with details of the tsuba patina.

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Hi Jim,


I used a modified version of a formula I was given in 1997 by my teacher in Osaka, Toshimasa (Sakai Masaichi). I'm not sure where he got it but it is similar to others that show up here and there.


This would appear to be a version of a Yagyu group process; This recipe comes from the Yagyu Tsuba Zufu and was apparently in use by the Yagyu group of tsuba-shi around 1750.


There's no arsenic in the original recipes I've seen but the rat sh1t is missing.





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  • 7 months later...
  • 3 years later...

Mr. Kelso -- I know this is an old post, but I just started to carve and inlay iron - I am having trouble with the patina, and how do you patina the inlay after you color the iron? Does the rokusho affect the patina on the iron? I have small bits of gold, but mostly brass, copper and silver as inlaid accents....thank you for the help, I am a rookie and amazed by all the talent....

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Guardian, the patina techniques for ferrous and non-ferrous are mutually exclusive; iron will ruin the niage/rokusho bath, and the rokusho mix does not happily rust iron in the way that you would want. It's no doubt the reason you don't see many sword fittings with combinations of iron and copper alloys. Gold is mostly resistant to the sabitsuke so fairly often you will see gold touches on iron work.


I suspect it is possible but have not tried the following: mask non-ferrous inlays(finger-nail polish or some other heat resistant agent that can be removed with solvent) and follow through with the iron patina. You then need to mask the rusted iron and either use a 1)paste type rokusho or, using a heat-resistant masking agent, 2)mask the iron and on to the niage bath.


As you can see, a lot of fussy work. Not many historical pieces like this.

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