Rokusho

[MadSun]

Can you recommend a good source of rokusho patina?

[Ed Harbulak]

Reactive Metals Studio, Inc sells the chemicals for making rokusho solution along with instructions for its use. Their web site is www.reactivmetals.com. I've tried their mixture and if you follow the directions it does produce a good black finish on shakudo, depending of course on the quality of the shakudo. As with all chemicals, care is necessary and since the solution is used at a low boil, there is also a burn danger. 

[C0D]

I have some extra i can share and since i'm in the EU you won't have customs fees

[MadSun]

  On 6/3/2022 at 2:05 PM, C0D said:

I have some extra i can share and since i'm in the EU you won't have customs fees

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I only saw your reply now. Apologies. I'll PM you.

[Fuuten]

Reading I went like huh 🧐

 

Regarding metalworking, though I haven't checked it in a bit, Ford's forum (if I recall correctly), is a good place.

 

edit: seems it has gone AWOL.. 

[AntiquarianCat]

It depends on what you want it for. There are many academic publications that have recipies for making rokusho type solutions http://shura.shu.ac.uk/971/

 

Obviously I’m not endorsing it’s use on antique items or the like but I’ve used the coper acetate, coper sulfide, vinegar and NaOH forumula to great effect on arts and crafts coper metalwork my friends have gifted me.
 

Fair disclosure, it’s more a reverse engineer of rokusho than actual rokusho. The actual rokusho seems to be something Japanese artisans pass in a secretive way and would probably be hard for us to make using a lot of organic mater. Still, I’ve found it to work very well for my crafts and according to the papers the chemical substitute nearly replicates rokusho patina.

[1kinko]

The nice part about the Sheffield Hallam University publication is the comparison of different formulas on different alloys. I will note however that Ford has never recommended anything but the rokusho, copper sulfate combination, with alum as needed. There is another source of patina formuli but it’s all in Japanese and requires some translation of Japanese units and depend on the same chemicals in different proportions: Kinko Dento Giho (Traditional Soft-Metal Workers Techniques) by Katori Mashiko, 1986 (ISBN 4 8445 8550 9 C 3972). Available from Amazon.jp, about $45 plus shipping.

[IBot]

Long before I had contact with any other nihonto collector and when the only source of information I had access to was Basil Robinson's 'Arts of the Japanese Sword', I was faced with acquiring swords whose fittings ignorant pervious owners had polished bright. I had absolutely no idea how these items were patinated originally, but because I worked in a chemical laboratory at the time, I was in a position to experiment on ways to restore the colouring. I found it relatively easy to re-colour shibuichi and shakudo by de-greasing the part with alcohol and then hanging it on a cotton thread in a cold solution of copper sulphate and bringing it up to the boil. After colouring I would wash the parts in distilled water before drying them. This worked reasonably well on those two alloys but had the unfortunate effect of turning any copper a bright pink! Curiously I also found I had to use a fresh copper sulphate solution each time as it failed to have any effect once it had been boiled. I post this simply as an interesting historic account of the weird and wonderful ways we early collectors resorted to, and certainly do NOT recommend anyone trying it today. 

Ian Bottomley