Homemade "Rokusho"

[ralph G]

Hello

I`d like to share some of my experimenting with Rokusho patination. I begun to experiment with it some time last year and was after the elusive red on Copper.

 

I used a hommade recipe, based on copper acetate and copper sulfate, its Niiro #4 according to the paper on Rokusho from the sheffield Hallam university. Its a fairly well made study on the subject but debated by the experts.

You can find it here: http://shura.shu.ac.uk/971/

 

According to the experts its not the "real" stuff , the recipe in eitoku sugimoris Book is also questionable I was told - but the japanese dont tell exactly whats in it and so I started with the informations from the aforementioned paper.

Alternatively you can put some vinegar and salt in a copper pot and let it evaporate naturally. The leftover greenish residue crystals can also be used as a rokusho alternative.

 

If you are USA based its probably the easiest just to buy it from reactivemetals, if you cant - or want to experiment here's what I found:

 

 

You will need some white vinegar, Hydrogen peroxide (6% strength is sufficient) , some copper sulfate and a pinch of table salt.

 

I first made some copper acetate by submerging copper in a whithe vinegar and hydrogen peroxide solution. Dont add too much H2O2 up front otherwise you will produce lots of greenish foam after it stops bubbling just add some more slowly. The solution will turn a dark bluegreen.

Decant it and boil off the liquid until the copper acetate is left.

 

 

I used some copper test plates, did a daikon pretreatment and let it simmer in Niiro#4 in a copper pot for about 10 1/2 hours.

Both test plates were done at the same time, the right one was checked upon relatively often since I could not curtail my curiosity, the left one was checked upon only 2-3 times during the whole operation. As you can see the left one turned out much better, exposing the piece too often during patination is obviously not such a very good Idea and led to discoloration and unevenness in the right piece.

 

 

 

I wanted to know if there would be some changes in the patina over time and had the 2 testplates sit on the windowsill (indoors) for about a year. I almost forgot about them and just recently made a new photo. As far as I can see there is not much change so the patina is fairly stable. The color difference you see between the two different photos comes mostly from using a different camera (my old one broke) and the lighting conditions (sunny vs overcast) I whish I had the same camera and would have included the vic for color reference in the first photo. Well, so much about foresight from my side...

 

All in all I would have liked it to be even more vibrant red but for a hommade Rokusho done by a mere beginner I am fairly satisfied. Maybe tweaking the recipe a bit or adding some plum vinegar (could not find here) or the quality of the used copper will influence the result to give an even more red than what I was able to get.

 

 

 

Thanks for your Interest.

 

Best Regards

Ralph

 

 

 

 

 

 

[Jim Kelso]

Nice results Ralph. The proof is in the pudding as they say. In other words, results speak out as a clear ringing statement. Have you achieved results on shibuichi and/or shakudo with your homemade Rokusho? Each of these alloys presents its own variety of difficulty.

I’m glad to see activity along these lines outside of Japan (I assume you are that), where the production method of rokusho is highly secretive.

I think the scientific work by Dr. Ó Dubhghaill is admirable and a valuable contribution to the knowledge base. He did seem unaware at that time of professionals working in their studios, claiming in the second paragraph of his abstract that, ”At present the production of irogane alloys and their patination is an unreliable process”. I think this was simply an academic oversight, and he was quite kind in an email reply, stating, “It has been interesting working on the niiro (niage) research with material scientists, but difficult to get consistent results and to really understand the variables”.

Personally I am certain that both the scientific and artistic approaches are valuable and have their contributions to make.

I suppose experts in any field will disagree often about what they think can’t be done, until someone goes ahead and does it. Some analysis has been done here and there on rokusho. I asked the Smithsonian to look at some with a spectroscope a few years ago, but the results were not very revealing. Breaking it down by analysis into constituents does seem to miss something. I suspect that a breakthrough will come from efforts such as your own, working from an imaginative, intuitive point, rather than the often flawed reductionist track.

Keep up the good work.

[ralph G]

Thanks for the kind words Mr Kelso. I am just begining and try to follow a road that others like you or Ford with much more knowledge and skills have shown to us.

 

So far I have not tested this on shibuishi or shakudo since I was specifically after the red copper but am setting myself up for some lost wax casting (mainly for Bronzes) and do my own alloying so I will also make some shakudo in times to come. I guess I could just have ordered some rokusho from the US but I am from Germany and importing chemicals of any kind here (regulations, regulations- we germans are annoyingly good at that ) is always a hassle with customs. I like to experiment and improvise when necessary , the ingredients I used are readily avaliable so I just gave it a try.

 

I took this approach because this way I can work with known quantities of relatively pure substances and tweak the recipe and take recordings of what has been done. I considered using the vinegar/salt evaporation method but according to experiments from others that I have read about it can vary from batch to batch in strength because during the natural evaporation the quantity and balance of the formed various coppersalts and other oxidation byproducts is not always the same - which makes it even harder to get consistent results and keep track of what works why...

[Mark Green]

I would say that did a very nice job.

Like Jim said, the real test would be shakudo, or shibuichi .

I have made home made copper salts a few ways. All did fine on copper, but there is nothing like the real thing, on shakudo.

Nice job.

[Tski]

Ralph, how did you get that finish after the 10.5 hrs? Did you polish it at all or did it come out that way when you took it out of the solution? Also, I just made some and mine has been simmering for about 4 hrs. I checked it and it looks more peach color then red right now, does that sound right?