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Japanese Alloys


Karl Carvalho

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Guest ford hallam

suits me, I've said my bit anyhow ;)

 

and apologies to all for creating the distraction on this thread :huh: , I'll try not to play so loudly in future :blink:

 

regards, Ford

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A short word on raw copper or "yamagane". from my own experience I know it is a rather brittle metal.

It work hardens faster than refined copper and when melted it seems to be more viscous than normal copper.

 

The sections with the Taka zogan (raised zogan) is the forementioned yamagane. One can see the colour difference between fine copper (raised inlay) and the ground.

 

Aloha Karl,

 

Thanks for the word on your experience regarding working properties. All this talk of compositions has little context for me without some reports of how this material handles.

I'm a little fuzzy as to what you are referring to in your description. Are you saying that all the raised blocks are yamagane? or the little inlay squares in them? :D

 

KC

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Are you saying that all the raised blocks are yamagane?

I think he means the wedges underneath the blocks, that's how I read it.

 

Since my copper isn't workable yet, I hope you'll forgive my backstep to some more technical thoughts, Karl -

First, Jim said “According to Gowland, shirome is a by-product of the separation of silver from copper by liquating with lead.” Then, Ford said “Gowland's own analysis of shirome ( from Echizen province ) is as follows…Silver, 1.33%...”

I think Gowland was wrong about it being a by-product of a silver separation if they left 1.33% in the mix, Silver and Gold are too easy to grab from other metals to have that much in a by-product. But it could be his numbers are bad, too, many analyses from before recent times are way off.

One thing I’ve noticed in making metal in pre-industrial ways, what comes out of the furnace is often very different then what went in. If you are not using an induction melter under vacuum alloys change quite a bit. So having modern smelting/melting products that were created in antique ways analyzed would be a good idea, once one figured out a consistent method that resulted in consistent results. Metal analysis is pretty expensive, at least compared to rock analysis, so unless you could line up free testing (as part of a research project or something) you’d want to get a consistent thing going in the process so your expensive numbers would have some meaning.

 

Some analyses of various speise from mining areas in Europe:

http://books.google.com/books?id=FswKAAAAIAAJ&pg=PA216

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Guest ford hallam

Hi Jeff,

 

it does seem a little odd that Gowland so describes Shirome. Having said that I have copies of quite a few ( perhaps all?) of his papers on Japanese metalwork and find his description of technical matter to be generally very thorough. He was also employed by the Japanese government to help in the creation of a modernized mint. As such I've found him to be possibly the most reliable reporter writing in English. Roberts-Austin is also a reliable source of analyses. Probably the most inaccurate account of Japanese metalwork technique is that given by W A Young in 1937. What is amazing in this case is the complete confidence of the man who appears to have just made stuff up based on no real practical metalwork experience. :D

 

There was a specific edict passed in 1764 to ensure shirome was added to the bronze intended for coinage. The use of shirome as a very specific ingredient evidently predates this time though. I'd suggest that perhaps both of Gowland's descriptions are accurate, to a point, and that shirome might be better described as a byproduct of the refinement of copper which itself could be further refined. That it evidently hasn't could indicate that the specific composition at this stage is the most useful in terms of its application as an additive to bronze casting alloys. It's use in Shakudo is obviously a minor application by comparison.

 

just more for the crucible :)

 

I also have analyses of copper from 4 different locations in Japan which were refined by "native process", these analyses also done by Prof. Gowland. If anyone's interested I could add those.

 

Ford

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I think he means the wedges underneath the blocks, that's how I read it.

 

HiAll,

 

Only Jeff understands me. :D

 

But the patina achived on the whole piece isnt a "real" rokusho patina. This particular piece I made for study was repatinated (`cos the "true" rokusho patina failed totally by the high zinc content of the brass) with a bath I made based on a recipe by Ernest Hart (9,4g copper sulfate, 3,6g copper acetate, 5ml vinegar on 1 litre water, the original recipe was given in grain in relation to 1gallon water- I increased the vinegar and sulfat content) - the time into the bath was very long: 6 hours.

 

This is a tube of mokume made of yamagane and shakudo forged in masame direction using rokusho patination

 

- Very sublile indeed - a very dark brown with a metallic hue and typical shakudo black, the white spots are solder filled cracks- yamegane is brittle

 

One thing I’ve noticed in making metal in pre-industrial ways, what comes out of the furnace is often very different then what went in. If you are not using an induction melter under vacuum alloys change quite a bit.

 

This happens through the low boiling points of some metals. Zinc, arsenic, lead, tin even some silver are vaporising by the heat you´re using during melting. Experienced casters are adding always more of these metals to their alloys to get the right proportions. (breathing tin or zinc vapor causes "Metallfieber" this metal induced illness feels like a heavy influenca)

 

Regards Berlin Karl

 

Ps. Soldering tutorial in on the way. (But it´a long one)

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Aloha Jeff, Ford

 

Thanks for the additional research notes. Forgive this novice metallurgist wanna be, but I need a brief pause to recap. :D

Native copper in it's metallic form (88%+/-) is "relatively" pure worldwide. Or should I say more pure than yamagane?

Yamagane has a higher As content, which may be introduced? Why?

Kuromido is like yamagane, but with higher As content?

Shirome is a by-product of Ag separation process that is like yamagane with more "impurities"?

 

Help Ford, I need that chart. :D I followed up on that source for kuromido that you mentioned (Komokin). Google led me to a tech paper by the Pijanowskis from the 80's (?). Besides citing the same supplier, they list two kuromidos. :lol: A 99/1 as Cu/As and a second 97/3 with the 3% as a witches brew of Pb,As,Sb,Fe,Ni,S,Al and S. Curiously (or not), these elements all cluster around each other on the periodic table.

I wonder how the edicts affected smelters like that guy in your print in the hinterlands. Especially after "business hours" and a bottle of sake. :)

 

KC

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Hi Karl,

it is a bit tricky :lol: if you want to surf the japanese part of the web. This is a link that will take you to Jim Breens Online Kanji Dictionary the results will be given to a search on Google Japan (with possible translation - and translation caused nausea :) )

 

 

- Yamagane or San dô: (mountain metal) unrefined copper with a high content of arsenic and antimony. The composition varys with the place from were the ore comes. See Further the Kodu Zuroku

 

Shirome: is a copper alloy with 10-20% arsenic antimony lead. It is byproduct of the old copper refining process .Its composition als varys greatly. It is stated to have a white to gray colour.

 

Kuromedo (blacktasting copper) (copper 98%, 2% arsenic), Karasudô or Nigurome or Chin-Shô (crow copper) is stated to be refined copper with small additions of shirome but sometimes said to be the same like yamagane.

The terms vary by school and with the time. (in meiji and edo time differend terms were used to name the same alloy)

 

Shirome was and is used to enhance patina and casting performance of copper alloys. The Koji Hoten says Nigurome is 2 parts lead or tin or antimony on 100 parts copper. Its patina should have the indefinable colour of old matt and dirty red copper with a fainted haze of gray as it was tinned long time ago.

Some Tsuba made of these materials can be seen here

 

It seems like that there is no definite composition of all these metals. The patina also varys. All these matters are related to the japanese aesthetic of wabi and sabi.

 

Further reading on the subject is really the Kodo Zuroku. The bitches brew of elements comes from the affinity of these metals to each other. Most of the have similar characteristics and were found into the same ore.

 

Hope that helps rather than confuse :D

 

Berlin Karl

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Hi again,

 

the colour of the brass I wanted to obtain on my ring were inspired by these two tsuba (and of coure some others :D )

 

 

 

The hotei-tsuba was made by Tsugiyoshi or Chikayoshi and stated to be made of cast sentoku

The monkeys are made by Nakajima Haruhide and are in brass and copper

 

But as Ford stated elsewere the old japanese brass differs greatly from modern european composition (I have no idea were I could gain gilding metal)

 

regards, Berlin Karl :)

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(I have no idea were I could gain gilding metal)

 

Would it help if I said that gilding metal is frequently designated CZ101 or CuZn10? There's also CZ102 & CZ103, can't remember the compositions though.

 

http://www.severnmetals.co.uk

http://www.rudgwickmetals.co.uk/products.htm

http://www.londonmetal.co.uk/Company/Brass_Bar.htm

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I'd suggest that perhaps both of Gowland's descriptions are accurate, to a point, and that shirome might be better described as a byproduct of the refinement of copper which itself could be further refined.

Sounds resonable to me. And yes, please post the copper data :)

 

Native copper in it's metallic form (88%+/-) is "relatively" pure worldwide. Or should I say more pure than yamagane?

Yamagane has a higher As content, which may be introduced? Why?

 

Native copper is 99% + pure, from what I've found on the web recently. More pure than one average analysis of yamagane, posted on this thread recently. Any other analyses out there? Seems to be little published info.

I suggested the As may have been introduced just because it was ALOT higher than the content in a bunch of smelted copper objects from around the world that I have looked at over the last week, but I didn't mean to imply that it was likely - probably just a complex ore.

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Further reading on the subject is really the Kodo Zuroku.

Hope that helps rather than confuse :)

 

Aloha Karl, Jeff

 

Yes, it helps. Thanks for taking the time to write that up. Better to get the full story, so I went for the Kodo Zuroku. I was lucky enough to snag the $9 copy over the $45 one.

I relayed my research exploits to my teacher in class last night. With a twinkle in his eye, he said "Of course the material was unique to it's source. That's the art; they worked with it."

So, applying the Wunderlich method, I'll start mixing, melting, forging and rolling out small test batches this weekend. For patina trials. That's the point of all of this. Right?

 

Jeff

Did not mean to misrepresent your data. Just guessing. Sorry buddy. :(

 

KC

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Did not mean to misrepresent your data. Just guessing. Sorry buddy.

No problem, nothing to apologise for - guess I didn't use enough smileys in that post :(

I hope I'm not coming across as a wanna-be expert or anything, I'm just trying to understand some of these traditional materials, and their context in both the crafty world and the analytical world....that's why I put so many conditionals in my posts, I don't know what is true or real yet. :)

So, applying the Wunderlich method, I'll start mixing, melting, forging and rolling out small test batches this weekend. For patina trials. That's the point of all of this. Right?

Exactly, learn your materials and use them to the best of your abilities. The wide variation in composition points towards something like using what is available, like the local food movement going on now. ;)

EDIT: Okay, it used to mean using what was available, now it means going to great lengths to AVIOD the homogenous piles of stuff that surround us :D:D:D

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The home-made copper in its raw state is almost exactly the color of regular copper, perhaps a slight silver tinge – this photo is not ideal, I don't know where my white balance got to. ;)

A short dip into weak Liver of Sulfur indicates it will patina faster and darker than the commercial stuff.

The home-made copper is sitting on top of a square of commercial copper sheet in the photos.

Both samples were finished to 1500 grit with sandpaper, etched for ~20 seconds in weak Ferric chloride, then dipped into weak L. of S. and rinsed, twice.

 

 

post-1173-1182443948.jpgpost-1173-1182443963.jpg

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The home-made copper in its raw state is almost exactly the color of regular copper, perhaps a slight silver tinge – this photo is not ideal, I don't know where my white balance got to. ;)

A short dip into weak Liver of Sulfur indicates it will patina faster and darker than the commercial stuff.

The home-made copper is sitting on top of a square of commercial copper sheet in the photos.

Both samples were finished to 1500 grit with sandpaper, etched for ~20 seconds in weak Ferric chloride, then dipped into weak L. of S. and rinsed, twice.

post-1173-1182443948.jpgpost-1173-1182443963.jpg

 

Very Cool Jeff,

How much yield do you think was obtained from your ore? what are the dimensions of the plate?

I recieved my copy of the Kodo Zuroku yesterday. It is a short read compared to Agricola text. Very simple and straight forward, Thanks Karl for the recommendation. I had a freind trying to tell me about this book a while back, but he had lent it out and did not know where. So I have been looking for this book for awhile I just did not know exactly what to call it!

Jeff,

If you are interested I would be happy to treat that plate with Roshuko for a more classical color comparison. I run a bath every couple of weeks anyway. I'll post photos of it and send it back to you of course.

Patrick

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Are you able to try other patina treatment like ...rokusho?

Yes, I just grabbed the easy chemical to see if it reacted differently than commercial copper. I would have to do a bit of digging to unlimber my rokusho set-up, so I might take Patrick up on his offer (PM me your address, Patrick :D ).

How much yield do you think was obtained from your ore?

 

Hard to say, as I didn’t weigh any starting ingredients with a real scale. I only cooked about a third of the ore, though, so now that I know it works, I’ll weigh everything before and after when I reduce the rest of the rock. It cannot be nearly as efficient as with the magnetite iron ore 60 - 70% returns I’m used to, maybe 100 grams of workable material from 1.5-2 kilos of ore. I’ll take a photo of the ore before and after roasting, too, so you can see what I’m working with.

 

what are the dimensions of the plate?

 

Roughly 2”x ¾” x 1/16”, 16 grams, not the whole production of the initial run.

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I ran 3 kilos of ore through the initial smelt process yesterday, and tried to high-grade the ore as much as possible visually (since I don’t know much about concentrating copper ore via the various other methods). I also lowered the temperature of the smelt, to lessen the amount of iron reduced. Ended up with 280 grams of copper/iron alloy, of which hopefully 50 – 60% will be the final yield.

Now if only I could remember which mine those rocks came from, I would grab some more ore, since that finishes off the pile of desert souvenirs I started with. B)

 

An un-roasted bit next to a roasted bit, the rust spots are post-collection contamination and not something to look for when you are out collecting rocks. :( The ore is disseminated through the host rock as veins & pockets with quartz.

 

post-1173-1182691421.jpg

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Aloha Jeff,

 

Just a side note. I was watching Digging for the Truth on the History Channel recently. They showed a possible smelting technique for copper near Stonehenge. They started with malachite (?), and using a small crucible and two skin bellows over a pit fire, managed to extract a goodly puddle in 15-20 minutes. No info on purity. :(

 

KC

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Hey Jeff,

Here is the test pickle. The Samples are 20mm across. The coupon on the left is your home smelt and the the coupon on the right is commercially pure copper 99.99. Both spent 20 minutes pickling in the Roshuko bath side by side. The difference is more slight than I anticipated. I think your material is relatively pure. Cool :lol:

post-40-1183532671.jpg

Patrick

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Interesting!

The ore did seem pretty clean, I bet if the purity is high it is more from the ore than from over-refining. The refining is definitely not simple or easy, at least it is not easy to tell if you are doing the right steps to the correct amount while you are doing it. I’m trying a couple different methods with the second batch, I’ll let you know if anything becomes clear. :)

Now if only I had access to XRF or some other alloy measurement system, we’d know just how pure the stuff really is.

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Guest ford hallam

Hi Karl,

 

thanks for the link, pretty impressive ingots :) , although they do look suspiciously like half made pizza :)

 

cheers, Ford

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