Casting My Own Shibuichi Alloy in Local Sandstone

Daniel Fairly Knives

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I decided it would be good to cast my own alloys and use them for the knives... mainly fittings, guards and menukis. I decided to try a Menuki to make it interesting. So here's what I did...


I have been fascinated by Shibuichi for a long time, it is an alloy of Silver and Copper and best known for the wide range of deep patinas it can produce. The Shibuichi can patina to black, red, silver, gold, purple and more. It is difficult to make and extremely expensive to purchase but it is all worth it in the outcome!

I located some sandstone (it is everywhere on my property) and lapped two pieces flat by rubbing them together. I was surprised how effective this was... it took a while but I was happy seeing the results!

I carved a rough mold in one piece. I also carved a second old that I think came out much better after getting a feel for the sandstone, I decided to keep it for my next attempt as I had no idea what was going to happen.

Th pour! I heated some scrap silver and copper after some calculations to determine my alloy content and cranked the torch! I used a medium soldering tip so the melting was all about the firebrick I set up. It is very tricky to get up to the high temp required without overcooking everything. When the metals got to a melting point it was hard to control my enthusiasm... there is something cool about liquid molten metal!

I did the pour and got a bit of a volcano effect which was beyond frightening... I think my vents were not carved deep enough! I did a partial pour because of this and got a hole in the casting. I consider this a full success though and can not wait for the next pour!

The alloy itself is almost indescribable.... gold, silver, rich pink coppers, dark golden bronzes, cherry red, brown... so much in the raw casting! I spent a couple minutes polishing the high parts and see great potential. :D



casting setup! firebrick, soldering torch, crucible, borax was used for flux but is out of the pic...



Raw casting and sandstone molds I carved.



dirty.... quickly polished with fire scale still on


top of the sprue... lots of texture and I like the color



raw casting
 
What Booby said!
Daniel- I think you and mecha are cut from the same cloth.
 
I've always wanted to try casting! That's awesome! I think my forge can get there for temp. Btw, 90/10 is what the high relief peace dollars from 1921-1928 were made of.

-X
 
Daniel you can add regular sand to prevent the volcano effect or reduce your Flux amounts as it seems similar to what happens with my sodium hydroxide Flux plus test material.

Not sure if it's possible to bring your ratio lower say 10:1 or 6:1 but then again I'm doing different metallurgy.
 
Warming your mold might help too. You might also put the mold in the oven on low, and slowly heat it up, sandstone is a very porous material, it might have a bit of water in it. That might also be causing your volcano... very cool project! Casting metal is a LOT of fun!
 
I've always wanted to try casting! That's awesome! I think my forge can get there for temp. Btw, 90/10 is what the high relief peace dollars from 1921-1928 were made of.

-X

Thanks X! Your forge should get to temp, it is probably a good size too. Just watch the flux eating the bricks away.

Good call on the coins, I went through all of mine! pre 65' half dollars are too... no luck so far but I keep looking! I'm glad I have lots of scrap from selling Sterling Jewelry over the years.


Daniel you can add regular sand to prevent the volcano effect or reduce your Flux amounts as it seems similar to what happens with my sodium hydroxide Flux plus test material.

Not sure if it's possible to bring your ratio lower say 10:1 or 6:1 but then again I'm doing different metallurgy.

Big thanks! I really appreciate the help. I did add my flux three times which may have been too much. It was really interesting what a little sprinkle would do to the metal.


Warming your mold might help too. You might also put the mold in the oven on low, and slowly heat it up, sandstone is a very porous material, it might have a bit of water in it. That might also be causing your volcano... very cool project! Casting metal is a LOT of fun!

I'll be sure to try that! I slowly warmed it with a low flame to provide a carbon layer for release but it wasn't heated evenly. That makes sense along with possibly damp sandstone. I lapped the pieces wet then dried them for a week but it has been rainy here. I was a little worried they would explode! I really appreciate the help, thanks!




Thanks everyone! I'm planning on pouring more Shibuichi for Menukis, fittings and bars. I have wanted to do this ever since I made my first Kogotana and saw the ingot mold at our local jewelry supply. I'm eventually going to purchase a sand casting setup but my main intrigue has been tufa stone casting. It is a nearly lost art and mostly done in my area. I want to use these techniques to come up with something completely different and unique for the knives.
 
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