Casting materials

kuraki

kuraki

Fimbulvetr Knifeworks
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Jun 17, 2016
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I'd like to get into doing some lost wax casting of guards/fittings. I'm pretty familiar with the process, and casting in general having worked in an iron foundry and in aluminum die casting in the past. What I'm mainly wondering is what materials are feasible to cast in a small home foundry for our purposes?

I know brass, bronze are the most likely candidates. But is there another material that has similar physical properties, but isn't yellow? Aluminum is out. Silver is expensive. What else is there?

And if there isn't anything suitable, are there methods for coloring brass or bronze outside of forced patinas? Or could they be alloyed to change color?
 
If you are going to melt metal to cast, I'd seriously consider making those japanese alloys containing copper and silver or copper and gold.
 
Mokume isn't so much casting, as a more complicated version on Damascus.

As for a silver color, how about nickel silver? Shouldn't be too different than bronze
 
He's talking about Shibuichi not Mokume, which might be exactly what I'm looking for as apparently varying the silver content allows many different patina color variations.
 
I think he is referring to shakudo and shibuichi.

There are many casting grain alloys available in various colors of bronze. Some have names like "new gold" or "Herculoy gold". Of course, white bronze and white brass (nickel silver) are fine too. All these will darken and yellow in time.

Sterling isn't too expensive for casting, as old flatware and stuff can be had for scrap value or less. Most silver fittings only have a few bucks worth of silver in them.
 
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I guess all I'm really wondering now is how hard/durable Sterling Silver or shibuichi is (understanding the latter is variable depending on alloy content).

I mainly just didn't want to go down the road of building/buying the equipment to do casting if I was going to be stuck with only varying shades of yellow.
 
You can treat Shibuichi and shakudo with various patina chemicals to get very permanent blues, blacks, and browns.

Getting any metal fittings other than white gold and platinum to stay silvery is pretty much not going to happen on a knife.
I personally like the look of bronze once it forms a patina.

Another thing that is beautiful is copper that is patinated with sulfur compounds. The surface becomes a shiny deep gray/black that looks like the silver sulfide of niello, which is the black silver used in Siamese jewelry. I use copper pipe and fittings to make Japanese blade hardware and soak it repeatedly with steel wool rubs between soaks until it is shiny black. It should stay that way forever. I use livers of silver and various commercial silver black compounds to get the patina.
 
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Perfect. Thanks Stacy. Blues blacks and browns is perfect.
 
White bronze isn't actually nickel silver-but it's close.
Real nickel silver is notoriously difficult to cast in a small casting setup.
 
Argentium is a sterling silver that is very resistant to tarnish and should do well casting Check it out .
Niello IIRC is silver sulfide for the most part .Brittle though.
The Japanese have created many copper alloys and ways to color them.
My mother had some fine custom jewelry made by combining various colors of gold - green , red, white. yellow .A very nice mix.
Find a website that describes the various Japanese copper alloys !
 
Bronze, gin shibuichi, and shakudo would be first on my list. Those Japanese alloys are cool. I was at a demo where shibuichi was alloyed from silver and copper, then an ingot poured in water. It was pretty rad.
 
Stacy E. Apelt - Bladesmith said:
Another thing that is beautiful is copper that is patinated with sulfur compounds. The surface becomes a silver sulfate that is hard and shiny black. It is basically niello, which is the black silver used in Siamese jewelry. I use copper pipe and fittings to make Japanese blade hardware and soak it repeatedly with steel wool rubs between soaks until it is shiny black. It should stay that way forever.
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I try to understand this.
How does copper become silver sulfate?

And doesn't 999 silver stay silvery?
 
Sorry, I was running ahead of myself.

I meant that the patina formed is similar looking to the silver sulfate in niello.

Also, I meant "white brass" in reference to nickel silver.

I edited those sentence.
 
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Cu => Ag sulfate ? That proves that eating haggis makes you an alchemist so he can do it !
It's stretching my memory but silver tarnish is silver sulfide not sulfate .
The argentium I mentioned will resist tarnishing much better than other Sterling silvers .Thanks to a bit of Germanium [ the metal not the flower ] . But I digress .
 
Randy3000 said:
This topic interests me. OP what kind of foundry are you thinking about?
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Pretty small. Somewhere between a coffee can and a 2.5 gallon bucket. Just large enough to do melts for typically sized guards and such. I don't have any interest in casting bigger items, at that point it makes more sense for me to forge it or weld/machine it. But small intricate guards and the like, makes more sense to carve wax, when you can mess up and do over, than carve the part itself.
 
It makes a lot of sense. You can make a relief in the middle for the tang to slip in. It would cut down a lot on the filing. I'm going to give this a try. Should be able to use my forge burner, just need a good crucible and insulate a paint can or something.
 
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