1. Home
  2. ⏣ General Metalworking
  3. Question about making Field's metal

Question about making Field's metal

I'm planning on trying to make some Field's metal. I need that specific alloy and can't substitute anything else. I'm going to make about seven ounces of it.

I've never made an alloy before, or worked with molten metals, so there's a good chance I'll fail. However, I was hoping some folks here could point out any obvious pitfalls in advance.

I'm planning to melt tin, bismuth and indium together in the proper proportions. After putting chunks of each metal into the ceramic crucible,I assume I'll have to heat the crucible (with a propane torch) to around 520 degrees, which is hot enough to melt all three metals. At that point... I don't know. Do I have to mix them, or will they just spontaneously mix? Is there any risk that the metals will oxidize from the heat and air, and ruin the alloy?

Reply to
Ernie Sty
Loading thread data ...

melt the low temp metal 1st then add the others, you shouldn't need to raise the temp above 313 indium melts at 313F $1000/kg or $100 for the 3.5 oz you need but certainly more expensive by the ounce Bismuth melts at 520 F $5/lb Tin melts at 450F $7/lb

Pricey if you screw up, Wood's metal with no indium is a whole lot cheaper

Carl Boyd

Reply to
Carl

I didn't stay in a Holiday Inn Express last night so I ocbiously don't know what I'm talking about...

But is is considered ok to put all this together as chunks?

Or should it be ground down like coffee first?

Richard

Reply to
cavelamb himself

Are you sure? How do you get a higher melting point metal to melt at 313F? Seems to me the tin and bismuth would just sit there in a puddle of indium.

Now I wonder if one melted the tin with the bismuth, what that alloy would melt at.

Wes

Reply to
Wes

The higher melting point metal can dissolve in the molten lower melting point one. Just the same way that sugar dissolves in water. It hadn't occured to me before until I asked a guy that made pewter how they go the copper into the mix when it melts above 1000C IIRC and tin is about

300C.
Reply to
David Billington

[ ... ]

???

As in the quoted bit above, you start by melting the lowest temperature metal first, then progressively add the others (probably in order of melting point) and they dissolve in the metal which is already melted -- perhaps changing the meting point in some direction or other. No need to grind it up first, but stirring might be beneficial, if you can find something to stir it with which won't also dissolve into the alloy you are building.

Enjoy, DoN.

Reply to
DoN. Nichols

In my experience with babbit and with alloys melting below 200F it is wise to stir before pouring and to be careful not to overheat or to keep molten for long periods of time. The metals will stratify over time so the alloy composition will change with depth. Even in a shallow container. ERS

Reply to
Eric R Snow

Thanks!!

Reply to
Ernie Sty

Crap! I forgot all about that. I got a ceramic crucible, but the tongs are stainless--I don't know what'll happen if they contact the liquid... Come to think of it, doesn't Field's metal wet glass? I hope not too much of it sticks to the ceramic. This would all be merely interesting if it weren't for price I paid for the indium...

Oh, well.

Reply to
Ernie Sty

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.