Smelting Babbitt Lead, oxidizing issues

[Steel185]

I purchased a bunch of lead a while back, 1400#, of various types. WWs, lead sheets, and Babbitt material. I have been smelting down bunches of it separately to mix as I need later on. The issue is when I got to the Babbitt stuff fluxing and getting it into an ingot mold is challenging. The issue looks to be (I could be wrong) that once in liquid state it oxidizes very quickly. I fluxed with hard wood sawdust, and paraffin wax as I did with other alloys (others came out great) but this alloy keeps clumping up and turning very thick. The seller said he got it from some shop and it was the drippings from some type of soldering, or welding. I can't get in contact with him (he moved) but I'm assuming it has a high content of tin, and thus a much lower melting rate? And I'm over heating it, causing it to oxide badly? Any suggestions?

[Edubya]

You don't think that could be zinc, do you? Have you done any kind of hardness test on it?
I would think that if it were tin, or a high % of tin it would flow nicer even at lower temps.

EW

[runfiverun]

could be nickel babbit also and that stuff acts like zinc poisoning too.
just be aware that this might be an issue.
i have used nickel babbit but use half what the amount of tin i think i need from it and make up the diff with another source of tin.
it could also be fairly high in copper content.
i use babbit type materials for the tin but you need to be aware of the hazards of using the unknown content.

[475/480]

If it is high in copper content you will see a red/orange color in the mix.

Sean

[sagacious]

Solder drippings should be melted at a temp way below that required to melt bulk lead sheet.

One thing is sure-- less heat makes for less drossing. Lower the heat and see if that reduces the drossing. Good luck.

[Steel185]

I haven't gotten a hardness testing on it, saving for a tester, but even if i had wouldn't it be only slightly helpful? Its an unknown material? I will try a much lower heat and see how it does. low heat just seems to take a long time....I'll try it this weekend and let you know, thanks.

[glicerin]

I have tested, researched and melted (IXL) babbit and (Nickel) babbit. Both were 80% tin, 12% antimony. The nickel name is a bit of a joke, might impress some, containing small amounts of nickel and copper compounds(salts, sulphates or other). It wouldn't be possible to put molten nickel or copper metal into lead. The Ni and Cu has never been a problem, great source of tin! This babbit is fairly hard and rings like a bell, Lead babbit is much softer and rings less(20% tin?).

[Steel185]

Glicerin:
This stuff is much harder to cut, it is in large un-uniform chunks, I have to cut into smaller pieces with my saws-all, and a metal blade, it is significantly harder than any lead alloy i have (ww, or pure lead). It might be closer to the 80% nickel babbit. I'm going to put the burner on low and see if i can get it to get into liquid before it oxidizes into the chuncky mess.

Any way to save the already oxidized stuff?

[sagacious]

It wouldn't be possible to put molten nickel or copper metal into lead.
May seem unlikely, but it is in fact possible. Very tiny amounts of copper and nickel can have huge effects in tin alloys. The nickel and copper enter the lead alloy as SnNi, and SnCu. Copper can also enter as PbCu, and Pb and Cu do form a eutectic. The Ni and Cu are pure intermetallics, and not compounded with non-metallics. As you say, it's a great source of tin.

Not arguing, just sayin! :drinks:

[sagacious]

Any way to save the already oxidized stuff?
Melting slow and low is the way to go (easy to remember :)).

You can use rosin or paraffin to recover the dross. Heat until most-- but not all-- of the dross is melted, and flux generously. Light the flux smoke with a match, stir very gently, and pour off the liquid metal as soon as practical. Good luck.

[glicerin]

Tin babbit should melt easily, low temp, and I have never had any chunk?. Oxidizing could give pretty colours. Chunky alloy could mean zinc or aluminum? impurity. When you hit an ingot of zinc on the edge with a hammer it will shatter with crystal like surface.
Sagacious: I've never heard of two metals forming a compound like SnNi or SnCu. I worked in a lab for 25 years and thought it would break the rules of chemistry.

[sagacious]

...
Sagacious: I've never heard of two metals forming a compound like SnNi or SnCu. I worked in a lab for 25 years and thought it would break the rules of chemistry.
Glicerin,
I think you're pulling my leg! When a caster alloys Sn into his Pb melt, he's forming SnPb. When lead and tin are melted and mixed together they combine chemically and an intermetallic compound is formed.

SnNi is a common intermetallic in lead-free Sn-based Ni-containing wave solders. SnCu is 1:1 bronze.

If you worked in an o-chem lab, then that might shed some light on your commentary, as organic chemistry does not deal much with intermetallics, but metals combine chemically in the same way that non-metals combine chemically. The Lyman Cast Bullet Handook article, "The Metallurgy of Molten Lead Alloys", refers to intermetallics such as SbSn. It's never a bad time to flip open one's Lyman CBH and read a refresher-course on the subject.

Regards, and good shooting. :drinks:

[glicerin]

sagacious: I stand corrected. Just read about intermetallic such as Cu3Sn. Always hated chemistry altho I worked in a nickel mining lab. Don't know how nickel at 1453C could be added to lead or tin at approx 300C without causing an exposion( violent vaporisation). www sources aren't too clear about difference between alloy, mixture, intermetallic and compounds. Wonder if steel185 identified his problem alloy.

[Steel185]

I haven't been able to doing any melting yet, I plan on trying to do the low slow melt this weekend sometime. I'll update you guys on how it went. If its that strong of a tin source I'm excitied, because that means i have a decent balance in my types of lead, WWW, pure (or close to it) and tin. Should be great.

[sagacious]

sagacious: I stand corrected. Just read about intermetallic such as Cu3Sn. Always hated chemistry altho I worked in a nickel mining lab. Don't know how nickel at 1453C could be added to lead or tin at approx 300C without causing an exposion( violent vaporisation). www sources aren't too clear about difference between alloy, mixture, intermetallic and compounds. Wonder if steel185 identified his problem alloy.
Glicerin,
No worries. OK, I see where you're coming from. What's happening here is not actually melting, but dissolution. Exactly like sugar does not need to be heated to it's melting point to dissolve in water, copper/nickel/etc does not need to be heated to it's melting point to dissolve/alloy into a molten metal that is it's solvent. This is not true for all metals, but is true for certain combinations.

In this case, the nickel is chemically bound to tin. The SnNi can then be alloyed into lead so that Ni-containing babbitt metals can be used as a source of tin for alloying with lead. If one used a Ni-containing Sn solder/babbitt, a small amount of Sn will enter the lead as the compound SnNi. To my knowledge, pure Ni cannot be dissolved into lead-- it must be bound to Sn to allow dissolution. This is not to say that lead alloys benefit from SnNi addition, just that that's what's happening when a Sn source that contains Ni is alloyed into lead.

Regards, and good shooting. :drinks: