New info - Pb/Bismuth/Sn/Sb alloys

[bangerjim]

I have pretty much exhausted the search engine on here and the net on alloys of lead + bismuth in casting what we do.....boolits. There is really no definitive experience with it by anyone I can find....so here goes with some fresh info........

Recently I happened on MANY pounds of large ingots of an unknown shiny alloy. I now call & stamp it "Banger's Alloy" (BA) so I can keep it segregated from the other shiny ingots in my "stash".

Upon analysis with a $40K x-ray gun, it is made up of:
Bi 56%
Pb 26%
Sn 13%
Sb 5%

It has a hardness of 22+ bhn on my Cabine tester.

It melts at EXACTLY 160F! It is reeeeeeely neat to drop a small hunk of this in some hot water right out of the microwave and see it melt in the bottom of the cup! Impresses the crapola out of people. It seems so strange to melt a 10# hunk of this stuff with no smoke/fumes/reducing on a hotplate set at medium! And......you can stick your finger (quickly ) in molten silver metal without getting 3° burns.

It is a eutectic alloy used for something, but is does not behave like Cerrobend (it does not shrink in 30 min) so you cannot get it out of a tube/barrel! It is somewhat brittle when in a thin form, something like Linotype. I think it may be some sort of low temp "holding" alloy used in the aerospace/aviation industry around here in the Southwest. Any thoughts from the crowd are most welcome!

There nothing on Rotometals that is close to this mix and there is NO Cadmium or Indium in it. Closest composition I can find on the net is Rose's metal, but it's melt point is at 200F+.

Well.....after several experimental melts/mixes, and ignoring the collection of several "Honey do's" that were gathering dust, I came up with the following:

1# of dead pure lead (~5bhn) + 1.5oz of BA gives me a perfect 14+ hardness "as air dropped" that becomes 18+ in 48 or so hours. It fills the molds beautifully.

After 48 hours, I did my standard "Banger's Impact Test" (pounding the slugs flat from nose to base on a 4" dia x 2" thick steel round with a 4# hammer) and there is absolutely no sign of flaking/brittleness/cracking.

So, we can now guestimate that a small ratio of Bi and Sn ( with a little help from the small amount of Sb) when alloyed with Pb work hand in hand and accomplish what we are all after - a hard shiny alloy that fills our molds perfectly!

I now have a lifetime+ supply of this stuff.

Hope this helps anybody else out there that has access to Bi/Sn alloys.

bangerjim

[lwknight]

Its probably used in fusible links for fire suppression systems.

[JonB_in_Glencoe]

Upon analysis with a $40K x-ray gun, it is made up of:
Bi 56%
Pb 26%
Sn 13%
Sb 5%

There nothing on Rotometals that is close to this mix and there is NO Cadmium or Indium in it. Closest composition I can find on the net is Rose's metal, but it's melt point is at 200F+.

If your '$40K x-ray gun' is accurate, I think there is something close

Roto217-440F
Bi 48%
Pb 28.5%
Sn 14.5%
Sb 9%

But according to Rotometals it shouldn't melt at that low of a temp.
http://www.rotometals.com/Low-Meltin...lloys-s/21.htm

[bangerjim]

If your '$40K x-ray gun' is accurate, I think there is something close

Roto217-440F
Bi 48%
Pb 28.5%
Sn 14.5%
Sb 9%

But according to Rotometals it shouldn't melt at that low of a temp.
http://www.rotometals.com/Low-Meltin...lloys-s/21.htm

I know. I did a double take on the temp. I have checked it with 3 different analogs and digitals. The digital uses a "point of contact" K t/c.

All were right on 160F.

The gun that was used just got back from it's certification and is accurate.

Anyway, the point of this thread is not the melting point...which IS neat.....but to point out if guys run across Bi alloys out there, they are useful in hardening our mixes.

bangerjim

[BACKTOSHOOTING]

I recently picked up a Coburn melter along with a couple other items and it had about 10 lbs of mystery metal in it that readily melted but it would not melt my alloy. It also took a very long time to solidify even a small puddle that spilled on the ground while makeing ingots with it that i've put aside till i find out what it is.
It melted around 200 according to my PID in my Lee pot and has a very <tinging> sound when tapped together.

I might have the same stuff

[bangerjim]

I recently picked up a Coburn melter along with a couple other items and it had about 10 lbs of mystery metal in it that readily melted but it would not melt my alloy. It also took a very long time to solidify even a small puddle that spilled on the ground while makeing ingots with it that i've put aside till i find out what it is.
It melted around 200 according to my PID in my Lee pot and has a very <tinging> sound when tapped together.

I might have the same stuff

You MAY have the Rotometals alloy described above. At least what you have melts at the published temp! Anyway, it is a good source of hardening alloy/tin for pure lead and other stuff you might have. The "tinging sound", although not a scientific definition of hardness , is an indication of a harder alloy in the 18-23 range. If you do not have a hardness tester, try the $10 artist pencil set test many use with success as described in a thread on here.

bangerjim

[popper]

Cool. Probably is fuse material. Bi is a good hardener. Wonder how it shoots?

[PbHurler]

Could this be "Woods" Metal? I remember melting that stuff in hot water when I was a young'n.

[sprinkintime]

I know. I did a double take on the temp. I have checked it with 3 different analogs and digitals. The digital uses a "point of contact" K t/c.

All were right on 160F.

The gun that was used just got back from it's certification and is accurate.

Anyway, the point of this thread is not the melting point...which IS neat.....but to point out if guys run across Bi alloys out there, they are useful in hardening our mixes.

bangerjim

I have some Cerro Bend and it has a melting temp of only 158 F degrees and also some Ostalloy and it melts at 281 F and we always used it in machining very fragile parts to hold them together from warping etc. Sprink

[Thompsoncustom]

wood's metal = 50% bismuth, 26.7% lead, 13.3% tin, and 10% cadmium by weight

[el34]

How does its weight compare?

[JWFilips]

something left over from the Roswell Crash ...no doubt

[bangerjim]

How does its weight compare?

a "one/half pound" ingot (in a Lee mold) weight ~5.5 oz. so it is lighter. But I would NEVER cast using the stuff pure. It's too useful mixing it with soft lead and seeing the hardness shoot up!

I have not done any extensive analytical weighing or density measurements on it. I really do not have to, as I am using only about 2 oz/pound of lead for hardening.

It is definitely NOT Wood's metal.

And it DOES not glow in the dark! HA.....ha.

bangerjim

[Graakall]

Found an old report on alloys with bismuth.

http://nvlpubs.nist.gov/nistpubs/jre...5p1085_A2b.pdf

I hope it's useful.