Another mystery alloy

[40Super]

I got a 10#ish block that looked like a stock car weight or on that order,it had a single hole through it. When melting it, it had layers, like it was poured and cooled quite a bit before more was pour on top, but it seemed solid.It melted around 550F but didn't form an oxide layer on top very easy(took a while)I poured into my muffin pan, took forever to cool, no grainy surface at all,but wanted to leave pits, also stayed shiny. Sample bullets casted looked ok(a little pitty) but air cooled came to 23-25bhn approx., water dropped made no difference,still 23-25bhn:confused: Have to wait 24 to 48hrs to see if hardness changes.
Monotype? never seen it so I don't know how it would look.

PS pics make them look rougher and ingots copper tinted but thats not what they look like,no tint.

[R.M.]

Any possibility that it's tin??????

[geargnasher]

What melts at 550F, is 23-25 bhn and doesn't seem to change with heat treating? Quite a mystery. Race car weights are typically wheel weights, body solder, roofing/plumbing lead (near pure), radiator shop drippings, and such. Most of the car builders are in construction or automotive trades and get what they can from their local business buddies, usually small contractors, so those are typical sources. I never checked the hardness of 50/50 lead/tin radiator solder, but that might well be what you have. It would explain the melt point, the lack of quench hardness, and the shiny part, I just didn't think it would be that hard.

The next question I have is how much lighter are those boolits than typical wheel weight versions?

Gear

[40Super]

The bullets are Lyman 200grswc , those cast from my pure lead weight 207.4gr pretty consistant, I had a bunch cast up out of range lead + 1% tin added weighed 205gr average 13-15bhn, these bullets weighed in at 191gr ! Thats light !
As far as being tin, I'm pretty sure not, they are too bright shinny, not the frosty silver that any tin I've seen. And there was no golden hue on the top of the melt.
I figured the block would be ww before I melted it, but not now. I had about 2lbs of pure lead in the pot before putting this chunk in, so there is that lead in the mix to remember, so that would have meant those bullets would be a couple grains lighter if it hadn't been there. Now I wish I would have emptied the pot before, but who'd have thought.

[Andy_P]

Specific Gravities

Lead = 11.35, Tin = 7.35, Antimony = 6.70

Brinell Hardness

Lead = 3.9 BHN, Tin = 5.2 BHN, Antimony = 30.0 BHN

Melting point tells us little.

Based on the numbers you've presented, it's probably approximately:

- 92% Lead; and
- 8% Antimony, an 8% Antimony/Tin combination.

It would seem to be approximately 92% Lead, and 8% Antimony (but could be a combination such as 4% Antimony and 4% Tin). It surely has Antimony, as Tin adds little hardness wise.

Only a lab analysis can tell for sure, but the above would be good enough for me.

[40Super]

If that were the case, wouldn't there be that "crystal" grain structure I've always seen with normal alloys that have antimony and tin in them? Although, I don't know how a high % antimony comes out. I'm believing it is more in the 20 -30% antimony and almost no tin, going by the hardness. But as said only a lab can tell for sure but not enough of it to pay for testing.
I have some raw lino that I have to smelt into ingots, I'll cast some test bullets out of it and weigh to compare. Maybe a pile of them so I can use them to reliably add to alloys for a certain recipe.

[R.M.]

But if it had an antimony content, it would heat-treat, right?????

[40Super]

I would think so,but does high lino content harden as much/the same as lower %? some testing with my pure lino is in order.
The air cool hardness is what is stumping me, well that and the light weight. Any other metals in that melting range that could harden and reduce the weight of lead ,but not react to heat treating? high tin content should get that golden dross/hue(like my avatar), I would assume. Oh well.

[MGySgt]

But if it had an antimony content, it would heat-treat, right?????

Nope - For heat treating you need antimony and a trace of arsnic.

By the way Linotype and monotype do not have arsnic so they would not heat treat either.

[lwknight]

That is a mystery metal.
Enough antinony to make a 30 BNH would require 3 to 4 % tin to make it behave
and stay smooth.
The mystery part is the 550. The melting point should theoretically be under 450 degrees.

[40Super]

Well I've got it figured out. LINOTYPE , or about 80%-90% with the rest the pure lead that I had left in the pot lead(not mixed up very well). I melted 20# of my raw lino and cast up a bunch of the 200gr swc and weighed them, 191gr, the exact same as the others. Hardness is a few bhn higher with the pure lino bullets though. The higher melt temp from earlier had to do with that pure lead that was in the pot,it took more heat to melt, tonight when I melted what was left of that alloy, it was turning to liquid at around 450F. It just needed to be mixed up good, cooled, and reheated to get an accurate temp.

So 10# lino @ $0.40/lb, I have to go back and dig into that slug on the bottom of that barrel this came out of to see if there is anymore in there.

[badbob454]

good score

[DrBill33]

If you have a scrap yard near you, take a sample. They have hand-held analyzers, and can tell you the makeup ... including percentages ... of the materials in your sample.