Why are my lead ingots testing hard?

[cdm254]

Guys,

Bear with me on this question!!.....I have been slowly acquiring mostly wheel weights from my local tire shops to cast into lead ingots to use later for bullet casting. My ingots after properly cooling have a "frosted look" I know that this my be due to high heat. However when I Brinell hardness test using my Cabine Tree tester it consistently indicates that the lead ingots are about 22BN. I am not sure why it is so hard.

I can say that I carefully sort all wheel weights to separate the junk (zinc & steel etc..) from the stick on styles. I frequently flux using paraffin wax. I have gotten other already melted wheel weights at my scrap dealer and they are shiny and bright and test as they are suppose to at 12-14BH. I have tested my casted ingots for excess zinc and come up with nothing. Is there a possibility that wheel wheel weights I am getting have a high antimony content? Or am I doing something wrong when I melt them etc...?

Any answers or suggestions would be a big help!!

Paul

[badbill2]

Frosted isn't bad. There is a problem testing 22BHN with WW that were sorted correctly?

[Springfield]

When you drop them on a concrete floor do they ring like a bell? If not, then the testing is incorrect somehow. Which IMHO it probably is anyway as I can't see WW being 22 Brinnell.

[imashooter2]

Did you water cool the ingots?

[cdm254]

Guys, thanks so for your feedback!! To answer your questions; I did not water cool any of the ingots. I merely let them cool on their own, then came back several days later to check hardness.

I realize that frosted is not a bad thing....I just wondered if it would give the outer layer (as I would call it) a hard exterior with a softer core.

As far as dropping them on concrete; I have. They generally have a dull thud but do have a ring to them. I am not exactly sure what I am listening for here. Should it be just a dull thud only? I plan to cut one in half and test the center for a different reading.

[Cowboy_Dan]

Frosting is antimony crystals. Antimony is much harder 22BHN, but the frosting is probably not very deep. Test the inside of one at differing distances from the edge. I am interested in how deep frosting affects alloy hardness, if that is what's going on here.

[cdm254]

Cowboy Dan,

Thanks for the info. I'll give it a try here in the next couple of days and let you know. Appreciate the info!

[fredj338]

Recheck your dial indicator. My clip ww ingots come in right around 12-14bhn on my CT. With most testers, you have to be uniform. On the CT, going over or under the "Stop" can make a little diff, but not that much. Also unless yo uget the ingot perfect in the tester, the readings will be all over the place.

[cbrick]

I just wondered if it would give the outer layer (as I would call it) a hard exterior with a softer core.

Not possible unless your testing heavy oxidation thus messing up the testing but it doesn't sound like it. Lead is not steel and unlike steel will be the same hardness all the way through. Most people are aware of case hardening via heat treating steel and the surface is harder than the interior. Not so with lead, same hardness through and through.

Rick

[konsole]

If you melt the stick-ons and clip-ons separate you will notice that the clip-on ingots will have a brighter and more matte finish and will also not sink in that much on the top of the ingots. With stick-on ingots they will have a darker look and a more mirror finish, plus the tops of the those ingots will cave in considerable more then the clip-ons.

I'm not sure if the "frosted look" that hes referring to is the crystal formations of antimony, or if hes referring to the overall frosted or matte finish of a clip-on ingot. Maybe he should describe this "frosted" look more?

[btroj]

Why do people insist on testing ingots? I got hardness doesn't matter, I got composition does. Composition is not going to change upon melting and casting, hardness will.

[geargnasher]

I agree with Btroj, testing ingots is pointless........unless you're shooting ingots. Cast a few bullets right out of the smelting pot, for each batch of alloy you prepare. they don't have to be pretty, just testable. I like something with a wide, flat nose, that heats up fast like my two-cavity Lee 45-255. Air cool a few pours and water-quench a few pours. After testing all of them over a period of days/weeks you'll be able to determine close enough what's in your alloy. Antimony, calcium, and arsenic all affect the toughness of the alloy differently depending on the rate it cooled, tin and lead itself, or the two together, are unaffected by rate of cooling. Calcium is a major contaminant in today's wheel weights and can add significant "hardness", in fact that's what it's there for, hardening battery plates. Scrap battery lead may be used for WW manufacture. I wondered why my clippy WW tested an air-cooled 14+ bhn and only contained 2.4% antimony, then I saw the calcium percentage in the assay. After a remelt of that batch and repeated fluxings with sawdust it tests around 11 bhn, though I never had it assayed again to see how much of the calcium I got out.

Gear

[cbrick]

I pretty much gave up on explaining that BHN testing ingots is a waste of time. What will determine the BHN of a Pb/Sb alloy is it's rate of cooling. There is no way that a 1 pound (or more) ingot will cool at the same rate as 200 gr bullet. Do it as Gear suggested or just wait until you cast your bullets to test the alloy.

Rick

[Savage99]

What a great thread!! So many ideas are now floating in my head. I started getting most of my lead about 25 years or so ago and did different mixtures. I scrounged WW, Lino, stick ons, and soft lead (from a black powder shop). I smelted them down into ingots and mixed them, however, the paper that described the "recipe" got wet and the writing disappeared, my casting bench is out in the backyard and the lead is in wood boxes (22 lbs. ea.) under the bench. There is about 800 lbs. that are separated but different and about 2-300 lbs. of soft lead somewhere I haven't found yet. Anyway, I like the idea of making several bullets, air dry and water quench and then check the hardness, testing an ingot just doesn't make sense to me. At the same time the mould manu's say the mould should throw a certain weight bullet. From that I was going to put the two together, i.e. BHN and weight, and attempt to reverse engineer the approximate composition of my alloys in question. I have a tendency to over think things, so bullet hardness and weight and LASC info will get me there. I am going to make more bullets for 38 special, 357 Mag, 44 Mag, 45 colt, 45 acp, 44-40 (blkpowder), 38-55 (blkpowder and smokeless) and 45-70. My head is about to explode now, so I will stop.

[btroj]

Don't use the manufacturers weight to help decide, they are often off. Slight weight variations are the norm for all mould manufacturers due to small differences in the cavities from mould to mould.

Use Aircooled and water dropped BHn and after a month of aging it will give a pretty good idea of what you have.

[mattd]

I'll throw in one more piece to the frosting thing.....I smelted and poured, all at once, some #7 chilled shot in my bottom pour pot. I think there was some junk in there other then good alloy. I was getting frosting with the pot turned low enough that if I took a couple sprue cuts and threw em back in the pot the whole top would solidify and take a few to return to liquid. Never did make anything good with them, until I re-smelted in my smelting pot and fluxed a bunch.

Also, I dont have a hardness tested, but my current batch of WW seems much harder then normal.