How to tell if it's lead or a lead alloy?

[etrain16]

There is a formula to calculate BHN using a known pure lead sample, an unknown hardness sample and a 1/2" or so ball bearing.
I bought a 99.9% pure lead ingot from Roto Metals, cast it into a muffin pan, and cast an ingot of the unknown hardness one into the pan too.
Put the ball bearing between the two ingots and press the ingots together with a vise, trying for about one third of the diameter of the ball as to depth. measure the diameter of both dents.
Lets say that the dent in the pure lead was .200", and the dent in the unknown was .150".
Divide the 200 by 150, ( no decimal point.) should be about 1.33. Square that, (1.33 X 1.33.) Should be 1.7689. Multiply that by 5, (BHN of pure lead.) Alloy should be 8.8445 BHN.( Round that off to 8.8 BHN, close enough...)
This only tells you the hardness, not the other elemental metals in the mix.
This formula was in the NRA cast bullet book.
Also, Roto Metals will test a sample for around $40, IIRC, but not worth it for only a few pounds...

Interesting piece of information - might be fun to try just for the heck of it.

 

[Rick4070]

Went home for lunch today, and picked up a 99.9% lead ingot, and an ingot of Linotype, brought it back to work, and using the above method, came up with 20 BHN on the Linotype. did it three times, and results repeated really close.
That being said, Linotype is supposed to be 22 BHN.
I got the Linotype from a printing shop that would sell you an ingot now and again from their multi-pallet order.
The ingots were poured about 37 years ago. I don't know if there is any loss of hardness over that many years.
I think I'll try and re-cast the Linotype, let it sit a couple of weeks and see if there is any difference in hardness..

 

[v0lcom13sn0w]

maybe u have some unobtanium

 

[Rick4070]

You might be right, although I stsmped "LINO" into the ingots all those years ago.

 

[ditchtiger]

I'd heard/read that anything can be cooked out of lead with heat and time. As in a zinc mix. Put some on the turkey cooker and burned it off for about 1/2 an hour. lots of crud was at the top. just skimmed, no mixing. Need to get back to it to see if it worked. Other wise it's sling shot or buckshot ammo.