Mysterious Lead Alloy

I got a 100 pound batch of "medical" lead. But after having casting and coating some boolits I have strong doubts about how pure it is.
To start with, at 500 degrees about a third of it is melted; at 620 degrees it's all melted; at 700 degrees it runs like water. The boolits take a long time to cool off and they are very frosted. I think my thermometer is okay, but have no way to test it without buying another.
The boolits weight is right on the money, but the alloy is too soft to reliably go up a feed ramp sometimes and other times it shows signs of being really brittle.

I'm sure it's an alloy, but I don't know with what and the ratios. I might be the lucky idiot that found a bunch of linotype and didn't know what he had.But it's giving me conflicting signs. I'm going to test hardness tomorrow with my new Lee Lead Tester.

But if this doesn't work does anyone know where I can have the composition of my lead tested? I don't mind paying for a lab if they can tell me exactly what it is.

IF you have a friend at a scrap yard...AND they happen to have an XRF Analyzer....they can tell you exactly what's in it.

Contact Member BNE he will test a sample for 1lb lead. http://castboolits.gunloads.com/member.php?29218-BNE

I doubt that the use of a hardness tester on fresh castings is going to be able to tell you much other than give you a starting point. Then testing again weekly until it reaches mature hardness. At least then you will know if it is nearly pure lead or not. An alloy will be identified a lot faster if you care to use the services of BNE. Or your friendly local salvage yard can help if they have an XRF scanner.

Lead/tin melts at 621, Linotype melts at 465, Tin melts at 450, Bismuth melts at 520.

Thanks guys, you've probably saved me a lot of aggrivation.

Just a thought: did you get the lead in original form and melt it yourself into ingots, or did it come to you as ingots?

With medical lead there seems to be some variation in the alloy depending on use and the manufacturer. XRay shielding lead may be pure or have some antimony. Sqlbullet deals a lot in isotope lead and what he found is that most has Sb and Sn in it similar to what is found in COWW with additional tin. Shielding bricks might be pure. The isotope containers I get, which come in several forms, are mostly about 2.5% Sb without tin at all, and some are very soft lead.

If you got different types, did you melt them all together in one batch, or did you make multiple batches that might vary in content depending on the different types put in?

Lagamor,
That stuff sounds akin to something I've had.
It's soft, frosty, makes great expanding hollow points, it can fracture before sufficient cooling, has harder crystalline structures within a matrix of soft metal. Mine was from recycling lead piping from a chemical plant.

Attachment 233905
Ingot Broken Before Cooling

That looks similar, I haven't seen the large crystals but the color is spot on.
Trying to upload pictures but get a message that the upload failed.

Do it the easy way
Contact BNE,

What I've seen here in Alaska and what might be termed "medical lead" was pure sheet lead removed from the walls of the xray room during a local hospital renovation. It was in something like 4ft square sheets and there was quite a stack of it. I'd sure like to have dragged all that home! I could see them using that stuff in places in the hospital where radioactive materials were used/stored also.