What is in this lead?

[larrye44]

A friend who just started casting boolits came over to melt down some lead in my cast iron dutch oven. It was a window weight and weighed about 15 lbs. It melted okay, but was difficult to keep liquid. I had my propane burner on high, the same setting I use for ww's and it melts and keeps the melt liquid. I put my thermometer in it and it was a little over 600 degrees. I poured it in Lee ingot molds and it wanted to go solid before I could pour it out of the ladle. It is very shiny, looks like an ingot of silver. This was out of an old building back when they used weight to hold open the window. Does anyone have any ideas as to what could be in this alloy?

I only use ww's and never change the ww alloy. I told him he needs to only use ww's because of the alloy being perfect for boolits. He wants to mix in lead he get from people that give him what they have. Origin unknown, alloy unknown. I told him the 94-4-2 (I think this is the correct numbers) alloy was perfect because it has the correct weight for the mold (45 ACP 200 gr. SWC) and the tin helps fill out the mold.

He said he would not use it (I hope I have him convinced), but we would like to know if this is something you guys have come across. Thanks everyone. Larry

[chris in va]

I'm a window cleaner and run across these things all the time. Most counterweights seem to be iron, but I'd suspect what you found is pure lead which melts at a higher temp than wheelweights.

[Echo]

I told him the 94-4-2 (I think this is the correct numbers) alloy was perfect because it has the correct weight for the mold (45 ACP 200 gr. SWC) and the tin helps fill out the mold.


Incorrect numbers. 95-4-.5, plus wee bit of arsenic, and maybe iotas of other stuff. Some additional Sn seems to help...

[sqlbullet]

That weight would have been pure lead based on the melt point.

[Mk42gunner]

Where do you people find these lead window weights? Everyone I have ever seen was cast iron. And I worked for a plumber/ general contractor for a few years in high school.

Robert

[82nd airborne]

I find them next to my dads casting bench, then to the bed of my truck with them.

[geargnasher]

I agree it's probably mostly pure lead with trace impurities, from an era where antimony and arsenic weren't added to lead alloys intentionally.

Pure lead IIRC melts at 622*F and is mirror shiney when cooling. It takes a lot more heat to melt, over 100* more than wheel weights, and absorbs it more slowly. I'll bet you could gouge those ingots with your thumbnail and carve shavings off of the sharp edges with a pocketknife.

Gear

[larrye44]

Thanks, everyone. It will dent pretty easy when stabbed with a screwdriver. I kept a 1/2 lb. ingot for identification and I just took my knife and sure enough, it shaves right off. I'll let him know it is pure lead and give him the correct numbers (94-4-0.5). Larry

[lwknight]

You just need to get a cowling around the burner to make all the heat stay to the pot instead of blowing away out the sides. Pure lead is a little harder to melt.

[larrye44]

Thanks, L W Knight. The burner sets directly under the cast iron dutch oven. I guess that's why I never thought about a cowling. Thanks for the great idea. I'll not only get better heat, I'll save gas. I love this forum. Not only do you get expert tips on casting, you get tips on things that are not always obvious to you. Sort of like the forest for the trees thing. Larry

[Tom Myers]

It probably isn't really important but, if my math is correct, 95 + 4 + .5 adds up to 99.5. Maybe the "iotas of other stuff" makes up the missing 0.5%

According to Lyman's Cast Bullet 3rd Edition, the composition of wheelweights is:

95% Lead + 0.5% Tin + 4.5% Antimony = 100%

Hope this helps.

[buck1]

.5% voodoo!