Lead Volume vs Weight - Where did it go?

[Old Ironsights]

Ok. SO I melted down a bunch of scrap on Sunday. http://i5.photobucket.com/albums/y180/MrMisanthrope/IMG_0281.jpg
600 lbs of various scrap from Roof sheeting to Diving weights.
http://i5.photobucket.com/albums/y180/MrMisanthrope/IMG_0279.jpg
Kept it at 650 until clean then warmed it up to 750 to cast.
http://i5.photobucket.com/albums/y180/MrMisanthrope/IMG_0284.jpg
The 20qt pot above was after dipping out the 16 qt + some of the 20.
Made a nice pile of ingots
http://i5.photobucket.com/albums/y180/MrMisanthrope/IMG_0285.jpg

BUT Here's somthing I don't get. 1 qt of lead weighs 22.72lbs. I had at LEAST 36 qts of CLEAN molten lead going - that's 817lbs. (Possibly 40qts -I had to ingotize some metal to get it all melted in a 20qt & a 16qt stock pot - that's 908.8lbs)

Yet, no matter how I count/weigh it, my ingots calc out at 650lbs(+/-). What gives? :confused: Surely there isn't that much shrink... :confused:

[Harpman]

I hope like hell you have someone riding shotgun carrying that much lead around the public streets, you know another caster sees ya and yur a dead man, shot, robbed,,could be terrible !!!!!!!!:drinks:

[Pepe Ray]

Hi OIS,
Sorry I can't solve your mystery. I'm consumed w/curiosity if you mixed the diving wgts with any of your KNOWN material. Of course, you may know who cast the diving wgts and can confirm the alloy is zink free.
Salvaging items like this always makes me extra work because I've spoiled a batch of lead w/zink. At the time a close friend wanted an anchor so I solved my problem by helping him out.
Up here in Yankee land, many divers scrounge lead for their wgts and are not discriminating. The zink works great for them.
Anyhow, just curious,
Pepe Ray

[Old Ironsights]

Was a cold smelt (600-650) and the only floaters I had were a few zinc & steel wheel weights. No lumpies or other weird bits, so I feel pretty secure. The weights were OLD too, and thumbnailed nicely.

[rhead]

The 22.72 pounds per quart is measured for a solid slug one quart in volume probably at 60 degrees F. It will expand some when heated to 750 degrees. I would be suprise to find that it expanded by a third but would not be suprised to find that the poss were also somewhat undersized. It could be a case of several things adding up. At least you did have 600+ pounds in and 600+ pounds out. That would really have been hard to figure.

[Blammer]

I think you need to ship me about 50 pounds for a thorough test of the alloy.

I'll let you know where the other "missing" lead went.

;)

[montana_charlie]

The only solution to the mystery is to remelt the whole batch and pour it into quart containers. Then weigh each one (subtracting for the container, of course) to get a total actual weight.
Count all of the 'lead' quarts, and multiply that number by your assumed weight of 22.72 pounds.
Compare both totals, 'actual' and 'assumed', and note the difference.

That difference may give you a clue about how much of the stuff in your alloy is not lead.

Then again...your metal may have come from a metric source...and needs to be poured off in liters.
CM

[BCB]

Old Ironsights,

I use the Lee ingot mold that pours two 1-pound bars and two ½ pound bars per filling. Now then, that adds up to 3 pounds. BUT, if I actually weigh it, it weighs in at about 4 pounds. That is a gain of approximately 33% of what the mold should weigh when filled. So maybe you are pouring ingots that are calculated to weigh a certain amount, but by weighing them they may weigh actually more than they are supposed to weigh according to the calculated amount.

Maybe that is where your discrepancy is coming from? If you are sure of your molten volume, then you know the weight as lead has a SG of 11.34 which is right at the 22+ pounds per quart you indicate. Maybe your ingots weigh more per piece than you are aware?...BCB

[cohutt]

Fun with Geometry and Lead, by Mayco:

http://www.maycoindustries.com/Calculators/geometry_xls.htm

[FISH4BUGS]

Old Ironsights,

I use the Lee ingot mold that pours two 1-pound bars and two ½ pound bars per filling. Now then, that adds up to 3 pounds. BUT, if I actually weigh it, it weighs in at about 4 pounds. That is a gain of approximately 33% of what the mold should weigh when filled. BCB

Clear as mud - it just depends upon how full you fill the ingot mould. A 1/4" more of lead in a 1lb ingot can make it weigh more than a pound! Do a test. Find out just WHERE a 1lb ingot will fill to.