Check my math, please

[Jim]

Using the weight of pure lead per square foot, I calculated the weight of a cylinder of lead. The diameter of the cylinder is 2.625" and the length of the cylinder is 1.625". My references say lead weighs 708 lbs./sq. ft.
Would one o' y'all check behind me and verify my calculations? I came up with 3.6 lbs.

[wills]

I think you need cubic feet, not square feet.

[Jim]

Yeah, you're right. Thanks, Will. I did do the calc based on cubic feet, I just blew the post by writing square feet.

[BCB]

Jim,
Yep, it would weigh 3.603 pounds as you indicated, if lead does weigh 708 pounds per cubic foot. Your math is correct...BCB

[Lead melter]

Ditto on the math. Would have answered sooner, but my calculator runs on its own time. It's the same model Fred Flintstone used.

[Jim]

I figgerd I figgerd right, but I figgerd I better git somebody else to figger, too.
Thanks, guys!
The "cylinder" is a 2.5" copper pipe cap. I'm gonna drill a 3/8" hole in one side near the open end and put a 3/8" threaded rod in it for a handle. I'll use this to cast pigs. I figger I'll wind up with pigs that'll run about 3 1/2 lbs. each or there abouts. Close enough fer me.
By the way, I saw a cast iron biscuit pan at Sportsman's Warehouse last night. It's got 6 individual places for the dough and I thought that would be a good pigging mold. The sides of the depressions are tapered, so the pigs oughta' drop out purdy good.
Ya' reckon?

[jawjaboy]

I reckon it will Jim! I got 2 cast iron muffin pans that I use sometimes...works good.

[cohutt]

easier to go here maybe:

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

[Scrounger]

I didn't do the math but seems I remember lead is about 24 times as heavy as water, which I happen to remember (correct or not) from 8th grade science as 63 pounds per cubic feet. So a cubic foot of lead should be somewhere in the area of 1500 pounds.

[GLL]

Scrounger:

Lead is 11.35 times as dense as water so the 708 lbs/cubic foot is about right.

Jerry

[hunter64]

I also use a small muffin tin for the 3 lb. size ingots, for long term storage size I use a cast iron bread loaf pan that I got from a garage sale for 5 bucks. When filled right to the top it weights 25 lbs. So when I get two or three 5 gallon pails of WW's I cast 4 25 lb. bread loafs first then the rest in 3 lb ingots for day to day use. I have 2500 pounds of long term storage bread loafs in the corner of the garage along the wall and I think I need more. lol

[Scrounger]

Scrounger:

Lead is 11.35 times as dense as water so the 708 lbs/cubic foot is about right.

Jerry

You're right; I didn't look it up. I remembered a quart of lead is about 24 pounds but I only gave a quart of water credit for 1 pound instead of the 2 pounds it actually is. I'm going to have to kick-start my brain a little earlier...

[454PB]

Seems to me that a copper ingot mould would get soldered pretty quickly.

[flinchnjerk]

Fun (or maybe no fun) with figures:
Water weighs .0361273 lbs./cu/in. The specific gravity of lead's 11.34. This gives lead's weight as .4097 lbs./cu/in. Bear in mind that that's the weight of solid lead. Molten lead's lighter; I've forgotten how to work with coefficients of expansion ( as well as a whole lot of other things), but using a value of .3935 lbs./cu/in. for molten lead when calculating what weight an ingot mold will drop is close enough.

[auzzie101]

Does a gallon of water and a gallon of milk weigh the same? I've always thought that fluid ounces were volume and weight ounces were well, weight. Does a quart of water (32 ounces) really weigh 2 lbs?

[Jim]

454,

The copper pipe cap is what I'm gonna use as the ladle cup.

[garandsrus]

Auzzie101,

According to the web site http://www.fourmilab.ch/hackdiet/www/subsection1_4_2_0_7.html, the weight of water is:
Gallon 8.345404
Cubic foot 62.42796

No, a gallon of milk doesn't weight the same as a gallon of water...

John

[MT Gianni]

Auzzie101,

No, a gallon of milk doesn't weight the same as a gallon of water...

John

Different specific gravities. Gianni

[dagamore]

IIRC

fluid ounces are based of a pure water, just like the ml are. so if there is anything in with the water, it will weigh more then 1oz of weight, per oz of displacement.

now let me finish cooking my duckbreast and foie gras (de canard) the small joy of living 30 minutes from France.

[floodgate]

"A pint's a pound
The world around"

[Dam' round-earthers!]

[Scrounger]

IIRC

fluid ounces are based of a pure water, just like the ml are. so if there is anything in with the water, it will weigh more then 1oz of weight, per oz of displacement.

now let me finish cooking my duckbreast and foie gras (de canard) the small joy of living 30 minutes from France.

so if there is anything in with the water, it will weigh more then 1oz of weight, per oz of displacement.

Or less.

[dagamore]

so if there is anything in with the water, it will weigh more then 1oz of weight, per oz of displacement.

Or less.

Right, If what ever is displacing/coloring/impuring the liquid has a spec gravity of less then 1 (such as close Cell foam(aka styrofoam) the end liquid will weigh less then 1 oz of water per oz of displacement.

I forget what this math rule is, but basicly

if A+B=C
then C-A=B, and C-B=A must also be true.

thanks for the follow up there Scrounger.

[AZ-Stew]

I do computer aided design for a living.

I just created your lead cylinder as a computer solid model and "weighed" it using pure lead material properties.

Volume: 8.794 cubic inches

Weight: 3.495 pounds

If Antimony or Tin are added to the alloy, the weight will decrease in the same volume.

Regards,

Stew