My math skills must suck

[Jtarm]

I went out to the farm yesterday for my first big smelt of what I thought was 678 lbs of COWW (more on that later.. Aiming to smelt a batch of 98/2.

My pot is an old 12-qt Dutch oven. I measured it with water. I only managed 2 potfuls before getting low on propane (improvements to the fryer are coming.)

Each time I melted until I had 10 qts of clean, molten lead, which, if I understand specific gravity, should weigh about 230 lbs. Then added 5 lbs of pewter (each pot) and fluxed.

After finishing, I weighed the clean, alloyed metal, and it came to 313#.

I might have to go over this again, but I’m pretty annoyed at the prospect of having wasted 4 lbs of pewter. I guess the boolits should fill out well and be nice & shiny.

I’m going to re-measure the pot and do the math again before any further attempts.

I also weighed the remaining COWW and somehow came home with 70# more lead than I left with, despite leaving a can with about 35# of clips out at the farm.

[ulav8r]

I would like to know where you got this lead that is gaining weight. I need some like that. If left long enough it might double it's weight.

[Dusty Bannister]

You might take into consideration that lead is more dense than COWW. Next time consider making ingots and then weigh out the batches you wish to make. Keeping it simple is always a good idea.

[JimB..]

Imperial measurements kinda suck.

231 cubic inches in a gallon.
57.75 cubic inches in a quart.
577.5 cubic inches in 10 quarts.
Lead weighs 6.556 oz per cubic inch
3786 oz of lead per 10 quarts.
16oz in a lb, so 236lbs of lead in 10 quarts.

Your math is good, but I think your scale is bad.

313lbs of alloy less 5 lbs of lead is 308lbs of lead.
Thats 4928 oz
751.68 cubic inches
3.254 gallons
13 quarts.
It couldn’t have fit in your dutch oven.

[high standard 40]

You didn't waste pewter. Just remelt the ingots and add more COWW to get to the mix you desire. Or make some COWW ingots and use some along with your current ingots when you cast.

[Jtarm]

It couldn’t have fit in your dutch oven.

It wasn’t all at once. I filled it twice.

Apparently what I thought was 230 lbs of lead was more like 150.

So according to my calculations, I have 313 lbs (yes, maybe time for different scales) of roughly 97-3 and need to add about 190 lbs of COWW to reach 98-2.

[Mr_Sheesh]

So just about 60% added COWW, if you can find something at that 60% and cast COWW in that then put in 1 ingot mix and 1 smaller COWW together at a time, you'll have 98-2

Also a 2:1 mix would be pretty close to 98-2 if you just want to use 2 mix ingots and 1 COWW ingot

[dverna]

Easy to check the scale. Then go from there.

[Jtarm]

I would like to know where you got this lead that is gaining weight. I need some like that. If left long enough it might double it's weight.

Yeah that was a plus.

I found a couple of live primers when sorting, but apparently missed one. No visit from the tinsel fairy, but it sure got my attention.

[kevin c]

How did you figure on each melt being ten quarts?

I've tried to fill molds to marks made on their sides, shooting for a specific volume and therefore a specific weight of a given alloy, but unless the mold was perfectly level, hitting the mark didn't give me the weight, being high if the mark was above level, or low if the mark was below level.

It's worse in my 12" diameter processing pot, where one inch of lead is 40# of alloy. Rather than going to the trouble of getting the pot perfectly level and filling to a predetermined mark, I preweigh everything that goes in, added in ratios calculated to give the final alloy I want.

[Land Owner]

I melt pure lead and COWW's together in 100# batches, pour batches into 3# ingots, weigh the ingots, write the ingot weight on the side of the ingot, and store ingots in ammo cans. When it is time to add an ingot to the casting pot, I add the already weighed ingots of Pb-WW alloy to a significantly lesser weighed amount of tin to create an final alloy of 49-49-2 Pb-WW-Sn. I find no need to predetermine the tin for 100# batches. The tin is a small percentage (2%) and for me, more easily added at the casting pot level than the bulk batch level.