20# pot?

[Land Owner]

I'm going to measure the interior diameter (when hot), melt the pot, stick in a rod, and measure that for the depth to the rim, then calculate the theoretical weight of lead. I will report back.

[onelight]

The simplest way to check if you have a scale that will read in that weight range is weigh the pot empty and weigh it full .

[Mitch]

lol well now 2/3 full and add 6lbs of alloy seems that makes atleast 18lbs of lead in the pot.no matter seems it is working for you.if you want 20 lbs of bullets out of your pot go buy the 40lb magma lol

[Land Owner]

The pot is full of cooled alloy. Melting, dipping a steel rod in to the bottom, measuring the rod, measuring the pot diameter, and doing the math calculation:

Volume of pot (cubic inches) = Pi * (pot diameter/2) ^ squared * depth of pot (all measurements in units of inches) [Eq. 1]

Weight of Lead = 0.41 pounds per cubic inch [0.41pci]

Weight of pure lead = 0.41pci * Volume of pot [Eq. 2]



Unraveling this "math" in reverse, a 20# pot of pure lead has to be 20#/0.41 pci or 48.78 cubic inches.

I measure my pot diameter to be: 4 and 1/8" diameter and not more than 5.5" deep (cold, full, can't take apart to see where heating elements are, etc.). My pot is at most 73.50 cubic inches and most probably 48.78 cubic inches...so I am closer to the pin of a 20# pot, theoretically, than before I started this thread.

[Land Owner]

lol well now 2/3 full and add 6lbs of alloy seems that makes atleast 18lbs of lead in the pot.

Mitch, I emptied the pot to 1/3 of its capacity, not by 1/3.

[Burnt Fingers]

The pot is full of cooled alloy. Melting, dipping a steel rod in to the bottom, measuring the rod, measuring the pot diameter, and doing the math calculation:

Volume of pot (cubic inches) = Pi * (pot diameter/2) ^ squared * depth of pot (all measurements in units of inches) [Eq. 1]

Weight of Lead = 0.41 pounds per cubic inch [0.41pci]

Weight of pure lead = 0.41pci * Volume of pot [Eq. 2]



Unraveling this "math" in reverse, a 20# pot of pure lead has to be 20#/0.41 pci or 48.78 cubic inches.

I measure my pot diameter to be: 4 and 1/8" diameter and not more than 5.5" deep (cold, full, can't take apart to see where heating elements are, etc.). My pot is at most 73.50 cubic inches and most probably 48.78 cubic inches...so I am closer to the pin of a 20# pot, theoretically, than before I started this thread.

There's a BIG difference between 73.50 and 48.78 cubic inches.

Using your given measurements your pot would have 73.5 cubic inches, which would make it a 30 lb pot.

The heating elements on a Pro-Melt are not in the pot, they surround the pot.

[Land Owner]

Let me be clear(er). The pot is nearly full of alloy and cold. Not wanting to heat the alloy just to measure the pot depth, I measured the outside of the Pro-Melt housing, top to bottom, as a "cannot-be-deeper-than-this" number. So 73.5 ci is a big number, but is not representative of the "pot" that actually holds the alloy when it is liquid.

[44magLeo]

When you draw the pot down to 1/3 left, who do you determine it's 1/3 left? If it's at 1/3 and it's a 20 lb. pot you should be able to add 13 lbs. If you are only adding 6 lbs. you are not drawing it down to 1/3 left, you are drawing it down to 2/3 left.
The only way to now for sure is to heat the pot and measure the depth of the pot and the depth of the lead at what you think is 1/3 left. If you don't want to do either then I guess you don't really want to know.
Leo

[popper]

Try advertising an 17 & 3/4# pot.
Just fill with alloy you weigh before hand and get to casting.

[Alan in Vermont]

Is the RCBS Pro Melt considered to be a "20#" pot? If it is, I can get no more than 10 weighed pounds of lead ingots in mine to reach its maximum capacity.

Which pots are actually 20# capacity - or are there any? Perhaps the name sticks because the pot, ingots, and supporting structure weigh 20#'s when full?

Something weird is happening, my Promelt when filled to the rim and then emptied yields 22 pounds of small ingots.

[Land Owner]

Alan - yes. Just guessing.
44magLeo - I will quit the speculation and measure the pot when it is next molten.

[Frank H]

My lee 4-20 can melt right at 20lbs of pure lead and slightly less from ingots made from wheel weights.

[Mitch]

No matter where you are taking the pot down to when you stop to refill.Apples to Oranges.you may be only refilling 6 lbs but there is still 20bs or more in the pot when full.Me when I get to a point I stop to refill the pot I drop in 2 ingots 4lb each then put in the sprues>this works out pretty good for me with my RCBS promelt.I get it it would be nice if we could pour 20lbs of lead from the casting pot but not going to happen with any 20lb pot.my lee holds about 18lb and the Promelt holds about 22lbs.this is toltal lead in the pot from empty to full.Depending on the bullet and size of the sprue i need to pout i get about 6 yo 8lbs of bulllets from the Lee and 8 to 10lbs of bullets from the Promelt. Now if you want to cast 20lbs of bullets you need the Magma master pot it holds 40lbs.anymore I welcome the break between filling.

[Mike W1]

I'm guessing here but I suspect the bottom of the pot MIGHT be rounded like my Lee !0# is. Just put some water in the thing to the level you fill to and measure that water capacity. Simple matter to convert water volume to what an equal volume of lead would weigh! Also depends on how full you fill and I doubt anyone fills a lead pot up to the brim anyways. 18, 20 ,22 pounds what difference does it make?

[onelight]

Makes no difference to me I know my 20 holds a lot more than my ten.

[ioon44]

My 2006 vintage RCBS Pro melt holds 22 lb.