How long does an ingot take to cool?

[boho]

Well I found 3 of the 7 ears of corn cast iron corn bread molds cheap today at the local flea market. Guess I'm gonna have ear ingots! Not ideal but effective and affordable. Thanks for all the ideas everyone!

[Le Loup Solitaire]

Ear ingots are ok but they don't stack very well. Bread stick molds are a little better as are cupcake shapes. I originally used pop cans but a full one weighs about 10 pounds and won't usually fit in a bottom pour pot; cutting the can in half or less is better. Large ingots will almost always drop the pot temp and cause freeze up for a while. After a lot of trying different things I wound up using the condiment cups that are sold in sets of four a Walmart. They are stainless steel and a set is all of about 90 cents. Usually you need a pliers or a lock wrench to turn them over when full. The trapezoidal shapes of the ingots made by RCBS, Lyman, Lee or similar old ones by Ohaus, Saeco, etc. are good and they stack tightly and compactly. Similar ones result from molds made from angle iron that is welded together. All are of reasonable size and when added to the pot usually don't freeze the melt...unless you put in too many at once. Marking them is easily done on the flat sides with a felt pen or a steel stamping set and a mallet. LLS

[MaryB]

Condiment cup ingots stack okay if you alternate up/down

[boho]

The 2 walmarts within 30 miles of me only had plastic cups. The 2 dollar generals within 20 miles didn't have the 1 piece muffin tin. When I went to the local scrapyard they were loading the steel on a truck, looked at the owner in disbelief. Then I found the cast iron. My luck has been poor for my ingot molds, but I scrounged 226# of usable WW this week for .30 a#. Poop with the sugar I guess.

[RogerDat]

I don't use the corn molds but do have a couple of those ingots from someplace. Bet they fit in a coffee can or bucket just fine, both of those containers will stack.

Heck if you don't like the ingots it's not that hard to do over later, or better still cast em into bullets and stop using the molds if you get something you like better later. If it puts a possum in the pot for dinner then it works fine.

[boho]

Appreciate everyone's input! I couldn't find what most of you suggested. I did find at a flea market 10 really small cast iron skillets for $10. 5 were decorative and 5 were plain, so the Lil lady got something cute outta the deal! Using a 2oz commercial kitchen ladle bought for $.75 at the thrift stores the ingots avg a pound & a half. Thanks again!

[leadbutt]

Thrift stores..... cant beatem

L. Bottoms

[fredj338]

I figured to pour it 3\4 full. I thought it would be about a 3# ingot. I don't even have an electric pot yet, not sure if I'll ever get one. I am planning on working wood fire and cast iron. I'm just trying to store material now, using what I already have. Suggestions are welcome!

I think closer to 8-9#. Put it on the concrete slab, it will cool more quickly. A 3" channel iron section 4-5" long makes 1-3# ingots depending on how much you fill it. If yo uknwo a welder or have one, just by some at the scrap yard.

[lightman]

The cooling time will progress, each fill will heat the mold more and take longer to cool. Most of us use several molds for this reason.Your skillet is going to make a mighty big ingot! You would be better served with a smaller mold if you can find something. Also, the bigger ingots will cool your lead in the casting pot more than smaller ones will. If you have to, use what you have and be on the hunt for something better. Many of us have done it this way!

[konsole]

This is my preferred ingot mold...

http://www.walmart.com/ip/Mainstays-...-Pack/32802093

I found a few of them at a local donation store. The ingots fit nice in your hand and filling the pans completely with lead yields about a 10 pound brick. I've actually used it as a melting pot directly on the stove.

As for cooling/solidifying (since its unclear which you meant), without using water quenching, the ingots are cool enough to briefly pick up with a leather glove without damage to the glove after about 10 minutes, and hold longer without glove damage after about 15 minutes. If you meant "solidified" then the first thing I do to test for solidification is just tap the mold and see if any liquid lead flows in the mold. If the ingot doesnt flow at all then I use a piece of wood or flat metal like a spoon and tap the top of the ingot in the corners and in the middle. The corners on the top of the ingot will solidify faster then the middle on the top of the ingot. If the corners feel solid and the middle sounds either just as solid or pretty close to the same solid feel, then the ingot is ready to drop out of the mold.

[mikeym1a]

The length of time it takes to cool is inversely related to the thickness of the glove.

[RogerDat]

Larger ingot takes longer to cool than smaller ones, but might be useful when doing a bigger batches to speed things up. Especially if one uses a casting pot large enough to take the bigger ingots. Some of those gains in ease and speed depend on ability to deliver larger amount of lead to the larger mold. Large ladle or big bottom pour smelting pot.

The cheap Harbor Freight welding gloves prove the point mikem1a made, seems that wearing those gloves everything takes forever to cool down!

[konsole]

I don't remember exactly how long my 8 pound lead ingots took to cool to the point of handling them with my bare hands, but a 5 pound zinc ingot that I made was too hot to hold bare hands like an hour after it solidified.

[NavyVet1959]

It's been a LONG time since I've done any calculations like this, so if anyone sees an error in them, feel free to point it out.

Because of the latent heat of vaporization of water (i.e. 970 BTUs per pound of water), either using a fine mist over the ingots or setting them on a wet towel will remove a lot of heat. A BTU is defined as the amount of energy necessary to raise 1 lb of water 1 degree Fahrenheit.

The heat required to melt a solid can be calculated as

q = L_m m (1)

where

q = required heat (J, Btu)

L_m = latent heat of melting (J/kg, Btu/lb)

m = mass of substance (kg, lb)

Lead has a latent heat of melting of 9.65 BTUs per lb.

So, if you started out with a 5 lb ingot mold with 5 lbs of just barely molten lead in it, you would need 9.65 * 5 BTUs to go from liquid to solid (48.25 BTUs). This would work out to be about 0.796 oz (wt). A fluid ounce of water weighs about 1.0425 oz (wt), so for rough estimates, you can go by the old adage "a pint equals a pound" and equate 1 oz (fl) of water equaling 1 oz (wt).

Another term to consider is the "specific heat" of the various substances. The specific heat of water is 1 BTU / lb F whereas lead is 0.0305 BTUs / lb F. As such, it takes less BTUs to raise a pound of lead 1 degree Fahrenheit than it does to raise 1 lb of water that same amount.

So, let's assume a lead melting point of 622F. If you want to get that down to 212F, that means that you need to remove 410F from it. That means 12.505 BTUs per pound or 62.525 BTUs for our 5 lb ingot. This works out to be 1.03 oz of water.

Getting to cooler than 212F is not as efficient in its use of water for cooling, so I'll stop there. Plus, as long as everything you are working with is 212F or above, you significantly reduce the chance of introducing liquid water under molten lead (which will result in a visit by the tinsel faerie.

So, assuming my calculations are correct, less than 2 oz of water sprayed in a very fine mist would get a 5 lb ingot from molten to a handling temperature of 212F. Maybe not *bare hand* handling temperature, but a temperature that you could move around with even cheap gloves.

Of course, you would also need to take into account the weight of the ingot mold and the specific heat of whatever it was made from.

[RogerDat]

I think that cool enough to dump from mold and refill are the goals in the Original Post. I'm guessing there might be people that would need or want to move the dumped ingots faster for them some water mist or a damp towel might prove useful. Be careful of steam burns in addition to the tinsel fairy precautions when having water around molten lead. If you get water on you gloves the heat will come right through the wet area. Don't ask how I know that little tidbit.

Me I just line up three molds in front of the pot and by the time the last is filled the first is set up enough to move aside and be replaced. By the time all of them have been filled the first ones are ready to dump. But my largest mold currently is a muffin tin that holds 1.5 lbs. in each cup with some lee mold and mini-muffin tins that only hold 1/2 lb. all of those set up enough to be moveable pretty quick.

[ssnow]

Here is a picture of the mini-loaf pan, an ingot, and the fork I made for handling them;



The next picture shows the bottom of the pan and how the fork fits;



The handle of the fork is around 3 feet long. It makes it easy to move the ingots from below the spout to a place for it to cool. It really works well for my application, but I have a large smelting pot, and can smelt a full 5 gallon bucket of wheel weights at one time.

Should anyone decide to build a fork, note that the flat stock is 1 1/2 inch material. This allows the sides to match the angle of the pan, and still have the pan protruding from the bottom. This allows you to set the pan down, drop the fork another 1/2 inch, and slide it out easily without worries of binding on the pan anywhere.

[RogerDat]

That is a really nice set up you have made for handling bulk ingots ssnow.

[ssnow]

Thanks. It works very well for me, and the ingots stack nicely.

Of course, not everyone wants a 10 pound ingot. But there is nothing to say you have to fill them full if one desires smaller ingots. They wouldn't work so well for the guy using a Lee 10 pound pot. If you make the ingot an inch thick or so, it will only fit about half way down in the smaller Lee pot before it jambs on the plunger. They would work fine for the larger Lee 20 pound pot though.

I have a larger melting pot, so the 10 pound ingots are idea for me, and you can't beat the price