Leaving lead in lead pot and molds for storage?

[Horseman]

I have made a habit over the years of refilling my Lee lead pot with my favorite WW alloy at the end of each casting session so it's ready to go for the next session, and also keeps the dirt and bugs out of the pot between sessions. I assumed I was also helping to prevent rust/corrosion that may result from a humid garage environment.

I also finish my casting sessions by leaving my mold cavities filled and sprues intact - for the same reasons. I figure as long as the mold is full, there's no way its going to get scratched or contaminated. I do store them carefully in boxes.

Are either of these bad practices? I've read all kinds of posts about coating molds with various oils for storage but I didn't find any related to leaving lead/bullets in the pot/molds. I use mostly aluminum and brass molds. Only one iron mold that I do coat with oil as it's rarely used and I worry about the exterior rust as much as the interior.

Thanks!

[Finster101]

I leave the pot filled, but I definitely do not leave my molds that way. There may be nothing wrong with it, but I would not want to break that hardened sprue to start casting again.

[Wheelguns 1961]

I do not leave either filled, and have never noticed any rust or corrosion problems. What I did notice is that full cold pot takes twice as long to heat, compared to adding the ingots while the pot is heating.

[Velosa]

I always leave the pot full, but molds empty. No rhyme or reason why, probably just the way I was taught.

[Winger Ed.]

I leave the pot fairly full, but clean and oil the molds.

[Wheelguns 1961]

I need to add that all of my molds are brass or aluminum.

[imashooter2]

The lead shrinks and doesn’t form a seal in either case. It does help keep debris out I suppose, but not humidity or rust.

[Soundguy]

I leave my pot about half.. It heats up faster. I leave my molds full..but I cut the sprues.

[Dusty Bannister]

I leave my pots half full to avoid the expansion eruption as it heats up. Molds are empty. Just my way, not that other methods are wrong.

[Rickf1985]

I leave my pot full but not my molds. I have timed the pot both full and empty and it is actually faster starting full, by a fair amount. If you think about it you will see that you are heating all metal and no wasted heat going into the air. The hot coils are right against the metal instead of heating the walls of the pot which is only touching little bits and pieces of ingots and other pieces of lead. Then you are adding cold lead to it as it warms up.
My dad used to store the molds full but I found a few that the bullets had oxidized inside the molds so I no longer do that. The strange part was that even though the bullets were oxidized the molds were perfectly clean and no rusted.

[pworley1]

I have always filled the pot and my single and double cavity molds. The six cavity sprues are too hard for me to break.

[country gent]

I leave my pot full as it heats and melts faster the next time, and after a session om tired and dont want to pour ingots. For corrosion when it has cooled some I drop a small ball of beeswax or paraffin on it to seal the areas between pot and lead. You can do the same with bullet moulds fill let cool some and just touch the beeswax to them. it will seal all the cracks up

[GhostHawk]

Another pot full but molds empty guy here.

I don't worry about aluminum corroding or oxidizing between uses. Pot is another story.

[MattOrgan]

I empty my pots as part of my shut down process. I find letting the melt run completely out and then scraping the gunk from the insides and dumping it out keeps the nozzle clear and neither my RCBS or Lee pots drip. I never leave molds filled. If they are going to be put away for a while the get coated with Ed’s Red made with Lanolin.

[Texas by God]

I do the same thing as the OP with no drama occurring yet.

[bangerjim]

I leave an inch or so of normal alloy in my pots (3 of them). Heating up next time is much faster! About every three melts I will dump the crud in it completely at the end and clean it.

I NEVER leave lead in my molds (Al and Brass). I have seen people do that, but I always ask them WHY......only answer is "someone told them to do that". (probably back in the dark ages?) It really gains nothing, as the Pb shrinks and still will let moisture and humidity in as said above. Why waste the time?

[Horseman]

I really appreciate all the great feedback! I will continue leaving the pot full for a quicker startup the next time (great explanation Rickf1985) and will probably start storing my molds empty, treating the iron one for sure and maybe the brass/aluminum if I don't anticipate using them for a while. Thanks!

[lightman]

I leave the casting pot full. I empty the mold and give it a squirt of oil after it cools off.

[uscra112]

Harry Pope said to leave a mould full. Who am I to argue?

[Winger Ed.]

if I don't anticipate using them for a while.

Years ago, I had a mold rust up and ruin after it had sat for a couple of years.
Now, If I'm not going to use a mold for a long time,
I put it in a 1/2 pint jelly jar full of motor oil and screw the lid on.
Long term storage for dies-- they get oiled, wrapped in a oily rag, and vacuum sealed in a 'food saver' bag.
So far, so good, and no more ruined dies or mold.

[Gtek]

I am on the coast in Florida and have learned nothing left unseen and a coat of something if you can and care about it. Molds are covered with oil, bagged and in Tupperware with silica bags. I leave 1/2"-3/4" usually in pot of whatever alloy and make a wire loop to set down in melt. When it cools lift out puck and mark alloy type and these are stored until next melt of type to get it going quick.

[Walks]

I always leave the pot full, but molds empty. No rhyme or reason why, probably just the way I was taught.

Same goes for Me. Dad used to loan molds. If they ever came back with lead in them, NONE were ever loaned to that person again.

[jsizemore]

I've never understood heating the same lead in the casting pot twice. I know a little in the bottom helps the melting process next time. Trying to cut room temp lead in the mold is hard on it and you can't check it's condition after casting with it if it's full of lead.

[GregLaROCHE]

I leave the pot around one quarter full and spray my molds with Ballistol.

[dale2242]

I live in a high humidity area.
I leave ALL my molds empty and oil the iron ones.
The pot is left empty when I am done casting because I use 3 different alloys and have no idea which will be needed for the next casting session.

[dverna]

If a Master Caster is left full, it will leak when starting back up until the alloy in the pot is melted. I leave the Lyman furnace about 1/2 to 2/3 full for no good reason except simplicity.

I leave molds empty.

[Mal Paso]

I usually stop pouring when I get down to about an inch left in the pot. If I am stopping I will turn the pot off at that point. Whether stopping or going for another batch, I'll put a couple fresh ingots in the pot and fill around those with the sprues.

I store molds empty.

I found the story of oxidized bullets in an iron mold with no rust interesting. Is the lead alloy acting as a sacrificial metal like zinc is used to protect boat parts. Could be where the idea started. I still hate cutting cold sprues though, it's hard on the mold.

[Walter Laich]

I leave my pot full--thinking the solid lead transmits heat better than ingots that have space around them as they melt

also use a lid on my pot to keep the heat in

20 lbs Pro-Melt (original model, not the "2" model) is up to 715° in 30 minutes. Do have to hit the spout with a quick blast from propane tourch to get it flowing.

all the molds are empty: Al and Brass. Iron ones are oiled

Know I'm heating the lead twice with this method but when I am ready to cast I don't want to wait around.

PID will keep melt within 1 to 2° if I don't add lead during the session--if I do then the PID will go 20° above the set point unless I keep adding as temp rises--all depends if I am going for a marthon casting session or just a 30 min one.

[fredj338]

I rarely empty my BP pot, surest way to get drips. I leave it about half full, heats up much faster. The molds all get stored empty. Alum nothing to do, iron get a light spray of rust prevent.

[fredj338]

If a Master Caster is left full, it will leak when starting back up until the alloy in the pot is melted. I leave the Lyman furnace about 1/2 to 2/3 full for no good reason except simplicity.

I leave molds empty.

I have not found this to be true. I leave my Master Caster at least half full. It might drip a bit but usually not. Again, want drips, empty the pot so all the crud gets into the pour spout.

[dondiego]

Whenever I needed to empty a pot to clean or change alloy I would carefully lift it and pour the molten metal out into ingot molds so the spout was bypassed.

[JSnover]

I leave the casting pot full and write the alloy on the surface with a Sharpie. I leave the ingot pot empty. My molds are left empty; they live in my basement when they're not casting (finished, with central air and a dehumidifier).

[Rickf1985]

I do not understand the "Heating the lead twice" bit? Just because the lead is left in the pot means you are heating it twice? Well, let's think about this for a minute here. If the pot is empty where is the lead you are going to melt stored? Is it stored in another pot in a molten form? If so you must have one hell of an electric bill. No, your lead is stored just like everyone else's is, on the floor in the garage or something similar. So you now have to heat that lead up,............... again. Plus you are doing it in a pot where only small parts of the ingots are actually touching the hottest parts of the pot that are able to melt the lead. So nothing is melting but the edges and the bottoms of the ingots that are in the liquid melted on the bottom. THIS is called MELTING the lead, a second time. Same as if it were kept in the pot. But that stuff kept in the pot would be done in a much more efficient way.

[Gtek]

I can jump around between five to six alloys depending on whims, leaving in pot doesn't work real well for myself. Having the puck of similar which was removed from that pot works very well for starting up. Installing puck and stacking on top firing off, ingots start sliding into melt then adding more as needed to start heating up above until desired pot level is achieved. Most of us can swim, we just stroke a little different!

[oley55]

great thread! thanks to the OP for starting it.

I generally leave my bottom pour Lee 4/20; 3/4 to full unless I plan to use a different alloy next time. I do not leave alloy in my moulds. Although I live on a Florida coastal saltwater marsh, I rarely coat or contaminate any of my molds with anything. I only have 10 molds so I store them in my golden rod conditioned gun safe and have yet to have a rusted mold.

[jsizemore]

I do not understand the "Heating the lead twice" bit? Just because the lead is left in the pot means you are heating it twice? Well, let's think about this for a minute here. If the pot is empty where is the lead you are going to melt stored? Is it stored in another pot in a molten form? If so you must have one hell of an electric bill. No, your lead is stored just like everyone else's is, on the floor in the garage or something similar. So you now have to heat that lead up,............... again. Plus you are doing it in a pot where only small parts of the ingots are actually touching the hottest parts of the pot that are able to melt the lead. So nothing is melting but the edges and the bottoms of the ingots that are in the liquid melted on the bottom. THIS is called MELTING the lead, a second time. Same as if it were kept in the pot. But that stuff kept in the pot would be done in a much more efficient way.

The OP stated that he refilled his casting pot after casting to keep the dirt and bugs out. That assumes he melts the alloy he refills the pot with. Ingots in the pot won't keep the dirt and bugs out. He turns it off for storage until the next casting session. He heats the alloy till liquid to start the next casting session. I believe that qualifies as "heating the same lead twice".

I do leave about an inch of lead in the pot to aid in melting ingots next casting session. It gets heated twice in the pot. Even if I take it out, it still gets heated twice. That's about 2-3 lbs of alloy instead of 17-18 lbs if full.

A full pot is a bunch of trouble to deal with if the element decides not to work OR you discover the bullets from your last casting session ain't working and you need to change your alloy. You not only have a bunch of bullets that don't work but not you have a pot full of alloy that you got to get out. Let's say you only need to change it a little. If your looking for repeatable results, how do you know exactly how much alloy you have in the pot?

I've got 4 different pots for my 4 most common alloys I cast. I leave a inch of alloy in each when finished. I got 1 more pot for slugging, lapping, or testing different alloys. If I didn't have all these pots (I started that way like everyone else) I would and did empty the pot. Not good for the pot. I had one element burn out and 2 spouts give out.

[45DUDE]

I have a mold and know what weight it is supposed to drop. I mix accordingly until it drops what I need and leave full. The molds I do both ways. If I sell a mold that is full I can post what size it drops and the weight without having to fire the pot up.