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.