Yesterday while casting some 40's & 45's I had something happen that I've never experienced in 45 years of making my own bullets.
My casting setup is the tail gate of my truck, I place a 1" thick piece of wood (18"X24" on the tail gate, place my lead furnace on one side & an old shirt on the right side of the pot to drop the bullets on & start making the little beauties.
We are in Arizona for the winter, the temp is high 60's & life is good but I did get a little surprise when adding more lead, actually linotype to the pot. I always wear glasses & heavy leather gloves, more than once over the years I've had a few little pop ups that can burn the skin if it isn't covered, nothing serious but molten alloy can be very dangerous.
Normally when my pot gets 2/3's empty I add the sprues back into the pot & then any additional metal that I need to get the pot full. I had a 2 lb ingot of linotype & I eased it into the molten alloy.....the linotype was dry & nothing visible on the surface. I usually hold my gloved hand over the pot for 2-3 seconds when adding any new metal, just in case something pops.
After removing my hand I walked over to my RV & opened up one of the storage doors to get something when I heard a loud pop, looking over at the pot 10 feet away there was quite a bit of lead that had popped out of the furnace, if I had been sitting there it would have been quite a stampede getting off that stool, there was probably 2 ounces of lead on the seat of the stool.
Some how I had gotten a steam explosion of some kind & was very fortunate that I didn't get burned. I've found from past experience that it takes a minimum of 3 laps around the house to get the burning to stop.....thats if I'm wearing my Steelers Croc's, if I'm wearing the regular green ones it takes 4 laps.
Just a heads up to everyone who casts, sooner or later you will get a pop off of lead & I've heard of some guys who have needed plastic surgery to repair the injuries....not good!

Dick

Sometimes impurities can get caught inside the ingots...... Whn we were little we used to melt wheel weights with acetylene torches and make "swords" I know not so safe, and we had that happen one time , I guess there was water or something in there and a big chunk of lead came flying out it burnt my budies jacket, but luckily no one was hurt.

sixshot I've cast for 40 years myself including 5 days this week. I've seen some strange things happen but its been years since anything got out of the pot on me. Not sure if it would have helped in your case but I always preheat my ingots. Still there are times I have a little "boiling" when an ingot is inserted. Glad you weren't hurt.

FWIW, I have taken ingots that were as dry as a preacher's kitchen, dropped them into a pot and had them bubble profusely... nothing has ever come out of the pot, but I have to believe there was some sort of impurity in the ingot that allowed moisture to collect.

Dick, thanks for the reminder to always protect ourselves. In my almost 35 years of casting, I have had a few incidents of getting splattered, but nothing of real concern. Thankful so far!!!

If you have an ingot that was cast with internal porosity the gas in the porosity can become pressurized when heated.

You can also have porosity that is what is called surface connected. Such porosity will have a worm hole out to the surface and can result in moisture being present inside the ingot.

Either way is not too good.