Tinsil fairy visit

[mooman76]

I decided today was a good day to cast being cold and windy outside. Doing it in the garage where is colder than my house but being Vegas, not really that cold, about 45 degrees. I was getting low enough in the pot I could add some lead and had a diving weight that has been sitting on my bench for at least 6 months and I have had it a few years. It was absolutely dry so I'm thinking the temp difference caused it or maybe a large air bubble inside. I slowly put it in, putting the corner in first for a few seconds and then let it drop the rest of the way in. My pot started bubbling like it was boiling and I knew right off I was in trouble so I started backing away and then it happened. Exploded all over my work bench. I only got a few specs on my clothes but about ten# of lead all over my bench and some on the floor. Spent about an hour cleaning up. Most came up easy but the stuff that stuck to plastic and cloth near the bench are abit harder to clean up. I also stand on a foam mat and it won't come off it without destroying it so it will stay. Keep your guard up!

[Bonz]

It happens so fast there is just no way to stop it. I admit not wearing the correct personal protective stuff on (most of the time) while casting bullets or cores and I'm sure that I will regret that one day. I really need to buy some welding sleeves and a heavy apron because I cast while seated.

[bangerjim]

Always......Always.......ALWAYS.....preheat your feed ingots (and molds!) to FULL casting temperature ( not just warm). Saves tons of time and will prevent that extreme temp differential boil you just say.

It was NOT moisture. It was the extreme temp differential between the 45F lead hunk and your 750ish pot.

I have seen that B4 I started preheating. And that feed lead was AZ desert dry!.

Heat using the hotplate and you will be safe and good to go.

banger

[pretzelxx]

Holy crud sticks. I was about to start casting with winter weather. Lesson learned. Never take shortcuts.

[Eddie17]

Just came in from casting. bangerjim is spot on! Do not drop a large alloy block into the mix.
Emptied my Lee 20LB twice, Go slow when you resupply the pot!

[mooman76]

Always......Always.......ALWAYS.....preheat your feed ingots (and molds!) to FULL casting temperature ( not just warm). Saves tons of time and will prevent that extreme temp differential boil you just say.

It was NOT moisture. It was the extreme temp differential between the 45F lead hunk and your 750ish pot.

I have seen that B4 I started preheating. And that feed lead was AZ desert dry!.

Heat using the hotplate and you will be safe and good to go.

banger

I put the lead under the pot to preheat it some but must admit, I didn't leave it there long. I usually use 1# or less ingots and haven't had a problem but this chunk was like 2-3#. Live and learn. I'm just glad I had enough warning to step back before it happened.

[rbuck351]

Your talking diving weight, like one that has been deep enough in water to pressure force water into very tiny voids in the lead. Lead does not boil anywhere near casting temps. I don't recall the expansion ratio of water to steam but it's a bunch. I have dumped below freezing (32 degrees) lead into melted lead without so much as a bubble. ANY moisture on or in voids in the lead will get you a visit from the tinsel fairy. Diving weights are really asking for it if not pre heated. Really glad you weren't hurt. I have a bunch of diving weights that will be boolits someday. Thanks for the reminder to be extra careful with these. Sometimes I get in to big a hurry and the diving weight thing would be easy to overlook.

[skeettx]

I use two pots, both full to start. empty one(not totally so you have a heat sink), and turn it off, wait a bit and then fill it with ingots, now turn it back on.
While it is heating work on the other pot, and when it is empty the first one will be ready to use.
Continue procedure.

[ShooterAZ]

I will NOT melt diving weights ever again for this very same reason. Water gets trapped in voids or something. I had some blow the lid off of a cast iron dutch oven once. Thankfully I was nowhere near it when it happened. It made a heck of a mess, but it would have been a lot worse if I didn't have the lid on it. Not only that...but I have encountered some diving weights that were zinc contaminated. No more dive weights for me!

[mooman76]

Your talking diving weight, like one that has been deep enough in water to pressure force water into very tiny voids in the lead. Lead does not boil anywhere near casting temps. I don't recall the expansion ratio of water to steam but it's a bunch. I have dumped below freezing (32 degrees) lead into melted lead without so much as a bubble. ANY moisture on or in voids in the lead will get you a visit from the tinsel fairy. Diving weights are really asking for it if not pre heated. Really glad you weren't hurt. I have a bunch of diving weights that will be boolits someday. Thanks for the reminder to be extra careful with these. Sometimes I get in to big a hurry and the diving weight thing would be easy to overlook.

I know it wasn't boiling, I was just describing what it looked like. If I have questionable lead I will sit it on the pot before turning it on that way it heats up slower and has time to burn off anything like moisture. I did not know this about diving weights or I would have either not bothered with it or heated it slowly. I have plenty of ingots but thought I would just use it up.

[Down South]

I really hate it when that happens. Seems to have happened to most of us at one time or another.
Best route to take is to melt all of your lead starting in a cold pot and pour into ingots. Preheat the ingots before dropping them into the casting pot. I don't have any problems doing that.

[runfiverun]

I do like skeetx and use 2 pots.
one is warming and I'm pouring from the other once the first gets low I ladle the last few pounds of gunk into the other pot and start over again.
yes it is slower.
yes I got the scars to splain why.
I don't ever want a plop of lead to land on top of my head again, I need all the hair I got.

[Down South]

I will NOT melt diving weights ever again for this very same reason. Water gets trapped in voids or something. I had some blow the lid off of a cast iron dutch oven once. Thankfully I was nowhere near it when it happened. It made a heck of a mess, but it would have been a lot worse if I didn't have the lid on it. Not only that...but I have encountered some diving weights that were zinc contaminated. No more dive weights for me!

I don't know Jack about diving weights but I do know if I pile all of the scrap lead, diving weights or whatever into a cold pot then turn the heat on, I don't have any problems with a tinsel fairy. Well, not so far.
If the alloy is allowed to heat up from cold to melting temp the moisture escapes before the alloy is at high enough temp to cause a problem even though the moisture might be embedded.
Clean the alloy from starting with a cold pot, pour into ingots, keep em dry, preheat the ingots before dropping into the casting pot and happy casting.

[Beagle333]

Cold ingots will bubble and sputter like crazy. Of course moisture and air pockets are much worse, but a LOT of my muffin and RCBS ingots will bubble enough to be spooky if they aren't warmed really good before sliding them in.

[Mk42gunner]

Putting cold dry lead into a pot of melted lead will not cause the already hot lead to boil. That's like saying if you add ice to a 150 degree pot of water it will start to boil, just doesn't make sense.

If there is any moisture at all on or in the cold lead, you get the burbling of the tinsel fairy knocking on your door. I have heard the evil fairy start knocking a time or two with ingots that were stored inside, luckily I still had hold of them with the pliers and was able to pull the ingot out of the melt before she very bad things happened.

Too help prevent giving her an invite, I use a slightly modified BruceB ingot and heating style. My ingots are made from angle iron, anything from 1¼" to 2", from 8 to 10½" long; depending on what I have available when I made the molds. I preheat by laying them across the top of the meting pot, wither a Lee 4-20 or an RCBS Promelt.

As long as I leave them there long enough to thoroughly heat; and don't try to add one until there is room for it in the pot (don't ask),I have no problems.

Robert

[Beagle333]

Maybe it's just the air in the ingot expanding and coming out..... it's not like a steam explosion, but a cold one will bubble when introduced quickly into a 700°+ pot, sometimes violently, until it melts. I saw it again just today.... several times.
I'm sure it didn't reach the boiling point of lead, that isn't what I am describing.

[bangerjim]

The lead is NOT actually BOILING!!!!!!!! That is figuratively speaking. Why do so many on here take everything so literally? Sheeh. It is a thermal differential causing the molten lead to "move" around rapidly, causing a sometimes violent "boiling-like" effect. It does happen. Hear me now and believe me later.

Lead would have to be above 3,182F to actually vaporize and really come to an actual boil.

To avoid the potentially dangerous situation, pre-heat your feed ingots. Problem solved.

bangerjim

[triggerhappy243]

Once again, an excellent thread. and it has given me an idea to dry out potential moisture. I smelt and cast with a cast iron dutch oven. my idea is to lay a piece of expanded metal on top of the pot while smelting the first batch, lay out a pile of my wheel weights and other lead items on top of the expanded metal... pre heating them to dry out any hidden moisture. repeat with several piles for the next melt. why waste the heat?

[skeettx]

AND several pieces of expanded metal to make the change out easy and safe

[Tatume]

My ingots are stacked indoors on a concrete floor. The stack has been there several years. Concrete holds moisture. Yesterday I picked up some ingots from the top of the stack, about a foot above the floor. One of them had a black widow spider on the bottom. As you may know, black widows only live in very high humidity. This tells me that those ingots, a foot from the floor, are moist. And yes, if I add one to a pot of molten metal, they do bubble and boil. This is caused by moisture, not temperature difference.

I threw down the ingot immediately and didn't get bitten.