Popping lead during casting???

[Maximumbob54]

I’m working with second hand information on this issue but I can ask my cousin any questions you may need answers to on this issue. My question is about why would lead pop while in the pot during casting??? She isn’t letting it get too hot. She isn’t getting water into the melted lead. She adds an ingot and after a short time the lead has popped some and left splatter everywhere. Not fun. She says she is working with some kind of typesetting lead so I believe she is working with linotype. She says she smelts it into ingots and then adds the ingots to the melting pot as needed to keep the pot full. My best guess is she must be getting voids that are popping during the melt down. But she swears that can’t be happening as she is pouring them into the ingot mold. I also thought she may be adding cold ingots to hot lead but she says they are just room temp in a heated room so I don’t think that should be an issue. What are we missing here and how do we prevent this? Is there something I don’t know about linotype?

[Charlie Two Tracks]

First of all, I haven't been casting all that long. OK, some of the ingots that I have poured will have a less than perfect exterior to them. Water from the air can condense on them and if I put them in the casting pot, I can have it bubble or worse. I preheat the ingots and that eliminates any condensation problems. I smelted down 50 lbs of linotype and I with I would have left it as it was. It is easier to measure the correct amount needed when you are dealing with little type set than a big ingot. The typesetting lead I have tests out at BHN 33 and is way too hard and brittle for making boolits without mixing with WW or pure lead.

[shotman]

The lead is not clean. It wasnt fluxed and has ink or what ever in the mix . Would remelt the ingots and get temp up more LINO melts higher and if she is doing it on electric its not getting hot enough

[stubshaft]

Is her ladle large enough to fill the ingot mold in one pass or does she have to scoop some more to fill the mould? If she does take 2 or more ladles full to fill the ingot then there may be small voids in the ingots that through capillary action will draw moisture in. If possible preheat the ingots on a hot plate to over 212 deg. Then add into the pot. If the problems persists then there is some other form of contamination in the ingots.

[Dale53]

I have a dedicated casting station in my utility barn. It is not heated except when I cast (electric wall heater). Every thing in the barn picks up condensation (not really visible) from the quick temperature change. It can also pick up moisture from no heat in between sessions.

The only sure way to avoid popping and bubbling (sometimes serious enough to splash hot lead and burn the operator) is to simply pre-heat the ingots on a hot plate. There is NO problem with the first melt as it is gradually brought up to heat and the moisture is driven off without drama. However, drop a cold ingot in molten lead and you are guaranteeing that condensation will be created. The cold ingot is heavier than molten lead, will carry the moisture under the melt and created the problem. Not a good thing.

I have a hot plate next to my lead pot for pre-heating moulds. It also works beautifully for pre-heating lead ingots. Just be sure you don't overheat and melt them on top of the hot plate.

If you have a hotplate with open Calrod units, then place a cheap frying pan or piece of sheet metal on the burner to keep from melting the lead. I set my hotplate to "medium". It really doesn't take much heat to drive off the moisture. This also has the advantage of speeding up the melt when adding ingots to your pot. Handle hot ingots with care...

Dale53

[Maximumbob54]

She lives in the desert and while it is the snowy season I doubt there is that much humidity in her heated garage. She adds these ingots to pure lead and while I didn’t ask I’m sure she fluxed it. Perhaps not enough though. I will pass this all along. Thank you all.

[sargenv]

One thing I do to keep the level of the pot up is to prop twi corn muffin ingots onthe top of the casting pot.. when I cast about 50 bullets, the ingots have heated up enough to keep any condensation in check and in they go. I then prop two more on top, and the cycle continues..

[Duckiller]

She put water in the melt. The popping was the water turning to steam. Did a similar thing this afternoon. Turning weights into ingots and poured hot lead into an ingot mold that was evidently damp. Snap, crackle and pop and lead flying all over the place. No damage ,just exciting. If anyone has popping and flying lead you have water where it shouldn't be. Don't be in denial. Figure out where it came from and avoid it in the future.
While cooking this afternoon I place a cold ladle that had been stored outside in my melt. SNAP, CRACKLE, and POP. Everyone knows stainless steel doesn't absorb water, but there was enough moisture on the ladle to make noise. Nothing was visible.

[atr]

any bit of moisture, and I mean ANY bit, will pop and spatter....

[stubshaft]

Snap, crackle and pop, the tinsel fairies theme song...