Plugging of Lee bottom fill pot

[RonC]

I am new to casting. I have read and actually understand most of the Lyman Casting Handbook. I have recently acquired the 4# Lee bottom fill pot. Here are my questions.

1) I am having trouble with it leaking. I have tried twisting the valve back and forth with a screwdriver but still seem to get some seepage.

2) The pot pour has become sluggish. I have poured the pot out into molds. The bottom has a shiny residue like molten solder but the area around the valve is grainy. Is this dirty lead, a temp problem or something else.

I am using a mixture of wheel weight lead and spent bullets from a range backstop. I have melted the range lead and removed the cladding and skimmed the dirt using the RCBS cast iron lead pot and then cast into 1# ingots. I use candle wax for fluxing, stirred in with a small metal spoon..

3) One of my problems is I don't know what the lead is supposed to look like after fluxing. I cannot tell if I am skimming dirt or oxide. I can gather the scum into a small area and scoop it out with a spoon. It is granular and looks mossy. But is this lead oxide or dirt?

[docone31]

It sounds like the pot has some zinc in the melt. I ran into my pot dribbling, then slowing down. I had melted in some zinc wheel weights.
I melt my alloy, then turn it down to let the zinc float to the top. I then skim it out.
How did the zinc get in there?
Wheel weights, some of them are zinc. Range lead, some of it has zinc. If you are like me, I melted everything first. I enjoyed watching it melt. Only after did I realize it has zinc, and later I realized it was not a good choice per/se.
I do have zinc in my melt. I have found a combination that works for me. I also crank up my pot. Once in a while I have to unplug my spout with a paper clip.
You could put a small pair of Vise Grips on the valve handle. The extra weight helps with the drip although my pot has never dripped.
If you stir with a wooden dowel, it also helps the alloy. The wood turns into carbon which absorbs oxygen. Oxygen makes the oxided we scoop out. I use Kitty Litter and just leave it on top. Eventually it turns into powder. Then I scoop it out by letting the pot cool and just turning it on its side and brushing it off. What is left I leave there.
I have found, if you scrape all the dross, more is made to fill the vacancy.
You will get the hang of it. Hang in there.

[Namerifrats]

My Lee pot has never dripped either. My question is this, do you "pre smelt" you lead into ingots and then melt the ingot in your pot? Or do you put wheel weights straight into the pot?

[higgins]

My old Lee pot leaks a bit after casting for a while. I too keep a bent paper clip handy and occasionally will open the valve and stick the paper clip in from the bottom to dislodge the crud that builds around the entrance of the valve where the stem seats; the lead will flush it out. It makes a bit of a mess, but it cleans out the spout. I usually leave some alloy in the pot between casting sessions to speed up the next melt, but occasionally pour it out of the top of pot into an ingot mold and give the interior of the pot a cleaning. You'll be surprised how much crud builds up inside the pot, even if you use clean ingots.

Range dirt will look like dust instead of moss, and it won't clump. I always first smelt my wheelweights and range lead in a small iron skillet on a Coleman stove and pour into ingots for later use in the lead pot.

[Gohon]

I think you have a 10# pot. At least that's what I thought was the smallest bottom pour pot Lee makes. I could be wrong............Anyway, with the 20# pot I have if the temp drops low my pot will not pour at all. Seems the lead is colder at the bottom than the top. Once I get the temperature back above the 600 degree mark all is fine. Mine will occasionally drip but a few turns of the valve stem stops it. I go to the paint section of Walmart and grab a hand full of those paint stir sticks that are free and that is what I stir my pot with. When you are through casting leave a 1/8 or 1/4 inch lead in the bottom of the pot. That will keep put the crud and dirt. I finally gave up on trying to keep rust out of the pot. Now I just fire it up, flux real good and dip out the crud.

[RonC]

Thanks for the advice, all.

I bought the wheelweight lead off eBay a while back. It is cast in 2# ingots in a muffin tin. I have no idea what the alloy might be. It was sold as suitable for bullet casting.

All the smelting I have done is initially melted in the RCBS cast iron pot on a Coleman stove. This lead is cast in the 1# sections of a Lee aluminum mold. I am thinking of remelting the backstop lead ingots and recasting the ingots. Pouring out of the RCBS pot is kinda like bottom pour, the scum stays in the pot on top of the melt while the melt pours out from under.

I may have made a mistake the first time out by draining the melt in the Lee pot too low, almost dry, exposing the valve. Should probably leave a bit of lead in the bottom.

I have been stirring with a metal spoon. I will switch to the wooden stick, next time.

Again thanks for the advice and encouragement.