Lead Questions

[dave951]

One other factoid- the type of bullet and mold will also have differing operating temps. If you cast minie balls, best results are often had running the pot as hot as it will go while round balls are fine at about 750.

For a lead pot thermometer, I did some research and found that probe thermometers designed for BBQ grills operate in the same range (300ish-1200) and cost half as much as one advertised for casting. My guess is they're made by the same folks, they look the same and have the same temp range.

 

[MaterielGeneral]

Sounds to me like the lead scum you are getting is actually lead oxidizing. The hotter you run your pot, the more and faster it will form so try to keep your pot as hot as you need without over heating it.

Maybe your lead is too hot (it seems that is so), the theory say that the lead bath is at 700°F and the mould at 400°F. Of course, without a thermometer and regulator it is very difficult to remain constant. However if you have an electric crucible you should be able to see how to do this by keeping your molten lead on the number that give te best result and by presenting the mold regularly under the casting, not too fast and not too slow. It can be learned quickly with a few lead casts ...
It also depends on the material of your mould which can be either aluminium or steel and in this case (with steel) you will have to stay at the beginning of the casting for ~3 seconds with the bullet in the mould so that it rises well in temperature then, when your bullets will be beautiful, you will have to unmould more quickly but regularly...
For the right temperature of the melt bath nothing is better than a small thermometer to stay around 700F and have lead without oxides...
The best when you are making a big lead cast is the Lyman M25 (temperature is really regulated) but it is too expensive if you only cast balls by little quantity ans I don't know the good position number for a Big Dipper model with a manual lead dipper...
I have a Lee furnace (LEE PRO 4 20LB 220V) modified to receive an electronic regulator like on the M25. The regulator and the captor are coming from Ali Express, very low cost but works well and it stay at 700°F...

Othe thing that can help is to put crushed charcoal or sawdust over the lead bath: this reduces contact with the oxygen in the air and reduces oxidation...

Heat was most defiantly part of my problem. I had it way to high. I have it turned down to half way and I am getting excellent results now. I still have to experiment a little. But thanks to all of you guys for your help.