help me with dirty lead

[Indiana shooter]

Last Thursday a coworker gave me a bucket full of range scrap that he picked up wile rebuilding his berms on his personal range. I took the scrap home, washed it off and set it out to dry. Yesterday I smelted it down on a propane stove, carefully removed the jackets and other large debris. I then added a bit of paraffin and mixed the pot to reintroduce the tin. After doing this I added a handful of pine shaving waited for it to turn black and mixed the pot again carefully focusing on the bottom and sides of the pot.I repeated this 3 times. Then poured my ingots.

Last night I tried my new lee bottom pour (surprisingly it didn't drip). I added my lead and tin, a pinch of paraffin and a hand full of pine, and went to town. When I noticed the pot getting low I scraped off the surface of the lead and there was what appeared to be dirt on the surface, lots of it. I looked at my boolits and had to reject over half of them due to pitting.

Where did I go wrong?

[Tatume]

Is there a lumber yard near you? If so, ask them to let you wander around a collect sap drippings. The sap that forms rivulets on pine lumber is the best flux for dirty lead that I've ever used. Use it generously when smelting.

[btroj]

When you added the pine sawdust to the casting pot did you force it below the surface of the melt? If so then you are seeing bits of ash. Get the pot melted and stir it well. Then scrap the sides of the pot with a metal spoon from bottom to top. You want to help get all the debris to the surface. Flux well again but don't force the stuff beneath the surface. Spoon the lead from bottom to top and pour it thru the flux. Stir really well again and skim.

When you melt range scrap skim the jackets and most of the debris. Then stir vigorously. Flux a couple times. Scraps the sides and bottom of the pot. Again, the purpose is to get debris held below the surface to the top where they can be removed.

[bhn22]

And after fluxing the second time or so, go in the house and take a break. Drink a Coke or whatever. The break will give some of the trash a little time to float to the surface, where it can be removed.

[runfiverun]

it takes a little time for all the dirt to ride the heat currents out of the alloy.
if I run ww's that are grungy or even rinsed off range scrap I have to work it over a couple of times at a higher heat level to get everything to float out.

I will even re-melt all of the years worth of alloy and blend it together to get a big batch of one, and it will get another cleaning or two in that process.

it seems a bit excessive to many but I have my reasons for doing it that way, plus I hate fluxing in my shop where I cast.

[Indiana shooter]

Okay, it sounds like I should have waited a bit after fluxing and be careful not to force the carbon down in my pot. How long should I wait? Flux once wait 10 min flux again wait 20 min or what?

[pls1911]

There's a continuous process when it comes to "clean enough" lead... you're never really finished.

Lots of things work pretty well for flux when smelting, event the roof flashing with tar and paint and mastic in the roof flashing I melt, but ashes -to-ashes, it cleans up pretty easily, but stinks. (The first pass with that is an outside job for certain!)

After cleaning well in the initial smelting, and alloying with lino, babbit, tin or what ever in 200 pound lots, I cast into ingots.
Also Iflux and clean again periodically while casting.

[RogerDat]

Awhile back someone on the forum suggested a slotted spoon with the tip ground flat so it can better scrape the bottom and get into the bottom corners. I find that works pretty well but have not smelted anything dirtier than WW's to test it with. Does seem to work well for that.

[runfiverun]

10 minutes is enough then a reduction of the oxides that form on top will get a bit more gunk.
I try to cherry pick the center of the pot and not stir up the bottom or sides when pulling alloy from the pot.
Work everything down gently and clean and scrape again when you start to see the dirt and carbon start to gather on top again.
The whole point of smelting everything down is to get the cleanest alloy you can, take your time and keep cleaning as you go.
It pays off in the casting pot and in your finished boolits.