the lead turned blue

[MDman]

So I was smelting the old wheel weights and everything was going normal, then after I had skimmed off the metal clips the top of the liquid lead went from silver, to gold to blue to purple. I assumed it was some sort of crud in the lead floating up. but no matter how many times I skimmed the stuff off it kept changing colors on me. I dumped this batch as I fear there is something wrong with it.

any idea as to what is going on?

[Ricochet]

Bismuth in it, perhaps.

[floodgate]

MDman:

This question has been coming up at least once a week for the past month. What you are seeing is "interference colors" from a very thin (approximately one wavelength) film of oxide on the lead, allee-samee an oil film on water; generally indicative of relatively pure lead. Pefectly normal, and nothing to worry about.

floodgate

[SharpsShooter]

Absolutely normal coloration and as floodgate said it is indicative of purity. It is good to go for casting.

SS

[44man]

It is normal and comes from the increase in temperature as your lead got hotter. Oxides form faster. Better go get the lead back in the pot and make ingots. [smilie=1:

[crowbeaner]

I get the same purple color when I use used linotype, and all this time I thought it was from the cheap ink from India! WHEW! I thought the purple was cool. CB.

[MDman]

well thats a relief...thanks all!

[charger 1]

Absolutely normal coloration and as floodgate said it is indicative of purity. It is good to go for casting.

SS

Ya I got sick of trying to git rid of it so decided to pour with it and it was perfect

[Ricochet]

Even if it is bismuth (which I think is a good possibility), that's not a bad thing to have in your alloy. Hardens it.

[georgeld]

Turn the heat down some should keep it silver.