View Full Version : the lead turned blue
MDman
10-08-2007, 09:32 PM
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
10-08-2007, 09:38 PM
Bismuth in it, perhaps.
floodgate
10-08-2007, 09:51 PM
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
10-09-2007, 07:21 AM
Absolutely normal coloration and as floodgate said it is indicative of purity. It is good to go for casting.
SS
44man
10-09-2007, 08:22 AM
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
10-09-2007, 09:25 PM
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
10-09-2007, 10:30 PM
well thats a relief...thanks all!
charger 1
10-10-2007, 06:07 AM
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
10-10-2007, 08:48 AM
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
10-14-2007, 04:11 AM
Turn the heat down some should keep it silver.
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