Blue blotches on lead ingots

[Fiftyfour]

I just melted a bunch of used lead flashing and the ingots have blue blotches which almost looks like the blue on case hardened steel.
I realize that flashing is not 100% pure. Does this blue indicate other metals?  It looks like the were lightly smudged with Prussian blue.
I did not think I over heated the lead. Fluxed with bees wax. There was mortar, tar and adheasive on the flashing.
Any ideas of what caused the blue to appear? Hoping to make round balls for a rifle withis lead.  Thanks.

[Tim Ault]

I see the blue and gold hues a lot when I'm melting pure or near pure lead I dont recall seeing it when it cools when making ingots ? I wouldn't worry about it though

[Pukka Bundook]

The higher the temp when melting, the more blue you will get.   If pouring lead and it turns blue, it's time to turn it down a bit.

[Cobweb]

You're correct Pukka. When I started my apprenticeship in the plumbers union it was all cast iron soil pipe put together with oakum and lead. I've melted tons of the stuff before the days of a hack saw and plastic pipe that made everyone a plumber!

The blue is a sign of overheating.

John

[hanshi]

Any colors on lead ingots are an indication you need to send the lead to me...pronto. 

[stubshaft]

Any colors on lead ingots are an indication you need to send the lead to me...pronto. 

I was thinking that any balls that were cast should be sent to me for quality control.  Wouldn't want blue lead to cause flyers.

[Iktomi]

Any colors on lead ingots are an indication you need to send the lead to me...pronto. 

I was thinking that any balls that were cast should be sent to me for quality control.  Wouldn't want blue lead to cause flyers.

 I think blue balls could be indicative of a much more serious problem

[Leatherbark]

A buddy of mine once remodeled an old church from back in the 1800's . It had lead window weight he gave me and I melted them down for balls and the lead had a blueish hue.  Guys on a Muzzleloading forum said it was pure virgin lead.

Bob

[smylee grouch]

I once got over 200 lbs. of the lead from the stained glass windows and those ingots had a bluish hue to them, I assume from the extra heat I used to burn off the impurity's .

[J.E. Moore]

 I use to work in a battery plant a few years ago as a cast on strap operator and had a huge lead pot on my machine, I'm guessing probably about the size of a 35 gallon tub. The bars or "pigs" we're around 75 lbs. They were marked with different color paint strips to note the hardness. Some were remelted lead from scrap and weren't marked. I've seen the blue color as well as gold and green, and sometimes a combination of all like gas on water. That pot ran into two manifolds that we're a higher temp than the lead pot itself and once it ran though the manifold it would sometimes change colors or be the sliver we're use to seeing. I always figured it was due to different temps as as well as a different alloy or a mixture of alloys. Main thing is have no cold pours and keep the drouse to a minimum to help with splash and hold some heat in the top. And don't over heat your mold. I don't believe the color will mean much.