Coloured ingots?

[Nardoo]

I just got through melting 90lbs of old lead flashing into ingots. Some lots came out nice and silver whilst other smelts have a distinct blue or purple tinge. And one lot came out with a golden hue.

What is going on here? Impurities, temperature problems, contamination? I do not remember this happening before.

http://i131.photobucket.com/albums/p317/nardoo/100_2249.jpg

Nardoo

[floodgate]

nardoo:

TOTALLY NORMAL for good, acceptably pure lead. What you are seeing is optical interference from an oxide film of approximately one wavelength of light of the color in question, of the order of 4 to 5 ten thousandths of a millimeter.

floodgate

[Nardoo]

Floodgate,

Thankyou. I have just cast up about 20 lbs of the lead without any problems. Perhaps my new glasses are allowing me to see what has always been there!

Nardoo

[jameslovesjammie]

This is really cool!

I'm new to casting and find things like this fascinating!