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Posted

I found 3kg of lead sheeting under the house and tonight I decided to cast it into small ingots. After melting it down and removing the crud with a spoon it had taken on a blue / green tinge.

 

I then poured it into small muffin moulds and to my horror this is what fell out 10 minutes later:

 

http://img526.imageshack.us/img526/4876/img0001gn7.jpg

 

Note the good ones to the right, they were from a diffrent batch.

 

http://img105.imageshack.us/img105/4142/img0005wf7.jpg

 

I have had a few look a bit like this but they only small divots and a few had a yellow tinge which is normal if you overheat the lead.

 

Any ideas?

Posted

Something tells me those sheets weren't pure lead.

 

The color change is a clue, but I don't know where it leads....

 

It almost looks like water bubbles formed during casting, but that would have produced explosive amounts of steam.

 

A chemist will chime in here, I'm sure.

 

M

Posted
Just define for me the word "Lead sheeting"... ANd then I would be able to bet taht te color is due to the Lead/Antimony mix (lost the wright word)... But the bubbles
Posted
I've never seen anything that extreme, but smaller dimples and divots can come from lead not being hot enough when it is cast. Might want to try a flux next time. Honestly I have no idea what happened there.
Posted
Your muffin tins didn't happen to be coated with anything did they?
Posted

Tell, me were your muffin moulds in Aluminium?

 

EDIT: Was the inside of the moulds attacked by the lead?

Posted
The lead probably contains tin, because of the blue. The bubbles could have been created by something like moisture or grease evaporating in the molds.
Posted
Moulds were clean and had been used fine for about 50 times prior.
Posted
That still doesn't explain the extreme dimpling though.
Posted
Looking around at some casting sites hey think it may be caused by gas dissolved in the molten lead. I don't really know what to make of it though.
Posted
Lead sheeting/flashing is normally "dead soft" or pure (99%+ anyway) lead. I have a piece about 1/8" thick x 18 x18 and I can crumple the whole sheet in my hands and then pull it flat again.
Posted
I cant see the pics but the dimpals might have been from boiling the lead. It cooled with air pockets in it. Had it happen the other day.
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