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Mystery Metal
- Thread starter Hardcase
- Start date
...Another melt test, is to take a sample know lead piece and unknow alloy and lay them in the bottom of a flat pan and slowly bring it up to temp. In most cases, the lead will melt before the alloy..
A lead/tin alloy will ALWAYS melt before pure lead. It's the main reason tin is alloyed with lead for bullets, it lowers the melting temp. It also increases the fluidity of the lead, causing it to form those intricate corners of the lube grooves and sharp corners at the base. The addition of antimony is to harden the alloy.
Black powder shooters find they have to run at much higher temps to get well-formed round balls and conicals when making them of pure lead.
Sparks1957
New member
Ductility and malleability are not always coextensive – for instance, while gold is both ductile and malleable, lead is only malleable
^ +1
I've always understood them to be two different things, both due to similar reasons in the metallic bonds.
I would challenge the statement that lead is not ductile. When it is drawn into wire (stretched), the wire has not lost any material strength.Ductility and malleability are not always coextensive – for instance, while gold is both ductile and malleable, lead is only malleable.
Rich, Jack C. (1988). The Materials and Methods of Sculpture. Courier Dover Publications. p. 129. ISBN 0-486-25742-8.
malleable (ml--bl)
Capable of great deformation without breaking, when subject to compressive stress.
http://www.thefreedictionary.com/malleable
ductile (dktl)
1. Easily stretched without breaking or lowering in material strength.
http://www.thefreedictionary.com/ductile
Nevertheless, I will concede that INTERNET searchers show results that support opposing views.
It thuds, it cuts and, as it turns out, it does melt, eventually. It's definitely lead. It just takes a bit longer to melt that the usual stick on wheelweights.
My assumption is that it's almost pure lead, so it needs a higher temperature to melt. My smelting pot just makes it to a bit below 650 degrees, which is right on the hairy edge for pure lead.
My assumption is that it's almost pure lead, so it needs a higher temperature to melt. My smelting pot just makes it to a bit below 650 degrees, which is right on the hairy edge for pure lead.
Usually "pure" lead develops a dull grey oxide when exposed to the elements. The metal in the OP seems to look too bright to be lead that has been used as a wheel weight.
It's probably hard to tell in the photo, but it's got some kind of protective coating on it, probably just paint.