Originally Posted by
kevin c
Thanks banger, for the link to the Wikipedia entry on white metal. What I get from it is that suspected white metal may be fine for our purposes (lead, antimony, tin) or not (cadmium, zinc) and that at least the example they provide can melt close to tin/pewter's melting point. I didn't get a clear sense of hardness or bendability, but my sense is that some pewter can be fairly hard and difficult to mark. Seems to me that such alloy would more likely be in those hard wearing parts you describe. If thicker, with more metal present for the sake of strength, such a bit of pewter like a solid leg on a tray might not respond to a small flame very well (my experience matches your comments - it took something like fifteen to twenty seconds of steady point application of a wide open propane torch to start melting the edge of a thick three pound pewter plate that was later confirmed by BNE analysis). It might be a problem trying to see if it will melt in proven pewter, though may be not if the mass of the test sample is low.
I may resort to using dikes on suspicious parts: if it is as hard as zinc, I will treat it as such, even if it is on a touch marked piece.
A question to you, banger, and to roger dat: of the marked pewter you've processed, what proportion actually had zinc parts or anything else that messed up your pewter melt or the alloy made from it later?