I purchased several 10lb bars of plumbing lead from a hardware store probably in the early 1990s. It's still available in this form so far as I know.
I asked Jim Zimmerman to use a cold chisel to chop off a lump of one of the bars and pound it into a nice primitive-looking lump. (Sawing it off would have generated poisonous lead dust.)
Source: Hardware Store
Contributor: Theodore Gray
Acquired: 15 April, 2002