Brent Hilpert wrote:
Weren't drums and early disks done with
nickel or some-such plating, rather
than binder & oxide?
Nickel plating would definitely not work. Some of the earliest drums
used cunife (copper/nickel/iron alloy) wire tightly wound around an
aluminum cylinder, then turned on a lathe to get a flat surface. Some
drums included magnesium, cobalt, or other metals in the alloy. Later
drums used various coating methods rather than wire.