[R-390] Painting Knobs

[Dave Merrill]

Hi Barry,

Decades ago, I managed to track down a supplier who cast R-390 knobs. I
wanted to see if the still had the molds for the Mc/Kc knobs since they
were in short supply. The shaft tabs often broke due to the material used
and the high torque, especially the Mc knob.

After checking, they didn't have the molds anymore. The plant was being
shut down by the EPA due to pollution by zinc and other metals.

So I'm pretty sure the Mc/Kc knobs were cast from pot metal that included
zinc.

Dave N9ZC