Morris Dovey wrote:

I'm planning to get a half-gallon of NH barber pole spiral lacquer for
the barrel itself, and a quart of star-spangled blue for the top. I
did give serious consideration to pukey-duck yellow and woodworkers'
burple, but decided those colors would seem overly pretentious in my
rather plebeian shop. The interior of the barrel and underside of the
lid should probably be painted BH black so as to absorb as much as
possible of the radiation from dust explosions...


Great idea but why not dispense with the fancy colors and go with "flat
black?" That way you could park the barrel outside the shop on the wall
with the southern exposure and plumb it through the wall, using the
barrel as a solar collector? With your DC and filter back inside the
shop you could be re-heating all that air instead of just moving it
around. g