Defrost Fan
I used a 40mm square (approx. 1 1/2" fan opening) computer type fan,
some
internally tapered PVC pipe for a reducer, and a 1 1/4" aluminum
flange.
The scat tube screws on over the small rivets and a tie wrap will
keep
everything in place. We shall see if this will actually
defrost.
With this setup either ambient or warm air can be used
depending on the position of the heater control.