Found at the local junk shop

[curious aardvark]

those are great little duct units.
Work a treat. You can pick the fans up for a couple of bucks. https://www.amazon.com/uxcell-Cutter...s=24v+40mm+fan
Just remember you need a 24volt fan not 12 volt.

[Torby]

I thought I was going to be stuck for a week with a negative balance. That didn't happen (yet). Have one coming.

[Torby]

Fan arrived yesterday. I seem to have an extra fan connection on my makerbot "Mighty Board" revision E. I'd need to find how to turn it on and off using Makerware, or perhaps just leave it run?