A mounting bracket for a 40mm fan with integral duct that directs cooling airflow towards the extruder tip of a Printrbot 3d printer.
I have a Printrbot LC Plus. This bracket inserts between the extruder and the extruder carriage. The fan is a 40x40x10mm dc fan. You will want a 12v fan to use with the Printrboard that comes with the Printrbot. RadioShack sells the fan, or you can find it at Amazon, DigiKey, Mouser, Fry's, etc. The Printrboard uses a two-wire fan.
There are alignment studs on the bracket for the fan screw holes. I tacked it on with CA glue then ran a bead of RTV silicone around the periphery to make sure there was no bleed air out the sides. Make sure you have the polarity correct when you connect it to the Printrboard. You can easily check to see if the fan is turning the right direction by placing a post-it note to the fan. It it sticks, the fan is blowing the right direction. I find it hard to tell by feeling it with so little airflow.