This is an addition to my Folger Prusa i3 Dual Extruder Conversion. It is a mount for blower fans to cool the filament for both extruders. The fans are 50mm blower fans and the mount sits on top of the extruder motors.
Once printed M3 nuts need to be pressed into the holes on the back of the mount. The blower fans should be bolted onto the mount with M3 bolts, snugly, but loose enough to adjust the angle. The blower ducts should be attached to each fan. The mount should sit on top of the extruder motors. Last, a thin zip tie must be threaded through the slot on the bottom of the mount on one side and threaded back up through the slot on the other side. Then take another zip tie and slide it over the loose pointed end until you have secured the tie snugly against the motors. Finally, clip the 2 loose zip ties to an appropriate length.
Wiring the fans is still a bit up in the air. I am using a Fan Extender (http://www.geeetech.com/wiki/index.php/Reprap_Ramps1.4_RRD_Fan_Extender) to run both my extruder motor cooling fans and the filament blower fans wiring each set in parallel. But I have run into some power consumption issues that cause my print jobs to crash when both extruders and all 4 fans are running. I still have to work that out and will update this when I figure out the correct wiring configuration.