45 deg. air guide / fan duct for 30 and 40mm fan

this was designed because the hotend's fan sucked in hot air from the print surface and kept cooling the printbed too much. Fits on E3D V6 30mm Fan.
yet, I used some tape to guide the airflow, but it looks much more professional this way :)

note: all angles off the Z-axis are max. 45° to keep it printable. the wall thickness of this part is 0.8mm to get a good print with two perimeters out of my 0.4 nozzle. Let me know if you need a thinner/thicker wall.

*Update 18 Okt. 2015: Added a ne