Summary

Since my printer is inside I wanted to use the port on the back of the printer cover to extract fumes and expel them outside. The cheapest duct I could find was a standard vacuum cleaner hose, cost around us$ 4. It needs to be flexible so the print cover can be lifted easily with the duct attached. This design is for a 35mm OD hose tip, with clips as per the photos. It can be printed with no support and will print cleanly. 20% infill. I used PETG.

I intend to create an adapter for the other end which will house a small brushless fan to keep the flow moving.

The attachment screws align with the holes on the printer cover. They are designed to take a 3mm-4mm helicoil. Keep in mind that m4 specifies 0.7mm thread pitch, m3 specifies 0.5mm thread pitch. The holes are 'tapped' at 4mm / 0.5mm thread pitch. The helicoils should be glued in place. I tested this and it works well.