Easily removable two part 4" (100mm) vertical K40 exhaust - port and duct with optional gasket
I've included a version of the duct with manually added support which saves on time and material
The optional gasket is 1mm thick and fits both between the port and the K40 chassis and between the port and the duct - use two if you'd like. OR you could just trace out a paper gasket or some other material.
I drew inspiration from these designs: https://www.thingiverse.com/thing:3460670, https://www.thingiverse.com/thing:1627210, https://www.thingiverse.com/thing:2748726
Credit to those designers.
Print standing up from the base.
I printed with 5 perimeters and 5% infill - pro tip: use more perimeters for more strength, infill does very little.
Remove the original fan port. Add two M3 bolts from the inside out and fasten with hex nuts - line the hex nuts pointing horizontally. Add gasket. Slip the port in from the back. Add gasket. Attach the duct and fasten with hex nuts. (See pictures)
The author hasn't provided the model origin yet.