Prusa MK4 Bi-Directional Fan Duct
Prusa MK4 / MK4S · part-cooling duct · print in PETG or better
The MK4’s stock part-cooling blows from one side, and overhangs on the other side know it. KyleTW’s duct wraps the nozzle and cools from both directions — the fix Prusa itself later adopted in spirit on the MK4S.
Rated 4.9 by the people who printed it, and it survives because the geometry is right: even cooling, no melted droop near the hotend, PETG or better. If your MK4’s overhangs curl on one side only, you already know why you’re here.
License as published on Printables: Creative Commons Attribution (CC BY). Objectibles never hosts model files — the button takes you to the designer’s own page, where the files and the latest version live. Entry checked against the designer’s page on Nov 9, 2026.
