From the Loftsmith Workshop
Radiator booster fan duct for PC fans (Type 21/22/33)
Gives a panel radiator some help pushing its warmth into the room. Two PC fans sit on small footed mounts under a long slotted duct that spreads their air along the bottom edge. Set the radiator length and depth to match yours.
2 parts · 117 g · 131 × 128 × 33 mm
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No adjustable sizes
Ask for the sizes you want to tweak, e.g. “make the width adjustable”.
How to print it
Parts
- fan-duct ×2 · PETG · Flange down on the bed, as modelled; no supports
Quantity follows the Radiator length slider: one module per 50 cm, rounded, 1 to 3 (2 at the default 1000 mm). At the defaults each module is 130.5 × 128 × 32.5 mm, about 58 g and 81 min at 2 walls and 15% infill. PETG suits radiators that stay under about 65 °C. Print in ASA or ABS for hotter radia
Print settings
- Layer height
- 0.2 mm
- Walls
- 2
- Infill
- 15%
- Supports
- None
- Notes
- Default figures from the build report: about 58 g and 81 min per module, so about 120 g and 2 h 47 min for the two modules at the default 1000 mm radiator length. If you want a stiffer top lip, 3 walls / 15% gives about 158 g and 3 h 39 min for both. Use PETG for radiators that stay under about 65 °
Hardware
- 2 × PC case fan, 25 mm thick (80, 92 or 120 mm to match the Fan size choice) · One per module. Use low-voltage fans only: 5 V USB fans, or 12 V fans on a plug-in adapter.
- 8 × Neodymium disc magnet 10 × 3 mm · 4 per module. Glue them flush in the top pockets.
- 8 × Self-tapping case-fan screw (the kind supplied with fans) · 4 per module. They pass through 5.3 mm holes in the 2.7 mm flange seat and thread into the fan's corner holes.
- Epoxy or cyanoacrylate glue · Holds the magnets in their pockets. The module's weight pulls on this glue joint.
Assembly
- Measure your radiator and set the sliders. Depth is front face to back face. Panel thickness is the flat bottom edge of the front panel. Also measure the length, and the height from the floor to the radiator's underside.
- Print the modules flange-down with no supports.
- Glue four 10 × 3 mm magnets into the four top pockets of each module, flush with the top face, and let the glue cure fully.
- Hold the fan under the flange with its airflow arrow pointing up into the duct. Drive the four fan screws down through the corner access holes into the fan.
- Run each fan lead along the back of the fan, then to a USB or 12 V supply at the end of the radiator. Do not use mains wiring.
- Lift each module under the radiator so that the magnet rails touch the bottom edges of the front and back panels and the slot sits in the gap between them. Keep the modules spaced evenly and away from the valves. To remove a module, pull it straight down.
Good to know
- The magnet hold has not been tested. The check assumes each 10 × 3 mm magnet keeps at least 4 N on painted panel steel, and needs 1.57 N per magnet at the defaults with a 2x bump factor. Test the hold on your radiator before leaving it running.
- The magnets need flat steel under them: at least an 11 mm wide bottom edge on the front and back panels. Rounded or seamed panel bottoms will hold less.
- Designed for double and triple panel radiators (Types 21, 22 and 33, 64 to 160 mm deep). It does not fit single-panel Types 10 and 11, and it is not for electric, oil-filled or storage heaters.
- PETG softens near 75 °C. Use it only where the radiator stays under about 65 °C, and print in ASA or ABS for hotter systems.
- Low-voltage fans only (5 V USB or a 12 V plug-in adapter). Keep leads away from the valves and pipes.
- The fan flange is wider than shallow radiators. With a 120 mm fan under a 100 mm deep radiator, it sticks out 14 mm at the front and 14 mm at the back, so check the space between the radiator and the wall.
- No energy-saving claim is made. The fans move more warm air off the radiator, but they do not lower bills by themselves.
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