Fan duct for airbrush compressor

Fan Duct for Airbrush Compressor – Custom Bolt‑Mounted Design

This fan duct is designed specifically for small airbrush compressors and mounts directly onto the four bolts surrounding the compressor’s piston housing. The duct is held securely in place by friction. The design keeps JH3D’s original press‑fit mounting concept and the idea of using offset tube heights to clear the compressor handle.

Everything else — the fan duct, the extended airflow vents, the centered and offset variants (tank / no‑tank), and the 7 mm / 8 mm bolt versions — is newly designed.

Four versions are available to match common compressor variations:

Tank version – 7 mm bolt mount

Tank version – 8 mm bolt mount

No‑tank version – 7 mm bolt mount

No‑tank version – 8 mm bolt mount

The tank versions use a centered duct, while the no‑tank versions use an offset duct to avoid the pressure regulator assembly.

All versions are tested on Fendga‑type compressors, with and without tank. These compressors are extremely common and sold under many different names, including AS‑186, AS‑189 (tank models) and AS‑18‑2 (no‑tank model).

Purpose

The duct channels airflow directly toward the compressor’s cooling fins and also down along the sides of the piston housing through the extended vent openings.

This helps reduce overall compressor temperature during longer airbrush sessions and cools the outgoing air. Cooler air reduces premature paint drying at the needle tip, helping to minimize dry tip, clogging, and inconsistent spray patterns.

This model is intended for active cooling while airbrushing, improving both compressor performance and paint behavior.

Fan Compatibility

• Fits 120 mm and 140 mm PC fans

• Standard fan thicknesses work well (typically 25 mm for 120 mm fans, 25–30 mm for 140 mm fans)

• Most PC fans include arrows on the side of the fan frame indicating airflow direction and rotation direction — use these to ensure correct mounting

• Fan attaches using standard PC fan screws

• If you don’t have fan screws, zip ties work perfectly well and are easy to thread through the fan frame

Mounting Instructions

1. Align the four mounting tubes with the bolts on the compressor’s piston housing.

2. Important: Mount the duct with the shortest tube facing the compressor body. The tubes are offset to clear the compressor handle, so correct orientation is required.

3. Press the duct straight down until it seats firmly.

4. Attach your fan to the front of the duct using screws or zip ties.

5. Ensure the fan blows toward the compressor (intake direction). Most PC fans have arrows on the side of the frame showing airflow and rotation — follow these markings.

The friction fit keeps the duct stable during operation. No tape, pads, or rubber spacers are needed.

Print Notes

This model is easy to print and works well with most standard slicer profiles.

• Supports:

  • Required under the center of the fan ring, which is completely flat

  • The angled duct walls are 52°, which normally print cleanly without support

  • Organic supports recommended for the cleanest removal

• Orientation:

  • Printing opening down gives the cleanest exterior surface and the most stable print This is the recommended orientation and the one tested.

  • Printing opening up is possible, but generally requires more support:

    • The shorter mounting tubes will need support due to the height offset

    • This orientation has not been tested, so results may vary

• Material:

  • PLA works perfectly fine

  • PETG recommended if your compressor runs warm during extended sessions

Compatibility

Compatible with common Fendga‑type airbrush compressors, including:

• AS‑186 (tank)

• AS‑189 (tank)

• AS‑18‑2 (no tank)

These compressors are widely sold under many different brand names.

Available in both 7 mm and 8 mm bolt‑mount versions to accommodate manufacturing variations.

If you have a different compressor model, feel free to ask — I may be able to help adapt the design if you can provide accurate measurements or reference photos.

Additional Notes

Active cooling can extend the compressor’s duty cycle and reduce heat buildup. Lowering the temperature of the outgoing air also helps prevent dry tip and clogging during airbrush work.

Feel free to remix the duct for other compressor models or mounting geometries. You’re also welcome to reach out if you need help adapting the design to fit your specific compressor.