This is an experimental auto syphon I designed, inspired largely by mrmattandmrchay’s YouTube video on auto syphons. I originally created this model a few years ago and decided to share it in case anyone would like to build and use it for their own projects. I have personally printed and tested it, and it functions successfully about 95% of the time.

Materials Used

Plastic: Clear PETG Filament

Fasteners: 4× M3 × 10 self-tapping socket screws (to secure the dome over the core)

Tubing: ¼" rubber fuel line (for initiating the syphoning sequence, see reference images)

Mounting: ½" conduit locknut (for attaching to the desired tank), sealed with two rubber gaskets

Notes & Recommendations

Viewing Panel: Unless you can achieve high optical clarity, I recommend printing the viewing panel as part of the staging core model.

Sealing: Each snap-in section must be fully liquid-tight for proper operation. I sealed the joints using clear E6000 adhesive, which provides a reliable watertight bond. This unit also needs to be printed with 100% infill to minimize as much gaps as possible.

Dome Alternative: If the syphon fails to operate due to print quality, try replacing the 3D-printed dome with half of a soda bottle. This component must remain completely airtight to function correctly.