PET Water Balloon Filler Cap with Check Valve

Fill water balloons outdoors using a PET bottle.

This 3D printed cap is a simple portable solution for filling water balloons without needing to stay near a kitchen tap or outdoor faucet. It features a built-in ball check valve that helps reduce water flowing back into the bottle, while small air holes allow air to flow back in to the bottle

Great for summer parties, garden play, outdoor fun, and family water fights.

Features

• Fits common PET bottles
• Helps fill water balloons outdoors
• Built-in ball check valve
• Vent holes
• Compact and practical design
• Fun functional mechanical print

How it works

The cap screws onto a PET bottle and uses a ball valve inside the cap body.

• Water flows out in to the balloon
• The ball helps reduce reverse flow
• Small vent holes let air enter the bottle
• This helps the bottle empty more smoothly

Print settings

• Layer height: 0.16 mm
• Walls: 3
• Infill: 15%
• Material: PETG recommended for long time outdoor use. PLA works as well
• Supports: Required. Tree recommended. Print profiles available in both PETG + PLA (interface layer), PLA only and PETG only

Tips

• Make sure the ball moves freely
• Clean the air holes after printing if needed
• Test fit on your bottle before final use
• For better sealing, use slower outer walls and good layer adhesion

Please support the model

If you like the design, please consider leaving a like, downloading, boosting, and sharing a photo of your print. Seeing other people use it is always appreciated and helps support more functional designs. Also, let me know if you have any feedback and/or suggestions for improvments