Aqua Pen 2 – Pocket Ambush

Aqua Pen 2 takes the original water-spraying prank pen a step further. This version is a fully functional ballpoint pen with a retractable tip and a twist-lock mechanism, while still hiding a small water atomizer inside.   The redesigned body has a more refined appearance and offers more opportunities for color and texture customization. Although the internal water reservoir is smaller than in the previous version, it still provides approximately 10–12 water sprays per refill. Required materials Spray atomizer taken from a 30 ml spray bottle (check BOM for more Details) Compression spring: 0.3 × 4 × 20 mm Ballpoint pen refill with a 1 mm tip and a length of 98 mmAlternatively: TROIKA 99Z119 refill Lubricating oil, for example Bambu Lab Lubricant Oil Cyanoacrylate adhesive (superglue) The TROIKA 99Z119 refill fits without trimming, but it may be more difficult to source. A standard 98 mm refill can also be used after following the included cutting template.   Spray atomizers are not fully standardized. Choosing an atomizer from a 30 ml spray bottle gives you the best chance of finding the same or a compatible model used in this design. The BOM includes links to example 30 ml bottle listings to help you source the required type. Reference dimensions are also provided below so you can verify the atomizer after removing it from the bottle.   Required tools Filament cutters Utility knife Protective gloves Please take appropriate precautions when working with sharp tools and cyanoacrylate adhesive. Available print profiles Three print profiles are included: Multicolor – Print by Object The most efficient multicolor option. All parts are printed together in their assigned colors. This profile is prepared for the Bambu Lab H2C and may require adjustments for other printers. Multicolor – Split by Plate Parts are separated across multiple plates and grouped by color. Single Color – All in One All parts are placed together on a single plate for single-color printing. Included assembly helpers The downloadable files also include: A cutting template for the atomizer tube A cutting template for a standard ballpoint refill A spring spacer designed for the TROIKA 99Z119 refill Customizing the texture The pattern on the middle section was created using the BumpMesh tool by CNC Kitchen. A separate STL file of the middle section is included in the downloads, allowing you to apply your own texture or pattern. Assembly instructions The video below guides you through the complete assembly process, including preparing the atomizer, trimming the required components, gluing the printed parts, assembling both refill variants, and filling the water reservoir. I recommend watching the full video before starting the assembly.