Polymaker PolyDryer Cereal Box Adapter

0.2mm Layer Height, 2 Wall Layers, 15% Infill

No supports needed! Even if your slicer gives a slight warning, ignore it—the model has no critical overhangs! I guarantee it prints perfectly without supports.

For those of you who own a Polymaker PolyDryer and use Amazon 4L cereal boxes to store your filament, here's my solution: an adapter that lets you quickly connect your PolyDryer to the cereal box.

Polymaker sells dedicated filament dryer, but let's be honest, they're expensive, and you'd need multiple if you have various filaments. So, I designed a more budget-friendly alternative: this adapter fits onto the small round cap of your cereal box and features two ports—one for the PolyDryer's hot air output and another for vacuum intake. This setup keeps your filament dry for extended periods without breaking the bank.

Why is this solution better than others?

1. Quick Installation: Just open the small round cap (it's part of the larger lid). No need to undo the four clips of the main lid like with other solutions.
2. Minimized Moisture Ingress: Other adapters replace the entire lid, meaning you constantly switch between the original and drying lids, exposing your filament to ambient humidity. This design reduces that by keeping the sealed environment intact and only opening a small, valve-like passage.
3. Self-Sealing Fit: The adapter slides into the small cap hole and seals naturally due to gravity and its dimensions. No extra gaskets needed, no leaks.
4. Secure and Easy Connection: The PolyDryer's interface fits snugly with the adapter—tight enough to prevent leaks, but not so tight that it's difficult to attach or detach.

Tested and Improved Over Time

This is already the fifth version of my design. I've tested multiple iterations to improve usability in different setups. The biggest change? I rotated the dual-tube section by 90° relative to the central tube that fits the cap. This allows the PolyDryer not to interfere with the lid when opening it, while keeping the entire setup as low-profile as possible.

Inside the box, the adapter works whether your spool is free-standing or mounted on a printed roller system. Many people use rollers to feed directly from the box, which slightly elevates the spool. To avoid interference with the spool flanges, I've added an offset to the hot air port, ensuring it doesn't hit anything.

Printing Tips – No Surprises, No Hassle

1. PLA or PETG? If you only plan to dry PLA, you can print this adapter in PLA, as it won't soften under the PolyDryer's PLA drying program. If you want a more versatile solution, print it in PETG—same print settings, no extra tweaking needed.
2. Designed for Easy Printing: The model has no critical overhangs, so even if your slicer gives a slight warning, ignore it—you don't need supports. I guarantee it prints perfectly without supports.
3. Default Settings Work: If you have a Bambu Lab A1, you can print it with default settings—no profile modifications needed.
4. Bed Adhesion is Key: Make sure your first layer sticks well! When in doubt, use a skirt or brim for security.

How to Use – No Guesswork

1. This ensures the hot air port aligns with the deeper opening inside the box (pushing hot air further in), while the vacuum port aligns with the higher intake, optimizing airflow and drying efficiency.