The Ultimate Cereal Container Filament Drybox

My previous filament drybox model became more popular than I ever imagined, and after taking on a lot of great suggestions for improvements and new features, I'm ready to release this updated version.

This new system has a few variations and options you can choose from. I'll do my best to list them all below, but the most complete look into everything you can do with these dryboxes is in this YouTube playlist:

Hardware

In addition to the printed parts, you'll need some hardware. Below are Amazon links to the items I used. Most of these parts are fairly common items and sold by various brands so definitely shop around to get the best deal. The cereal bins themselves are maybe the most difficult to find usable alternatives; what you're looking for is ones that have the molded hexagon shape on the side of the lid opposite the opening.

• Storage containers: https://amzn.to/4f6PgdU
• Bearings: https://amzn.to/4l9Lrrp
• Hygrometers: https://amzn.to/46iyXXw
• Bowden couplers: https://amzn.to/3A3yBI3
• M3x8 screws and nuts: https://amzn.to/46iuUdV
• Desiccant: https://amzn.to/3YgGhkA

Note that some of the items listed above are optional depending on which features you want to include in your dryboxes. The storage containers, bearings, and bowden couplers are required for all versions.

The Core System

To assemble the most basic drybox, you'll need to print everything in the Core System folder – one base, four axle holders, two axles, a lid seal, a coupler nut, and a coupler cap. All of the STLs will load in the suggested orientation for printing and the only one that needs supports is the axle. If you're planning to use the optional active drying system, you'll want to print everything with a filament that can withstand higher temps (I use ASA for my dryboxes), but if you're not doing active drying standard PLA will be fine.

To assemble:

1. Remove the plastic flap that came with the container lid
2. Insert the printed lid seal into the circular opening in the lid
3. Turn the lid upside down and fit the printed base into it
4. Press a bearing into each of the printed axle holders
5. Fit one axle holder with bearing on each end of the axles
6. Slide the axle assemblies into the base
7. Drill a 10mm (3/8in) hole into the container body. I've included a printable “coupler hole jig” part to help align the hole. See the included images for an example of how to line this up.
8. Insert a bowden coupler through the hole and screw on the printed coupler cap from the inside of the container
9. Place a spool of filament on the base, feed the filament through the coupler, and clip the container together
10. Fit the filament end into the printed coupler cap and press it in place over the coupler

Optional Parts

You can add features to the core system using some optional parts:

• The base cover fits onto the base before sliding the axle assembly in place. It can be used to contain loose desiccant. You can use one base cover and fill half of the base with desiccant, or print two base covers and fill the entire base. Note that if you're planning to use the active drying option, I recommend to only put desiccant in the back half of the base so that the circular opening is easily accessible for the dryer attachment.
• The hygrometer holder allows you to place a hygrometer inside the container. It presses in place onto the coupler nut.
• The tag holder allows you to print a tag to label your filament. The tag fits into the holder and the holder presses in place on the coupler cap.

Examples of these options are shown in the included photos.

Extended System

The extended system adds a few additional features:

• Stacking - The extra printed parts create a flat platform on top of each container that allows for perfect stacking.
• Wall mounting - Using the included mounting slides with your organization system of choice, you can hang the containers on a wall or pegboard.
• Filament rollback management - Whether you're using a MMU or just manually pushing filament back into the container when changing filaments, the extra guides in the top corners of the container keep the loose filament from tangling.
• Tag and coupler cap holder - At the top front of the container, there's a place for your filament tag and a handy clip to hold onto the coupler cap when it's not in use.

To install these parts, you'll need to print two of the inside brackets and one each of the front and back parts. Press the front and back parts firmly onto the outside of the container (they have printed cutouts to help them align perfectly), mark the two holes in each part, drill 3mm (1/8in) holes, and use m3 screws and hex nuts to screw the parts into the inside brackets.

Active Drying

If you have the PolyMaker PolyDryer system (https://amzn.to/3RrN5ad), there's a printable adapter in the tools folder that will fit on top of the PolyDryer base. Then to dry your filament, simply remove the lid seal from the underside of the drybox and place the drybox onto the PolyDryer adapter.

Future Plans

This is an ongoing project. At the time of sharing it here at Printables (April 2025), I'm considering it to be in a beta state. I don't expect the overall design to change drastically, but it's likely that I'll be making small updates to the printable parts based on feedback from the community. The latest versions of the STLs will always be published here.

If you have feedback, suggestions, questions, or run into any issues with the drybox system, I'd love to hear from you. Feel free to leave me a message here on Printables, or if you'd like to have a more in depth discussion you can find me on my Discord server: https://discord.gg/G73Z3pDa8X

Changelog

April 4, 2025 - Updated axle-holder_x4.stl and base-cover.stl with minor size adjustments to ensure proper snap fitting of parts.

April 6, 2025 - Updated base-cover.stl with an improved vent design.