I came up with this dry box holder after using 22L Samla boxes for a while to store my filament. Here are the advantages of using a 45L Samla box instead:

• It fits up to 10 spools compared to the 8 spools in 2x22L boxes while requiring the same space
• Filament swaps are less of an hassle as the likelihood of having to open multiple boxes is at least halved
• The setup is cheaper, as 2x22L boxes are more expensive than 1x45L

The 45L box is perfect for PLA and PETG, I have between 40-50% humidity in my area and with desiccant I can store it below 20% for 6+ months depending on how frequently I have to open the box. I still use 22L boxes for hygroscopic material like Nylon, TPU or PVA, but with a gasket.

Change Log:

• 2024-03-29 v1.1: Added loose fit variant of connectors and original tight ones are printed in PETG now
• 2024-02-24 v1.0: Initial release

Features

• This design has been optimized to minimize waste of filament
  • One frame piece is 30g which is possible as it is only there to position the rod holders
  • The complete print is 215g, that is less than many 22L spool holders out there
• The rods have been tested with double the load (5 stacked spools instead of 2.5 per section) for multiple days
• The rod holders are designed to leverage the additional space in the upper part of the box, generating the required space to fit 10 Bambu spools
• Optimized for loose desiccant as you can more easily see the color-change. Use the clips to easily get the frame out in one piece, when it is time to dry the desiccant
• Includes a hygrometer holder that is angled 45 degrees to be easily readable, when the box is on the floor

Printing instructions

Note that the design requires a print bed of 250x170mm or bigger. You could split the frames in the middle, though. Print each plate in the profile once, except the last two. The last two plates are containing connector clips and hygrometer holder, which are optional. The tight fit variant is designed to be printed in PETG and the loose fit variant for PLA. Here are the key settings should you use another slicer than Bambu Studio:

• Print the frame with two perimeters/walls at 0.28mm layer height and 15% cubic infill
• Print the rods with 4 perimeters at 0.28mm layer height and 25% cubic infill and reduce the speed, if you have a high-speed printer with stock nozzle
• Print the hygrometer holder with 0.16mm layer height and 15% infill, it has been designed to print without supports, but there is a small overhang benefiting from the lower layer height
  • The tight fit connectors are recommended to be printed in PETG. PLA does work, but requires proper flow calibration and the latches of the connectors might break apart when not assembled carefully
  • Loose fit connectors can be printed in PLA

Assembly

• Put the 4 frames together as shown in the assembly view below or use the assembly view in your slicer
• Put the 4 rods together and install them onto the rod holders. Note that the angled side of the rod holders have to face the outside rod holders
• Optional: Put the digital hygrometer into the holder and clip it on one of the long edges. The holder is for hygrometers with a 41mm diameter on the inside (not the top). I bought the hygrometer on Amazon
• Optional: Use the other two connectors to keep the 2x2 frames together. Only required, if you put loose desiccant into the box and want to more easily remove the holder in one piece without removing the hygrometer first