While messing with my silica gel to get it restored I realized that I had a dryer source sitting right next to my printers. I went looking for a model that would allow me to use my single spool filament dryer to restore my silica gel and was unable to find anything that fit my needs. I took to OnShape and did my best to model up an object the approximate size and shape of a filament spool. Because I'm still really new to CAD I couldn't figure out an easy way to punch a bunch of holes through the object to allow good airflow that wouldn't let silica gel come streaming out so I ended up settling on using the “0 top and bottom layers” trick to let the infill do the job for me. The final project came out really nice.
Print Settings PLA (PETG or ABS may work better depending on how hot you run your dryer) 0.2mm layer height 6 Wall Loops 0 Top Surface 0 Bottom Surface
The 3MF I included has the correct orientation and settings already applied so use it for reference.
Usage After printing simply fill the container section with silica gel then snap the lid into place. As long as your dimensional accuracy is good you should be able to press fit the lid without issues. It maybe require a little finagling to remove it as I haven't figured out a good way to put any sort of handle on it, yet. Then simply place the spool in your filament dryer as normal. I have set mine to PLA temps to start (Eibos Easdry) for testing but you could probably go higher. I've tested this printed in PLA at ~60C for 3 days and it held up with no issues.