**EDIT 12/04/25:  I updated the design to better fit the thermostat and made the built in support easier to remove and less filament waste.  Also updated reinforced the rear tongue and groove for a better hold and protruded the spring button out farther so it doesn't get stuck in the frame.

I took inspiration for a DIY filament dryer from @Allthingstl at Printables and his dryer box: https://www.printables.com/model/1004352-heated-filament-dryer-box.

I wanted to customize it to work like the Polymaker Dryer system using Cereal Boxes.  I'm using the ones designed by @GunplaMark https://www.printables.com/model/1249376-the-ultimate-cereal-container-filament-drybox.  This should with any, you just might need to turn the thermostat the other way around.

I'm a total noob to CAD and 3d printing so willing to take suggestions on changes.  

My dryer is designed to work with either the Shigeer (I believe they're the same the ones from Ali Express )  or the Praki Cereal containers.

I already had quite a few 80mm computer fans laying around and a few old 12v transformers for obsolete routers so I bought the cheapest PTC heater and thermostat I could find.  All in it cost me $16 plus about $3 worth of ABS.  

To wire everything up, I have the heater controlled by the switch but I wanted the fan to run constant. So that's how it's listed on the image posted.  You'll need to break open the 12v transformer and take out the circuit board.  You should solder better wire onto the board, but not necessary. It's important to get the positive/negative correct to the fan or it won't work.  The line/load on the 110v can swap without issue. Make sure you direct the fan to blow toward the heater and not the other way around. Most fans have a direction of flow embossed on it.

Slicer will say you need supports, but you won't.  In the file, I added supports for the bridge of the thermostat opening which you can just cut out with flush cutters.  This will need to be printed in ABS or PA as petg and pla will melt.  If using ABS use some Acetone to fuse the hole inserts into the lid.  You'll want to superglue it if using PA.  I think that's it, if you have any questions, feel free to ask.  I'm happy to share the solidworks files if you wish to edit for your needs (they might be messy, I've only been using CAD for a couple of weeks). 

Below I linked the items I used or similar items to what I had.

Items you'll need:

Cereal Containers: 

Shigeer: https://www.amazon.com/SHIGEER-Containers-Dispenser-Organization-Container/dp/B0FG1VZ56G/

      https://www.aliexpress.us/item/3256808875958347.html

     Praki: https://www.amazon.com/Containers-Storage-Airtight-Kitchen-Organization/dp/B09ZLBJQDW 

110v Thermostatic Switch:

W3230: https://www.amazon.com/dp/B0FJMD7NTH

12V DC Transformer:

https://www.aliexpress.us/item/2251832154179413.html

80mm Computer Fan:

https://www.amazon.com/80x80x25mm-Brushless-Cooling-Replacement-Computer/dp/B0BDLDZZQW

PTC Heater:

https://www.amazon.com/dp/B0DDJS2QDW

110 Power cord…just about any extension cord. I cut the cord off an old halogen lamp I was throwing away.

M4x8 screws x 2