Some filaments like TPU, Nylon, and PETG absorb moisture quickly and print poorly when wet. The AMS helps with regular PLA/PETG, but for specialty filaments fed through the external spool input, a dedicated drybox is the way to go.
I printed the Retracting Spool Holder — a compact, round enclosure that uses two 3D printed side plates, a cylindrical body, and snap clips to keep everything sealed. A PTFE tube routes the filament out to the printer, and a knurled knob secures the spool axle. I use it to store my TPU filament.
The base is a custom mount I designed based on the official base, adapted to fit the AMS riser v2.
features
- Sealed enclosure with silica gel desiccant to keep humidity low
- PTFE tube output with dust filter for clean filament feeding
- Label tag holder to identify the loaded filament at a glance
- Compact round design that sits neatly beside the printer
Here it’s mounted next to a Bambu Lab P1S with the AMS on top, feeding TPU-95A directly through the external spool input. Simple, effective, and keeps hygroscopic filaments printing cleanly.