Filament storage is one of the most overlooked parts of 3D printing — until you start getting stringing, bubbling, popping sounds, or poor layer adhesion on prints that used to come out perfectly. The culprit is almost always moisture.
Here's how to store your filament properly and protect your spools.
Why Moisture is the Enemy
Most 3D printing filaments are hygroscopic — they absorb moisture from the air. Once filament absorbs too much moisture, it degrades fast:
- Popping or crackling sounds while printing — steam escaping from the nozzle
- Stringing and oozing — moisture lowers viscosity
- Bubbles and rough surfaces on prints
- Weak layer adhesion — causing brittle, breakable parts
- Clogs — in extreme cases, steam pressure causes blockages
In South Africa's coastal and humid regions (Cape Town, Durban), filament can absorb enough moisture to noticeably affect print quality within days if left open.
How to Store Filament Correctly
Short term (between prints):
- Keep spools in a sealed zip-lock bag or airtight container with silica gel desiccant
- Never leave a spool on the printer exposed to air overnight
- Store in a cool, dry place away from direct sunlight
Long term (months):
- Use vacuum-sealed bags with desiccant — the gold standard
- Airtight storage boxes work well
- Monitor humidity inside your storage with a cheap digital hygrometer — aim for below 20% RH
Filament Dry Boxes
A dry box is a container that keeps filament sealed and dry while you print. You feed filament directly from the sealed box to the printer, bypassing the need to reseal between every session.
You can buy purpose-built dry boxes or DIY one from a food-safe airtight container with a PTFE tube fitting for the filament to feed through.
How to Dry Wet Filament
If your filament has already absorbed moisture, you can dry it out:
| Filament | Drying Temp | Time |
|---|---|---|
| PLA / PLA+ | 45–50°C | 4–6 hours |
| PETG | 55–65°C | 4–6 hours |
Use a food dehydrator (ideal), a filament dryer (like the Sunlu S2), or an oven on its lowest setting with the door slightly ajar. Never exceed the recommended temperature or you'll warp the spool.
Filentra Filament Arrives Ready to Print
Every Filentra spool is vacuum sealed with desiccant — so it arrives moisture-free and ready to load. Once you open a spool, follow the storage tips above to keep it in top condition.