FILAMENT STORAGE REPORT
Good storage has one job: reduce unnecessary exposure between prints. The best system is not the most expensive one—it is the one that matches material sensitivity, workflow and humidity and that you actually keep closed.
QUICK SYSTEM
01 · Seal
Use a genuinely closed box or bag.
02 · Desiccant
Maintain or regenerate it instead of assuming it lasts forever.
03 · Monitor
Use RH readings when they will change a decision.
04 · Return
Put spools back promptly after printing.
Storage is not active drying. A wet spool may still need a heated drying cycle before it goes back into controlled storage.
Storage box, dry box, vacuum bag or dryer?
| Method | Main job | Best use |
|---|---|---|
| Sealed storage box | Slow moisture uptake between prints | Several spools stored together |
| Print-through dry box | Controlled storage while feeding filament | Long prints or sensitive materials |
| Vacuum bag | Compact sealed storage | Spools used infrequently |
| Heated filament dryer | Actively remove absorbed moisture | Spools already showing credible moisture symptoms |
PRUSA USS DRYBOX REFERENCES
| Material | System-specific RH reference |
|---|---|
| PLA | Below 30% RH; short-term up to 40% |
| PETG | Below 20% RH |
| TPU | Below 20% RH; ideally below 15% |
| PVA | Below 20% RH |
| BVOH | Below 30% RH |
| PC | Below 20% RH |
| ABS | Below 30% RH; ideally below 15% |
| ASA | Below 30% RH; ideally below 10% |
These values describe Prusa’s USS Drybox guidance, not universal RH limits for every box, sensor or filament brand.
Choose storage by workflow
Frequent use
A monitored dry box can reduce repeated opening and allow print-through storage.
Long-term / compact
Vacuum bags or sealed containers make sense when spools sit idle and space matters.
Already wet
Use appropriate active drying first; storage is for preserving condition afterward.
DESICCANT INFERENCE
Clariant describes molecular sieve as relatively strong at low humidity and silica gel as gaining more adsorption capacity as RH rises. Applied to filament storage, molecular sieve can be attractive when very low RH matters, while silica gel remains a practical everyday option. That is an application inference from desiccant performance data—not a filament-specific Clariant recommendation.
The habit matters more than the gadget.
A modest sealed system used consistently is more useful than expensive storage equipment that stays open.
Sources: Prusa USS Drybox · Clariant desiccant types. Checked September 13, 2026.