Drying Filament Properly: The Complete Guide
Wet filament is one of the most common causes of print problems. Many filaments are hygroscopic – they absorb moisture from the air. In this guide, you will learn how to recognize wet filament, dry it properly and store it.
Why dry filament?
Most 3D printing filaments are hygroscopic – they absorb moisture from the air. The stored water evaporates suddenly when heated in the hotend and causes various print problems.
Materials like PA (Nylon), TPU and PC are particularly critical, but PETG and even PLA can become problematic with high humidity.
Symptoms of Wet Filament
Here's how to recognize if your filament has absorbed too much moisture:
Moisture Sensitivity by Material
Not all materials react equally sensitively to moisture:
| Material | Sensitivity | Max. Humidity | Note |
|---|---|---|---|
| PLA | Low | < 50% | Tolerates a lot, but dry after long storage |
| ABS | Low | < 50% | Less critical than PETG |
| PETG | Medium | < 40% | Dry when stringing occurs |
| ASA | Medium | < 40% | Similar to ABS |
| TPU | High | < 30% | Must be stored dry |
| PA (Nylon) | Very high | < 20% | Must always be printed dry! |
| PC | Very high | < 20% | Very sensitive, dry box recommended |
| PVA | Extreme | < 15% | Dissolves in water – extremely sensitive |
Drying Temperatures and Times
The correct temperature is crucial: too hot can deform the filament, too cold doesn't dry effectively.
| Material | Temperature | Duration | Max. Temperature |
|---|---|---|---|
| PLA | 45–50 °C | 4–6 hours | 55 °C |
| PETG | 60–65 °C | 4–6 hours | 70 °C |
| ABS | 60–70 °C | 4–6 hours | 80 °C |
| ASA | 60–70 °C | 4–6 hours | 80 °C |
| TPU | 50–55 °C | 6–8 hours | 60 °C |
| PA (Nylon) | 70–80 °C | 8–12 hours | 85 °C |
| PC | 70–80 °C | 8–12 hours | 85 °C |
| PVA | 45–50 °C | 4–6 hours | 55 °C |
Drying Methods
Filament Dryer
The best solution for regularly drying filament:
- Precise temperature control
- Direct printing from dryer possible
- Multiple spools simultaneously (depending on model)
- Purchase cost
Kitchen Oven
Economical alternative, but use with caution:
- No additional cost
- Suitable for large spools
- Temperature control often imprecise
- Risk of exceeding temperature
- Heating elements can melt filament
💡 Tip: Use an oven thermometer to verify actual temperature. Preheat well and place filament in the center, not near heating elements.
Food Dehydrator
Economical solution with good results:
- Good temperature control
- Reasonable price
- Limited space
- Max temperature often limited (65°C)
Proper Filament Storage
Proper storage prevents filament from absorbing moisture:
- Vacuum bags: With desiccant packets (silica gel)
- Dry box: Airtight container with desiccant
- Humidity: Keep below 20% in container
- Temperature: Stable room temperature
- After opening: Store immediately in dry bag/box
Our Drying Solutions
Polymaker PolyDryer™ Box
Polymaker PolyDryer™ Dry Dock
Polymaker PolyDryer™
Bundle: 1x Polymaker PolyDryer & 5x Polymaker PolyDryer BoxFrequently Asked Questions
How long can filament stay in open air?
Depends on the material and ambient humidity. PLA can stay several weeks, Nylon absorbs a lot of moisture in a few hours. When in doubt, store dry.
Can you dry filament in the microwave?
No! Microwaves heat unevenly and can melt or deform the filament. Always use an oven or filament dryer.
Is silica gel alone enough?
Silica gel prevents moisture from entering, but cannot extract moisture already absorbed by the filament. Active drying is needed for that.
Does new filament also need to be dried?
Usually no. But for very sensitive materials (PA, PVA), it's recommended as moisture can infiltrate during transport and storage.
Related Guides
- PA (Nylon): Extremely Durable
- TPU Filament: Flexible and Resilient
- PETG Filament: Robust and Versatile
- PLA Filament: The All-Rounder
- The Perfect First Layer
Note: Values are indicative. Drying times may vary depending on initial moisture and device. Always follow the manufacturer's recommendations for your filament.