Why and how to dry your filament properly
Hygroscopicity – the ability of plastics to absorb moisture from air – is a real issue. Even PLA, often considered "low‑maintenance", degrades noticeably after a few days in a humid environment.
Signs of wet filament
- Hissing and steam coming from the nozzle during heating.
- Uneven surface, bubbles or pimples on the walls.
- Reduced strength and poor inter‑layer adhesion.
- Excessive stringing (especially with PETG and nylon).
Drying methods
- Dedicated filament dryer – the best option with adjustable temperature and air circulation. Prices start around $40.
- Conventional oven – can work, but temperature must be stable and not exceed 60–70 °C for PLA, 70–80 °C for PETG, 80–90 °C for nylon. Keep the door slightly ajar to let moisture escape. Do not use a gas oven without convection – risk of overheating.
- Heat gun or hot‑air blower – only for emergency drying of a small section, not effective for a whole spool.
- Airtight box with silica gel – good for storage, but not for active drying (silica gel removes moisture very slowly).
Temperature and time guidelines
| Material | Temperature | Time (hours) |
|---|---|---|
| PLA | 50–55 °C | 4–6 |
| PETG | 65–70 °C | 6–8 |
| ABS/ASA | 70–80 °C | 4–6 |
| Nylon (PA) | 80–90 °C | 8–12 |
| TPU | 50–60 °C | 4–5 |
Pro tip: Store open spools in vacuum bags with silica gel. Before any important print, dry your filament – even new rolls are not guaranteed to be moisture‑free from the factory.