How to Dry Filament: Temperatures, Times and Signs of Moisture
2026-08-22
Why moisture ruins prints
Every 3D printing plastic is hygroscopic to some degree: a spool left out of its bag pulls water straight from the air. In Batumi, with its sea humidity, this happens faster than in a dry climate. Inside a hot nozzle the water boils instantly, and steam tears the melt from within. Hence all the classic symptoms:
- crackling and hissing at the nozzle while printing;
- a rough, cloudy surface instead of a smooth one;
- bubbles in the walls of the part;
- stringing between parts of a model - damp filament strings far worse than dry;
- weaker layer bonding, so the part delaminates more easily.
How to tell your filament is wet
Each material shows it in its own way:
- PLA crackles in the nozzle and prints a rough surface.
- PETG hisses in the nozzle and prints a cloudy, rough surface; stringing gets noticeably worse.
- ABS bubbles and prints matt. It is less hygroscopic than PETG, so it gets damp less often.
- TPU bubbles at the nozzle and prints a torn surface. It absorbs moisture faster than most plastics.
A simple test: print the same small model first from the spool as it is, then again after drying. If the crackling is gone and the surface is cleaner, moisture was the problem.
Drying temperatures and times
| Material | Temperature | Time |
|---|---|---|
| PLA | 45-50 °C | 4-6 hours |
| PETG | 60-65 °C | 6-8 hours |
| ABS | 65-70 °C | 4-6 hours |
| TPU | 50-55 °C | 6-8 hours |
The rule that matters most is not to overheat. For PLA this is critical: a PLA part already deforms at 50-60 °C, and an overheated spool fuses so that the filament no longer unwinds.
Dryer or oven
A filament dryer is the predictable route: it holds the set temperature, and many models let you print straight from the dryer while it runs. A household food dehydrator does the job too, if the spool fits inside.
An oven works, with caveats. Household ovens hold low temperatures poorly: the real temperature can swing by tens of degrees, and for PLA even a small overshoot means a fused spool. If you do dry in an oven, check the real temperature with a separate thermometer and do not leave the spool unattended.
Storage: keeping it dry beats drying it
- Keep spools in sealed bags or boxes with silica gel.
- Indicator silica gel changes colour when it is saturated itself - time to replace or re-dry it.
- A spool that lives on the printer for weeks should also go back into a bag between sessions - especially PETG and TPU.
- Prevention does not replace drying: if the filament is already damp, dry it by the table above.
Detailed print settings for each material are on the PLA, PETG, ABS and TPU pages, and the helper will match a plastic to your job.
Frequently asked
- How can I tell my filament is wet?
- Crackling or hissing at the nozzle, a rough or cloudy surface, bubbles in the walls and worse stringing between parts of a model. Print a small model before and after drying: if the crackling is gone, moisture was the cause.
- How do I dry PETG?
- 6-8 hours at 60-65 °C. PETG is noticeably hygroscopic: a damp spool hisses in the nozzle, prints a cloudy surface and strings heavily.
- Can I dry filament in a kitchen oven?
- Yes, with care: household ovens hold low temperatures poorly. Check the real temperature with a separate thermometer, especially for PLA - an overheated spool fuses. A filament dryer or a food dehydrator is more reliable.
- Why does my filament crackle while printing?
- Most often it is moisture: water in the filament boils in the nozzle and steam tears the melt. Dry the spool by the table for your material and store it with silica gel afterwards.