18.08.2026
How moisture ruins prints: a filament drying guide

Filament is hygroscopic — it pulls moisture from the air. A damp spool turns that moisture to steam inside the hot nozzle, which shows up as crackling, surface bubbles and weak layer adhesion.

Signs of a damp spool

  • Crackling or popping while printing
  • Foaming and matte patches on the surface
  • Weak layer bonding — parts snap easily
  • A clear increase in stringing

Drying temperatures and times

  • PLA / PLA+: 45–50 °C, 4–6 hours
  • PETG: 60–65 °C, 4–6 hours
  • ABS / ASA: 70–80 °C, 4–6 hours
  • TPU: 50–55 °C, 4–8 hours

Use a filament dryer rather than a kitchen oven: household thermostats can be off by ±20 °C and will deform PLA on the spool.

Storage

Keep opened spools in a sealed bag with silica gel. Apex 3D Tech spools ship in humidity-controlled vacuum packaging — open it right before you print.

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