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.