Wet filament (popping, bubbles, fuzzy surface)
The nozzle pops and hisses, the surface is rough or fuzzy, and there's far more stringing than usual.
Also described as popping, crackling, hissing, bubbles, steam, moisture, damp filament, fuzzy surface
Try these in order
Most likely and quickest to check first. Change one thing at a time so you know what fixed it.
Filament has absorbed water from the air
Nylon, TPU and PETG absorb water quickly. PLA does too, more slowly. Water boils in the nozzle and leaves bubbles.
- Dry the spool in a filament dryer or oven at the material's drying temperature.
- Store spools in sealed bags or boxes with desiccant.
- Print nylon straight from a dry box.