Most filaments are hygroscopic — they absorb moisture from the air. A damp filament is the most common cause of mysteriously degraded print quality: the printer is fine, the profile is fine, but prints suddenly look bad.
What moisture does to your prints
Water in the filament turns to steam in the nozzle. You know the result: crackling and hissing during extrusion, bubbles in the extruded material, stringing (fine threads between walls), a rough matte surface, and weaker layer adhesion — the part ends up more brittle than it should be.
Rules for proper storage
- Don't store spools out in the open air. After printing, return the spool to a sealable box or bag.
- Use silica gel (ideally an indicating type that changes color when saturated) and dry or replace it occasionally.
- Monitor humidity — a cheap hygrometer in the box tells you more than any rule of thumb. Aim for under ~20% relative humidity.
- Open the original packaging just before printing. We ship our spools vacuum-sealed with silica gel.
Drying filament
If the filament has already absorbed moisture, drying helps. A temperature-controlled filament dryer is the most reliable option — every material has a different safe drying temperature (PLA tolerates the least, technical materials more). We're happy to send the technical data sheet (TDS) for a specific material on request.
Caution: too high a temperature will deform the spool or fuse the filament. Always follow the manufacturer's data for the specific material, not a generic table from the internet.
Summary
Dry filament = consistent printing. Store it in a sealed box with silica gel, check the hygrometer, and dry it at the first signs of moisture. With filaments from our own production, you can count on a stable ±0.02 mm diameter — the rest of your print quality is down to proper storage.