How to Fix 3D Printer Stringing
Cause 1: wet filament
This is the single most common cause of sudden stringing in a spool that was printing fine last week. Water in the filament flashes to steam at the nozzle, leaving wet trails on travels. Dry the spool (4 to 6 hours at 50 C for PLA, 65 C for PETG) and re-test before touching any settings.
Cause 2: temperature too high
Hotter filament oozes more. Drop the nozzle temp 5 C and run a temperature tower. Stringing usually clears noticeably 10 to 15 C below the supplier's max recommended temp.
Cause 3: not enough retraction
- Direct drive: start at 0.5 to 1.5 mm retract distance, 25 to 45 mm/s retract speed
- Bowden: 4 to 6 mm distance, 30 to 50 mm/s speed
- Test with a retraction tower in your slicer
Cause 4: slow travel
Slow travel moves give the nozzle more time to leak. Raise travel speed to 150 to 200 mm/s if your printer can handle it.
Cause 5: nozzle wear
A worn nozzle has a larger, less round opening that oozes more. If you have been printing matte or composite filament with a brass nozzle for weeks, swap it out and re-test.
PETG specifically
PETG strings more than PLA because it is naturally sticky in the melt zone. Lower temps (10 C drop from PLA recommended) and slightly higher retraction usually fix it. Coasting and wipe in the slicer help too.
Browse drying-friendly storage and the filament range
Spool storage matters: browse all filament. Every spool ships with silica gel and a resealable bag.