Why is my 3D print stringy?
Stringing is those thin hairs of plastic stretched across your print, like cobwebs between the tall parts. It happens because plastic keeps oozing out of the nozzle while it travels through empty space. Almost every case comes down to three fixes, and the order matters more than the settings do.
The short answer
Dry the filament — this is usually it
Wet filament is the number-one cause of stringing, and it's the one people skip because it feels too simple. Plastic absorbs water from the air — PETG and TPU within days, even PLA over a few weeks. Inside the hot nozzle that water flashes to steam and sputters the plastic out in wisps.
The tell: prints that used to be clean slowly got worse, or you hear faint popping and crackling while printing. Before touching a single setting, run the spool through a drying cycle and reprint. For a lot of people, that's the whole fix.
Lower the nozzle temperature
Hotter plastic is runnier, and runny plastic drools out during travel moves. If dry filament still strings, drop the nozzle temperature 5 °C and reprint a small test. Repeat until the strings fade — but stop the moment it comes out clean, because too cold means weak layers or a clog.
Most PLA prints happily around 200–210 °C. If you've been running 220 °C out of habit, that alone is often the culprit. Every spool is slightly different, which is why the number on the label is a starting point, not a rule.
Tune retraction
Retraction is the printer briefly pulling the filament back before a travel move, so pressure at the nozzle drops and less oozes out. Distance (how far it pulls) is what to adjust — and the right amount depends on your printer:
| Extruder | Distance | How to spot it |
|---|---|---|
| Direct drive | 0.5–1 mm | Motor sits right on the nozzle. Most modern printers. |
| Bowden | 3–5 mm | Motor on the frame, feeding through a long tube. |
Watch out
The 30-second checklist
- Dry the spool first — it's free and it's usually the answer.
- Drop nozzle temperature 5 °C at a time until strings vanish.
- Match retraction distance to your extruder type, then reprint.
- Turn on “wipe” or “combing” in your slicer if it has them.
- Accept a few fine hairs — brushing them off beats chasing perfection.
Switched filament and it started? That's expected
If stringing appeared right after you changed materials, the material is probably the reason — PETG and TPU string far more than PLA by nature, and both drink moisture fast. That's not a defect, it's the trade for their toughness. SeePLA vs PETG for what each is actually good at, or let the Filament Picker suggest a material and starting temperatures for your specific project.
Common questions
Why is my 3D print stringy all of a sudden?
The most common reason is moisture. Filament — especially PETG, TPU, and any spool that's been open for a week or two — pulls water out of the air. When that water hits the hot nozzle it turns to steam, blows tiny holes in the plastic, and leaves wisps everywhere. If your prints were clean and got stringy over time, dry the spool before you change any other setting.
Does higher temperature cause stringing?
Yes. The hotter the plastic, the runnier it is, and runny plastic oozes out of the nozzle during travel moves. If drying didn't fully fix it, drop the nozzle temperature 5 °C at a time and reprint. There's a floor — go too cold and you get weak layers or a clog — so stop as soon as the strings disappear.
What retraction settings stop stringing?
On a direct-drive printer (the extruder motor sits right above the nozzle — most modern machines), 0.5–1 mm of retraction is plenty. On a Bowden setup (motor mounted away from the hotend, connected by a long tube), you need more, often 3–5 mm. Change one thing at a time and reprint a small test so you know what actually helped.
Is a little stringing normal?
A few fine hairs you can brush off with your hand are normal and don't affect the part's strength — chasing an absolutely perfect result can cost more than it's worth. Thick strings, blobs, or a fuzzy web across the whole print are the ones worth fixing.