Stringing and oozing

Thin hairs between towers or across gaps. Almost always molten plastic leaking out of the nozzle during travel moves — so the fix is either less pressure in the nozzle, or less time for it to leak.

Looks like: Thin plastic whiskers strung between separate parts of the model.

Fixes, in the order worth trying

1 · Try this first

Dry the filament

Wet filament is the single most common cause and no retraction setting will fix it. Water in the filament flashes to steam at the nozzle and pushes plastic out. PETG, TPU and nylon absorb moisture in days; PLA takes weeks but still does it.

Dry at 45–55 °C for 4–6 hours for PLA, 60–65 °C for 6–8 hours for PETG and nylon. A filament dryer, a food dehydrator, or an oven that can hold a low temperature all work. Tell-tale sign: popping or hissing from the nozzle while printing.

2 · Try this first

Lower the nozzle temperature

Hotter plastic is thinner and leaks more easily. Drop in 5 °C steps and re-print — the difference between 215 °C and 200 °C on the same PLA is often the whole problem.

Printing Temperature: Cura → Material → −5 °C at a time, down to the low end of the spool label
Nozzle temperature: OrcaSlicer / Bambu Studio → Filament → Filament → −5 °C per test
Nozzle → Other layers: PrusaSlicer → Filament Settings → Temperature → −5 °C per test

3 · Common cause

Increase retraction distance

Retraction pulls filament back so pressure drops before a travel move. Too little and it keeps oozing. Direct drive needs far less than Bowden — using a Bowden value on a direct-drive printer causes its own problems.

Retraction Distance: Cura → Travel → Direct drive: 0.5–1.5 mm · Bowden: 4–7 mm
Retraction length: OrcaSlicer → Filament → Setting Overrides → Direct drive: 0.5–1.5 mm · Bowden: 4–7 mm
Length: PrusaSlicer → Printer Settings → Extruder 1 → Retraction → Direct drive: 0.5–1.5 mm · Bowden: 4–7 mm

4 · Common cause

Raise travel speed

The faster the head crosses open air, the less time any ooze has to form a visible string. This is a real fix, not a workaround — it often clears the last faint hairs after temperature is already right.

Travel Speed: Cura → Speed → 150–200 mm/s if your frame handles it
Travel speed: OrcaSlicer → Process → Speed → Travel → 150–250 mm/s

5 · Less common

Turn on combing / avoid crossing perimeters

Keeps travel moves inside the model where a string will not show on the outside surface. Does not stop the ooze, but hides what is left of it.

Combing Mode: Cura → Travel → Within Infill
Avoid crossing walls: OrcaSlicer → Process → Quality → Enabled

Change one thing at a time. If you adjust temperature, retraction and speed together and the problem goes away, you have learned nothing and you will be back here next month. Re-print the same test object after each single change.

Frequently asked questions

Why does my PETG string so much more than PLA?

PETG is stickier when molten and absorbs moisture much faster — a spool left out for a week is often already wet. Expect to dry PETG far more often than PLA, and to run it 10–20 °C above PLA temperatures, which also makes it ooze more readily.

Does more retraction always mean less stringing?

No, and past a point it makes things worse. Too much retraction pulls molten plastic up into the cool zone of the hotend, where it can jam, and it grinds a flat spot into the filament. On direct drive, anything above about 2 mm is usually a sign the real problem is temperature or moisture.

Can I just remove the strings afterwards?

For a one-off, a heat gun on low or a quick pass with a lighter will melt light wisps away. It is a cosmetic patch, not a fix — heavy stringing usually means the same underlying cause is also hurting dimensional accuracy and surface finish.