How to Fix 3D Print Stringing: Every Cause, Every Fix

Stringing is thin wisps of plastic stretched between parts of a print, caused by molten plastic oozing from the nozzle while it travels without printing. You fix it by drying your filament, lowering the nozzle temperature and tuning retraction, in that order, then tidying up travel moves if any strings remain.

This guide covers every cause we know of, how to tell them apart, and the exact settings to change in OrcaSlicer, Bambu Studio, PrusaSlicer and Cura. It works for any FDM printer, direct drive or Bowden.

Quick fix checklist

If you just want clean prints, work down this list and re-print a small stringing test after each change:

Dry the filament, especially PETG, TPU or a spool that has been open for weeks.
Lower the nozzle temperature by 5 °C at a time.
Increase retraction distance in small steps: 0.2 mm for direct drive, 0.5 mm for Bowden.
Set retraction speed to about 25–45 mm/s.
Speed up travel moves and turn on avoid crossing walls.
Turn on wipe, and check the nozzle is clean and not worn.
Use the right profile for your filament before fine-tuning anything else.

A blue dragon print covered in fine plastic strings

Close-up of fine strings between the spikes of a blue dragon print

What is stringing?

Stringing (also called oozing, whiskers or “hairy prints”) is fine threads of plastic left between separate parts of a print. It happens on travel moves: when the nozzle finishes one area and moves to another without printing, a little molten plastic leaks out and stretches into a thread as the nozzle pulls away.

Stringing: thin threads crossing open air between two parts of the model.
Oozing: plastic leaking from the nozzle while it isn’t printing. Oozing is the cause of stringing; it also shows up as a drip before the print starts.
Blobs and zits: small lumps on the surface of the part, usually where a layer starts and ends (the seam). They come from retraction and restart settings too, but they’re a separate fault.
Spaghetti: a mess of loose filament from a print that came loose from the bed. That’s a bed adhesion problem, not stringing.

A drop of molten plastic hanging from a nozzle tip — Top: oozing at the nozzle, molten plastic leaving it, and strings and blobs across a plate. Bottom: stringing on test towers, and two cases of spaghetti, which is a different fault.

Close-up of a nozzle extruding a thread of clear plastic — Top: oozing at the nozzle, molten plastic leaving it, and strings and blobs across a plate. Bottom: stringing on test towers, and two cases of spaghetti, which is a different fault.

Why stringing happens

When the nozzle travels, the plastic inside the hotend is still molten. Gravity and the pressure still in the hotend push some of it out. Printers fight this with retraction: just before each travel move, the extruder pulls the filament back a little to relieve that pressure, then pushes it forward again when printing resumes.

So stringing comes down to three things: how runny the plastic is (temperature and moisture), how well retraction relieves the pressure (distance and speed), and how long the nozzle spends over open air (travel moves).

retract 0.8 mm · 35 mm/s · 205 °C · strings: few

drag ↔ retraction distance
← → retraction ±0.1 mm (Shift ±0.5)
↑ ↓ nozzle temperature ±5 °C
− + retraction speed ±5 mm/s
Space travel now
Home reset

During a travel move molten PLA oozes from the nozzle and can stretch into a string. Retracting 0.8 mm at 35 mm/s pulls the melt back (direct drive works at about 0.5–2 mm and 25–45 mm/s); a hotter nozzle (PLA prints at 190–220 °C) makes it runnier, and past about 2.1 mm the melt is drawn up into the heat break, where it can cool and clog. Motion is slowed down.

Isometric drawing of a print head travelling between two test towers

Close-up of the direct drive extruder and its retraction dial

Cause and fix reference

What you see	Most likely cause	Fix	Step
Stringing started suddenly on a spool that used to print fine	Wet filament	Dry the spool	1
Popping or crackling sounds, rough or fuzzy surface	Wet filament	Dry the spool	1
Lots of fine, thin strings everywhere	Nozzle too hot	Lower temperature in 5 °C steps	2
Thick strings, drips at the start of travel	Too little retraction	Increase retraction distance	3
Grinding or clicking after you raised retraction	Too much or too fast retraction	Reduce distance or speed	3, 4
Strings only across big gaps	Slow travel, travel over open air	Faster travel, avoid crossing walls	5
Small blobs where travel starts	Ooze not wiped off	Turn on wipe	6
Stringing on every filament, even after tuning	Worn or dirty nozzle, leaking hotend	Clean or replace the nozzle	7

Step 1: Dry your filament

Try this first, especially if stringing appeared suddenly. Most filaments absorb moisture from the air. In the hotend that water turns to steam, which pushes extra plastic out of the nozzle and makes it ooze. Wet filament also pops or crackles while printing and leaves rough, fuzzy surfaces.

PETG, TPU and nylon are especially sensitive, but PLA gets wet too.¹1Nylon is the thirstiest: an open spool can pick up enough moisture to print badly within a day in a humid room. PLA usually takes weeks.

How to dry it:

Use a filament dryer, or a food dehydrator, for 4–6 hours.
Typical temperatures: PLA 45–50 °C, PETG 60–65 °C, TPU 50–55 °C. Check your filament maker’s guidance.
Don’t use a kitchen oven unless you trust its low-temperature accuracy. Many overshoot and soften the spool.
Store dried spools in a sealed box or bag with desiccant, and keep the desiccant fresh.

A spool of natural PLA filament on a shelf

A 1 kg spool of PETG filament in its box

Step 2: Find the right temperature

Hotter plastic is runnier, so it oozes more and makes thinner, longer strings. Lower the nozzle temperature in 5 °C steps and re-test.

The best way to find the right temperature is a temperature tower: one test model printed in sections at different temperatures. OrcaSlicer, Bambu Studio and PrusaSlicer have calibration tests built in. Pick the coolest section that still has strong layer bonding and a clean surface.

Filament	Typical nozzle range	Start at
PLA	190–220 °C	205 °C
PETG	220–250 °C	235 °C
TPU	210–235 °C	220 °C
ABS / ASA	230–260 °C	245 °C

Don’t go too low. Under-temperature causes weak layers, under-extrusion and a clicking extruder.

Stringing test towers printed at 190 °C with 0.8 mm retraction — The same PLA test at nine temperatures with retraction fixed at 0.8 mm. Strings start to build above about 210 °C and get worse with every step.

Stringing test towers printed at 195 °C with 0.8 mm retraction — The same PLA test at nine temperatures with retraction fixed at 0.8 mm. Strings start to build above about 210 °C and get worse with every step.

Step 3: Tune retraction distance

Retraction distance is how far the extruder pulls the filament back before a travel move.

Direct drive extruders: start around 0.5–1 mm and try up to 2 mm.
Bowden extruders: start around 4–5 mm and try up to 7 mm.

Increase in small steps (0.2 mm for direct drive, 0.5–1 mm for Bowden) and use your slicer’s retraction test if it has one.²2Bowden setups need more retraction because the filament can compress and slide inside the long PTFE tube before the pull reaches the nozzle.

Stringing test towers with 0.0 mm of retraction at 205 °C — Retraction from 0 to 2.8 mm on a direct drive printer at 205 °C. Strings are gone by 1.6 mm; past about 2.1 mm the melt is pulled into the heat break.

Stringing test towers with 0.4 mm of retraction at 205 °C — Retraction from 0 to 2.8 mm on a direct drive printer at 205 °C. Strings are gone by 1.6 mm; past about 2.1 mm the melt is pulled into the heat break.

Close-up of the retraction dial marked in 0.25 mm steps

Where to find these settings in your slicer

Setting	OrcaSlicer / Bambu Studio	PrusaSlicer	Cura
Retraction length	Printer settings → Extruder → Retraction (filament profiles can override it)	Printer Settings → Extruder 1 → Retraction → Length	Travel → Retraction Distance
Retraction speed	Printer settings → Extruder → Retraction	Printer Settings → Extruder 1 → Retraction → Speed	Travel → Retraction Speed
Nozzle temperature	Filament settings → Nozzle temperature	Filament Settings → Filament → Temperature → Nozzle	Material → Printing Temperature
Travel speed	Process → Speed → Travel	Print Settings → Speed → Travel	Speed → Travel Speed
Avoid crossing walls	Process → Quality → Avoid crossing walls	Print Settings → Layers and perimeters → Avoid crossing perimeters	Travel → Combing Mode
Wipe	Printer settings → Extruder → Wipe while retracting	Printer Settings → Extruder 1 → Wipe while retracting	Experimental → Wipe Nozzle Between Layers
Coasting	not available	not available	Experimental → Enable Coasting

Menu names move between slicer versions. If you can’t find a setting, type its name into the slicer’s settings search box.

Step 4: Tune retraction speed

Retraction speed is how fast the filament is pulled back. Too slow, and plastic leaks out before the retraction finishes. Too fast, and the extruder gears can grind a notch into the filament.

A good starting range is 25–45 mm/s. Most modern printer profiles already sit in this range, so tune distance first and only change speed if strings remain.

Stringing test towers with retraction at 15 mm/s — Retraction speed from 15 to 55 mm/s at 0.8 mm. Once the distance is right, speed makes a small difference. Then: the extruders that do the pulling.

Stringing test towers with retraction at 25 mm/s — Retraction speed from 15 to 55 mm/s at 0.8 mm. Once the distance is right, speed makes a small difference. Then: the extruders that do the pulling.

Step 5: Travel moves

The less time the nozzle spends moving over open air, the less it can ooze.

Increase travel speed. Most printers can travel at 150 mm/s or faster; modern CoreXY printers go much higher.
Turn on avoid crossing walls (combing in Cura). The nozzle travels over the inside of the part instead of open space, so any ooze stays hidden inside.
Be careful with Z-hop. Lifting the nozzle on every travel stops it dragging across the print, but it doesn’t reduce oozing, and on some printers it makes strings longer. Use it only if the nozzle is catching on the part.

The X gantry beam carrying the print head

A printer head laying down plastic over small parts

Step 6: Wipe, coasting and cooling

Wipe moves the nozzle back over the part as it retracts, wiping the drip off on the print instead of carrying it across a gap.
Coasting (Cura) stops extruding a fraction of a millimetre before the end of each line, using up the pressure in the nozzle. Start small; too much leaves gaps at the ends of lines.
Cooling: a strong part-cooling fan freezes thin strings before they sag, which makes them easier to remove. It won’t stop oozing on its own.

An extruder assembly with a small cooling fan attached

Step 7: Check the nozzle and hotend

A worn nozzle, or plastic stuck to the outside of it, drags strings around and drips at the start of every travel.

Heat the nozzle and wipe the outside with a brass brush (carefully, it’s hot).
If your nozzle is old, or you’ve printed abrasive filaments (glow-in-the-dark, carbon fibre, wood-fill), replace it. Brass nozzles are cheap.
Make sure the hotend isn’t leaking around the threads. That needs a hot tighten following your printer’s manual.
If you’ve had heat creep (filament softening too high in the hotend), check the hotend fan works. A failing fan makes oozing and jams far worse.

A hotend encased in a large blob of plastic

A blue silicone-wrapped heater block with a brass nozzle and heat break

Settings by material

Material	Strings?	Nozzle	Retraction (direct / Bowden)	Notes
PLA	Low	190–220 °C	0.5–1 mm / 4–6 mm	Easiest to tune
Silk PLA	Medium	200–225 °C	0.8–1.5 mm / 5–6 mm	Strings more than plain PLA
PETG	High	220–250 °C	0.8–1.5 mm / 5–7 mm	Expect a few wisps; keep it dry
TPU	Medium	210–235 °C	0–0.5 mm / Bowden not recommended	Little or no retraction; print slowly
ABS / ASA	Low–medium	230–260 °C	0.5–1 mm / 4–6 mm	Needs an enclosure

If you’ve changed slicers or printers, start from the manufacturer’s profile for that exact filament before tuning anything.

Green and white PLA filament spools side by side

A spool of flexible PLA filament with its label

Temperature and retraction together

Temperature and retraction work as a pair. A cooler nozzle needs less retraction; a hot nozzle needs more. That’s why you change one setting at a time and re-test.

Stringing test towers at 195 °C with 0.0 mm retraction — Rows: 195, 210 and 225 °C. Columns: 0, 0.8 and 1.6 mm of retraction. At 195 °C, 1.6 mm clears every string; at 225 °C, even 1.6 mm still leaves a few.

Stringing test towers at 195 °C with 0.8 mm retraction — Rows: 195, 210 and 225 °C. Columns: 0, 0.8 and 1.6 mm of retraction. At 195 °C, 1.6 mm clears every string; at 225 °C, even 1.6 mm still leaves a few.

When stringing won’t go away

If you’ve worked through every step and still see strings:

Try a fresh spool of the same material from a different brand. Some filaments just string more.
Reset to the stock profile and change one setting at a time. Several half-tuned settings can fight each other.
Check the extruder tension. Too loose and the gears slip on retraction; too tight and they flatten the filament.
Look for a partial clog. Inconsistent extrusion together with stringing can mean debris in the nozzle. A cold pull or a new nozzle fixes it.

Cleaning up stringing that’s already there

A few light strings are easy to remove:

Pass a heat gun or a hair dryer on high quickly over the print. Thin strings shrink and disappear before the part itself softens. Keep it moving.³3It works because a string far thinner than a print line heats up in a fraction of a second, long before the solid part around it softens.
Snip larger strings with flush cutters.
Rub small hairs off with your fingers or a soft brush.

Your action plan

Dry the filament.
Print a temperature tower and pick the coolest clean section.
Increase retraction distance in small steps.
Keep retraction speed around 25–45 mm/s.
Speed up travel and turn on avoid crossing walls.
Turn on wipe; clean or replace the nozzle.
Use the right profile for your material.

FAQ

Why does my PETG string so much more than PLA?

PETG stays soft and sticky over a wider temperature range, so it oozes more easily and stretches into strings instead of snapping. Dry it, print at the low end of its range, add a little retraction and accept a few wisps you can clean off with a heat gun.

Does more retraction always reduce stringing?

No. Past a point it stops helping and starts causing problems: grinding, under-extrusion after travel and, worst, molten plastic pulled into the heat break where it can jam. If 2 mm (direct drive) or 7 mm (Bowden) doesn’t fix it, look at temperature and moisture instead.

Can wet filament cause stringing?

Yes, and it’s the most common cause when stringing appears suddenly. The moisture turns to steam in the hotend and pushes plastic out. Popping sounds and a rough surface are the giveaways.

Does Z-hop reduce stringing?

Not usually. Z-hop lifts the nozzle during travel so it doesn’t drag across the part, but the nozzle still oozes, and the extra movement can make strings longer. Use it to stop the nozzle catching on prints, not to fix stringing.

What’s the difference between stringing and oozing?

Oozing is plastic leaking from the nozzle when it shouldn’t; stringing is what oozing leaves behind when the nozzle travels across a gap. Fix the ooze and the strings go away.

Why did my printer start stringing out of nowhere?

Usually a wet spool, a new spool from a different brand, or a profile change after a slicer update. Start with drying, then check that the filament profile and temperature match the spool.

Can I remove strings after printing?

Yes. A quick pass with a heat gun or hair dryer removes thin strings; flush cutters handle thicker ones. Fixing the cause is still better, because heavy stringing also leaves blobs on the part’s surface.

To understand the parts involved (extruder, hotend and nozzle), read parts of a 3D printer explained. New to printing? Start with the complete beginner’s guide.