Stringing: The Complete Fix List, In Order

Start With the Cause, Not the Slider

Stringing — the fine hairs and cobwebs that stretch between separate towers or islands of a print — has one of the longest fix lists in 3D printing. Retraction distance, retraction speed, temperature, travel speed, combing, wipe, z-hop, coasting. Most of these help some of the time, which is exactly why people get stuck. They nudge one slider, see a small improvement, nudge another, and end up with a slicer profile full of compensations for a problem they never actually identified.

This guide puts the fixes in order. Not the order they appear in your slicer, but the order of likelihood. The cause that explains the most stringing comes first. Work down the list and stop when the strings stop.

The Quick Diagnostic

Symptom	Likely cause	Fix
Strings plus popping or crackling sounds while printing	Wet filament	Dry the spool before touching any setting
Strings on a roll that printed clean a few weeks ago	Moisture absorbed in storage	Dry the spool
Strings on every roll, including fresh ones	Retraction under-tuned or temperature too high	Steps 2 and 3 below
Fine fuzz on PETG even after tuning	Normal PETG behavior	Minimize, then accept and post-process
Blobs or zits where travel moves end	Pressure not relieved before travel	Retraction speed, wipe settings
Thick, droopy strands rather than hairs	Temperature far too high	Drop nozzle temperature

Step 0: Confirm It Is Actually Stringing

Stringing means thin strands bridging gaps the nozzle traveled across. It is worth separating from two look-alikes. Blobs and zits on surfaces are a pressure and seam problem, not a travel problem. And rough, pitted, bubbly surfaces are a moisture problem that happens to produce strings as a side effect. If your "stringing" comes with surface texture problems and audible popping, skip straight to Step 1 — it is the whole story.

Step 1: Dry the Filament

This is the step most tuning guides bury at the bottom, and it belongs at the top. Filament is hygroscopic: it absorbs moisture from the air while it sits on the shelf. At printing temperature that moisture flashes to steam inside the nozzle, and steam pressure pushes molten plastic out of the tip during travel moves. No retraction setting can hold back steam. If the filament is wet, you can tune retraction all week and the strings will stay.

The tell-tale signs of moisture: faint popping or hissing while extruding, strings that look fuzzy or bubbly rather than glassy, rough surface finish, and weaker layer bonding than you remember. PETG, TPU, and nylon absorb moisture quickly; PLA does too, just more slowly.

The fix is unglamorous: dry the spool. A dedicated dryer like the SUNLU S2 Filament Dryer holds a spool at a controlled low temperature for several hours and can feed the printer directly while it works, which matters for materials like nylon that re-absorb moisture during a long print. Typical drying practice: PLA around 45–50°C, PETG around 60–65°C, for four to six hours.

Print the same stringing test after drying. If the strings are gone, you are done — and you have learned that your storage, not your slicer, was the problem. A sealed box with desiccant keeps it from coming back.

Step 2: Retraction Distance and Speed

If a known-dry spool still strings, retraction is the next lever. Retraction pulls the filament back a short distance before each travel move so the nozzle is not under pressure while it crosses a gap.

Distance depends on your extruder type. Direct-drive extruders typically want short retractions, somewhere in the 0.5–2 mm range, because there is very little filament path to decompress. Bowden setups need more, commonly 3–6 mm, because the long PTFE tube acts like a spring. Start at your printer profile's default and increase in 0.5 mm increments (0.2 mm for direct drive), printing a small two-tower test between changes.

Resist the urge to keep going up. Excessive retraction drags soft filament high into the heatbreak, which invites heat-creep clogs — a worse problem than the one you started with. If you are past roughly double the typical range for your extruder type and still stringing, the problem is elsewhere.

Retraction speed matters too. Faster retraction relieves pressure before ooze starts; common working values sit in the 25–45 mm/s range. Very high speeds can grind soft filament, so increase moderately.

Step 3: Temperature

Hotter plastic is runnier plastic, and runnier plastic oozes. If retraction tuning plateaus, drop the nozzle temperature in 5°C steps within the material's working range — PLA generally prints at 190–220°C, PETG at 230–250°C. A temperature tower (a single test print with bands at decreasing temperatures) shows you the trade-off directly: somewhere below your current temperature, stringing fades; somewhere below that, layer adhesion suffers and surfaces go dull. Pick the band where strings are minimal and layers still fuse well. Check the spool's printed range and our filament compatibility matrix for sensible starting points per material.

Step 4: Travel Behavior

The remaining levers reduce the opportunity for ooze rather than the ooze itself.

Travel speed. Faster travel means less time over the gap. Most modern printers handle 150 mm/s or more for travel moves comfortably; raise it if yours is set conservatively.

Combing / avoid crossing walls. This keeps travel moves inside the part's perimeter where small ooze marks are invisible, instead of crossing open gaps. It slightly lengthens travel paths but removes most visible strings on many models.

Wipe. A short wipe along the wall after retracting cleans the nozzle tip before it leaves. Cheap insurance, usually on by default in current slicers.

Z-hop. Lifting the nozzle during travel prevents it from dragging through strings and knocking parts loose, but the lift move itself can stretch a fine hair. If you have tuned everything else and see faint vertical wisps at island edges, try disabling z-hop and compare.

Material Notes: PETG and TPU

PETG strings more than PLA at the best of times — it is simply a stickier, stretchier melt. A well-dried, well-tuned PETG profile still tends to leave occasional fine wisps; a quick pass with a heat gun shrivels them instantly. If an old PETG roll strings badly no matter what you do, a fresh dry roll such as Overture PETG makes a useful control test before you blame the printer. See our PETG material guide for the full settings picture.

TPU is its own case: it is flexible, so aggressive retraction just stretches it inside the filament path. Print it slowly, ideally on a direct-drive extruder, with minimal retraction, and rely on travel speed and combing instead.

When Strings Will Not Quit

If you have dried the filament, tuned retraction, dropped temperature, and cleaned up travel behavior, and the part still strings, look at hardware. A worn or partially clogged nozzle drools unpredictably. Loose extruder tension lets retraction commands slip. And some printer-material pairings are simply harder than others — the matrix flags combinations that need an enclosure, a hardened nozzle, or a direct-drive extruder to behave.

FAQ

Does z-hop cause stringing?

It can contribute a specific kind: faint vertical wisps where the nozzle lifted away from an island. Z-hop also prevents the nozzle from crashing into curled edges, so it is a trade-off. Tune everything else first, then A/B test z-hop on a model that shows the problem.

Can I just remove strings after printing?

Yes, and for PETG you often should. A brief pass with a heat gun or lighter flame shrivels fine hairs without marking the surface if you keep it moving. This is a finishing step, not a fix — heavy stringing also means blobs and surface defects that will not burn away.

Why does my PETG string when PLA prints clean on the same machine?

PETG's melt is stickier and stays stretchy longer as it cools, so it draws fine threads where PLA would break clean. It also absorbs moisture faster. Expect to run PETG cooler within its range, with slightly more retraction, and to tolerate a little fuzz that PLA would not produce.

Will more retraction always reduce stringing?

No. Past the useful range, extra retraction does nothing for strings caused by moisture or temperature, and it actively causes heat-creep jams by pulling soft filament up into the cold side of the hotend. If doubling the typical distance for your extruder type has not fixed it, the cause is something else.