STRINGING AND OOZING BETWEEN PARTS

Thin hairs or threads of plastic span the gaps between separate parts of a model, draped across the print like a spiderweb.

Your nozzle is full of molten plastic at all times during a print. Between extrusion moves the nozzle travels through open air at print temperature. If pressure inside the nozzle is not relieved before that travel begins, plastic continues to ooze out and gets dragged behind the nozzle as a thin string. When the nozzle starts extruding again on the other side, the string has already been deposited. Retraction relieves nozzle pressure mechanically by pulling filament back into the cold zone before travel. The amount of retraction needed depends on the distance between extruder and nozzle - direct drive needs only 0.5-2 mm because the filament is already close to the melt zone, while Bowden setups need 4-7 mm because pressure must be relieved through a longer tube full of compressible molten plastic. Moisture in filament makes stringing dramatically worse and almost no amount of retraction tuning will fix it. Water inside filament boils to steam in the nozzle and pressurises the melt chamber, ejecting plastic uncontrollably during travel moves regardless of retraction settings. This is why drying is the most-confirmed fix - users discover that their carefully tuned retraction profile only works on dry filament.

Based on 272 confirmed fixes from r/FixMyPrint, these are the causes ranked by how often they actually worked: 1. Wet filament - drying the filament was the most common confirmed fix across all printer types. Many users had been trying retraction tweaks for weeks before someone suggested moisture. 2. Retraction distance too low - the classic Bowden case of 3 mm not being enough, 4-5 mm fixing it. Almost always the fix on Ender 3 family printers running PLA out of a sealed bag. 3. Temperature too high - confirmed by running a temperature tower (search Printables for one) and dropping nozzle temp 5-15C below the brand's recommended range. 4. Combing or 'avoid crossing perimeters' disabled - enabling it routes travels over already-printed areas where ooze is hidden. 5. Travel speed too low - bumping travel from 100 to 150-200 mm/s reduced the time the nozzle spent dripping over open air. Data sourced from r/FixMyPrint - one of the largest 3D printing troubleshooting communities on Reddit. This represents real user-reported issues and community-confirmed fixes, not theoretical advice.

If you hear popping or crackling while printing - it's wet filament. Almost certainly the cause regardless of your settings. If strings disappear after a few hours of printing then return after the spool sits out overnight - moisture absorption from ambient air. Especially likely with PETG, TPU or nylon. If stringing started after a printer move or filament swap - retraction distance is wrong for the new setup. Adjust retraction first. If stringing only appears at certain heights or features - travel routing is the issue. Enable combing or avoid-crossing-perimeters. If lowering temperature 10C significantly reduces stringing - you were running hot. Find the lowest temp that still gives clean layer adhesion. If stringing affects PETG much more than PLA - this is normal PETG behaviour. PETG strings at temperatures and retraction settings that produce clean PLA. Lower expectations and use a PETG-specific profile.

Cause 1: Wet filament Dry in a filament dryer. PLA: 45-50C / 4-6 hrs. PETG: 55-65C / 4-6 hrs. ABS/ASA: 60-80C / 4-6 hrs. TPU: 50-60C / 4-8 hrs. Nylon/PC: 70-90C / 8-12 hrs. Don't exceed these temps - PLA above 55C will fuse the spool. Test after 2 hours: if popping has stopped, drying is working. Once dried, store in a sealed container with desiccant (target below 20% RH). Cause 2: Retraction too low Direct drive: 0.5-2 mm at 25-45 mm/s. Bowden: 4-7 mm at 25-45 mm/s. The community-confirmed Bowden fix was specifically '3 mm to 4 mm' - bump in 0.5 mm increments and run a stringing test between each change. Don't push past 7 mm Bowden / 2.5 mm direct - filament grinding starts. Cause 3: Nozzle temperature too high Run a temperature tower (one print, 5C steps from 230C down to 190C for PLA). Pick the lowest temperature that still produces clean layer bonding. Most filaments work 5-15C below their recommended range without issue. Typical lows: PLA 195-205C, PETG 230-235C, ABS 235-245C. Cause 4: Combing disabled Cura: Combing Mode = 'Within Infill' or 'All'. PrusaSlicer/OrcaSlicer/Bambu Studio: enable 'Avoid crossing perimeters' or 'Avoid crossing walls'. This routes travel over already-printed areas where ooze lands inside the model. Cause 5: Travel speed too low Set travel speed to 150-200 mm/s. The nozzle spends less time over open air, so less ooze accumulates per travel. Travel doesn't extrude so this has zero quality cost.

Bowden printers (Ender 3, CR-10): Stringing-prone by design because of the long tube between extruder and hotend. The 3 mm to 4 mm retraction confirmed fix lives here. Start at 5 mm if you're unsure, work down by 0.5 mm if grinding. Never run a Bowden printer with retraction off. Direct drive printers (Bambu, Prusa MK4S, Voron): Much less stringing-prone. Retraction 0.5-1.5 mm is usually enough. If you're getting Bowden-level stringing on a direct drive printer, the cause is almost always wet filament or temperature too high. Enclosed printers (Bambu P1S, K1 Max): Chamber heat keeps the cold zone of the hotend warmer, which can cause heat creep and effective stringing. If you're getting stringing only on long prints, the chamber may be overheating - vent the front door for PLA.

PLA / PLA+: The least stringy common filament. With dry filament and retraction tuned, stringing is rare. Travel speed and combing settings are usually enough. PETG: The most stringy common filament. Strings at temperatures and retraction settings that work fine for PLA. Lower temp 5-10C below recommended, retraction 4-5 mm Bowden / 1.5-2 mm direct, travel speed 200 mm/s, combing on. Even with all this, accept that some PETG stringing is normal and clean it off post-print. ABS / ASA: Less stringy than PETG but more sensitive to draft and chamber temperature. Print in an enclosure, use lower retraction (3-4 mm Bowden because the heat chamber keeps plastic fluid further up). TPU: Cannot be retracted aggressively without grinding. Direct drive only. Retraction 0.5-1 mm. Lower temp than recommended (215-225C for typical TPU). Most TPU stringing is wet filament - dry first.

Store every spool in a sealed container with fresh desiccant. The single biggest prevention is keeping filament dry from day one - dried filament re-absorbs moisture in days if left out. Dial in retraction once per filament family (one PLA setting, one PETG setting) and save it as a slicer profile. Stringing tests take 10 minutes and the result lasts forever. Watch for printer environment changes - moving to a humid garage, switching from a dry winter to humid summer, leaving spools on the printer overnight. These are the moments when previously-fine settings start producing strings.

Use FixMyPrint to get retraction distance, retraction speed, travel speed and nozzle temperature tuned for your specific printer and filament - based on what actually worked for similar issues in the community. Go to /settings-generator to generate yours.