Short answer: stringing on Bambu Lab printers is caused by three things, in this order of likelihood: wet filament, nozzle temperature too high, and retraction settings. Dry your filament first (PLA 45–50 °C for 6–8 h), drop the nozzle temperature by 10–15 °C (PLA 210–215 °C, PETG 240–245 °C), then set retraction in Bambu Studio to 0.8–1.2 mm at 30–40 mm/s with "Wipe while retracting" on. The same settings apply to the A1, A1 Mini, P1S, P2S, X1/X2D and H2 series because every current Bambu Lab printer is direct-drive. In our Sydney workshop that sequence fixes well over 90% of stringing complaints we see.
Not sure it's stringing? Thin, wispy hairs between parts are stringing. Clicking extruder and gappy layers are a clog; lifted corners are warping; a poor first layer is covered in our first layer adhesion guide.
Step 1: Dry your filament (fixes most cases)
PLA and PETG absorb moisture from the air, and much of coastal Australia sits at 60–80% relative humidity for a good part of the year. Wet filament turns to steam in the nozzle, and that steam drags fine hairs of plastic between travel moves — no retraction setting can compensate for it.
- PLA: dry at 45–50 °C for 6–8 hours
- PETG: dry at 60–65 °C for 6–8 hours
- TPU / Nylon: 70 °C+, 8–12 hours (nylon strings dramatically when wet; for TPU grades and feeding see our TPU hardness guide)
A dedicated filament dryer is easiest, but an oven with an accurate thermometer works, and the AMS 2 Pro and AMS HT dry spools in place. If you print regularly, keep spools in a sealed box with desiccant and a hygrometer so you can see when humidity creeps above 20–25% — full details in our filament storage guide.
Step 2: Drop the nozzle temperature
Hotter plastic is runnier plastic. If a dried spool still strings, lower the nozzle temperature in 5 °C steps and reprint a stringing tower test:
- PLA (including BIQU PLA GO and Bambu PLA Basic): try 210–215 °C instead of the 220 °C many profiles default to. On high-speed profiles don't go below ~205 °C or you risk under-extrusion.
- PETG (PETG Basic strings more than PLA by nature): 240–245 °C rather than 255 °C.
Step 3: Tune retraction in Bambu Studio
Bambu's stock profiles are good, but per-filament tweaks help. In Bambu Studio, edit the filament profile → Setting Overrides:
- Direct-drive machines (all current Bambu printers): retraction length 0.8–1.2 mm. More is not better — long retractions on a direct-drive can grind filament.
- Retraction speed: 30–40 mm/s.
- Enable "Retract on layer change" and "Wipe while retracting".
- Increase travel speed — faster travels give oozing plastic less time to bridge the gap.
Step 4: Check the nozzle itself
A worn or partially clogged nozzle strings no matter what you set. If you have printed abrasive filament (glow, carbon fibre, glitter) through a standard nozzle, the bore may be oversized. A cold pull cleans partial clogs (step-by-step in our clogged nozzle guide); a genuine replacement Bambu Lab hotend or nozzle is the fix for wear — we keep them in stock in Sydney.
Quick checklist
- Dry the filament (6–8 h) and store it dry
- Nozzle temp −10 to −15 °C, test again
- Retraction 0.8–1.2 mm @ 30–40 mm/s, wipe on
- Cold-pull or replace the nozzle
FAQ
Why does my Bambu Lab A1 string even with brand-new filament?
"New" does not mean dry. Filament can absorb moisture inside a vacuum bag if the desiccant is exhausted, and spools manufactured months ago may have been humid since packaging. Dry new spools for a few hours before judging them.
Does stringing mean my filament is bad quality?
Usually not. Any PLA or PETG strings when wet or run too hot. Budget filaments like BIQU PLA GO print cleanly on Bambu machines once dried and run at 210–215 °C.
What retraction settings should I use on a P1S or X1C?
Start at 0.8 mm length and 30 mm/s speed with wipe enabled — both are direct-drive machines and need far less retraction than a Bowden printer.
Why does PLA Matte or Silk string more than PLA Basic?
Silk PLA is formulated to flow at higher temperatures and oozes more, so run it at the bottom of its range; matte PLA sheds more dust into the nozzle and shows moisture faster. Dry both, drop 5–10 °C, and keep wipe enabled — see our PLA Matte review for its settings.
3D BRO is an authorised Bambu Lab reseller and Australia's authorised Bambu Lab service centre, based in Regents Park, Sydney. Stuck on a print problem? Get in touch — we print every day.
