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, drop the nozzle temp by 10–15 °C, then tune retraction. In our Sydney workshop that sequence fixes well over 90% of stringing complaints we see on A1, P1S, X1 and H2-series machines.
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)
A dedicated filament dryer is easiest, but an oven with an accurate thermometer works. 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: 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; 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.
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.
