How to Fix Stringing on Bambu Lab Printers (Every Cause, Every Fix)
Diagnosis-first guide to fixing stringing on Bambu Lab X1C, P1S, P2S, A1, and A1 Mini. Covers wet filament, temperature tuning, retraction settings, and known firmware bugs.
Stringing — those thin plastic cobwebs stretching between parts of your print — is one of the most common complaints on r/BambuLab. The frustrating part is that stringing has multiple causes, and the fix for one cause actively makes another worse. Apply the wrong fix and your print gets worse.
This guide gives you a diagnosis-first approach: figure out why you’re stringing before touching any settings.
Quick Answer: Why Is My Bambu Lab Printer Stringing?
The most common causes, in order of frequency:
- Wet filament — moisture causes the plastic to ooze from the nozzle during travel moves. Looks like fine hair-like stringing. Drying the filament fixes it in minutes.
- Wrong temperature — too hot = more ooze during travel. Lower nozzle temp 5°C at a time.
- Wrong filament profile selected — using “Bambu PLA” profile for a third-party filament often causes stringing. Switch to “Generic PLA.”
- Retraction settings need tuning — too little retraction leaves molten plastic in the nozzle during travel. Too much causes jams.
- Z-hop interference — on A1/A1 Mini, a known Bambu Studio bug causes stringing when timelapse is disabled. Fixed by enabling timelapse or upgrading to OrcaSlicer.
Step 1: Diagnose Your Stringing Type
Fine, hair-like strings across the whole print: → Almost always wet filament. Start here before touching any settings.
Thicker strings, visible ooze at travel start/end points: → Temperature too high, or retraction insufficient.
Strings only on one particular color/slot during multi-color printing: → Purge volume too low or wipe tower position causing contamination.
Stringing started suddenly on a spool that was printing fine: → Filament absorbed moisture since last use. Dry it.
Stringing only on the A1 or A1 Mini, started after a firmware update: → See the A1/A1 Mini Z-hop bug section below.
Fix #1: Dry Your Filament (Check This First)
This is the single most effective stringing fix for most people. Wet filament creates steam bubbles inside the molten plastic, causing it to ooze continuously from the nozzle even when not extruding — which drags as strings across travel moves.
Signs your filament is wet:
- Audible popping, crackling, or hissing during printing
- Stringing that’s worse on humid days or after the filament has been sitting out
- Rough or pitted surface finish on vertical walls
- Stringing that appeared on a spool that used to print fine
How to dry filament for stringing
AMS 2 Pro (easiest): Load filament → select type → start drying. 4–8 hours depending on material.
P1S enclosed printer (no dryer): Place spool on heated bed under a PA-CF or PC cover, set bed to 45–65°C depending on material, dry for 4–8 hours. (P1P, A1, A1 Mini cannot be used as dryers — they’re open frame.)
Dedicated filament dryer: Sunlu FilaDryer, Bambu AMS HT, or PrintDry all work well. Set to the correct temperature for your material.
Drying temperatures:
| Material | Temp | Time |
|---|---|---|
| PLA | 45°C | 4 hours |
| PETG | 65°C | 6 hours |
| ABS/ASA | 70°C | 6 hours |
| Silk PLA | 40°C | 4 hours (lower — heat can cause silk layers to fuse) |
| TPU | 50°C | 8 hours |
| PA/Nylon | 80°C | 8–12 hours |
After drying, immediately return filament to sealed AMS or a ziplock with desiccant. Dried PLA can re-absorb meaningful moisture in 4–8 hours in a humid room.
Fix #2: Use the Right Filament Profile
This is the second most common cause of stringing and the most overlooked.
Bambu Studio and OrcaSlicer have different filament profiles with different default temperatures and retraction settings. If you’re using “Bambu PLA Basic” settings for a third-party PLA, you may be printing 10–15°C hotter than optimal, causing excessive ooze.
What to do:
- If using Bambu-brand filament: use the matching Bambu profile
- If using third-party filament: switch to Generic PLA (or Generic PETG, etc.) instead of the Bambu-brand profile
- The Generic profiles use more conservative temperatures that work better across brands
Silk PLA special case: Silk PLA is significantly more prone to stringing than standard PLA due to higher additives and different flow characteristics. It needs lower temperatures and often lower retraction speed. Start with the “Generic Silk PLA” profile if available, or create a custom profile starting from Generic PLA and dropping temp by 5–10°C.
Fix #3: Lower Nozzle Temperature
Temperature is the most direct lever for stringing. Higher temperature = lower viscosity = more ooze during travel.
Start here only after confirming filament is dry and profile is correct.
For PLA: try dropping from 220°C → 215°C → 210°C in 5°C increments, printing a stringing test (the classic “torture tower” or any model with lots of travel moves) at each step.
The floor: Going too low causes under-extrusion, poor layer adhesion, and brittle prints. Stop at the first temperature where layers look properly bonded. Stringing decreasing while layer quality degrades = you’ve hit the floor.
Material-specific temperature ranges for stringing reduction:
| Material | Typical Bambu Default | Stringing-Optimized Range |
|---|---|---|
| PLA | 220°C | 205–215°C |
| PETG | 240°C | 230–235°C |
| ABS | 260°C | 250–255°C |
| Silk PLA | 230°C | 215–225°C |
| TPU | 230°C | 220–225°C |
Fix #4: Tune Retraction Settings
Retraction pulls the filament back slightly when the nozzle travels between print areas, reducing the ooze that causes strings. Too little retraction and plastic drools. Too much and you get jamming, grinding, and gaps at the start of lines.
Finding retraction settings in Bambu Studio: Filament settings → Filament → Retraction section
Finding retraction settings in OrcaSlicer: Filament → Retraction → Retraction length
Recommended starting points by material
| Material | Retraction Length | Retraction Speed |
|---|---|---|
| PLA | 0.8–1.0mm | 40–60 mm/s |
| PETG | 0.4–0.6mm | 30–40 mm/s |
| ABS/ASA | 0.8–1.2mm | 40–60 mm/s |
| Silk PLA | 0.6–0.8mm | 30–40 mm/s |
| TPU | 1.0–2.0mm | 20–30 mm/s |
PETG note: PETG is uniquely sensitive to retraction. Too much retraction pulls molten PETG partially back into the nozzle where it cools and creates a partial clog. Start conservatively (0.4mm) and only increase if you’re seeing clear stringing — don’t tune PETG retraction the same way you would PLA.
Testing retraction: Print a stringing torture tower (available on MakerWorld and Printables) to systematically find your optimal retraction without wasting filament on full models.
Fix #5: Enable or Adjust Z-Hop
Z-hop lifts the nozzle slightly before travel moves, reducing the chance of the nozzle dragging molten plastic across the print.
In Bambu Studio: Filament settings → Filament → Z-hop height (typically 0.2–0.4mm works for PLA/PETG)
However: Z-hop increases print time and can occasionally introduce its own artifacts. On models with lots of small travel moves, Z-hop can slow prints significantly.
Recommended: Slope-type Z-hop. Bambu Studio supports different Z-hop modes. “Slope” (also called “spiral” Z-hop) is smoother and faster than vertical Z-hop — it ramps up and down rather than lifting straight up and straight down. This reduces both stringing and print time compared to standard Z-hop.
Fix #6: A1 and A1 Mini Z-Hop Bug
This is a documented Bambu Studio bug that affects A1 and A1 Mini users specifically.
The bug: When timelapse is disabled on A1/A1 Mini, Bambu Studio doesn’t apply the configured spiral Z-hop on layer changes. Instead, it uses a straight Z-hop, which causes stringing at layer transitions — specifically the “fine lines at layer changes” pattern that doesn’t respond to temperature or retraction tuning.
Fix option 1: Enable timelapse in Bambu Studio. This restores the spiral Z-hop behavior even if you don’t want actual timelapse footage.
Fix option 2: Switch to OrcaSlicer, which doesn’t have this bug and provides more control over Z-hop behavior across all models.
This was reported and documented on r/BambuLab in August 2024 and remains present in some firmware versions. If your A1 stringing started after a Bambu Studio update, this is the most likely culprit.
Fix #7: Multi-Color Stringing Between Colors
Multi-color stringing (color contamination between wipe towers and objects) is a different problem from normal stringing.
Cause: The purge volume between color changes isn’t high enough to fully flush the previous color before printing resumes.
Fix: In Bambu Studio, increase the purge volume for color transitions. Start by increasing by 20–30% and print a test. Dark-to-light transitions (black → white, any dark → yellow) need significantly more purge than light-to-light transitions.
Wipe tower strings: Thin strings between the wipe tower and your model are usually caused by:
- Wipe tower too far from the print — long travel move allows ooze to form
- Travel speed too low between wipe tower and print
- Avoid travel through model option not enabled
In Bambu Studio’s process settings, “Avoid crossing perimeters” keeps travel moves inside the print footprint where possible, dramatically reducing wipe tower stringing.
Fix #8: Travel Speed
Higher travel speed = less time for the nozzle to ooze during the move = less stringing. Bambu’s default travel speeds are already fast (200–300 mm/s), but if you’ve slowed them down for any reason, stringing will increase.
Check your process settings: Travel → Travel speed should be at default or higher. Don’t lower travel speed to fix other problems without being aware that it will worsen stringing.
The Correct Order to Troubleshoot Stringing
Work through these in order. Stop when stringing is resolved — don’t apply all fixes at once or you won’t know what worked.
- Dry your filament — 4–8 hours. This fixes 60%+ of stringing cases.
- Check your filament profile — switch to Generic if using third-party filament.
- Lower temperature — 5°C increments from default.
- Enable/adjust Z-hop — use slope/spiral mode.
- Tune retraction — use retraction tower to find optimal values.
- A1/A1 Mini users — check for the timelapse/Z-hop bug.
- Multi-color stringing — increase purge volume, enable avoid-crossing-perimeters.
What Doesn’t Fix Stringing (Common Mistakes)
Increasing retraction excessively: Going above 1.5mm on a direct-drive system like Bambu’s will cause grinding, jams, and gaps. The fix is usually lower temperature, not more retraction.
Lowering speed on everything: Slowing print speed doesn’t significantly reduce stringing and wastes a lot of time. Lower temperature is more effective.
Changing material brand: If you’re stringing, the brand usually isn’t the problem — the moisture content and profile settings are. Dry first before blaming the brand.
Tuning settings on wet filament: Any calibration done on wet filament is worthless. The filament will behave differently once dried, and your “fixed” settings will cause new problems. Always dry first, then calibrate.
Recommended Products for Preventing Stringing Long-Term
- Filament dryer: Bambu AMS 2 Pro (if you have the printer), Sunlu FilaDryer S4 (~$45), or Bambu AMS HT for engineering materials
- Desiccant: Bambu’s official silica gel or any fresh orange-indicator silica gel packs (avoid calcium chloride — it can damage electronics)
- Storage: AMS (best), vacuum-sealed bags with desiccant, or airtight filament containers
- Stringing test model: “Stringing Test — Temperature Tower” on MakerWorld is the quickest diagnostic tool
Still stringing after working through this guide? Post on r/BambuLab (369K members) with your printer model, filament, profile settings, and a photo of the stringing. The community is fast and thorough.