Updated 3 months ago ​by Tomáš Chvalina

Stringing usually appears if your print settings are not accurate, while you are printing complex objects (such as Moon city) or multiple objects at once. This is recognizable as a marginal line of plastic left behind or between the object/s. In other words, it’s that hairy bit of plastic we don’t like to see.

Keep in mind that some filaments, such as PETG or flexible filaments, may be stringy even with perfect print settings. In the photo below, you can see an extreme case of stringing. Usually, the stringing is not so severe, but if you encounter something similar to the objects in the photo, follow the instructions below.


  1. Check the tension bolts – Before you touch any of the settings, make sure that the Tension bolts located on the extruder idler are properly tightened, although, this is not that common.
    1. Original Prusa i3 MK3: simply check STEP 17 in the MK3 E-axis assembly.
    2. Original Prusa i3 MK2/S: simply check STEP 16 in the MK2 Extruder assembly.
  2. Use proper printing settings – We highly recommend using the preset settings in PrusaSlicer. However, if you are printing with your own settings, make sure that you have the retraction settings set correctly. Retraction settings can be found in Printer Settings – Extruder 1.
  3. Try to lower the nozzle temperature – Lowering the temperature will minimize stringing. Therefore, you can try to decrease it by 2-5°C. Do so only for materials which are experiencing strings, if you lower the temperature too much, the extruder can clog.
  4. Don’t bother, just use a heat gun! – If you don’t feel like tweaking any of the settings, well, then there is an alternative. You can get rid of the strings with a heat gun (or possibly with a lighter). Just set it to around 200°C and aim at the strings for one or two seconds. This will melt the strings, and the printed object should remain undamaged.


Find out more troubleshooting tips here: Community Forum | Assembly Manuals | Youtube channel |

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