How do you remove stringing from a 3D print?
Pull or cut the loose strings off first, then clear the fine wisps with hot air. Prusa says to set a heat gun to around 200 °C and aim at the strings for one or two seconds. Any longer can deform the part, because PLA (polylactic acid) starts to soften at 54 to 60 °C.
The number
| PLA | PETG | |
|---|---|---|
| Heat gun on the strings (Prusa) | Around 200 °C, one or two seconds | Same; Prusa gives one setting with no split by material |
| Hair dryer, hottest setting (Dyson Supersonic) | 100 °C | 100 °C |
| Melting point | 160 °C (Bambu Lab PLA Basic) | None listed; Bambu Lab classes PETG as amorphous |
| Glass transition | 60 °C (Bambu Lab PLA Basic) | 69 °C (Bambu Lab PETG Basic) |
| Vicat softening | 57 °C (Bambu Lab PLA Basic) | 69 °C (Bambu Lab PETG Basic) |
| Heat deflection, ISO 75 at 1.8 MPa | 54 °C (Bambu Lab PLA Basic), 55 °C (Prusament PLA) | 68 °C (Bambu Lab PETG Basic and Prusament PETG) |
The heat gun row comes from the Prusa Knowledge Base article on stringing and oozing, the hair dryer row from Dyson’s Supersonic technical specification, and the material rows from Bambu Lab’s technical data sheets V3.0 for PLA Basic and PETG Basic and Prusa Polymers’ datasheets (version 1.1) for Prusament PLA and PETG.
Why does a quick pass of hot air work without ruining the part?
Because the strings and the part reach their limits at different times. A string is far thinner than the wall it hangs from, so in hot air it heats through at once and melts: Prusa’s 200 °C is above the 160 °C melting point on Bambu Lab’s PLA Basic sheet.
The wall warms from the surface inward. PLA gives way at 54 to 60 °C and PETG (glycol-modified polyethylene terephthalate) at 68 to 71 °C, so once the surface catches up, edges and thin features sag. That is why Prusa caps each pass at one or two seconds and warns that longer “may deform the part”.
The OpenFlexure Microscope project, whose parts must keep their dimensions, does not recommend melting strings off with a heat gun at all. On a snap fit or any part with a tolerance, cut the strings instead.
- Heat gun kept moving
- Hot air
- Strings under the hot air melt away
- Strings outside the air stream still span the opening
How do you clean up stringing by hand?
Pull what hangs loose, then cut what is anchored. UW-Madison’s ME Design Lab pulls strings off with fingers or pliers and calls it quick but dirty. The OpenFlexure project uses fine tweezers and warns that strands “will bend rather than break”, so a loose grip folds them instead of pulling them free.
For strings fixed to the surface, Polymaker names a razor blade. Draw it flat along the wall so it shears each string at its root without gouging the layer lines. Cutting is the one method that cannot warp the part.
How do you use a heat gun on stringing?
Set it to around 200 °C and aim at the strings for one or two seconds, as the Prusa Knowledge Base says. Keep the nozzle moving so no spot gets more than that, and hold it back from the surface: UW-Madison’s guide warns that a gun held “too close for too long” melts the part.
Let the part cool for a couple of seconds, then wipe it clean with a finger, as UW-Madison does. Several short passes beat one long blast.
Can you use a hair dryer to remove stringing?
Yes, more slowly. Bambu Lab’s post-printing guide lists a hair dryer next to the heat gun. It runs far cooler, though: Dyson’s spec sheet puts the Supersonic’s hottest setting at 100 °C, half Prusa’s heat gun figure.
That is enough to soften PLA, which gives way at 54 to 60 °C, but short of its 160 °C melting point. Expect more passes than with a heat gun, and save it for fine wisps rather than thick strands. Check your own dryer’s manual for its hottest setting.
Can you use a lighter or a torch on stringing?
A lighter, carefully. Bambu Lab says to pass the flame quickly over the strings, and Prusa says a lighter often works “but be very careful”. Bambu adds that both hot-air and flame methods need attention to safety.
Bambu Lab’s data sheets rate PLA Basic and PETG Basic as flammable, so a flame that lingers can set the part alight. Neither maker mentions a torch. If you use one anyway, the lighter rules apply: one fast pass, with nothing that burns nearby.
Is PETG stringing harder to remove than PLA?
Usually. Polymaker says it is “just about impossible to avoid some strings when printing in PETG” and expects a razor blade or heat gun for the rest (why PETG strings so much).
PETG is also the tougher plastic. In Prusa Polymers’ Charpy impact test, which strikes a test bar with a pendulum, Prusament PLA bars broke at 13 to 14 kJ/m² and Prusament PETG bars did not break at all. Expect PETG strands to resist snapping off by hand, and cut them. Under heat, PETG has more margin: it softens at 68 to 71 °C, against 54 to 60 °C for PLA.
How to check it on your own print
- Pull the loose hairs with fingers, pliers or fine tweezers.
- Cut anchored strings flush with a razor blade. Stop here on parts that must keep their dimensions.
- Sweep hot air over the fine wisps: a heat gun set to around 200 °C, one or two seconds per spot, or a hair dryer on its hottest setting.
- Let it cool, then wipe off what is left with a finger.
- Check thin walls and pegs. If one has bent, hold the gun farther away and shorten each pass.
- Fix the cause for the next print: start with why your print is stringing, then calibrate retraction distance.
Sources
- Stringing and oozing, Prusa Knowledge Base (accessed October 30, 2026)
- Work After Printing Finished (removing, cleaning, bonding the prints and cleaning the build plate), Bambu Lab Wiki (accessed October 30, 2026)
- Hairy or Stringy Prints, Polymaker Wiki (accessed October 30, 2026)
- Post Processing, ME Design Lab, University of Wisconsin-Madison (accessed October 30, 2026)
- Stringing in printed parts, OpenFlexure Microscope assembly instructions (accessed October 30, 2026)
- Bambu Filament Technical Data Sheet V3.0, PLA Basic, Bambu Lab (accessed October 30, 2026)
- Bambu Filament Technical Data Sheet V3.0, PETG Basic, Bambu Lab (accessed October 30, 2026)
- Prusament PLA Technical Datasheet, Version 1.1 (Prusa Polymers) (accessed October 30, 2026)
- Prusament PETG Technical Datasheet, Version 1.1 (Prusa Polymers) (accessed October 30, 2026)
- Dyson Supersonic technical specification, Dyson UK (accessed October 30, 2026)