How to Fix PETG Stringing

No material strings like PETG. The same stickiness that makes it tough and layer-bonded also makes it cling to the nozzle, ooze during travel moves and drape fine hairs between towers. You cannot make PETG string-free the way PLA can be — but you can get very close, and the order you try fixes in matters more than with any other filament.

Why PETG strings more than anything else

Three properties gang up on you. First, PETG is hygroscopic: it pulls moisture out of the air within days, and wet PETG turns every travel move into a steam-driven glue gun. Second, molten PETG is tacky — it wets the nozzle tip and gets dragged along instead of breaking off cleanly. Third, PETG prints hot: Bambu’s stock profile runs the nozzle at 250 °C, and the hotter the melt, the runnier it is.

Because the causes stack, people who start with retraction usually lose. Work top-down instead.

Step 1: dry the spool — not optional with PETG

Step 2: come down from the hot end of the range

Other vendors’ stock PETG profiles sit all over this window, which tells you how much slack there is: Prusa’s generic PETG defaults to 240 °C, RatRig’s to 235 °C, while Flashforge runs PETG at 265 °C. If your machine’s baseline is at the hot end, you have the most room to drop.

Step 3: retraction, wipe and z-hop

• Direct-drive printers (all Bambu machines, most modern CoreXY): start from the profile’s 0.4 mm retraction and add 0.2 mm at a time, stopping by 1.2 mm. Long retractions on direct drive pull sticky molten PETG up into the heatbreak and trade strings for clogs.
• Bowden printers (Ender-3 class, deltas): the long tube needs far more — typical stock values run 1.2 mm and up (Creality’s generic PETG baseline uses 1.2 mm). Tune in 0.5 mm steps.
• Keep z-hop on. With z-hop at 0 the nozzle drags across the top surface and smears any ooze into visible strings.

What not to do

• Don’t max the part fan to freeze strings. Bambu’s PETG cooling window is deliberately modest (30–60 %); blasting 100 % fan weakens PETG’s layer bond, which is the whole reason to print PETG.
• Don’t chase strings with flow. The stock flow ratio is 0.95; cutting it further causes under-extrusion long before it stops oozing.
• Don’t leave the spool out between prints. A dried PETG spool reabsorbs enough moisture to string again within days. Dry box or sealed bag with silica, always.

Accept the last 2 %

Even perfectly tuned PETG leaves an occasional wisp on a bad geometry — dozens of isolated towers, tall thin pins. Those come off with two seconds of a heat gun or a lighter flick held at a distance. If a part truly cannot tolerate any stringing, print it in PLA; that is a material decision, not a settings failure. For the general theory (and other materials), see the main stringing guide and the complete PETG settings guide.