PETG sits in an odd spot between PLA and ABS: hotter to print than PLA, far less prone to warping than ABS, but with its own quirks that a generic engineering-filament guide tends to skip over. This guide covers PETG’s nozzle and bed temperature ranges, why it wants noticeably less cooling than PLA rather than more, the over-adhesion problems that show up on PEI and glass, and stringing and retraction tuning. PETG is also more moisture-sensitive than PLA, though the full drying procedure lives in a separate guide linked below. For how PETG compares to other filaments before you commit to a spool, see the 3D printer filament types guide.
Nozzle temperature: hotter than PLA
PETG needs meaningfully more heat than PLA to flow and bond well. Prusa’s knowledge base lists 230°C for the first layer and 240°C for the rest on Prusament PETG, though PrusaSlicer’s newer default profile for the same filament runs as high as 250°C, a good illustration of how much this varies even from the same brand. MatterHackers puts its PETG line at 230°C to 250°C, typically settling around 245°C, and Simplify3D’s general PETG range is 230°C to 250°C as well. Treat 230-250°C as the band to test in, and expect your specific spool’s printed range to land somewhere inside it rather than at either edge.
Bed temperature
PETG bed temperatures run higher than PLA’s, typically 70°C to 90°C depending on brand. Prusa recommends 85°C for the first layer and 90°C after, MatterHackers suggests 70°C to 85°C, and Simplify3D lists 75°C to 90°C. Because PETG has very little thermal shrinkage, the bed heat is not doing warping-control work the way it does with ABS, it is mainly there for first-layer bonding. If a part comes off distorted at the base despite correct temperatures, check squish and adhesion before adding more heat, and if corners do lift despite PETG’s low shrinkage, the PETG warping guide covers the specific causes rather than ordinary shrinkage.
Cooling fan: PETG wants less than PLA, not more
This is the setting that trips people up coming from PLA. Where PLA wants near-full cooling almost immediately, PETG bonds better between layers when it stays warm longer, so heavy cooling works against it instead of for it. Prusa recommends printing the first few layers with the fan off entirely, then running it at roughly half power afterward, and notes that for the toughest possible parts you can leave the fan off for the whole print. MatterHackers describes a similar picture, with 50% as a practical ceiling for tricky overhangs and many prints running fine anywhere from 0% to 50%. If a PETG print has weak layer adhesion or delaminates under light stress, check for cooling that is too aggressive first, the opposite instinct from troubleshooting PLA.
Bed adhesion: when PETG sticks too well
PETG’s most distinctive quirk is that it tends to bond too aggressively to some surfaces rather than too weakly. Prusa’s own guidance is direct about it: do not print PETG straight onto a smooth PEI sheet, because the adhesion can be strong enough to damage the sheet when you remove the part. Bare glass carries a similar risk, where PETG can fuse hard enough that prying a part off threatens the plate. A textured or powder-coated surface is the safer default for PETG. If you are stuck with smooth PEI or glass, a thin layer of glue stick works as a release layer rather than an adhesion booster, giving the part something to let go of instead of bonding directly to the plate. If parts already come off cleanly, you do not need it.
Stringing and retraction tuning
PETG strings more readily than PLA because its melt stays viscous and stretchy across a wider temperature window, so ordinary travel moves can pull thin threads between features. Retraction distance needs differ by extruder type: Bowden setups commonly need somewhere in the 5 to 7mm range, sometimes more, while direct-drive setups usually only need 1 to 4mm for the same effect. Retraction speed around 25 to 45mm/s is a reasonable starting point for either. Z-hop can make stringing worse rather than better, since lifting the nozzle while filament is still oozing stretches the strand instead of avoiding it, so keep it off or very small if stringing is the specific problem you are chasing. Print speed plays a role too: PETG generally does better around 40 to 60mm/s, slower than a lot of PLA profiles, because it needs more time to melt and bond consistently at the nozzle.
Moisture: PETG is more sensitive than PLA
PETG absorbs moisture from the air faster than PLA does, and wet PETG shows up as increased stringing, a crackling or popping sound at the nozzle, and rougher surfaces even when temperature and retraction are otherwise dialed in correctly. If a spool has been open for a while or stored somewhere humid, dry it before assuming a settings problem. This guide is not the place for the full drying procedure. The filament drying guide covers oven and dedicated-dryer methods, times and temperatures in detail. If you are weighing PETG against ABS for a part that needs to handle heat or outdoor exposure, see the PETG vs ABS comparison, and the ABS print settings guide for ABS’s own numbers once you’ve made that call.
PETG settings checklist
- Nozzle temperature set within 230-250°C, tested against the spool’s printed range.
- Bed temperature between roughly 70°C and 90°C on a textured or powder-coated surface.
- Cooling fan off for the first layers, then no higher than about 50% afterward.
- Smooth PEI or glass avoided, or protected with a thin glue stick layer.
- Retraction distance matched to extruder type, longer for Bowden and shorter for direct drive, with minimal Z-hop.
- Filament dried before printing if it strings or pops despite correct temperature and retraction.