PETG is the workhorse of functional 3D printing — tougher than PLA, easier than ABS, food-safe (with caveats), and UV-stable enough for outdoor use. It also strings like nothing else and sticks to PEI sheets so well it can tear them. This guide covers every setting that matters and the two big tricks (glue stick as a release agent, dry before printing) that make PETG predictable.
Nozzle 230 °C, bed 75 °C, fan 30–50%, glue stick on PEI as a release agent (or use textured PEI). Dry the filament at 65 °C for 6 hours before every long print. Use for outdoor parts, mechanical brackets, food storage, water bottles, and anything PLA can't handle. Don't use for fine miniatures (PLA is better) or for anything that will see >75 °C continuous heat.
PETG is polyethylene terephthalate with added glycol (the "G") that prevents the brittleness of pure PET. The same plastic family as water bottles, with extruder-friendly modifications. It's slightly less stiff than PLA, much tougher (won't snap), and survives outdoors for years.
PETG strings even with perfect retraction. Strategies that actually help:
See the full stringing and oozing article for the exhaustive list.
PETG bonds chemically to PEI on hot beds. The bond is often stronger than the PEI sheet itself, so removing the print rips the coating. The standard fix:
Avoid for: fine miniatures (stringing leaves cleanup work), parts needing chemical resistance to acetone (use ABS), parts above 75 °C continuous (use ABS, ASA, PC), repeated dishwashing (use PP or commercial molded plastic).