PETG
Why is my PETG brittle or weak?
By SSS
Published . Updated .
- Nozzle220–250 °C(428–482 °F)
- Bed70–90 °C(158–194 °F)
- Speed50–100 mm/s
- Dry65 °C · 6 h(149 °F)
- Density1.25 g/cm³
Heat resistance: HDT 78 °C (172 °F) (ISO 75, 0.45 MPa) · Vicat 84 °C (183 °F) (ISO 306) · Tg 81 °C (178 °F) · source →
Heat resistance: HDT 75 °C (167 °F) (ISO 75, 1.8 MPa) · Vicat 84 °C (183 °F) (ISO 306) · Tg 81 °C (178 °F) · source →
Speed, Drying. Source: Polymaker TDS · Last checked 18 October 2026
Ranked filaments
| Rank | Filament | Nozzle | Bed | Datasheet | Buy |
|---|---|---|---|---|---|
| 1 | Polymaker · Polylite PETG | 220–250 °C428–482 °F | 70–90 °C158–194 °F | Datasheet | |
Technical data sheet, drying checked 18 October 2026, lists a nozzle of 220–250 °C (428–482 °F), a bed of 70–90 °C (158–194 °F), and drying at 65 °C (149 °F) for 6 h. Heat dataset, checked 21 October 2026, lists HDT 78 °C (172 °F) at 0.45 MPa and 75 °C (167 °F) at 1.8 MPa, ISO 75. No brittleness test is stored. | |||||
| 2 | Bambu Lab · PETG HF | 230–260 °C446–500 °F | 65–75 °C149–167 °F | Datasheet | |
Technical data sheet, drying checked 18 October 2026, lists a nozzle of 230–260 °C (446–500 °F), a bed of 65–75 °C (149–167 °F), and drying at 65 °C (149 °F) for 8 h. The hour count is this spool. It is not PolyLite's 6 h. | |||||
| 3 | ELEGOO · RAPID PETG | 240–270 °C464–518 °F | 65–75 °C149–167 °F | — | |
ELEGOO Rapid PETG lists drying at 60 °C (140 °F) for 8 h on the 1 kg page checked 17 October 2026, with a nozzle of 240–270 °C (464–518 °F) and a bed of 65–75 °C (149–167 °F). A third spool, a third dry cycle. | |||||
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Start with the dry cycle and the nozzle on the spool, because those are published. Then read the fan comments as comments. PETG printing, brittle filament, PETG drying, and layer adhesion split the question into the pieces the comments actually touch.
The published cycles
PolyLite PETG lists 220–250 °C (428–482 °F), a bed of 70–90 °C (158–194 °F), and drying at 65 °C (149 °F) for 6 h, checked 18 October 2026. Heat-deflection temperature is 78 °C (172 °F) at 0.45 MPa and 75 °C (167 °F) at 1.8 MPa. That is a heat number, not a brittleness number. Bambu PETG HF lists 230–260 °C (446–500 °F), a bed of 65–75 °C (149–167 °F), and drying at 65 °C (149 °F) for 8 h. ELEGOO Rapid PETG lists 240–270 °C (464–518 °F), a bed of 65–75 °C (149–167 °F), and drying at 60 °C (140 °F) for 8 h. The order is three documented dry cycles. It is not a ranking of which PETG is less brittle.
What the community says
a Reddit thread in r/FixMyPrint says fan anywhere from 0% to 100%, with less fan for layer adhesion.
a Reddit thread in r/FixMyPrint: A comment uses about 25–30% and says the plastic is cured 5 mm out of the nozzle.
a Reddit thread in r/FixMyPrint uses 30–40 mm/s retraction and 1.8 mm instead of 1.2 mm.
Pros and cons
Pros
- The dry cycles are the sheets. The fan and retraction numbers stay on the comments.
- Three PETG rows show that brittle is not diagnosed by copying a single nozzle.
Cons
- No comments states a moisture percentage or a nozzle that was too low.
Printer considerations
- A comment says any fan from 0% to 100% can be right, and that a lower fan strengthens layer adhesion. prints at about 25–30% fan and says that is already pushing it. Those are comments. None of the three sheets above lists a fan percent.
- A comment uses retraction of 30–40 mm/s and 1.8 mm on a direct drive, against a tower that suggested 1.2 mm. That is the comment's result. It is not a PolyLite retraction cell.
- Drying is 65 °C (149 °F) for 6 h, 65 °C (149 °F) for 8 h, or 60 °C (140 °F) for 8 h on these three rows. One shared dry cycle would mis-state at least one of them.
Sources & notes
Published . Updated .
- Polymaker PolyLite PETG technical data sheet datasheet
- Bambu Lab PETG HF technical data sheet datasheet
- ELEGOO Rapid PETG product page manufacturer
- a Reddit thread in r/FixMyPrint reddit
- a Reddit thread in r/FixMyPrint reddit
- a Reddit thread in r/BambuLab reddit
- a Reddit thread in r/3Dprinting reddit
- a Reddit thread in r/BambuLab reddit
Related questions
- How do I get good PETG prints?PETG
- How do I improve layer adhesion?Strength
- How long and at what temp should I dry PETG?Drying
- Why is my filament brittle and snapping?Drying
Related data
- Cheapest filament per kg
- Cheapest PLA per kg
- Will my dryer cover this filament?
- Drying dataset
- How long to dry PETG
- PETG drying temperature and time
Questions
Should I dry it, or turn the fan down?
The sheets publish a dry cycle: 65 °C (149 °F) for 6 h on PolyLite PETG, 65 °C (149 °F) for 8 h on Bambu PETG HF, and 60 °C (140 °F) for 8 h on ELEGOO Rapid PETG. The comments publish fan and retraction. Dry PETG is the hour table. Layer adhesion is the bond page. PETG printing is the setup page. Brittle filament is mostly about PLA spools that snap. Do not collapse those into one knob.
Is 25–30% fan the PETG rule?
It is on r/FixMyPrint. on the same thread says the useful fan can be anywhere from 0% to 100%. The PolyLite, Bambu, and ELEGOO rows cited here do not list a fan percent.