PETG or ASA for a part outside
ASA where sun and load meet. PETG where the part is shaded or the job is small and plain. Here are the datasheet rows that decide it.
- PETG HF 62 °C against ASA 92 °C heat deflection
- UV stated in the ASA datasheets, not in PETG HF's
- PETG HF and ASA Aero: usually 1-3 working days
- ASA is ordered in; the quote gives the time
The short answer
Choose ASA (or ASA Aero) for anything in direct sun that also carries a load or sits near heat. Choose PETG HF for a part in shade, under a roof or in a box, where its lower price and speed count and its softening point does not.
The reason is in two rows of the datasheet. ASA deflects at 92 °C under load, PETG HF at 62 °C. And the ASA datasheets state UV resistance in words; the PETG HF datasheet does not.
The rows that differ
Figures from Bambu Lab's datasheets for PETG HF, ASA and ASA Aero, measured on test specimens, "for design reference and comparison only".
| PETG HF | ASA | ASA Aero | |
|---|---|---|---|
| Our status | most popular (24/7 WHITE PETG is white PETG HF) | ordered in | most popular |
| Heat deflection, 1.8 MPa (ISO 75) | 62 °C | 92 °C | 78 °C |
| Heat deflection, 0.45 MPa (ISO 75) | 69 °C | 100 °C | 85 °C |
| UV in the datasheet | not stated | "exceptional UV, weather ... resistance" | "extraordinary resistance to temperature, water, and UV rays" |
| Tensile strength X-Y / Z (ISO 527) | 34 / 23 MPa | 37 / 31 MPa | 32 / 21 MPa |
| Impact strength X-Y / Z (ISO 179) | 31.5 / 10.6 kJ/m² | 41.0 / 4.9 kJ/m² | 32.0 / 3.4 kJ/m² |
| Saturated water absorption | 0.40% | 0.45% | 0.80% |
| Density (ISO 1183) | 1.28 g/cm³ | 1.05 g/cm³ | 0.99 g/cm³ |
| Resistance to acid / alkali | not resistant | resistant | resistant |
| Largest part in one piece | 360 x 360 x 360 mm | 340 x 320 x 340 mm | 340 x 320 x 340 mm |
Water absorption is measured at 25 °C and 55% RH. Bambu Lab's store page ticks "UV resistant" for PETG HF, but its datasheet is silent, so we do not rate it for permanent sun. Bambu lists outdoor use as an application for both PETG HF and ASA.
Why heat matters outdoors
A dark part in direct sun gets hotter than the air around it, and any load on it makes softening worse. PETG HF has 62 °C to work with. ASA has 92 °C, ASA Aero 78 °C. For a bracket under load in sun, that gap is the decision.
HDT is a specimen test, not a service temperature. Tell us the load and where the part sits.
Choose PETG HF when
- the part is in shade, under a roof or inside a box
- it carries little load and sees no heat source
- you want it fast: 24/7 WHITE PETG is white only, so there is no colour change to wait for or pay for
- the part is one of a few and plain: a garden marker, a cable guide, a cover
PETG HF is also tougher across the layers than either ASA (10.6 against 4.9 and 3.4 kJ/m²), which helps with a part that gets knocked.
Choose ASA when
- the part sits in direct sun for months
- it carries a load, or sits near heat
- the load goes across the layers: ASA keeps 31 of its 37 MPa across them, PETG HF 23 of 34
Choose ASA Aero when weight is the point. It is a foaming ASA: Bambu Lab says prints come out at 50-75% of regular ASA density. It has the UV statement and is one of our most popular materials, and it gives up strength and layer adhesion: 32 MPa along the layers, 21 MPa and 3.4 kJ/m² across them. Good for a housing or a cover, a poor choice for a hook that takes a knock.
What we print most
24/7 WHITE PETG and ASA Aero are on the most popular list: usually 1-3 working days on average after you approve the price. Plain ASA is ordered in, so the quote gives its time. Any other colour of PETG is an ordinary order, with a setup charge. ASA and ASA Aero need a heated chamber, so the largest part is 340 x 320 x 340 mm.
Questions
Is PETG UV resistant?
Bambu Lab's PETG HF datasheet does not state it, and its store page ticks it. For a part in permanent sun we point to ASA, whose datasheet states UV resistance.
Which survives heat better outdoors, PETG or ASA?
ASA: 92 °C heat deflection at 1.8 MPa against 62 °C for PETG HF (ISO 75).
Is ASA stronger than PETG?
Along the layers they are close (37 against 34 MPa). Across the layers ASA is stronger (31 against 23 MPa). PETG HF is tougher across the layers in impact.
Which is cheaper?
PETG HF usually. 24/7 WHITE PETG carries no setup to wait for or pay for. The quote shows the price of each for your part.
Can ASA Aero take weight?
It is a light material for covers and housings. For a load-bearing outdoor bracket, ask for plain ASA.
How big can an outdoor part be?
360 x 360 x 360 mm in PETG HF; 340 x 320 x 340 mm in ASA and ASA Aero.
Where does the part live?
Send the file and say how much sun, heat and load it sees. A person picks PETG or ASA and replies with a price in 3 hours on average on workdays.