ASA and polycarbonate are both enclosure materials that keep their shape well above the limits of PLA and PETG. The choice usually comes down to where the part will live. Prusa describes ASA as a successor to ABS with better UV resistance and recommends it for outdoor parts. Polycarbonate offers more strength and a little more heat resistance, but asks more of the printer.
This page uses Polymaker's ASA and PolyLite PC data sheets, which share test methods and 100% infill specimens printed at 260 °C in a 90 °C environment. Prusa's guides cover printing and handling of its Prusament grades. Neither Polymaker data sheet gives numeric UV aging data, so the outdoor guidance below relies on Prusa's and Polymaker's qualitative statements.
ASA and Polycarbonate blends side by side
| Property | ASA | Polycarbonate blends |
|---|---|---|
| Nozzle temperature | 230–260 °C (Polymaker ASA); Prusa: 260 °C | 250–270 °C (PolyLite PC); Prusa: 275 °C |
| Bed temperature | 75–95 °C (Polymaker ASA); Prusa: 105 °C first layer, 110 °C after | 90–105 °C (PolyLite PC); Prusa: 110 °C first layer, 115 °C after |
| Enclosure | Needed, ambient temperature (Polymaker); Prusa: needed for large parts | Chamber needed at 70–100 °C (Polymaker); Prusa: strongly recommended |
| UV and outdoor use | Prusa: high UV resistance, suited to outdoor parts; Polymaker: improved weather and UV resistance (no numeric data) | Not stated |
| Heat deflection, ISO 75 (1.8 / 0.45 MPa) | 100 °C / 103 °C | 107 °C / 111 °C |
| Vicat softening (ISO 306) / glass transition | 105 °C / 98 °C | 120 °C / 113 °C |
| Tensile strength, ISO 527 (X-Y / Z) | 43.8 / 32 MPa | 69.1 / 52.8 MPa |
| Tensile modulus, ISO 527 (X-Y) | 2379 MPa | 2497 MPa |
| Elongation at break (X-Y / Z) | 6.7% / 1.65% | 4.8% / 2.7% |
| Flexural strength / modulus, ISO 178 (X-Y) | 73.4 / 3206 MPa | 106.1 / 2640 MPa |
| Notched Charpy impact, ISO 179 | 10.3 kJ/m² X-Y; 6.7 kJ/m² Z | 4.1 kJ/m² X-Y; Z not stated |
| Drying and annealing | Dry 70 °C for 7 h; no annealing listed (Polymaker) | Dry 75 °C for 6 h; anneal 90 °C for 2 h (Polymaker) |
| Density, ISO 1183 | 1.13 g/cm³ | 1.19 g/cm³ |
| Fumes and odor | Prusa: potentially dangerous styrene fumes; ventilated room | Prusa lists odor during printing as a drawback |
| Finishing | Prusa: sand, glue and vapor-smooth with acetone | Not stated |
Property values come from Polymaker's ASA (PolyLite ASA) and PolyLite PC technical data sheets (ISO methods; 100% infill specimens printed at 260 °C in a 90 °C environment), with printing, outdoor and safety guidance from Prusa's ASA and polycarbonate articles.
Outdoor use
Prusa lists high UV resistance first among ASA's strengths and calls it suitable for outdoor use and technical parts. Polymaker's ASA data sheet also describes improved weather and UV resistance, but neither source gives aging data such as hours of exposure or property retention.
Prusa's polycarbonate guide does not discuss UV or outdoor use, and Polymaker's PolyLite PC sheet gives no UV rating, so this page cannot say how PC fares in sunlight. If a PC part must live outdoors, a useful test is to leave a printed sample in the real location for a season and compare it with one kept indoors.
Heat
PolyLite PC is ahead on each heat measure Polymaker reports: 107 °C against 100 °C heat deflection at 1.8 MPa, 120 °C against 105 °C Vicat softening, and a 113 °C glass transition against 98 °C. The gap at 1.8 MPa is only 7 degrees, so ASA's heat resistance may be enough for outdoor housings that stay well below 100 °C.
Prusa quotes good high-temperature resistance up to 93 °C for its own ASA. That figure is for a different grade and Prusa does not name the test, so it is not directly comparable with Polymaker's ISO 75 values.
Strength and impact
PolyLite PC is much stronger: 69.1 MPa tensile strength in-plane against 43.8 MPa for Polymaker ASA, and 52.8 MPa against 32 MPa across layers. In bending, PC reaches 106.1 MPa against 73.4 MPa, although ASA has the higher flexural modulus (3,206 against 2,640 MPa), so it deflects less under a small load.
ASA handles notched impact better, at 10.3 kJ/m² in-plane against 4.1 kJ/m² for PC. Polymaker also reports a Z-direction notched Charpy value for ASA (6.7 kJ/m²) but not for PC.
Printing and fumes
Both materials warp. Prusa says large ASA parts need an enclosure and suggests PrusaSlicer's draft shield otherwise, and warns that printing a lot of ASA in an unventilated enclosure can deform the printer's fan shroud and plastic parts over time. Polymaker lists an ambient-temperature enclosure for ASA but a 70 to 100 °C heated chamber for PolyLite PC. Prusa calls polycarbonate very hard to print and says its PC Blend is much easier than pure PC.
Prusa warns that ASA releases potentially dangerous styrene fumes and recommends a well-ventilated room, and lists odor during printing among PC's drawbacks. Prusa also notes that ASA is partially hygroscopic and that pure PC is very hygroscopic; Polymaker lists drying at 70 °C for 7 hours for ASA and 75 °C for 6 hours for PC.
Which should you choose?
Choose ASA if…
- The part lives outdoors in sunlight, where Prusa recommends ASA for its UV resistance.
- Impact matters; Polymaker ASA's notched Charpy value is 10.3 kJ/m² against 4.1 kJ/m² for PolyLite PC.
- Your enclosure is unheated; Polymaker lists ASA at ambient chamber temperature.
- You want to glue or vapor-smooth the part with acetone.
Choose Polycarbonate blends if…
- The part must carry load at higher temperatures, with PolyLite PC's 107 °C heat deflection at 1.8 MPa.
- Strength matters most, including between layers (52.8 MPa Z against 32 MPa).
- The part stays indoors or out of direct sunlight.
- You can hold the 70–100 °C chamber Polymaker lists for PolyLite PC.
Common questions
Is polycarbonate UV resistant?
Neither Prusa's polycarbonate guide nor Polymaker's PolyLite PC data sheet gives UV or outdoor guidance, so the sources used here do not establish it. Prusa recommends ASA for outdoor parts because of its UV resistance.
Which handles more heat, ASA or PC?
PC, by a modest margin. Polymaker lists 107 °C heat deflection at 1.8 MPa for PolyLite PC and 100 °C for its ASA, with Vicat softening at 120 °C and 105 °C.
Do both need an enclosure?
Polymaker lists an enclosure as needed for both: at ambient temperature for ASA and as a 70 to 100 °C heated chamber for PolyLite PC. Prusa says large ASA parts need one and strongly recommends one for PC.
Sources
- PolyLite ASA technical data sheet Polymaker · Checked 2026-11-02
- PolyLite PC technical data sheet Polymaker · Checked 2026-11-02
- ASA Prusa Research · Checked 2026-10-15
- Polycarbonate (PC) Prusa Research · Checked 2026-10-15
This comparison summarizes the cited documentation; it is not a lab test. Properties vary by brand, grade, print settings and orientation, so check the data sheet for the exact product you buy.