ABS vs ASA
ABS and ASA are closely related styrenic plastics — ASA is essentially a weather-resistant ABS. ABS is the everyday choice for prototypes, housings and consumer parts, easy to print and machine. ASA swaps ABS's butadiene rubber phase for an acrylate one, giving it strong UV and weathering resistance, so it holds color and toughness outdoors where ABS yellows and embrittles.
The verdict
Choose ABS for indoor prototypes, housings and consumer parts where low cost and easy fabrication matter and UV exposure isn't a factor. Choose ASA when parts live outdoors — its acrylate chemistry resists UV, weathering and color fade, with a slightly higher ~85°C nominal rating and top chemical resistance (5 vs 4.5).
Side-by-side data
| Property | ABS | ASA |
|---|---|---|
| Category | Plastic | Engineering Plastic |
| Density (g/cm³) | 1.05 | 1.07 |
| Tensile strength (MPa) | 40 | 45 |
| Yield strength (MPa) | 40 | 44 |
| Elongation (%) | 10 | 25 |
| Hardness | R105 | R105 |
| Max service temp (°C) | 80 | 85 |
| Machinability | ●●●●● | ●●●●● |
| Corrosion resistance | ●●●●● | ●●●●● |
| Relative cost | ●●●●● | ●●●●● |
| Thermal cond. (W/m·K) | 0.17 | 0.17 |
| Typically used for | Prototypes, housings & consumer parts | UV-stable outdoor parts |
Which should you choose?
Choose ABS when…
- Parts are indoor prototypes, enclosures or consumer housings
- Low cost (1.5) and easy 3D printing, machining and molding are priorities
- UV and weathering exposure is not a concern
- You need the familiar, tough styrenic for impact-resistant housings
- The part will be painted, plated or kept out of sunlight
- You want the widely available, well-understood default styrenic
Choose ASA when…
- Parts are used outdoors and must resist UV, weathering and color fade
- Long-term toughness retention in sunlight is required
- The part is automotive exterior trim, signage, enclosures or roofing components
- A slightly higher temperature rating (~85°C nominal vs 80°C) helps
- Top chemical/weather resistance (corrosion 5 vs 4.5) is wanted
- You can accept similar cost (1.5) for the weathering upgrade over ABS
Key differences that matter
- ASA is the UV- and weather-stable counterpart to ABS — same styrenic family, acrylate rubber phase instead of butadiene, so it resists sunlight degradation.
- Strength is comparable: ASA ~45 MPa tensile vs ABS ~40 MPa nominal; both are easy-processing styrenics.
- ABS yellows and embrittles in UV; ASA holds color and toughness outdoors — the decisive difference.
- ASA rates slightly higher in temperature (~85°C vs 80°C) and chemical resistance (5 vs 4.5).
- Both print, machine and injection-mold; both cost the same (1.5), so weathering need — not price — drives the choice.
- For indoor parts ABS remains the cheaper, more familiar default; ASA's value shows only with sun exposure.
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Open the Material SelectorGet a Quote →Frequently asked questions
What actually makes ASA weather-resistant and ABS not?
ABS uses a butadiene rubber phase that's vulnerable to UV — sunlight breaks it down, causing yellowing, chalking and embrittlement. ASA replaces that with an acrylate rubber phase that resists UV degradation, so ASA keeps its color, gloss and impact strength outdoors. Mechanically they're similar; the difference is almost entirely weathering durability.
Can I just paint ABS instead of using ASA outdoors?
A good UV-stable coating can protect ABS, but any scratch, chip or coating failure exposes the ABS to degrade underneath. ASA is inherently weather-stable throughout its bulk, so it doesn't depend on a coating staying intact. For unpainted or long-life outdoor parts, ASA is the more reliable choice.
Do ABS and ASA 3D print the same way?
Very similarly — both are styrenics that print on heated-bed FDM setups with comparable temperatures and both can warp without an enclosure. ASA prints much like ABS and is the go-to filament when a printed part must survive outdoors. For indoor prints, ABS is cheaper and just as easy.
Is ASA stronger than ABS?
Marginally in tensile (~45 vs 40 MPa nominal) and slightly higher in temperature rating, but they're in the same class. The real reason to pick ASA is retained properties after sun exposure, not a strength advantage. Indoors, ABS performs comparably for less money.
Property values are typical/nominal figures for early-stage guidance only and vary by temper, grade, supplier and heat treatment. Confirm critical specifications against a certified datasheet or with an mfgiq engineer before production.