ASA vs ABS for Outdoor 3D Printed Parts

Both are styrene plastics, both want an enclosure, and both are sold on the same shelf at nearly the same price. The difference only shows up months later, and only if the part went outside.

The short answer

Use ASA for anything that lives outdoors. Use ABS for anything that doesn't.

That is nearly the whole decision. ABS is cheaper, prints slightly easier, and is the better-known material — but it degrades in sunlight. ASA costs a few dollars more per kilo and holds its colour and its strength through years of UV.

If you only read this far, you have the useful part.

What actually separates them

The two materials are close cousins. ABS is acrylonitrile butadiene styrene; ASA is acrylonitrile styrene acrylate. Swap the butadiene rubber for an acrylate rubber and you have ASA.

That swap is the whole story. Butadiene has a carbon-carbon double bond in its backbone, and UV light attacks exactly that bond. A printed ABS part left on a windowsill yellows, chalks on the surface, and gets progressively more brittle — the impact strength goes first, long before the part looks obviously wrong. The acrylate rubber in ASA has no such bond to break, so it weathers instead of degrading.

Everything else — stiffness, heat resistance, chemical behaviour, the way it prints — is close enough that you would struggle to tell two printed parts apart on the bench.

Printing either one

Neither is a beginner's filament, and they fail the same ways.

• Enclosure. Both shrink hard as they cool. Without a stable, warm chamber you get corner lift on the bed and split layers up the Z axis on tall parts.
• Nozzle around 240–260 °C, bed 90–110 °C. Follow the spool; Polymaker prints on the low end of that.
• Little or no part cooling. Cooling is what causes layer splitting in styrenics. This is the opposite of what PLA wants, and it is the mistake most people bring with them.
• Ventilate. Both give off styrene while printing. An enclosure with a filter, or a room you are not sitting in.
• Dry filament. Neither is as thirsty as nylon, but a wet spool prints rough and weak.

ASA is marginally the better-behaved of the two — slightly less prone to warping in our experience — which is a pleasant surprise given it is also the more capable material.

For a deeper treatment of enclosure temperatures and warping, Prusa's knowledge base is the most careful free reference we know of.

Where each one earns its keep

Reach for ASA when the part sees weather: RC and drone airframe parts, camera mounts, antenna housings, garden and irrigation fittings, mailbox and gate hardware, anything bolted to a vehicle exterior, signage, and sensor enclosures that live on a roof or a fence post.

Reach for ABS when it stays inside: jigs and fixtures, tool holders, enclosures for bench electronics, functional prototypes, printer parts, and anything you plan to smooth with acetone. ABS is also the better choice when you simply need a lot of it — at roughly ten dollars a kilo less, a big print is meaningfully cheaper.

Reach for neither when the part must be food-safe, must flex repeatedly without cracking, or must survive above about 100 °C. That is a different conversation — usually PETG, TPU, or one of the fibre-reinforced engineering grades.

What we stock

We carry Polymaker in both, split by spool size so the price on the listing is the price of that spool:

Material	From	Spool sizes	Colours
ASA	$29.39	1 kg, twin pack, 3 kg, 5 kg	25 in 1 kg
ABS	$19.93	1 kg, twin pack, 3 kg, 5 kg	21 in 1 kg

ABS also comes in two higher grades — ABS Pro at $21.59 and ABS Max at $23.99 — which Polymaker positions above the plain material for engineering use. Their own specifications are the authority on what each grade is tuned for.

The colour swatches on our listings are Polymaker's own published hex codes rather than our guess at what "Galaxy Black" looks like, which is why three different blacks show as three different colours.

Or have us print it

If you would rather have the finished part than buy an enclosed printer and learn to tune it, we print in both. Upload the model and the instant quote prices it against the actual machine that will run it — a real slicer, not a size-times-a-number estimate. Pick ASA or ABS from the material list and the price updates with it.

Frequently asked

Is ASA just UV-resistant ABS? Effectively, yes — with the caveat that it is a different polymer rather than ABS with an additive. That distinction matters because additives leach and wear out; a different backbone does not.

Will ABS survive outside if I paint it? Better, for a while. Paint is a UV barrier and a good one delays the problem by years. But any chip or scratch reopens it, and the part is still ABS underneath. If it is going outdoors permanently, start with ASA.

Can I print either without an enclosure? Small parts, sometimes, if the room is warm and draught-free. Anything tall or with a large footprint will warp. This is the single most common reason people conclude "ABS is impossible".

Does ASA smooth with acetone like ABS? Yes, though generally less dramatically. Test on a scrap first.

Which is stronger? Neither, meaningfully, when new. After a year outdoors, ASA — by a margin that grows every month.