Materials guide
PETG vs ABS: which filament wins for functional parts?
For end-use, load-bearing prints, the choice usually narrows to PETG or ABS. Both are tougher than PLA, but they solve different problems — one is easier to print and shrugs off UV, the other survives real heat. Here's how to pick.
The short answer
Pick PETG for outdoor brackets, containers, jigs, and anything that has to handle chemicals, moisture, or sunlight. Pick ABS when the part gets hot — automotive interiors, enclosures around motors, housings for LED drivers — or when you need acetone smoothing for a consumer-facing finish.
Heat deflection temperature
Heat is where the two filaments diverge. PETG's heat deflection temperature (HDT) sits around 70–75 °C — fine for most indoor use, but a black part on a summer dashboard will sag. ABS holds shape up to roughly 95–100 °C, which is why it's the default for anything mounted near stepper motors, power supplies, or under the hood.
Toughness and layer adhesion
- PETG has excellent inter-layer bonding out of the box — parts fail through the material, not along print lines. It flexes before it breaks, which is forgiving for snap-fits and clips.
- ABS is impact-resistant and machines/drills cleanly, but layer adhesion depends heavily on print environment. Without an enclosure you'll get delam on tall walls.
UV and outdoor use
PETG is essentially the go-to filament for anything that lives outdoors. It resists UV yellowing and doesn't get brittle from sun exposure the way PLA does. ABS also tolerates UV, but tends to fade and chalk on the surface over long exposure — ASA is the usual upgrade if the part is fully outdoors.
Printability
PETG prints on any modern FDM machine with a 70–80 °C bed and no enclosure required. It's stringy — retraction tuning matters — but otherwise well-behaved. ABS needs an enclosed, heated chamber to avoid warping and cracking on parts over a few centimetres tall. On our side we run ABS in enclosed printers with active chamber heating; for smaller shops PETG is the more practical choice.
Finishing
ABS smooths beautifully with acetone vapour — a glossy, injection-moulded look with almost no effort. PETG can't be solvent-smoothed the same way; expect sanding and paint, or a heat-gun pass for shiny spots on a rougher finish.
Quick comparison
| Property | PETG | ABS |
|---|---|---|
| Heat deflection (HDT) | ~70–75 °C | ~95–100 °C |
| Layer adhesion | Excellent | Good — enclosure required |
| Impact resistance | Good — flexes first | Excellent |
| UV resistance | High | Moderate |
| Chemical resistance | Good — resists water, weak acids | Attacked by acetone (useful for smoothing) |
| Printability | Easy — no enclosure | Tricky — needs enclosure |
| Finishing | Sand + paint | Acetone smoothing |
| Best for | Outdoor, wet, food-adjacent, jigs | Automotive, hot enclosures, housings |
Which should you order?
If the part will see temperatures over ~70 °C, choose ABS. For everything else — especially outdoor brackets, water-adjacent parts, and mechanical jigs — PETG is easier, tougher in day-to-day use, and prints reliably at any size. Still unsure? Read the full materials guide or compare with PLA vs ABS.