PLA, PETG, ABS or TPU: Which Filament Should You Actually Use?

Walk into any filament shop and you'll find a dozen materials, all promising to be stronger, tougher or more heat-resistant than the last one. For almost everything you will ever print, four of them cover the ground: PLA, PETG, ABS and TPU. Here's what each one is actually good at, and — more usefully — what each one is bad at. The short version PLA PETG ABS / ASA TPU Nozzle 190–220 °C 230–250 °C 230–260 °C 220–235 °C Bed 55–65 °C 70–85 °C 100–110 °C 40–60 °C Enclosure No Helpful Effectively required No Softens at ~60 °C ~80 °C ~105 °C Varies Difficulty Easy Moderate Hard Moderate Breaks by Snapping Bending Bending Doesn't Treat these numbers as starting points, not gospel. Brands vary, and the spool label is more authoritative than any table on the internet — but the label is often a wide range, and these are sensible places to begin inside it. PLA: use it unless you have a reason not to PLA is the default for good reason. It prints at low temperatures, barely warps, doesn't smell, doesn't need an enclosure, and holds fine detail better than anything else on this list. If you're printing something decorative, something you're testing, or anything that lives indoors and doesn't take load, use PLA. It is also stiffer than most people expect. PLA has a higher tensile strength than PETG on paper. What it lacks is toughness: it resists being pulled, but it snaps rather than bends when you overload it. Drop a PLA part on a tiled floor and it shatters; the same part in PETG bounces. The thing that catches everybody out is heat. PLA starts to soften around 60 °C. That sounds high until you leave a print on a car dashboard in summer, and come back to a sculpture. A closed car in the sun comfortably exceeds 60 °C. So does the inside of a window sill in July, a spot next to a radiator, and the top of a 3D printer's own power supply. If the part will sit in a hot place, PLA is the wrong answer, and this is the single most common material mistake beginners make. Good for: decorative prints, figurines, prototypes, cake toppers, indoor signs, boxes and organisers, anything you'll print once and look at. Bad for: car interiors, anything outdoors in summer, mechanical parts under load, anything that gets dropped. PETG: the practical middle ground PETG is what you move to when PLA breaks. It's tougher, more flexible before it fails, holds up to about 80 °C, resists water and UV reasonably well, and is a genuinely good outdoor material. It's the same family of plastic as drinks bottles. It is meaningfully fussier to print, in three specific ways. It strings. PETG likes to leave fine hairs between parts of a model. This is mostly curable — lower the nozzle temperature in 5 °C steps, increase retraction distance, and dry the filament — but expect to spend an evening calibrating rather than getting perfect results out of the box. It sticks to the plate too well. This sounds like a good problem and isn't. PETG bonds chemically to smooth PEI and to glass, strongly enough to tear the coating off the plate when you remove the part. The fix is to put a thin layer of ordinary glue stick down first — not as adhesive, but as a release layer that stops direct contact. Textured PEI is generally safe without it. It absorbs water fast. A spool left open in a humid room for a few weeks will print visibly worse — popping sounds, rough surfaces, more stringing. Keep PETG sealed with desiccant between prints. One more thing worth knowing: PETG doesn't bond as well between layers as it does to itself in a single layer, and it can be surprisingly weak against splitting along layer lines. Print important parts with more walls rather than more infill. Good for: functional parts, brackets, outdoor items, planters, things that flex slightly, phone stands, anything that needs to survive a drop. Bad for: fine detail (it rounds off crisp edges), your first ever print, anything where stringing would ruin the look. ABS and ASA: only with an enclosure ABS is what injection-moulded consumer goods are made of — Lego, car trim, tool housings. It's tough, machinable, holds up past 100 °C, and can be smoothed to a glossy finish with acetone vapour, which nothing else here can do. It also warps aggressively. As ABS cools it shrinks, and that shrinkage pulls the corners of your print off the plate with real force. Printing ABS on an open printer in a normal room means large parts will lift, split partway up, or simply fall off. An enclosure isn't a nice-to-have; it's the thing that makes ABS work. Ventilation matters too. ABS releases styrene and ultrafine particles while printing, with a distinct sharp smell. Print it in a ventilated space — not a bedroom, not a closed office you're sitting in. If your printer has a filtered enclosure, use it. ASA is ABS's better-behaved cousin. Very similar temperatures and handling, slightly less warping, and much better UV resistance. If a part is going to live outside in the sun, ASA holds its colour and strength where ABS goes chalky and brittle. For most people, if you're reaching for ABS, ASA is the better choice. Good for: car parts, tool holders, anything near heat, parts you want to sand and paint, outdoor items in direct sun (ASA). Bad for: open printers, unventilated rooms, large flat parts, anyone who wants a quiet life. TPU: flexible, and slower than you think TPU is rubber. You can bend it, squash it, and it springs back. It's sold by hardness on the Shore scale — 95A is the common general-purpose grade and roughly the firmness of a shoe sole. Lower numbers (85A) are floppier and much harder to print; higher numbers (98A, or Shore D grades) are stiffer and more forgiving. The main thing to understand is that you cannot push a flexible filament fast. The extruder is trying to shove a piece of rubber down a tube, and rubber compresses instead of pushing. Print TPU at 20–30 mm/s. Faster than that and the filament buckles inside the extruder and jams. Direct drive extruders handle TPU much better than Bowden setups, because the filament has a shorter unsupported path. You can print TPU on a Bowden printer, but expect more trouble and softer grades to be nearly impossible. Two more practical notes: use little or no retraction, since retracting a rubber string just stretches it; and dry your TPU, because it absorbs moisture even faster than PETG. Good for: phone cases, gaskets and seals, watch straps, tyres and wheels, protective bumpers, anything that needs to grip. Bad for: anything rigid, fast printing, fine detail, Bowden printers with soft grades. How to actually choose Rather than memorising the table, ask three questions about the part: Will it get hot? Above 50 °C — in a car, in direct sun, near a motor or a light — PLA is out. Go PETG, or ASA if it's outdoors and sunny. Will it take load or get dropped? If a crack would matter, PETG over PLA. PLA is fine for things that sit still. Does it need to bend? Then TPU, and only TPU. Nothing else on this list flexes usefully. If all three answers are no — and for most of what people print, they are — use PLA. It's cheaper, easier, prints faster, looks better, and you'll finish the job today instead of calibrating all evening. The one habit that helps with all of them Keep your filament dry. Every material here absorbs water from the air, some of them fast, and wet filament produces bad prints in ways that look like a dozen other problems: stringing, popping noises, weak layers, rough surfaces, inconsistent extrusion. People spend weeks tuning retraction settings to fix problems that a night in a dryer would have solved. Sealed boxes with silica gel are cheap. A filament dryer is better. Either beats troubleshooting the wrong thing.