Best Filament for Car Parts: ASA vs PETG vs ABS vs PLA vs Nylon

The best filament for car parts is ASA for anything that sees sun or heat, and PETG for interior parts out of direct sunlight. ABS works if you sand or paint, nylon suits clips that must flex, and TPU suits pads and grommets. Avoid PLA for anything that stays in the car: it softens at around 55–60 °C.

A printed part can have perfect dimensions and still fail in a week. The usual reason is the material, not the model. A car is a hard place for plastic: it gets hot, it gets cold, it vibrates, and the sun hits the same spots every day.

This guide compares the five filaments people actually use for car parts. It explains which one to pick for each kind of part, with real examples from our catalogue of 13,700+ STL files. It also gives starting print settings for each material.

Why heat decides almost everything

Every thermoplastic has a temperature where it starts to soften. Engineers call it the glass transition temperature. Below it, the part is rigid. Above it, the part slowly bends under its own weight or under the load of a clip.

A parked car in summer easily passes that point for some plastics. Cabin air can reach 60–70 °C on a hot day. Dark dashboard surfaces behind the windscreen get hotter still, often 80 °C or more. The engine bay is warm whenever the car runs.

So the first question is always: where does the part live? Once you know that, the choice gets simple.

• Dashboard top, rear shelf, exterior trim: highest heat plus UV. You need ASA.
• Doors, centre console, glovebox, boot: warm but shaded. PETG is enough in most cases.
• Engine bay (non-structural brackets, covers): heat and oil vapour. ASA, ABS or nylon.
• Workshop tools and jigs: load and impact. PETG or nylon with high infill.

The five filaments compared

The table below uses typical values for common brand filaments. Exact numbers vary by brand and colour, so treat them as a guide, not a guarantee.

ASA: the default for anything in the sun

ASA was developed for outdoor use. It is chemically close to ABS but keeps its colour and strength in sunlight. It is the material to choose for dashboard parts, mirror trim, grille badges and covers on the outside of the car. It needs a heated bed of about 100 °C and an enclosure to stop warping.

PETG: the easy all-rounder for the cabin

PETG prints almost as easily as PLA, sticks well between layers and bends a little before it breaks. That makes it good for caps, trays, cup holder parts and clips in shaded places. It strings more than other filaments, and it can creep in a hot dashboard, so keep it out of direct sun.

ABS: good for parts you will finish

ABS handles heat as well as ASA, sands easily and can be smoothed with acetone vapour. Its weakness is UV: it yellows and turns brittle in sunlight unless painted. Use it for interior parts you plan to paint, and print it with good ventilation, because it gives off styrene fumes.

Nylon and carbon-fibre nylon: for parts that flex or carry load

Nylon is the toughest common filament. A nylon clip can flex thousands of times without cracking, where PLA would snap on the first try. Carbon-fibre nylon (PA-CF) adds stiffness and heat resistance. Both absorb moisture from the air, so dry the spool before printing. Carbon-fibre filaments also need a hardened steel nozzle.

PLA: fine for test fits, not for the car

PLA is perfect for a quick draft to check fit. It is not suitable for parts that stay in the car. In the first hot week, a PLA cup holder or bezel can sag and warp.

Bonus: TPU for soft parts

TPU is a flexible filament. It is the right choice for pads, bump stops for panels, grommets and anti-rattle parts. One real example: the designer of our BMW E30 idle control valve holder printed it in TPU, so it holds the valve while damping vibration.

Which filament for which part? A real-catalogue example

Theory is easier with a real car. The BMW 3 Series E46 pack has 155 files. We grouped its ten largest part types and matched each to a sensible filament.

A pattern appears. Most car parts are either visible and sunny (ASA) or hidden and flexing (PETG or nylon). If you own only one engineering filament, ASA covers the most cases. If you have no enclosure, PETG is the practical choice for the cabin.

All 155 files are in the BMW 3 Series E46 pack for €49.99, worth €1,409.45 as single files. Other cars have their own packs in our packs collection.

Tools are a special case

Our catalogue also includes workshop tools. The BMW oil filter wrench 76 mm fits the 14-flute housing cap on the E46 318i M43 engine. Another example is the Styling 5 centre hub cap wrench, which its designer describes as very tough. For tools like these, use PETG or nylon, 5–6 walls and 50% infill or more.

Starting print settings for each filament

These are common starting points. Always check the label on your spool, then fine-tune with a small test print.

Material is only half the story. For clips and small parts, use 3–4 walls and 30–50% infill. Orient clips so the layers run along the arm, not across it. Warping is the main enemy with ABS and ASA. One of our designers stresses this for the E30 grille badge: a raft is very important to prevent warping.

For more on small fasteners, read our guide on how to 3D print car clips. For the bigger picture, start with our complete guide to 3D printed car parts.

One safety rule applies whatever filament you choose: we never offer models for safety-critical parts such as brakes, steering, seat belts, airbags or structural parts. No filament makes a printed part suitable for those jobs.

Common mistakes

1. Using PLA because it printed well. A clean PLA print can still warp on the first sunny day. Use it only for test fits.
2. Printing ASA or ABS without an enclosure. Drafts cause warping and layer splits. Close the printer or use a box, and add a brim or raft.
3. Printing wet nylon or PETG. Moisture causes bubbles, stringing and weak layers. Dry the spool before long prints.
4. Putting PETG on the dashboard. It can creep over months in direct sun. Use ASA for anything behind the windscreen.
5. Running carbon-fibre filament through a brass nozzle. The fibres wear soft brass quickly. Fit a hardened steel nozzle first.

FAQ

What is the best filament for car interior parts?

ASA for parts on or near the dashboard and in sunlight. PETG for shaded interior parts like trays, caps and console pieces. Both handle cabin heat far better than PLA.

Is PETG heat resistant enough for a car?

For shaded parts, usually yes. It softens around 75–80 °C, so it can deform on a dark dashboard in summer. Use ASA there.

What filament should I use for exterior car parts?

ASA. It resists UV, heat and rain, and keeps its colour. ABS works only if you paint it to protect it from sunlight.

Can I print car parts without an enclosure?

Yes, with PETG or PLA. For ASA, ABS and nylon an enclosure strongly improves results, because it stops warping and layer splits.

Do you sell printed parts or the filament?

Neither. We sell digital STL files. You print them at home or at any local or online print shop, in the filament you choose.

Written by the PartsRemade Engineering Team.