Materials 101: Choosing the Right Filament

PETG vs ABS vs ASA vs Nylon for Automotive Use

Material selection is critical for automotive parts. Car interiors can exceed 70°C in direct sun. Learn which filament to use for each application.

Heat Matters: Why Material Selection is Critical

A parked car in direct sun can reach 70°C+ interior temperatures.We don't recommend using PLA as it softens at 55-60°C. Parts on dashboards, door panels, and near windows will warp and fail if printed in the wrong material. For most automotive interior parts, PETG is the minimum. For exterior parts, use ASA.

Material Guide

ASA

Max temp: 85-105°C

UV: Excellent

Chem: Avoid gas, acetone, isopropyl

Flexibility: Low

Fumes: High - enclosure + ventilation

Best for:

Exterior trim, mirror caps, grilles, dashboard parts, and any sun-exposed interior

Avoid:

Isopropyl alcohol (causes stress cracking)

Our recommended default for most car parts. UV stable, heat resistant (105°C glass transition), and handles the extreme temperatures inside parked cars.

Nylon (PA6)

Max temp: 80-180°C (varies by type)

UV: Good

Chem: Avoid strong acids, phenols

Flexibility: High

Fumes: High - enclosure + ventilation

Best for:

Clips, retainers, fasteners, snap-fits, hinges, any part that needs to flex

Avoid:

Humid storage (must dry filament)

Extremely durable and flexible. Best for parts that need to bend without breaking. Carbon-filled versions (PA6-CF) add rigidity for structural brackets.

PA6-CF (Carbon Fiber Nylon)

Max temp: 120-180°C

UV: Good

Chem: Avoid strong acids, phenols

Flexibility: Low

Fumes: High - enclosure + ventilation required

Best for:

Structural brackets, engine mounts, load-bearing parts, high-heat applications

Avoid:

Bare skin contact surfaces — carbon fiber dust is a skin and lung irritant. Sand and paint any surface that will be touched or handled.

Extremely stiff and strong. The carbon fiber reinforcement adds rigidity but makes the surface abrasive. Requires a hardened stainless steel nozzle (carbon fiber destroys brass nozzles). Must be dried before printing. Always sand and seal or paint any surface users will touch.

TPU (Flexible)

Max temp: 60-80°C

UV: Good

Chem: Avoid strong acids

Flexibility: Very High

Fumes: Low

Best for:

Gaskets, seals, weatherstrips, vibration mounts, dust boots, grommets

Avoid:

Tight-tolerance parts (flexibility makes precision hard)

Flexible and abrasion resistant. Print slow with minimal retraction.

ABS

Max temp: 85-105°C

UV: Poor (yellows)

Chem: Avoid gas, acetone, isopropyl

Flexibility: Low

Fumes: High - enclosure + ventilation

Best for:

Under-hood brackets, high-heat interiors

Avoid:

Exterior (UV damage), isopropyl alcohol

Classic automotive plastic. Acetone smoothable. Largely replaced by ASA for car parts due to poor UV resistance.

PETG

Max temp: 65-80°C

UV: Moderate

Chem: Avoid acetone, strong solvents

Flexibility: Medium

Fumes: Low

Best for:

Workshop prints, prototyping, non-vehicle parts

Avoid:

Any part that stays in the vehicle — parked car interiors regularly exceed 80°C

Easy to print and no enclosure needed, but the low glass transition temperature (65-80°C) makes it unsuitable for parts that stay in a car. Use ASA instead for in-vehicle parts.

Quick Comparison Table

Property	ASA	Nylon	PA6-CF	TPU	ABS	PETG
Max Temp	85-105°C	80-180°C	120-180°C	60-80°C	85-105°C	65-80°C
UV Resistance	Excellent	Good	Good	Good	Poor	Moderate
Chem Resistance	Avoid gas, acetone, isopropyl	Avoid strong acids	Avoid strong acids	Avoid strong acids	Avoid gas, acetone, isopropyl	Avoid acetone
Ease of Printing	Hard	Hard	Hard	Medium	Hard	Easy
Fumes	High	High	High	Low	High	Low
Enclosure Needed	Yes	Yes	Yes	No	Yes	No
Impact Strength	High	Very High	High	Very High	High	Medium
Flexibility	Low	High	Very Low	Very High	Low	Medium
Skin Safe (bare)	Yes	Yes	No — sand & paint first	Yes	Yes	Yes

Material by Location

Quick reference for choosing materials based on where the part will be installed.

Dashboard/Interior (sun exposed)

ASA or ABS

Dashboards can exceed 70°C. Need 100°C heat deflection for safety margin.

Under-dash/Hidden interior

ASA

Even hidden interiors get hot in parked cars. ASA handles the heat.

Exterior trim (mirror caps, grilles)

ASA

UV exposure requires ASA's stability. ABS will yellow.

Engine bay (non-contact)

ABS or Nylon

High temps require 100°C+ heat deflection.

Clips and fasteners

PA6 (Nylon)

Needs flexibility without breaking. PA6 snaps into place without cracking.

Prototyping/test fits

PLA

Cheap, fast, accurate. Perfect for verifying fit before final print. Just don't leave it in the car.

Frequently Asked Questions

Why don't you recommend PLA for car parts?

PLA softens at 55-60°C. Car interiors regularly exceed 70°C in direct sunlight - even in moderate climates. We've seen countless PLA parts warp, sag, or fail completely. ASA is our recommended default — it handles UV, heat (105°C glass transition), and the extreme temperatures inside parked cars. See our ASA vs PETG comparison for more details.

What's the difference between ABS and ASA?

ASA is essentially ABS with UV stabilizers added. Both print similarly and have similar strength/heat properties, but ASA won't yellow or become brittle from sun exposure. For exterior parts, always choose ASA over ABS.

Do I need an enclosed printer?

For ABS, ASA, and Nylon, yes. These materials warp severely without stable ambient temperatures (40-60°C chamber). PETG prints fine in open air and is our recommended starting material.

What about carbon fiber or glass-filled filaments?

These add stiffness and dimensional stability but require a hardened nozzle (they're abrasive). Great for brackets that need to stay rigid. CF-PETG is a good middle ground for automotive use. Do not use on human touch surfaces - the CF and glass shards rub off and cause irritation.

How long do 3D printed parts last in a car?

With the right material choice, years. ASA exterior parts hold up well over time with minimal degradation. Interior PETG parts in shaded areas are very durable. The key is matching material to environment - heat and UV are the main killers.

Troubleshooting

PETG strings badly between parts

Increase retraction (5-7mm), lower temp by 5-10°C, enable coasting in slicer. PETG is stringy by nature.

ABS/ASA warps and lifts from bed

Use an enclosure, increase bed temp to 100-110°C, apply ABS slurry or glue stick. Draft shields in slicer help.

Parts are brittle and snap

Check for moisture in filament (dry at 65°C for 4+ hours). Increase nozzle temp 5-10°C. Ensure proper layer adhesion.

Nylon won't stick to the bed

Use Magigoo PA or PVA glue stick. Bed at 60-70°C. Enclosure helps. Ensure filament is bone dry.

Deep Dive: ASA vs PETG

Learn the specifics of choosing between these two popular automotive materials.

ASA vs PETG Guide Printing Settings