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. PLA 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

PETG

Max temp: 65-80°C

UV: Moderate

Chem: Avoid acetone, strong solvents

Difficulty: Easy

Fumes: Low

Best for:

Interior clips, brackets, under-dash parts

Avoid:

Direct sun exposure, exterior trim

Best balance of ease and performance. Our recommended starting material for most interior parts.

ABS

Max temp: 85-105°C

UV: Poor (yellows)

Chem: Avoid gas, acetone, isopropyl

Difficulty: Hard

Fumes: High - enclosure + ventilation

Best for:

Under-hood brackets, high-heat interiors

Avoid:

Exterior (UV damage), isopropyl alcohol

Strong fumes. Acetone smoothable. Classic automotive plastic.

ASA

Max temp: 85-100°C

UV: Excellent

Chem: Avoid gas, acetone, isopropyl

Difficulty: Hard

Fumes: High - enclosure + ventilation

Best for:

Exterior trim, mirror caps, grilles, any sun-exposed part

Avoid:

Isopropyl alcohol (causes stress cracking)

ABS with UV stability. The gold standard for outdoor automotive parts.

Nylon (PA)

Max temp: 80-180°C (varies by type)

UV: Good

Chem: Avoid strong acids, phenols

Difficulty: Hard

Fumes: High - enclosure + ventilation

Best for:

High-wear parts, hinges, low stress gears

Avoid:

Humid storage (must dry filament)

Extremely durable and flexible. Carbon-filled versions are very strong.

TPU (Flexible)

Max temp: 60-80°C

UV: Good

Chem: Avoid strong acids

Difficulty: Medium

Fumes: Low

Best for:

Gaskets, seals, vibration mounts, dust boots, grommets

Avoid:

Tight-tolerance parts (flexibility makes precision hard)

Flexible and abrasion resistant. Print slow with minimal retraction.

Quick Comparison Table

Property	PETG	ABS	ASA	Nylon	TPU
Max Temp	65-80°C	85-105°C	85-100°C	80-180°C	60-80°C
UV Resistance	Moderate	Poor	Excellent	Good	Good
Chem Resistance	Avoid acetone	Avoid gas, acetone, isopropyl	Avoid gas, acetone, isopropyl	Avoid strong acids	Avoid strong acids
Ease of Printing	Easy	Hard	Hard	Hard	Medium
Fumes	Low	High	High	High	Low
Enclosure Needed	No	Yes	Yes	Yes	No
Impact Strength	Medium	High	High	Very High	Very High
Flexibility	Medium	Low	Low	High	Very High

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

PETG

Lower temps, easy printing, good strength.

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

PETG or Nylon

Needs flexibility without breaking. Nylon for high-cycle use.

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. PETG prints almost as easily and handles automotive temperatures. See our ASA vs PETG comparison for exterior choices.

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