What’s on the Outside of Cars? The Materials Shaping Modern Vehicle Exteriors

Mostly painted steel and aluminum form the outer skin of today’s cars, supplemented by plastic fascias and trims, glass windows, rubber seals, and multilayer protective coatings. Depending on the vehicle and its purpose, automakers also use composites like fiberglass or carbon fiber, specialized plastics for bumpers and lights, and, in rare cases, unpainted stainless steel. Choices balance cost, weight, durability, safety, and styling—an equation increasingly influenced by efficiency targets and sustainability goals.

Body Panels: The “Skin” You See and Touch

The large exterior panels—hood, doors, fenders, roof, trunk, and quarter panels—are typically stamped metal or molded composites. While a car’s structural core (the body-in-white) is mostly hidden, the outer panels must look flawless, resist dents and corrosion, and meet crash and pedestrian-safety requirements.

• Painted steel (mild, high-strength, and advanced high-strength steels): The most common material for mass-market vehicles due to cost-effectiveness, formability, and repairability. Steels are usually zinc-coated (galvanized) for corrosion resistance.
• Aluminum (5xxx and 6xxx series): Widely used for hoods, doors, trunk lids, and in some models entire bodies, to save weight and improve efficiency. Found on many EVs and premium vehicles.
• Magnesium (limited use): Extremely light but costly and challenging to form; used sparingly in exterior parts.
• Composites (fiberglass/SMC): Common on performance and specialty models (e.g., Corvette body panels) for dent resistance and complex shapes.
• Carbon-fiber reinforced polymer (CFRP): Lightweight and rigid, used on high-end or low-volume cars (roofs, hoods, or full panels) where cost allows.
• Stainless steel (rare): Notably, the Tesla Cybertruck uses unpainted, cold-rolled stainless outer panels, trading paint for a durable, corrosion-resistant finish with a distinctive look.

Each material brings trade-offs: steel is affordable and easy to fix, aluminum cuts weight but can be pricier to repair, and composites enable sculpted forms with excellent dent resistance but add cost and complexity.

Plastics, Fascias, and Exterior Trim

Not everything you see is metal. Modern exteriors rely on engineered plastics that are tough, lightweight, and flexible—ideal for impact-prone areas and detailed styling elements.

• Bumper covers and fascias: Typically TPO (thermoplastic olefin) or PP/EPDM blends for impact resistance and paintability; mounted over energy-absorbing structures.
• Grilles and exterior accents: ABS or PC-ABS for crisp details; finishes include paint, metallic-look films, or PVD and trivalent-chrome coatings.
• Lighting lenses: UV-stabilized polycarbonate with a hardcoat to resist yellowing and abrasion; housings are often PC-ABS.
• Mirror housings and spoilers: ABS, PC-ABS, or reinforced plastics for shape and durability.
• Wheel-arch liners, splash guards, and underbody shields: PP or HDPE to shed debris, cut weight, and aid aerodynamics.
• Seals and gaskets: EPDM rubber for weatherproofing around doors, windows, and trunks.
• Badges and emblems: ABS or acrylic, sometimes with metallic coatings or thin aluminum appliqués.

These plastic and rubber components absorb impacts, resist weathering, and allow intricate designs, all while keeping weight and costs in check.

Glass and Transparent Surfaces

Vehicle glazing must balance clarity, strength, and safety—preventing shattering while reducing noise, heat, and ultraviolet exposure.

• Windshields: Laminated safety glass with a PVB (or similar) interlayer that holds fragments in place; often includes acoustic interlayers and solar-control coatings.
• Side and rear windows: Typically tempered glass for strength; some premium models use laminated side glass for noise reduction and security.
• Panoramic roofs: Laminated glass with tints and solar coatings; some offer electrochromic dimming.
• Headlamp/taillamp covers: Polycarbonate with a protective hardcoat rather than glass, enabling complex shapes and light signatures.

Glazing technology continues to advance with better acoustic performance, UV/IR filtering, and integrated antennas or heaters for defogging and de-icing.

Paint, Coatings, and Films: The Protective Finish

Beyond color, the paint system protects the body from corrosion, UV radiation, chips, and chemicals. Plastic parts often use flexible primers and matched paints to blend seamlessly with metal panels.

• Pretreatment: Cleaning and conversion coatings (e.g., phosphate or zirconium) to promote adhesion and corrosion resistance.
• E-coat (electrodeposition primer): An epoxy-based, electrically applied primer that uniformly covers seams and cavities.
• Primer-surfacer: Smooths minor imperfections and provides chip resistance; elastomer-modified versions are used on plastic fascias.
• Basecoat: The color layer, increasingly waterborne to cut VOCs; effects include metallic and pearlescent flakes.
• Clearcoat: A UV-resistant polyurethane or acrylic layer for gloss and durability; matte/satin clearcoats are now common on performance and luxury models.
• Galvanized steel and cavity waxes: Added corrosion defenses in hidden areas; seam sealers and underbody coatings protect against moisture and debris.
• Aftermarket wraps and protection: Vinyl wraps (usually PVC) change color/finish; paint protection film (aliphatic polyurethane) guards against chips; ceramic coatings add hydrophobic, easier-to-clean surfaces.

Together, these layers and optional films deliver the color you see and the protection your car needs, with automakers steadily moving toward lower-VOC, waterborne, and more sustainable chemistries.

Wheels, Hardware, and Other Exterior Elements

Surrounding the body are components that blend function with finish, playing a key role in appearance and durability.

• Wheels: Mostly aluminum alloys (cast or forged) with paint, powder coat, clearcoat, or diamond-cut faces; some base models still use steel wheels with covers.
• Exhaust tips and brightwork: Stainless steel, PVD-coated parts, or trivalent-chrome-plated plastics.
• Roof rails and trim: Aluminum or coated steel; window surrounds may be anodized aluminum or blacked-out plastic.
• Antenna “shark fins” and sensor covers: PC-ABS designed for radio transparency; camera and radar covers are RF-optimized plastics.
• Wiper arms/blades and fasteners: Painted or powder-coated steel/aluminum; blades use rubber compounds with performance coatings.

These pieces are engineered to withstand weather, road salts, and UV exposure while preserving styling cues and aerodynamic performance.

How Automakers Choose Exterior Materials

Material selection is a balancing act shaped by safety rules, manufacturing capability, cost, and brand positioning. Electrification and efficiency targets add urgency to reducing mass and drag without compromising durability.

• Safety and compliance: Crashworthiness, pedestrian impact standards, lighting regulations.
• Weight and efficiency: Lighter materials improve fuel economy and EV range.
• Cost and repairability: Availability of tooling, repair methods, and insurance considerations.
• Manufacturability: Formability, paint compatibility, and joining (adhesives, rivets, welds).
• Durability and corrosion resistance: Coatings, galvanization, and material selection for climate and road-salt exposure.
• Sustainability: Recycled content, low-VOC paints, and end-of-life recyclability.

The “right” exterior is often a multi-material blend, tailored to each model’s mission and price point.

Trends and Innovations (2020s–2025)

Recent models reflect rapid shifts in design and manufacturing, many driven by EVs and sustainability targets.

• Multi-material bodies and large castings: Mixing AHSS, aluminum, and composites; EV makers increasingly use giant aluminum “gigacastings” to reduce part counts.
• Lighter, cleaner coatings: More waterborne basecoats, low-VOC processes, and energy-efficient curing; growing use of trivalent chrome instead of hexavalent.
• Recycled and bio-based plastics: Rising recycled content in fascias and liners; experimentation with bio-based TPOs and binders.
• Advanced protective surfaces: Tougher clearcoats, broader adoption of PPF from the factory on high-chip zones, and OEM matte finishes with careful care protocols.
• Distinctive exteriors: Unpainted stainless panels (e.g., Cybertruck) and expanding use of factory black-out trims; concept-stage color-changing films (e.g., E Ink demonstrations) show where customization may head.

Expect continued convergence on lighter, more sustainable exteriors, with smarter surfaces and integrated sensors reshaping what “paint and panels” mean.

Care Tips for Exterior Materials

Proper care prolongs appearance and protection across metals, plastics, and coatings.

• Wash with pH-neutral shampoos; avoid harsh solvents, especially on plastics and rubber.
• Use separate cleaners for wheels and bugs/tar; rinse thoroughly to prevent staining.
• Avoid abrasives on matte paint and polycarbonate lenses; use products labeled safe for those surfaces.
• Maintain sealants, waxes, or ceramic coatings as recommended; inspect PPF edges for lifting.
• Promptly touch up chips on painted metal to prevent corrosion.

Routine, gentle maintenance preserves coatings and reduces long-term repair costs while keeping the car looking fresh.

Summary

The outside of most cars combines painted steel and aluminum panels with plastic fascias and trims, laminated and tempered glass, rubber seals, and multilayer protective coatings. Composites and, occasionally, stainless steel appear where specific performance or design goals demand them. Automakers assemble this mix to balance safety, weight, cost, repairability, and sustainability—choices that continue to evolve with EVs, advanced manufacturing, and greener coating technologies.

What is the coating they put on cars?

A car coating is a protective liquid applied to a vehicle’s paint that chemically bonds to form a hard, glass-like layer, offering long-lasting protection from environmental factors like UV rays, dirt, and stains. Unlike temporary waxes or sealants, coatings last for years, providing benefits such as increased gloss, a “self-cleaning” effect due to their hydrophobic (water-repelling) properties, and enhanced resistance to minor scratches and chemicals.
 
This video explains what a ceramic coating is and how it works: 1mChicago Auto ProsYouTube · Jul 3, 2018
How it Works

1. Application: A liquid polymer solution, often silica-based, is applied by hand to a meticulously cleaned and prepared car surface. 
2. Chemical Bond: The coating chemically bonds with the vehicle’s paint, creating a new, durable layer that becomes an integral part of the paint. 
3. Hydrophobic Barrier: This new layer is hydrophobic, meaning it repels water, causing it to bead up and roll off easily, taking dirt and grime with it. 

Key Benefits

• Long-Lasting Protection: Provides protection against UV damage (preventing fading), environmental contaminants, acid rain, and light scratches for several years. 
• Enhanced Gloss: Creates a deep, glossy finish. 
• Easier Cleaning: The hydrophobic surface makes it harder for dirt and debris to stick, and the slick surface allows for easier removal during washing. 
• Chemical Resistance: Offers better resistance to detergents and chemicals compared to waxes and sealants. 

Types of Coatings
While various protective coatings exist, ceramic coatings are a popular and advanced form, chemically bonding to the paint for superior, long-lasting durability. 
You can watch this video to see the application process for a ceramic coating: 58sPan The OrganizerYouTube · Jun 21, 2025

What is the outside of cars made of?

Car exteriors are primarily made of steel, but modern vehicles also incorporate aluminum, plastic, and carbon fiber to balance weight, strength, and cost. Steel is a traditional choice for its strength and affordability, while aluminum offers a lighter, rust-resistant alternative. Plastic is common for non-structural parts like bumpers, and carbon fiber is a high-tech, expensive option for lightweighting performance vehicles.
 
Main Exterior Materials

• Steel: Opens in new tabThe most common and traditional material, steel provides excellent strength and collision resistance at a lower cost, making it ideal for the structural chassis and body panels of mass-produced vehicles. 
• Aluminum: Opens in new tabUsed in luxury and performance cars, aluminum is significantly lighter than steel and resistant to rust, which helps improve fuel efficiency and performance, according to Quora users. 
• Plastic: Opens in new tabFound in non-structural components such as bumpers, door handles, and trim, plastic is chosen for its light weight, flexibility, and ability to be molded into complex shapes. 
• Carbon Fiber: Opens in new tabA high-end material used in supercars and advanced models, carbon fiber is exceptionally strong and very lightweight, contributing to improved performance and reduced overall vehicle mass. 

Other Materials 

• Glass: Used for windows and windshields.
• Paint and Clear Coat: The outermost layers that provide protection and a finished appearance.
• Rubber: Used for seals, weather stripping, and other components.

What is the outer covering of a car called?

2. Body Panels: – Body panels are the outer metal or plastic coverings that give shape to your car’s body. – They protect the internal components and passengers from external elements and impacts.

Are the outside of cars plastic?

Plastic. Plastic is the most common material used in car manufacturing. It makes up roughly 50% of the volume of a typical model in recent years.