Flexible Magnetic Sheeting for Vehicle Graphics: Design, Installation & Safety

Flexible magnetic sheeting provides a convenient way to create removable vehicle graphics for businesses, contractors, delivery fleets, service companies and temporary promotions.

A magnetic vehicle sign can be installed without permanent adhesive and removed when the graphic is no longer required.

But successful vehicle magnets require more than simply printing a graphic on magnetic material and placing it on a vehicle.

The magnetic material, vehicle body panel, paint condition, surface cleanliness, contact area, graphic size, installation method and operating environment all influence the performance of the finished sign.

Table of Contents

• 1. How Do Magnetic Vehicle Graphics Work?
• 2. Is the Vehicle Actually Magnetic?
• 3. Choosing Magnetic Sheeting Thickness
• 4. Magnetic Holding Force Matters — But It Is Not the Only Factor
• 5. Flat Contact and Vehicle Contours
• 6. Graphic Size, Shape and Edge Design
• 7. Preparing the Vehicle Surface
• 8. Installing a Magnetic Vehicle Graphic
• 9. Paint and Finish Considerations
• 10. Temperature, Weather and Outdoor Exposure
• 11. Driving, Airflow and Dynamic Loads
• 12. Removal, Cleaning and Reinstallation
• 13. Storing Vehicle Magnets
• 14. Printing and Finishing
• 15. How to Qualify a Vehicle Magnet
• 16. Common Vehicle Magnet Mistakes
• 17. Frequently Asked Questions

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1. How Do Magnetic Vehicle Graphics Work?

A flexible magnetic vehicle graphic uses magnetic attraction between the magnetic sheet and a compatible ferromagnetic vehicle body panel.

The magnetic material is normally magnetized on the side facing the vehicle. The opposite side carries the printable or finished graphic surface.

The system can be simplified as:

Printed Graphic → Flexible Magnet → Vehicle Steel

Unlike a pressure-sensitive vehicle decal, the magnetic graphic does not rely on an adhesive bond to the vehicle.

This allows the sign to be removable and reusable when the application and material are suitable.

For the fundamentals of flexible magnetic material, see SSKC-026 — Flexible Magnetic Sheeting Explained.

2. Is the Vehicle Actually Magnetic?

This should be the first question before producing a magnetic vehicle sign.

Flexible magnets require a compatible ferromagnetic target surface.

Many traditional vehicle body panels are made from steel and can provide a magnetic target. However, modern vehicles may also use:

• aluminum;
• plastic;
• fiberglass;
• composite materials;
• other non-ferromagnetic constructions.

Different panels on the same vehicle may also use different materials.

A magnet may therefore hold well on one door or body panel and not hold at all on another.

3. Choosing Magnetic Sheeting Thickness

Flexible magnetic sheeting is available in different thicknesses, and thickness is one factor that can influence magnetic performance and physical handling.

Common graphic applications may use materials such as 15 mil, 20 mil or 30 mil magnetic sheeting, depending on the product and application.

However, thickness alone does not determine whether a magnetic material is suitable for vehicle use.

Performance also depends on:

• magnetic formulation;
• magnetization pattern;
• pole configuration;
• vehicle steel;
• paint and coatings;
• surface contact;
• graphic dimensions;
• environment;
• vehicle operating conditions.

For a detailed comparison of common thicknesses, see SSKC-031 — 15 mil vs 20 mil vs 30 mil Magnetic Sheeting.

4. Magnetic Holding Force Matters — But It Is Not the Only Factor

A stronger magnetic material can improve attraction to compatible steel, but vehicle performance cannot be predicted from a magnetic pull-force value alone.

Real-world holding depends on the complete interface:

Magnet + Vehicle Steel + Paint/Coating + Air Gap + Contact Area + Geometry + Load Direction + Friction + Environment

Paint, coatings, dirt, trapped particles and imperfect contact can all create separation between the magnet and steel.

This separation acts as an air gap and can reduce magnetic holding performance.

For more on flexible magnet performance, see SSKC-033 — Flexible Magnet Holding Force Explained.

5. Flat Contact and Vehicle Contours

Magnetic vehicle graphics generally perform best when they can make broad, continuous contact with a relatively flat compatible surface.

Problem areas can include:

• sharp body contours;
• deep curves;
• creases;
• mouldings;
• trim;
• door gaps;
• panel edges;
• recessed areas;
• areas where part of the magnet cannot contact the vehicle.

If a portion of the magnet bridges over a contour instead of following the surface, the effective contact area decreases.

An exposed edge can also become more vulnerable to airflow and mechanical lifting.

6. Graphic Size, Shape and Edge Design

Vehicle magnets are commonly produced as rectangles, squares or custom shapes.

The design should allow the perimeter of the magnet to remain in good contact with the vehicle.

Consider:

• available flat panel area;
• body contours;
• door handles;
• trim;
• panel gaps;
• graphic orientation;
• edge exposure to airflow;
• handling during installation and removal.

Rounded corners

Rounded corners are often useful for magnetic vehicle graphics because they eliminate sharp points that can be more vulnerable to catching, bending or lifting.

Corner design alone, however, cannot compensate for inadequate magnetic contact or an unsuitable installation area.

7. Preparing the Vehicle Surface

Cleanliness is critical.

Before installing a magnetic graphic, both the vehicle surface and the magnetic contact surface should be clean and dry according to the applicable material and vehicle-care recommendations.

Possible contaminants include:

• dust;
• dirt;
• sand;
• road debris;
• oil;
• grease;
• wax;
• moisture;
• cleaning-product residue.

Particles trapped between the magnet and paint can interfere with contact and may also affect the vehicle finish when the magnet moves or is removed.

Do not use a cleaner simply because it is effective on magnetic material. Confirm that it is also appropriate for the vehicle finish.

8. Installing a Magnetic Vehicle Graphic

The exact installation procedure should follow the recommendations supplied for the magnetic material and the vehicle finish.

As general design principles:

1. Confirm the panel is magnetically compatible.
2. Inspect the paint and surface condition.
3. Clean and dry both contact surfaces.
4. Position the graphic on a suitable flat area.
5. Ensure broad contact across the entire magnetic surface.
6. Check the perimeter for lifted edges or bridged areas.
7. Reinspect the graphic regularly during service.

Do not intentionally stretch flexible magnetic material around complex vehicle contours unless the specific product and application have been qualified for that condition.

9. Paint and Finish Considerations

Magnetic compatibility does not automatically establish compatibility with every automotive finish.

Factors can include:

• paint type;
• paint age;
• repair history;
• clear coat;
• surface contamination;
• recent refinishing;
• existing damage;
• protective films or coatings;
• vehicle manufacturer requirements.

Extra caution should be used with newly painted, repaired or refinished surfaces. Follow the paint, vehicle and magnetic-material manufacturers’ instructions regarding required curing time and suitability.

10. Temperature, Weather and Outdoor Exposure

A vehicle graphic may experience a demanding environment, including:

• summer heat;
• winter cold;
• sunlight;
• rain;
• snow;
• road salt;
• humidity;
• freeze-thaw cycles;
• repeated wetting and drying.

In Canada, a vehicle can also experience substantial temperature changes between seasons and even within a single day.

Outdoor suitability therefore depends on the complete graphic construction, not only the magnetic layer.

Consider the:

• magnetic compound;
• printable face;
• ink system;
• laminate;
• edge condition;
• vehicle finish;
• expected service environment.

Product-specific temperature and outdoor-use limits should always come from the applicable manufacturer data.

11. Driving, Airflow and Dynamic Loads

A vehicle magnet is not a purely static application.

When the vehicle moves, the graphic can be exposed to airflow, vibration, water, road debris and repeated mechanical loading.

Risk can increase when:

• an edge is lifted;
• the graphic crosses a body contour;
• contact is incomplete;
• the target panel is weakly magnetic;
• contamination creates a gap;
• the material is damaged or distorted;
• the graphic is installed in an unsuitable location.

Because actual aerodynamic loading depends on the vehicle, sign geometry, installation location, speed and environment, a universal safe-speed claim should not be inferred from magnetic pull-force data alone.

12. Removal, Cleaning and Reinstallation

Vehicle magnets should not simply be installed and forgotten indefinitely.

Periodic removal allows the user to inspect and clean:

• the magnetic contact surface;
• the vehicle paint;
• the edges of the graphic;
• any accumulated dirt or moisture;
• signs of damage or distortion.

The appropriate removal and cleaning interval depends on the magnetic product, vehicle finish, climate, driving conditions and manufacturer recommendations.

After cleaning, allow the surfaces to reach the required clean and dry condition before reinstalling the graphic.

13. Storing Vehicle Magnets

Improper storage can deform a flexible magnetic graphic and make future installation more difficult.

The objective is to preserve:

• flatness;
• clean contact surfaces;
• edge condition;
• printed surface quality;
• overall dimensional stability.

Follow the specific magnetic-material manufacturer’s storage recommendations, especially if the graphic must be rolled rather than stored flat.

Avoid folding or sharply creasing flexible magnetic graphics.

Before reinstalling a stored magnet, inspect it for deformation, contamination or damaged edges.

14. Printing and Finishing

A magnetic vehicle graphic is also a printed graphic product.

The printing process must therefore be compatible with the magnetic media.

Variables can include:

• printer technology;
• media thickness capability;
• heat exposure;
• media transport;
• ink adhesion;
• lamination;
• cutting;
• finished edge quality.

For printer compatibility and media selection, see SSKC-035 — Printable Magnetic Sheeting: Choosing the Right Material for Your Printer.

For cutting and finishing methods, see SSKC-038 — Cutting and Fabricating Flexible Magnetic Materials.

15. How to Qualify a Vehicle Magnet

When evaluating a new magnetic material, vehicle type or graphic construction, test the complete system under representative conditions.

1. Identify the exact magnetic material.
2. Confirm that the intended vehicle panel is ferromagnetic.
3. Inspect the paint and surface condition.
4. Test the actual graphic size and shape when practical.
5. Confirm full contact across the magnet.
6. Inspect edges and corners.
7. Evaluate the printed and laminated construction.
8. Consider expected temperature and weather exposure.
9. Follow the material and vehicle manufacturers’ instructions.
10. Establish inspection, cleaning and maintenance procedures.

16. Common Vehicle Magnet Mistakes

Mistake 1: Assuming every vehicle panel is steel

Modern vehicles may contain aluminum, plastic, composite and other non-ferromagnetic panels.

Mistake 2: Selecting material based only on thickness

Thickness is only one variable. Magnetic formulation, magnetization and the complete application matter.

Mistake 3: Installing over dirt or moisture

Contamination can reduce contact and may create problems at the paint interface.

Mistake 4: Crossing sharp body contours

Bridging a contour reduces effective magnetic contact and may expose an edge to airflow.

Mistake 5: Assuming catalog holding force predicts road performance

Vehicle graphics experience dynamic loads that differ from controlled holding-force tests.

Mistake 6: Ignoring paint condition

Fresh, repaired, damaged or otherwise sensitive finishes require appropriate guidance before magnetic graphics are installed.

Mistake 7: Leaving the magnet installed without inspection

Periodic removal allows the vehicle and magnetic surfaces to be cleaned and inspected.

Mistake 8: Storing the graphic folded or sharply creased

Permanent deformation can reduce flat contact during future installations.

Mistake 9: Assuming stronger is always better

Magnetic strength matters, but proper contact, vehicle compatibility, geometry and maintenance remain essential.

17. Frequently Asked Questions

Can magnetic sheeting be used for vehicle signs?

Yes, when the specific magnetic product is suitable for the application and the vehicle has an appropriate ferromagnetic body panel with a compatible surface condition.

What thickness magnetic sheet should I use for a car magnet?

There is no universal thickness that is correct for every vehicle application. Thickness should be considered together with the magnetic formulation, magnetization, graphic size, target panel, surface condition and product manufacturer’s recommendations.

Is 30 mil magnetic sheeting suitable for vehicle graphics?

30 mil material is commonly associated with vehicle magnetic graphics, but thickness alone does not establish suitability. Confirm that the specific 30 mil product is intended for the application and that the vehicle and installation conditions are appropriate.

Will a magnetic sign stick to every car or truck?

No. Aluminum, plastic, fiberglass, composites and other non-ferromagnetic materials will not provide the same magnetic attraction as suitable steel. Always test the exact panel.

Why does my vehicle magnet lift at the edges?

Possible causes include contamination, poor surface contact, body contours, deformation, damaged edges, insufficient magnetic performance or an unsuitable installation area.

Should vehicle magnets have rounded corners?

Rounded corners can reduce sharp points that may be more vulnerable to catching or lifting, but they do not replace the need for proper material selection and full surface contact.

Can I put a magnetic sign over newly painted bodywork?

Do not assume that this is safe. Newly painted or refinished surfaces may require a specific curing period or other precautions. Follow the applicable paint, repair, vehicle and magnetic-material guidance.

Can a magnetic vehicle sign stay installed all year?

The appropriate service and maintenance schedule depends on the specific magnetic material, vehicle finish, climate and manufacturer recommendations. Regular removal, cleaning and inspection should be part of the application plan.

Can I take a vehicle magnet through a car wash?

Do not assume that a magnetic graphic is suitable for automatic or high-pressure washing while installed. Follow the magnetic-material and vehicle-care recommendations and remove the graphic when required.

Does a stronger magnet automatically make a safer vehicle sign?

No. Magnetic strength is only one part of the system. Full contact, compatible steel, graphic geometry, edge condition, installation, driving environment and maintenance all affect performance.

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Safety Reminder

A magnetic vehicle graphic is a removable exterior component exposed to a dynamic environment.

Use only magnetic material appropriate for the intended application, verify the actual vehicle panel, follow the applicable manufacturer instructions and inspect the graphic regularly.

If the material, vehicle surface or installation conditions are uncertain, test and qualify the application before regular road use.

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Continue Learning About Flexible Magnetic Materials

Start with SSKC-026 — Flexible Magnetic Sheeting Explained.

Compare common thicknesses in SSKC-031 — 15 mil vs 20 mil vs 30 mil Magnetic Sheeting.

Learn how to select flexible magnetic material in SSKC-032 — How to Choose Flexible Magnetic Sheeting.

Understand magnetic holding performance in SSKC-033 — Flexible Magnet Holding Force Explained.

For printing, see SSKC-035 — Printable Magnetic Sheeting.

For cutting and finishing, see SSKC-038 — Cutting and Fabricating Flexible Magnetic Materials.

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Need Help Selecting Magnetic Material for Vehicle Graphics?

Tell us the vehicle type, intended body-panel location, finished graphic dimensions, printing method, expected environment and quantity required.

For an unfamiliar vehicle or application, test the actual installation area before producing the full order.

Simple Signman — a leading Canadian source for flexible magnetic materials and neodymium magnets.

Sharing our magnetic expertise since 1969.