Home / News / Industry News / Experts teach you how to use automobile body adhesives correctly 2025-09-04
With the development of the automotive industry, demands for lightweight, stronger, and more durable body structures are increasing. Automotive body adhesives are playing an increasingly important role in modern vehicle manufacturing. From bonding body panels to sealing the body and securing composite materials, the proper use of adhesives directly impacts the safety and service life of the vehicle. However, many novice operators and small workshops often encounter problems such as improper application, weak bonds, and poor durability. This article will provide an expert's perspective on the proper use of automotive body adhesives, helping automakers and repairers improve their application skills and vehicle performance.
Automotive body adhesives are chemical materials specifically formulated for bonding vehicle body structures. They typically possess high-strength adhesion, temperature resistance, corrosion resistance, and a certain degree of elasticity. Compared to traditional welding or mechanical fastening methods, adhesives offer the following advantages:
Reduced vehicle weight: Adhesives eliminate the need for welding overlapping metal parts, reducing material usage and enabling lightweight designs.
Improved vehicle strength and durability: Modern automotive body adhesives disperse stress, preventing localized stress concentrations, and improving collision safety. Improved Sealing: For areas like doors, windows, and sunroofs, adhesives effectively prevent moisture intrusion and enhance the sealing performance of the vehicle body.
Adaptable to Multi-Material Bonding: Suitable for bonding steel, aluminum alloys, plastics, and composite materials, meeting diverse vehicle body material requirements.
Based on usage scenarios and performance requirements, automotive body adhesives can be divided into the following categories:
Structural Adhesives: Primarily used in load-bearing areas of the vehicle body, such as roof rails, door frames, and chassis connections. They are characterized by high strength and durability.
Sealants: Used in areas like doors, trunks, and sunroofs, their primary functions are to provide waterproofing, dustproofing, and corrosion resistance.
Damping Adhesives: Used to absorb vibration and noise, improving the vehicle's NVH (noise, vibration, and harshness) performance.
Instant Adhesives and Multi-Purpose Adhesives: Used for securing small parts and assisting in the bonding of components. They are easy to apply, but their strength and durability are relatively low.
Experts point out that applying automotive body adhesive isn't a simple matter of applying, but rather a systematic process that must be performed according to a scientific process. The following are the detailed steps:
3.1 Surface Preparation
Surface preparation is crucial for ensuring adhesive bonding strength. Experts recommend:
Cleaning the surface: Use denatured alcohol, acetone, or a specialized cleaner to remove grease, dust, and rust.
Roughening: For smooth metal surfaces, sandpaper or sandblasting can be used to improve adhesive adhesion.
Rust Removal and Corrosion Prevention: If rust is present on steel surfaces, remove it and apply an anti-corrosion primer to prevent poor bonding.
Tip: Inadequate surface cleaning is one of the main causes of bonding failure.
3.2 Adhesive Selection and Proportioning
Different vehicle body parts require different adhesive performance requirements:
Use high-strength structural adhesives for load-bearing areas;
Use weather-resistant sealants for sealing or waterproofing areas;
Use specialized adhesives for composite materials to ensure a good bond between metal and non-metallic materials. For two-component adhesives, mix them strictly according to the manufacturer's recommended ratio. Adding too much or too little may affect the curing effect.
3.3 Adhesive Application
Use specialized dispensing equipment or a manual glue gun to ensure an even adhesive layer thickness.
The bonding surfaces should be as close as possible to avoid air bubbles and gaps.
For load-bearing areas, clamps can be used to secure them to prevent displacement during curing.
3.4 Curing Condition Control
Adhesive curing is affected by temperature, humidity, and time:
Ambient temperature curing: Suitable for general workshop conditions, but with a longer curing time.
Heated curing: Heating with an oven or heat gun can accelerate curing and improve strength.
Humidity Control: Some adhesives are sensitive to humidity and require a dry environment.
Expert Tip: Never remove clamps before curing is complete, as this will result in a weak bond.
3.5 Post-application Inspection
Check for uniform bonding and any excess or leaks.
Perform tensile or shear tests on key load-bearing areas to ensure design strength is achieved.
Clean any residual adhesive to prevent it from affecting subsequent spraying or sealing.
4.1 Adhesive Debonding or Weak Bond
Cause: Improper surface preparation, thin adhesive layer, or poor curing conditions.
Solution: Reclean the surface, control the adhesive layer thickness, and strictly adhere to curing conditions.
4.2 Curing Time Excessively Long or Short
Cause: Low temperature or incorrect mixing ratio.
Solution: Adjust the curing temperature and ratio according to the manufacturer's recommendations; use heating equipment if necessary.
4.3 Bubbles or Voids
Cause: Uneven adhesive application and poor adhesion of the bonding surfaces.
Solution: Carefully vent the adhesive before applying and secure with a clamp to ensure close contact between the bonding surfaces.
4.4 Marks on the Surface After Bonding
Cause: Glue overflow or improper handling. Solution: Use masking tape to protect the surrounding area during application and clean any residual adhesive before curing.
Proper use of adhesives is not just a matter of application; it also involves ongoing maintenance:
Regular Inspection: For older vehicles, regularly inspect the adhesive for cracking or peeling.
Avoid prolonged exposure to high temperatures: Extreme heat can degrade some adhesive properties.
Promptly Repair Damage: If damage is found to the adhesive layer, remove the old adhesive and reapply it.
Experts advise that adhesive quality directly impacts bonding performance, making it crucial to choose a reliable supplier:
Brand Certification: Choose an adhesive manufacturer with automotive industry certification;
Technical Support: The manufacturer provides application training and technical guidance;
After-sales Service: Ensure that any application issues are promptly resolved.
High-performance automotive body adhesives not only ensure vehicle safety but also improve production efficiency and overall vehicle durability.
Proper use of automotive body adhesives is not only key to improving vehicle manufacturing quality but also a crucial component in ensuring vehicle safety and durability. From surface preparation, adhesive selection, application, curing, and inspection, every step is crucial. Experts emphasize that following a scientific application process, selecting high-performance adhesives, and incorporating the manufacturer's technical guidance are the best solutions for ensuring effective bonding and vehicle body performance. Whether in vehicle production, repair, or lightweighting, mastering the correct use of automotive body adhesives is an essential skill for every automotive professional.
Polyton is a professional automotive body adhesive distributor, dedicated to providing high-performance, reliable structural adhesives to automakers, repair shops, and parts suppliers. Leveraging extensive industry experience and comprehensive technical support, Polyton not only provides high-quality adhesives but also offers application guidance, formulation solutions, and training to help customers improve vehicle body bonding quality, sealing performance, and overall vehicle durability.
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