Adhesives & Sealants for Body-in-White and General Assembly

Structural adhesive applied to A-Pillar, B-Pillar, Roof Rails, Floor Tunnel, and Rocker Panels — delivering high stiffness and crash load transfer across the full body structure

Replacing spot-welds with continuous structural adhesive bonds is one of the most effective ways to increase body stiffness without adding mass. Where a weld creates a point load, adhesive creates a continuous bond line — distributing stress evenly across the joint and dramatically improving both torsional rigidity and crash energy absorption.

VAMS structural adhesive solutions for BIW cover the critical load-bearing zones:

• A-Pillar: Improves front impact performance — the structural adhesive bond line maintains column integrity during a frontal crash
• Roof Rails: Enhances rollover strength and rigidity — bonding the roof skin to rails prevents deformation in rollover events
• B-Pillar: Increases side impact resistance — continuous bond transfers side-pole impact energy into the floor and roof structure
• Floor Tunnel: Improves structural integrity and load distribution — critical in EVs where the battery pack creates new load paths
• Rocker Panels: Boosts torsional rigidity and durability — bonded rockers resist the twisting loads EVs impose due to the floor-mounted battery

Hem flange adhesive (green) seals and bonds the panel fold; anti-flutter bonding (blue) prevents inner/outer panel vibration at speed — before vs. after shows dramatic NVH improvement

Door and hood panels consist of an inner and outer skin folded together at the hem flange. Two problems need to be solved simultaneously: the hem must be sealed against water and corrosion, and the inner/outer panels must be prevented from vibrating against each other at highway speeds — a condition called panel flutter that generates low-frequency noise inside the cabin.

VAMS supplies purpose-formulated adhesives for both functions, applied in the same production step:

• Hem Flange Adhesive: High-strength structural adhesive secures hem flanges to improve joint integrity and long-term durability. Formulated to resist wash-off during the e-coat process before oven cure.
• Anti-Flutter Bonding: Precision bonding pads placed between inner and outer panel at key resonance nodes — eliminating panel flutter and the associated drumming noise at highway speeds.
• Corrosion Protection: The sealed joint blocks moisture and contaminants from entering the hem gap, where trapped water causes rapid corrosion of the inner panel edge.
• Panel Stability: Bonded panels are structurally stiffer, delivering better load distribution and a premium door closing sound — a key quality perception metric for EV buyers.
• Simplified Production: Hem flange adhesive and anti-flutter bonding applied in one pass reduces line complexity and improves throughput vs. separate operations.

Direct-glazing adhesive stack: tempered glass bonded to e-coated steel flange with high-modulus, crash-resistant polyurethane — with optional primer for enhanced adhesion

In modern EVs, the windshield and rear glass are not just transparent panels — they are structural elements. Direct-glazing adhesives bond them permanently to the painted body flange, contributing meaningfully to overall body stiffness and providing critical glass retention in crash events.

The direct-glazing system consists of four elements:

• Tempered Automotive Glass — the load-bearing structural element
• Direct-Glazing Adhesive — high-modulus, crash-resistant polyurethane bond, applied as a bead to the glass or flange
• Optional Primer — enhances adhesion to painted steel and provides additional corrosion protection at the bond interface
• Painted Body Flange — e-coated steel substrate, the structural mating surface