Automotive Undercoating Contamination

Undercoating contamination arises from rubberized or tar-based coatings applied to vehicle underbodies for protection against rust and road debris, where it hardens over time into a thick, adhesive layer. This pattern differs from oxide scales or grease residues by its elastic, bitumen-like texture that clings unevenly and releases volatile fumes when heated. On steel, it bonds aggressively and traps salts beneath, complicating adhesion loss, whereas on painted metal, it overlays loosely yet promotes delamination underneath. Challenges include incomplete vaporization leading to residue streaks, thus laser cleaning succeeds by targeted ablation that selects the organic layer for removal while substrate stays intact.