What is the purpose of seam sealer?

• A. To seal joints and prevent moisture intrusion
• B. To prime metal
• C. To bond panels
• D. To cure paint

Answer: (A)

Seam sealer is used to seal joints and prevent moisture intrusion. In auto body work, gaps where panels meet or welds are exposed to water and road debris, and sealing these seams blocks moisture from getting in, which helps prevent rust and corrosion. The material needs to stay flexible so it can accommodate the tiny movements of metal with temperature changes and vibration, maintaining a weather-tight barrier over time. It’s not for priming metal, bonding panels, or curing paint—those tasks involve other products. Seam sealers are typically polyurethane or silicone-based and are applied along seams, pinch welds, and other joints to keep out moisture while allowing movement.