What is the primary purpose of a gasket?

• A. To reduce friction between moving parts
• B. To seal joints and prevent leaks
• C. To transfer torque between components
• D. To absorb vibration

Answer: (B)

Gaskets are placed between mating surfaces to create a leak-proof seal. Surfaces aren’t perfectly smooth, leaving tiny gaps; when the joint is tightened, the gasket compresses and deforms into those gaps, forming a barrier that prevents fluids or gases from escaping and can accommodate temperature changes and internal pressure. The material chosen—rubber, metal, PTFE, etc.—depends on what’s being sealed and the operating conditions. While other parts of a system handle reducing friction, transferring torque, or damping vibration, the gasket’s primary job is to seal the joint and prevent leaks.