Two very different materials often get overlooked: natural rubber, the original shock absorber, and fiber, the firm dry-gasket washer. Here's when each is the right call.
Natural rubber
- Best at: shock, vibration, impact and abrasion resistance with excellent elasticity
- Temperature: about -40°F to 180°F
- Weak against: petroleum oils, ozone and prolonged sunlight
Natural rubber is ideal for vibration mounts, pads and cushioning where flexibility and rebound matter more than chemical resistance.
Fiber
- Best at: firm, compressible dry gasketing for threaded fittings
- Common uses: plumbing unions, fuel and gas fittings, banjo bolts
- Weak against: continuous water immersion — it's a dry-seal material
Fiber washers crush slightly to form a tight seal on threads where soft rubber would extrude.
Which to choose
Need give and bounce? Natural rubber — see our vibration damping guide. Need a firm threaded seal? Fiber. For sealing water or chemicals, step to another compound. Browse all sizes and materials here.