How to choose rubber seals

To choose rubber seals, first assess the application's environmental and service conditions, including temperature range, chemical exposure, and pressure. Next, consider the seal's physical properties like hardness and strength, and the required performance characteristics, such as friction resistance and durability. Finally, determine the correct dimensions and shape needed to properly fit the application. 
1. Assess environmental and service conditions
Temperature range: Select a material that can withstand the minimum and maximum operating temperatures, such as silicone for high temperatures or EPDM for a wide range. 
Chemical compatibility: Match the seal material to the substances it will contact, such as nitrile for oil and fuels or EPDM for water and steam. 
Pressure: Choose a material with sufficient strength and resilience to maintain a seal under the required pressure, especially in high-pressure applications. 
Environmental factors: Consider UV, ozone, or weather exposure. EPDM is excellent for outdoor applications due to its resistance to weathering, notes Elastostar Rubber Corporation. 
2. Consider physical and performance properties
Hardness: Use the Shore A scale to select a material that is soft enough to seal gaps but hard enough to withstand forces, according to Canada Rubber Group. 
Strength: Look for appropriate strength properties, like tensile strength for belts or tear strength for components that are frequently flexed, suggests TRP Polymer Solutions. 
Friction: For dynamic applications, consider breakout and running friction. Running friction can cause heat buildup and swelling, which can lead to seal failure.
3. Determine dimensions and shape
Measure: Use a tape measure or ruler to find the inner (ID) and outer (OD) diameters, as explained by The Rubber Company. 
Match shape: For seals like door or window weatherstripping, remove a small portion to match the existing shape, notes JA Seals. 
Verify: If a replacement seal is the same shape, carefully double-check measurements before purchasing.