A sealing material should be selected around the conditions it will encounter. Media compatibility, operating temperature and mechanical requirements are useful starting points, before selecting the final form and manufacturing process.
Begin with the contact media
Water, oils, fuels, solvents and outdoor exposure place different demands on a compound. EPDM is used for weathering, ozone and water-contact applications but generally not for mineral oils or fuels. NBR and FKM are common options where oil resistance matters. Silicone is considered where temperature range and electrical insulation are priorities, with its oil and mechanical limitations taken into account.
Consider temperature and compression
Separate continuous operation from short temperature excursions. Include low-temperature flexibility, the amount of compression and the time the part remains loaded. Typical material ranges are a starting point; formulation, hardness and the actual component geometry affect the result.
Choose the form and verify the design
Solid and foam forms serve different purposes. Select the profile, thickness and processing route around the assembly and evaluate the selected compound under representative media, temperature and loading conditions.