With so many products to choose from, making sure you select the proper sealant is especially important. Selecting the wrong industrial sealant, or applying the correct sealant in the wrong manner, can have serious consequences. Ross Noel, a senior applications engineer at Dow Corning, Midland, Mich., suggest sealant users keep the application in mind and select a sealant with the following characteristics:
Stability over a Wide Temperature Range. Once fully cured, high-quality sealants perform across a wide range of temperatures. The best sealants can withstand temperatures ranging -85 to 599oF (-65 to 315oC). Select a sealant that functions reliably at temperatures outside the performance range to accommodate unexpected temperature changes.
Weather Resistance and Chemical Stability. UV rays, radiation and weather can cause sealants to crack, crumble and become brittle. Look for sealants with good resistance to these and other erosive factors.
Good Bond Strength. Good sealants provide durable adhesion to a range of industrial materials, including glass, ceramics, wood masonry and many metals and plastics. Several factors contribute to bond strength, including cure type, chemical composition and substrate penetration.
Electrical Properties. If electrical properties are a concern, be aware that some organic sealants are less suited to applications where they may be exposed to electricity. In such instances, a high-quality silicone sealant may be a better option.
Low Flammability. In fire conditions, some sealants are more burn-resistant than others. Silicone sealants, in particular, are especially reluctant to burn and many comply with UL flammability standards.
Ross cautions that most importantly, users should select a sealant that can perform at the highest temperature required but also offers a secure, flexible hold at lower temperatures.