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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. Keep the eventual application of your sealant in mind, and also make sure it has the following characteristics:
1) 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 from minus-85 to 599 degrees Fahrenheit (minus-65 to 315 degrees Celsius). Select a sealant that functions reliably at temperatures outside the performance range to accommodate unexpected temperature changes.
2) Weather resistance and chemical stability – Ultraviolet rays, radiation and weather can cause low-quality sealants to crack, crumble and become brittle, compromising the seal over time. Look for sealants with good resistance to these and other erosive factors. Also, some organic sealants react to atmospheric pollutants or chemicals much like iron reacts with water to produce rust. Use a sealant that does not readily degrade after prolonged contact with common elements and industrial chemicals.
3) Good bond strength – Good industrial assembly sealants provide durable adhesion to a wide variety of industrial materials, including glass, ceramics, wood masonry, and many metals and plastics. A variety of factors contribute to the bond strength of individual sealants, including chemical composition, cure type and substrate penetration.
4) Electrical properties – If electrical properties are a concern, be aware that some organic sealants are less well-suited to applications where they may be exposed to electricity; in such instances, a high-quality silicone sealant may be a better option.
5) 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.
Most importantly, make sure you select a sealant that can perform at the highest temperature you require, but is also one that offers a secure and flexible hold at lower temperatures. When in doubt, consult with a qualified expert.
About the author:Ross Noel is a senior applications engineer at Dow Corning, supporting IAM (Industrial Assembly and Maintenance) and automotive sealants applications. For more information, visit www.dowcorning.com.