Reviews of Flex Seal are featured on ConsumerReports.org, Amazon and the CBS Pittsburgh website. Consumers and home-improvement experts give Flex Seal mixed reviews after using the product on various objects. Flex Seal is an aerosol sealant that protects surfaces from moisture and corrosion.
ConsumerReports.org tested Flex Seal's waterproof abilities by recreating a demonstration from a Flex Seal advertisement. To do this, ConsumerReports.org sprayed the product on a screen attached to a miniature rowboat and placed the boat in water. A stuffed animal served as a boat passenger, and Flex Seal successfully kept water out of the boat. When ConsumerReports.org used Flex Seal on holes drilled into copper pipes, the product performed poorly as water gushed through sealed holes. The product successfully sealed a cracked flower pot, but the area needed spray painting to conceal a messy repair.
An Amazon reviewer used Flex Seal to repair the aluminum flashing around his chimney and reported no leaks after two years. Alternatively, another Amazon reviewer applied Flex Seal on his home gutters twice, and the product failed to stop the leaking. One reviewer used two cans of Flex Seal on the interior of a fountain, and he claims it didn't work. A CBS Pittsburgh reporter had a professional carpenter conduct several tests using Flex Seal and found that the drying times are much longer than claimed.