can i use flex seal over it? i have rusty drain pan under a/c unit and pan now has a leak. Can't be replaced until a/c unit is

Chemical compatibility has not been tested by Loctite for the various Flex Seal products in contact with the Loctite Extend Rust Neutralizer. Depending upon which Flex Seal product you use it is possible the application may work over the Loctite Extend Rust Neutralizer if the Flex Seal product is not water-base. If the Flex seal is water-based, then you will need to use an oil base primer over the Rust Neutralizer first.