I have a 2x2:return duct where a 12" flex duct is attached in horizontal. The connection is not tight and I can see some yellow of the ductboard fiberglass. What will stick best to the bare fiberglass. Mastic? Foil tape?
Obviously replacing that section of duct would be best but for now I would like to try and repair.
Obviously replacing that section of duct would be best but for now I would like to try and repair.