I have some steel hatches. They are painted. I plan to glue rigid insulation to them. I would glue the foil side to the paint, so at least I won't have to worry about the gluten dissolving the foam. But what glue? I could use Liquid Nails. Cheaper and messier would be contact cement. The foam is so lightweight that even when on the underside a super strong bond isn't needed.
Don (e-mail link at home page bottom).