Hi Brj, This is something you could try. Get an old car or truck inner tube,the kind you go tubeing down the river with. Cut in half all around the center the entire outer circular tread area,where the outer tread would be. Get a metal strait edge(metal or wood yard stick) and with a razor knife trim rubber strips to the width you stated.You might have to cut the strip in different places but abut the edges, edge to edge, don't over lap,like wallpapering.To keep it in place before you attach the back panel use little dabs of painters caulk to act like a little adhesive.The caulk should come right off if its just a little dab every four inches or so with a putty knife when you need to take off the panel in the future. When you come to a screw hole,use a paper punch to make a clean hole in the rubber gasket that won't disrupt it when you re screw the panel on.That would make a removable air tight seal that even Lloyd Bridges of Sea Hunt would be proud of....Mark Korda.
