I went to a sheet metal business and got some metal that was textured dull so that it could be painted. I attached it to the frames with JB weld that you can get at automotive shops or Lowe's or Home Depot. I also used JB weld putty to seal the outside. If you clean the metal it sticks like a weld. Then caulk to seal it further. The panels including cutting them to fit cost a couple of hundred bucks.