I had some 6mil mdf boards cut a while back to make a gaming board for Flames of War. I have finally manage to get a start to building the board. I have decided to have a beach landing for a Normandy landing. My boards were basically cut to 4' x 2', there's three altogether. I bought some flooring insulation about 3-4mm thick, I have 2 layers on the first board, then 3 layers on the 2nd board and finally 50mm sheet of floormate on my third board. I used Gorilla glue to glue them down. Once the insulation board has been gripped to the board by the glue (about 2 hours), I will use a wire cutter to trim to size as I have parts over hanging the mdf. I didn't take any photos to show the process - maybe I should've.