I got a sheet of 3/4 5ply ext grade plywood for making my bulkheads and shelving and support for a 100 gallon fuel tank. I went to the local lumber yard. Picked out a sheet that was nice and flat. Got it home about a 15 min drive. The sheet already started to curl. Within an hour it was getting wavey. It makes real fun trying to cut out peices and get them to fit properly.
