Gator Board  is used by architects, designers, and artists. It's is light, rigid, and it does not warp. Like the "all others" category of  foam core, Gator board can be difficult to cut smoothly and accurately but it
is so dense that it can be scored and snapped. It is the most costly member of the foam core family but well worth it for a good, warp free, foundation, or where exceptional structural strength is required.  As an architectural design material, Gator board is not commonly found in retail stores. A good source is Dave Myers at GatorFoam.net. For more information about Gator Board, contact gatorfoam.net