Activity Feed › Forums › Sign Discussion › General Sign Topics › 10mm Foamalux 1m x 1m how to make more rigid? › Reply To: 10mm Foamalux 1m x 1m how to make more rigid? Mike Grant Member June 20, 2011 at 6:32 pm Ahhhh now I understand! 😀 How about 1" thick "Signfoam" High Density Polyurathane. I can send you a small piece to try if you want. The trouble with that stuff is that it can mark easily if your not careful.