The paper is almost the same weight as the XPS foam. The paper, on both sides, is what gives the strength to the board. Strength is achieved due to the foam sandwich construction, paper acting as a stressed skin. The paper can be peeled off easily. This can be used to lighten the structure, but also reduces the strength. Also without paper on one side the sheets can have a tendency to warp. Although the Foam is not CA safe, the paper is. CA is much, much lighter than Hot glue. Lighter models fly better, always. Recommend to use CA judiciously where possible, where the foam edges do not come in contact with the adhesive. Technical Specification: Material : XPS foam core laminated with Bright White Medium-Glossy paper on both sides Thickness- 3MM Density - 300 GSM Color - White Sheet Size - 8 inch x 8 inch Quantity - 8 Sheets per box.