The Army Painter GameMaster Terrain Sealer Matt Sealer, 300 mL Water-Based Acrylic Spray Paint Primer, Doesn't Melt XPS Styrofoam, for Tabletop Roleplaying, Boardgames, Wargaming Terrain : Amazon.co.uk: DIY & Tools
How To Seal & Paint MDF for Your CNC Woodworking Projects - YouTube