Slumpy's Ceratek Fiber Board is a quality fiber product that can be used as a surface to make projects on and then put them directly into kiln. Use Thinfire or fiber paper between board and glass to prolong life of board surface. Slumpy's Fiber Board has mild surface texture. Slumpy's Fiber Board can be cut with a saw or knife and be used as a mold if desired. Need for priming is optional Measurements: 0.5" Thick 18" sq.