Duncan High Gloss Sealer - AS 959 - 8 Ounce Bottle Brighten and protect your projects with Duncan's Brush-On Sealers. Our nontoxic Brush-On Sealers produce a smooth, hard coating on your acrylic, non-fired projects and provide the same excellent results as ceramic spray sealers. They dry quickly to an invisible appearance and are available in four finishes: Gloss, Matte, Satin and Hi-Gloss.