Applying Stone Coat Countertops Epoxy Undercoat is a fundamental step for flawless, long-lasting DIY epoxy countertops, tabletops, bar tops, and more. Designed specifically for use with epoxy, our undercoat is crucial must-have for ensuring a strong bond, eliminating issues like peeling or yellowing that can compromise the final look of your project. Unlike standard latex primers, our ammonia-free formula prevents off-gassing, helping to avoid any chemical reactions that cause discoloration. Plus, it provides a high-bond base layer, bringing enhanced performance and durability to every project, especially on porous surfaces like MDF. Key Features: High-adhesion undercoat formulated for DIY epoxy countertops. Ammonia-free to prevent off-gassing, discoloration, and yellowing. Low odor and quick-drying for hassle-free indoor application. Designed for multiple surfaces, from MDF to primed countertops. Application: Lightly sand new MDF or surfaces treated with Bonding Primer & Sealer using 220-grit sandpaper, remove dust, and clean with 91% isopropyl alcohol. Stir the Epoxy Undercoat thoroughly. Apply a thin, even coat with a 1/4 Inch Nap Microfiber Roller and use a 2 Inch Chop Brush for tight corners. Let dry for 1 hour, then lightly sand with 220-grit. Apply another thin coat, let it dry for 2 hours, then sand again with 220-grit. Allow 4 hours of drying after the second coat, prior to epoxy application. Clean spills and tools immediately with warm, soapy water. PRO TIP! Always start with two thin coats of our Bonding Primer & Sealer on old countertop surfaces before applying our Epoxy Undercoat. This will create a reliable foundation you can trust!