Hollow phenolic microballoons are used to thicken and/or light most resins including epoxy, polyester, vinyl ester, and polyurethane. Phenolic microspheres are added to make a lightweight paste. They are easily sanded and will add strength and flexibility to the resin. You can add in fumed silica along with the phenolic microspheres to prevent sagging. We recommend pre-measuring the resin and hardener and mixing the phenolic microspheres in with the resin prior to adding the hardener to save your work life. Once the phenolic microspheres are thoroughly mixed into the resin, add the hardener. Phenolic microspheres are great when filling large gaps.
