When using polyurethane paint, a hardener and drying accelerator are required to activate the paint and create your protective coating. Additionally, painters often use solvents to thin the paints and undercoats, facilitating an easier spraying process and smoother finished product. For high performance polyurethane and epoxy coatings, high purity solvents are required. Please be sure you have purchased the proper type and quantity of Additives and Solvents for your project.