Yes, they can, but be sure to stay within a manufacturer's finishing system and not mix product from different brands.
- In General Finishes line you can add up to 20% Gel Stain or Oil Base Stain to Arm-R-Seal to deepen the color for toning purposes.
- Simply stir the stain into the topcoat.
- Keep stirring during application as solids will settle very quickly when mixed into an oil urethane-based finish.
- Be sure to test in a hidden area before proceeding with your entire project.