Can oil based urethane topcoats be tinted with oil stain for use as a toner?

Yes, they can, but be sure to stay within a manufacturer's finishing system and not mix product from different brands.

1. 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.
2. Simply stir the stain into the topcoat.
3. Keep stirring during application as solids will settle very quickly when mixed into an oil urethane-based finish.
4. Be sure to test in a hidden area before proceeding with your entire project.