Sand the painted wood lightly to prepare the glue line surface. Use 120 grit sand paper and sand only where the glue line will be located. Sand just enough to gently rough the surface to allow the glue to bond to the wood. If you are gluing two pieces of painted wood, be sure to sand both pieces where the bond will be formed.
Apply Gorilla Glue to the sanded area. Squeeze the bottle of gorilla glue to extract the glue. Lay a line of Gorilla Glue along the sanded area where the bond will be formed.
Allow the project to dry for a couple of hours. If your project is small enough, you can use C clamps to clamp the wood together to quickly form a strong bond.