Place both twin headboards flat on your work surface. Draw a cut line on the right protruding bedpost of one headboard and on the left of the other. These are the sides to meet up when the frames are put together. Place the cut lines parallel with the top edge of the center of the headboards.
Cut along the cut lines using a circular saw. Keep the cuts as straight as possible. Sand the cut edges with medium-grit sandpaper.
Coat the surface of the headboards with paint stripper, using a paintbrush. Let the stripper sit for 20 minutes or until the surface of the headboard starts to crack and wrinkle. Remove the paint or sealant from the headboard using a steel wool pad. Rub the surface with the pad in a circular motion until all of the stripper and paint or sealant is removed.
Apply a lacquer thinner to the headboards. The lacquer thinner removes any remaining stripper from the wood and conditions it so that it is ready to accept new paint or sealant. Since manufacturers produce lacquer thinner differently, to ensure proper application, follow the directions on the product. Let the thinner dry overnight.
Paint or stain the surface of the wood. Let the headboards dry overnight.
Turn the headboards face-down on your work surface. Place the cut edges flush against one another. Place a metal bracket across the seam where the two headboards meet. Position it 2 inches down from the top edge. Place a second bracket along the center seam 2 inches up from the bottom edge. Place another bracket every 4 to 6 inches in the space between the first two brackets. Align the brackets so they stretch across the width of the headboard. Secure the brackets by inserting a screw through each hole on each bracket
Set the headboard upright. Attach a metal king-size bed frame to the front of the headboard.