Purchase headboards. Search your local flea market or second-hand store for matching or mismatched twin headboards. They should be approximately the same height and should coordinate well. They do not need to match exactly because you will be painting them the same color.
Place the headboards on a dropcloth or tarp in your back yard or driveway.
Clean the headboards thoroughly. Use a mild soap and water and a sponge to wipe the antique iron clean. Rinse the sponge and wipe away any soap residue.
Brush both headboards with a steel-bristled brush. This will prep the surface for paint as well as remove any rust that has accumulated on the bed. Use a swift back-and-forth motion to work on the rusted areas. Wipe the headboards down with a damp rag to remove any particles.
Paint the headboards with spray paint. Choose a paint formulated for use on metal. Use a matte finish for more of a shabby-chic finish. Use a steady back-and-forth motion to apply the paint. Two to three coats of paint will be more durable than one thick coat. Allow the paint to dry.
Attach the headboards to either end of the twin bed frame. Use the pre-drilled holes in the headboards to attach the frame. Push the long side of the bed against the wall.
Cover the bed with daybed bedding. Choose a bedding set that includes a bed skirt that will hide the bed frame.
Place king-size pillows against the wall to create a back for the daybed. Add additional throw pillows to further imitate the appearance of a couch.