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How to make an upholstered headboard
Purchase plywood that is inch (1.9 cm) thick and 4 feet (1.2 m) wide.
You can make a headboard out of almost anything, and in any size. However since it will soon be covered with fabric simple plywood should be fine-no need for expensive hardwoods when no one will see them.
Cut the length of the plywood to fit the width of the bed. Beds vary in width from full to king, so measure your bed so you can size your headboard appropriately.