Paint the metal sheet with rust-resistant paint and let it dry.
Measure and cut out a piece of fabric 6 inches longer and 6 inches wider than the metal sheet.
Lay the fabric out flat and cut a 2-inch square out of each corner of the fabric. Pin the edges of the fabric together that you cut the squares from and sew them with a straight stitch using the sewing machine.
Pin the 1/4-inch elastic to the unfinished seams on the fabric cover and sew it in place with a zigzag stitch. Cut off any excess elastic when you're finished sewing.
Place the fabric cover over the metal sheet.
String the hanging wire through the holes in the back of the metal sheet, near the top, and tie them together. Hang the garment steamer board on a wall hook to use.