Lay a piece of 3/4-inch marine grade plywood on the ground. Cut it into three or four 16-inch by 28-inch long panels.
Remove two pieces of the cut plywood. Apply a thin layer of resin glue to one of the pieces of plywood. Lay the other piece directly on top of the glue and press down. Wait about 24 hours for the glue to dry completely.
Cut two slats into the plywood, one on the left and one on the right side of the board, using a hand saw or jigsaw. These will be used to pass the straps through to support the piano.
Cut a small piece of wood that is 16 inches long and 3 or 4 inches wide. This will form the lip of the skid. Squeeze a line of wood glue onto the wood and attach it at one end of the skid. Hammer two to three nails into the wood lip to further secure it. This will help stop a piano from sliding.
Turn the plywood over and place one hardwood runner on each side of the plywood. Squeeze a line of glue onto each runner and press it firmly onto the plywood. Drill two screws into each runner to make sure it is secured to the plywood.