Measure 4 1/2 inches from one narrow end of the empty 12-pack box and draw a line across the box at this point. Rotate the box a quarter turn and again measure 4 1/2 inches from the top and draw a line. Repeat until all the sides of the box are marked at 4 1/2 inches. Cut on the line you drew, all the way around the box. Discard the rest of the box. This is the crown of your hat.
Cut 1-inch-deep slits at 1 inch intervals all the way around the cut side of the crown of your hat and bend these sections out. Set aside.
Open and flatten the empty 24-can box. Fold the box in half and make a sharp crease to flatten completely.
Set the hat you wear on top of the flattened box. Use the marker to trace the opening for your head.
Cut out the opening you traced with the X-acto knife. Cut through both layers of the box.
Open the box and spray the inside of both sides with spray adhesive.
Insert the crown section of the hat through the opening on one side of the box, so that the crown is on the outside of the box and the fringe you cut in the crown rests against the inside of the box. Adjust until the crown fits snugly against the opening.
Close the box and press all over to seal the crown piece between the two layers of box.
Trace the outline of the brim for your hat with the marker on one side of the box. Cut away the excess box with scissors or the X-acto knife.
Apply clear packing tape to the edge of the brim to seal.