To change that lets use a metal texture. The one I am using is courtesy of Shutterstock and you can find it at:With the Rectangle Tool (U) create some rectangles and rotate them until you get something like the image below. Tip: Start with the one at the top, then duplicate and move to the bottom, after that duplicate both and rotate 90º, the select all 40 and duplicate them. After that rotate them 45º and so on.