Yes, you can if you are working on a tight budget or if you just want to make your sketchbook more personal. You first need to buy some loose, good-quality watercolor paper and cut it to the size you want. Consider whether you want a portable journal size or a larger size for a poster. You then need to bind the pages together, which you can do by gluing them. You can also spiral bind the pages if you want. You need to complete the binding by choosing a soft or hardcover material and add some extra features such as an inside pocket or elastic band.