I bought all these clocks at thrift store for 49 cents a piece. First take apart the clock, keeping all the pieces. You don't need the inside of the clock. But the pieces are great for other projects to come.
Find a picture of a "Time" you want to share with dad.
Using the face of the clock, place over the picture and trace the outside of it. Cut to fit. Then reasemble the clock. Without the inside of course.