Make it wet by spraying hot steam on it. Make sure it gets nice and plieable, then wrap it around a PVC pipe. Tape it together using thin tape in many areas and let it dry. When it's dry, it will retain roughly the shape of a cylinder, then you can glue the ends together and sand them down to make a nice smooth shape. Inside of the wooden cylinder you should also glue in a circular support which holds the shape and acts as motor mount . Glue one in the middle and both ends.