What StevL said. But you can also use Monokote (or whatever to match the existing covering on the model) cut into long, narrow strips and ironed over the deflected hinge gap. You only have to do the bottom for full benefit, but for cosmetics you can do top & bottom (or both sides of the rudder). Watch if using clear tape that you don't use too thick a tape (i.e. - hinge tape over existing CA hinges or hatch tape).