If you want to add some strength to the control surface and minimize the chance of flutter or oscillation to even begin, you can make a control horn that extends further out on the control surface.This added leverage increases the support to the control surface and distributes the load further out, rather than having the load all at the hinge line.Check out the picture of my wing on the Speed Models Stinger 21 thread, you will see my home made plywood control horns.These are glassed both sides and are very strong.This in combination with sealing the surface will minimize the chance of any flutter.Regards Chris.