IMHO, throw away the nylon pin style hinges or plastic hinges and get some fiberglass CA hinges and ALWAYS PIN YOUR HINGES IN PLACE. I have had the nylon pin style hinges and the plastic hinges tear and seperate when put under high stress.

Dill a small hole in the center of the hinge slot of both surfaces, this will help the CA spread to the entire hinge/balsa joining surface. The hinge slot should look something like ---0--- Insert the hinge into one surface and push a small T-pin down through the surface and the hinge. Cut off the excess pin sticking out on both sides. Saturate the hinge with thin CA by squirting it into the hole that was drilled in the center of the slot. The fiberglass hinges will absorb the CA and help to strengthen joint and by glueing after pinning the CA will help strengthen the balsa around the pin. Follow the same steps on the opposite surface when joining. Pull the control surface into a full up or down position to make it easier to access the drill hole.

I use this procedure on all of my airplanes (.40 .60 & .90 size) and all surfaces. I have not had a control surface seperate since using this method. (knock on wood) If you follow these steps, I can almost guarantee that you will not have a control surface failure due to a hinge seperation.

Tips on flutter: Ensure that your control surface attach point gap is as tight as possible and be sure that the control horn/clevis attach point is directly over the hinge point.