I had the same problem on my SM L39 elevator[:@]. I repaired it using a silicon bead on the inside of the hinge. I have not had a problem after that. This system is used by the glider guys as a hingeing system for awhile. I was doubtful and made up a test piece using two bit of scrap fibreglass and left it to cure for a week. There was no way that I or anybody else could pull the joint apart on a strip about 3 inches long. Try it for yourself and you will be amazed.