Pinning CA hinges has absolutely nothing to do with the type of failure the original poster encountered. He said it "failed at the fold) which means they split at the hinge line. Pinning hinges would prevent them from pulling out, would have nothing to do with them tearing or splitting at the hinge line.

I don't quite know what would have caused something like this other than a possibility of bad hinges or hinges that were not adequate for the surface they were installed on.

Perhaps the best way to handle a situation like this would be to remove all the hinges and re-hinge with known good hinges. Or, go to the pinned hinges (pins at the hinge line) with epoxy in the slots. If you do that, melt some petrolium jelly and dip the hinge only in the melted jelly and let it harden. This will prevent epoxy from entering the hinge. Then slot the wing/aileron (or any other hinged surface) and put some 30 minute epoxy in there and slide the hinge in and let it set.

I've personally had only one problem with CA hinges, and that was on my Tiger 60 and because I applied the CA two times. The hinges pulled out of the ailerons but did not split. Pinning them may have helped, but I doubt it because they would simply have come loose and the only thing holding them would have been the pin.

DS.