The amount of CA used doesn't make them brittle. The problem with using too much CA is that the hinge can only wick so much of it, the rest is left to pool and harden in the hinge gap. This will cause the hinge to fail simply because when you delfect the surface, the hinge is being "stretched" over the dried pool of CA and will eventually break. Only use 3-4 drops per side and you will have solid hinges that will last.