I was building a trainer, and it was time to join the wing halves. I fitted the parts together without glue, and was amazed how perfectly they fit with just the right amount of dihedral (beautiful laser cut kit). The thing was just rock solid without any glue at all. So, I slopped on the 30 minute epoxy, and assembled the wing and left it over night. I didn't think I needed any support since it fit together so nicely.

The next morning, I found a perfectly straight wing with zero dihedral. I'm assuming the weight of the wing slowly deformed the balsa that was holding the dihedral in place.

Since there was absolutely no way to get the parts apart, I just flew the plane, and except for some odd looks and comments, it worked out just fine.

I still kick myself when I think of it. It would only have taken about 3 seconds to put a block under one wing tip.