After many faithful years of service, I fear my nifty fifty has suffered a mortal wound. I dropped it from should high onto some rocks today. The back element set (that sits behind the aperture blades) broke loose. It is easy to tell how it is supposed to be situated/mounted, though. Would it be possible/advisable to glue it back in place? I know that many will say: just replace it; it's only $100. And while I appreciate that sentiment, that's still more than I can just arbitrarily spend. Besides the 50/1.8 is too light to make a serviceable paperweight.