Step 3: Attaching The New Hinge
Once the hinge is trimmed, test-fit and cleaned, you can begin to glue the parts together. Even though the glue says it will hold to non-porous surfaces (like plastics) I still like to scuff the area to be glued and I did that on these glasses frames.
As a welder, I am fond of the following method for attaching two parts together: 1) Hold the parts together with pliers, 2) "tack" in one or two spots and continue to hold the parts until the "tacks" dry (15 seconds for super-glue), 3) remove pliers and glue the parts together entirely. The original (non-gel) super glue tends to wick nicely into the tiny gaps between the parts to be glued and I also made use of the holes that were already in the hinges as another glue location.
I glued the hinge to the lens side of the frame first as I knew the earpiece would be easier to adjust for the final alignment of the two parts. I noticed that for some reason if I lined up the earpiece to be level and symmetrical with it's counterpart while the glasses were open, it was slightly "off" when closed. I decided to leave it that way because the fit and comfort during use was more important than having them line up when closed.
After the hinge was fully glued and the glasses were one again, I set them aside so the glue could completely dry. I ended up leaving them for about 45 minutes before putting them in use.