If your glasses break at the hinge, you are left with few options: Replace the entire set of glasses at a optometrist, Or replace the hinge with a functional substitute. These are the glasses my wife wears at night after her contacts come out, so appearance was not a factor - only utility. She did want them to remain fold-able so they could go back in their case for travel and storage.
I found out that I could perform the operation with a donor from the hardware store sold as a hinge for small wooden crafts.
- Small Brass Hinge
- Super Glue
- Leatherman Pliers
- BIC lighter
Step 1: Hinge Removal
First, I grabbed the portion of the metal hinge that protruded from the frame with a set of leatherman pliers. Of course, you could use any type of needle-nose pliers for this step. I wouldn't use a heavier set of pliers like lineman's pliers, because they will take longer to heat up. The pliers need to heat up enough so that they can start to transfer heat to the hinge which will start to soften the plastic that is holding it in.
I thought about using a different heat source, like a soldering iron, to heat the metal hinge but thought that would just add a step because I still would have to use something to grab the hinge after it was heated.
Second, I used a standard BIC style lighter to heat the tip of the pliers' jaws. Care was taken to not heat or burn the plastic directly.
Third, I stopped applying heat with the lighter about every ten seconds and pulled the plastic frame to see if it would release the hinge. It seemed to only take about 30 - 40 seconds to heat the hinge enough to release from the plastic.
Overall, this method worked just like I had hoped.