It's not something you want to think about but occasionally breakage happens. A glass artist knows the sound and no one wants to hear it.
Occasionally it happens when a piece is being installed. It was a lucky thing that the breakage was in a convenient spot and easy to fix. So I packed up my tools and made the repair on site.
The client had send me pics of the damage - can I just say that cell phone technology is a wonderful thing? - so I was prepared with all the glass and sundries I anticipated needing.
First I cut through the zinc H came framing and had to pry the broken glass out. The cementing process had really sealed the glass in, so I had to be careful not to cause more damage in the removal process.
I used the broken glass to trace a pattern for the new piece and then shaped it down to fit and carefully wedged the new piece of glass back into place.
Once I had a fit that satisfied me I took a piece of lead came and framed it in, soldering it into place. The new piece of glass was sealed in place with lead putty.
Repair complete and the panel is ready to be installed! Crisis averted!