I know nothing on the subject. But I break enough glass on my own to want seek a solution for myself.
Started with a search for 'food safe silicone for glass' and got several hits. Then I read some Amazon reviews for a few of these sealants. There has to be a fully non-toxic solution for this out there. Plus their is so many unique ways to break an expensive glass piece, AMIRIGHT?
So there is a wide range of product that would be food safe and waterproof in some manner while avoiding products meant for hardware and cosmetic fixes, like say gluing a vase back together. I would avoid the hardware section and see what the kitchen department of the internet has to offer. The suggestions that have been made in this thread might very well be food safe already, just not packaged as food safe for their application.
But felt I had to start with the food safe answers first. Some of these products I found during my search are for sealing walk-in refrigerators and food service equipment that have glass windows. Others are for things like making cake molds.
Maybe we all should make cake molds out of our water pieces for insurance?
Or just thickly coat all our glass in silicone epoxy?
From my google search.
What kind of silicone is safe for aquariums?
Selleys Glass Silicone is an
acetic, acid-curing 100% silicone, which has excellent adhesion to glass and has been especially formulated for glazing and aquarium construction. This aquarium safe formula locks out water and forms a durable seal that does not shrink when drying.