I soldered mine back on with a soldering iron.

The main PIA about the whole job was removing and replacing the window. I remember it was heavy and I had to do it on my own so very PIA-ish.
I'm not expert enough at soldering(as well as welding) so I didn't dare try to solder it without removing the window first. Upsidedown soldering must surely be an art form(that I'm not familiar with).

It didn't require much I remember, and I can't remember the glass getting at all hot. It was touch and dab in quick actions to allow the solder to flow and cool(to solidify).
Memory about the entire process isn't the best, as this was getting on for 30years ago now, on a 79 RRC.

Memory is only clear and certain that the soldering process was the easy part.
The annoyance was removing those annoying philips type screws(hard to do) and holding the window frame with one hand whilst undoing the last fixing with the other, then the juggling the frame whilst trying to get screw into the correct spot and then lining up the frame so that it closed properly.

If a strong enough glue exists that conducts electricity at about 30amps .. I have no idea?