Thanks. I think stained glass usually contains lead. You wouldn’t want to vaporize that!
Lots of reasons ~ too hot to handle, leaves holes in carpet and pants legs, snorkles the nose, little teeny tiny slivers work their way in and out over decades!
If you make a window using the copper foil method, you use lead and soldering iron to run the bead, you inhale lead vapor, it cannot be helped...If you are doing leaded glass, you still use solder to hold it together...one you use 50/50 lead and the other you use 60/40 lead..