How To Insulate a Leaded Glass Window Using a Hot Melt Extruder Gun

This is called a
hot melt extruder gun. HOT MELT EXTRUDER GUN It extrudes hot, melted Butyl Butyl creates a really good seal
on the edge of insulated units. This gun heats it up and
pulls it off this coil and applies it to
the inside of this panel..

As found on YouTube

See also  Observations Series Post I