In August of 1842 a patent was granted to a brass-founder, William Raybould of St. James's Walk, Clerkenwell, in the county of Middlesex, for "a new or improved soldering iron." The patent record went on to note excitedly that it used screws instead of rivets:
"In the ordinary mode of making soldering irons the copper head is fastened to the shank by means of rivets... the patentee employs screws to fasten the copper head thereto, in place of rivets as heretofore, the object of which is to facilitate the removal of the head when required..."
Hot fusible metal solder has been around longer than home electricity. American Beauty brand soldering irons have been made since 1893 after a debut at the Chicago fair. That same year the American Electrical Heater Company of Detroit Michigan began manufacturing electric soldering irons. General electric may have been makling them as early as 1910. [SOURCE] Soldering irons have been around forever. I found a reference to one in an article on "Steam-carriages" in a section on "The Art of Coach Building" from 1833. But if you go back much further the term "soldering" is used in applications we'd now call welding. But I did find common lead solder described accurately in an 1819 edition of The Cyclopaedia
"The soft solder is composed of three parts of zinc and one of lead, and is applied by means of a common soldering iron, made red-hot. Solder for tin is made of two
-thirds of tin and one of lead"
Their glue is made of metallic nanorods which are very tiny rods with metal cores coated with indium on one side and galium on the other. These coated rods are arranged along a substrate like angled teeth on a comb. In the glueing process they interlace these teeth. When indium and galium touch each other, they form a liquid then the metal core of the rods acts to turn that liquid into a solid.