No human can solder a billion transistors on a computer processor, so your computer needed a robot in order to be built.
Fusing them together by a blow-pipe without the aid of solder (which would be quickly destroyed by the acid).
Microscopic accuracy has to be attained in cutting out the space for the insertion of the design, and while the latter must be soldered firmly in its place, not the slightest trace of solder or the least sign of junction must be discernible between the metal of the inserted picture and that of the field in which it is inserted.
Its use in soldering depends on the fact that solder only adheres to the surface of an untarnished metal, and consequently a little borax is placed on the surface of the metal and heated by the soldering iron in order to remove any superficial film of oxide.
In "autogenous soldering" two pieces of metal are united by the melting of the opposing surfaces, without the use of a separate fusible alloy or solder as a cementing material.