Method of soldering joints by moving them through a target area on which a stream of hot gas is focused

A method of soldering a number of component leads to a corresponding number of I/O pads along an edge of a printed circuit board, without desoldering any circuit components which were previously soldered to said board near said pads, said method including the steps of:

• forming a mechanical assembly in which respective joints of said pads and said leads and respective solder mounds are mechanically held together;
• moving said assembly at a predetermined speed on a conveyor such that said joints, but not said previously soldered components, sequentially pass through a target area which is small relative to the total number of joints;
• and
• melting and then hardening said solder mounds, without desoldering said circuit components, by directing a focused stream of hot gas at said target area as said joints move therethrough on said conveyor;
• said hot gas stream forming an angle with respect to both the plane of said circuit board and said board edge such that a majority of the gas which collides with said joint is deflected off of the edge of said printed circuit board and away from said previously soldered components.