Abstract: An apparatus for applying solder to an electronic circuit board substrate includes a solder wave device for generating a molten wave of solder and, above that, a movable substrate holder. The substrate holder includes a support for an electronic circuit board substrate inclined at an angle with respect to the direction and an opening on a bottom thereof for access of a protruding connector disposed near an end of the substrate to the molten solder wave. The angle of incline is sufficient to prevent a component disposed at a distance from the end of the substrate from contacting the molten solder wave when the substrate holder is moved over the solder wave device. A shield in the substrate holder prevents the component not to be soldered from contacting the molten solder wave.