Abstract: A cover plate extends over a solder reservoir and has a slot for a solder wave to extend up above the plate, a gas excluding oxygen is supplied under the cover plate and flows up through the slot on both sides of the solder wave to blanket the solder wave. It has been found that oxygen content on the surface of the solder and on the solder wave is reduced so that clean oxide free soldering occurs. The apparatus has a solder reservoir for holding solder with a solder nozzle projecting therefrom, a pump for forming a solder wave from the nozzle, a cover plate for covering at least a portion of the reservoir having a longitudinal slot for the solder wave to pass therethrough. Provision is made for supplying pressurized gas, which is oxygen free, to pass upwards through the slot on both sides of the solder wave to provide a gas blanket over the solder wave, and a conveyor conveys elements to be soldered to pass through the solder wave.

Abstract: A flux density control system controls the density of flux or other liquid by measuring the density and adding a thinner solvent or other liquid with a lower density than the flux. The apparatus includes a tank having an overflow adapted to maintain a set level of liquid in the tank, a liquid container positioned to receive liquid from the overflow in the tank, and a liquid pump adapted to pump liquid from the liquid container to the tank. A thinner container is provided with a thinner pump adapted to pump thinner from the thinner container to the tank. A density probe is positioned in the tank with a controller to turn off the liquid pump when the density of liquid in the tank rises above a predetermined set point, and turn on the thinner pump. The controller also turns off the thinner pump and turns on the liquid pump when the density of liquid in the tank drops below the predetermined set point.

Abstract: A foam fluxer for fluxing surface mounted devices on printed wiring boards is suitable for low solids content fluxes. The foam fluxer is for installation in an open tank containing liquid flux positioned under a conveyor path conveying the components. The fluxer comprises an aerator chimney housing with side walls and end walls for placement in and protruding above the open tank, the housing having a top foam outlet for positioning below the conveyor path, at least one vertical internal divider located in the housing below the foam outlet, the divider forming at least two chambers, and a porous aerator tube located in each chamber with connection means for a compressed gas supply to produce foam in each chamber, the foam from each chamber joining above the divider to exit upwards from the foam outlet.