Abstract: Apparatus for performing an operation with molten solder, such as soldering or desoldering a component mounted on a substrate such as a PCB including an enclosed reservoir, the reservoir including a contained space above the molten solder; a hollow nozzle for receiving solder from the reservoir; an element for conveying the molten solder in the reservoir to the nozzle; and a source connected to the contained space for introducing a pressurized gas into the space to raise the solder through the conveying means to a predetermined level within the nozzle and maintaining said solder at said predetermined level to thus effect the operation with the molten solder and then removing the gas to return the solder to the reservoir. The gas is pulsed at least during the time the solder approaches and reaches the predetermined level. The apparatus includes a plurality of different size hollow nozzles for receiving solder from the reservoir where the nozzles are removably attachable with respect to the reservoir.