Abstract: An improved flux composition is provided which is formulated for use in the brazing of aluminum alloy components, such as in the assembly of brazed heat exchanger units used in automotive applications. The flux composition is in a concentrated form, permitting its selective application to the joint surfaces of a heat exchanger's subcomponents, and contains a flux material which consists essentially of potassium tetrafluoroaluminate, a carrier system such as a glycerol-ethylene glycol system, a binder, and a liquid medium such as water. Most preferably, the potassium tetrafluoroaluminate constitutes at least about 96 percent of the flux material, and the binder is xanthan which substantially prevents the flux composition from separating during storage. The flux composition does not contain potassium aluminum fluoride.

Abstract: The present invention utilizes a novel flux-coated alloy member that is particularly adapted to be selectively positioned at the braze joints of a tube-and-center type heat exchanger. The flux-coated alloy member is suitably sized and shaped to place a predetermined quantity of flux compound and brazing alloy at the braze joints, so as to avoid the presence of excess flux compound and brazing alloy which may otherwise have a detrimental effect on the quality of the braze joints subsequently formed during a brazing operation. The flux coating of this invention is hard and durable, and is composed of potassium tetrafluoroaluminate particles which are dispersed in either a natural resin or a water soluble epoxy resin.