⊙ Magnesium - Effects on aluminum Brazeability - The brazing of aluminum alloys in controlled atmosphere furnaces, requires a filler metal and flux. - The flux acts by melting, spreading and then dissolving the oxide film. Melting starts at 562°C and is completed at 575°C. - As soon as the flux melts it starts to dissolve the oxide layer, but the solvating process will continue until the oxide i..