This relates to a process for controlled atmosphere brazing including, brazing an aluminium alloy without flux in a controlled atmosphere, while using brazing sheet including an aluminium alloy core upon which on at least one side a layer of filler alloy is clad, the filler clad layer having an inner-surface and an outer-surface, the inner-surface is facing the core, and wherein the filler alloy has a composition which is Na-free, Li-free, K-free, and Ca-free, and including, in wt. %: Si 3% to 15%, Cu 0.3% to 5%, Mg 0.05% to 1%, one or more elements selected from the group of: Bi, Pb, and Sb, and the sum of these elements being 0.35% or less, Fe 0 to 0.6%, Mn 0 to 1.5%, the balance aluminium.