Superior Aluminum Core Flux is formulated for solder wire manufacturers. This aluminum core flux is formulated for injection into tin-based solders that do not contain zinc. Aluminum core flux typically comprises 2.7 – 3.3% of the solder wire composition. This specialty core flux cuts through the tenacious oxides present on aluminum alloy services and promotes the spread of the solder alloy on aluminum surfaces. Post solder residues from Aluminum Core Flux are water-soluble and should be cleaned post soldering.