Anodizing may lead to a discoloration of the weld and its heat affected zone in comparison to the base material. Silicon leads to grey or black welds and Manganese to a slightly yellow colour. Due to this only the alloys AlMg3, AlMg5 and the pure Aluminium Al99.7 and Al99.5Ti are suitable for anodizing. The selection of the wire alloy should match the base material as good as possible. In case of colour-critical applications each batch of filler wire should be tested prior to welding.