Where colour match is important in the welding of aluminium and its alloys, care must be taken in selecting the filler alloy. This can be particularly important where post-weld anodising is required.
Where there is a choice of filler alloy, the one nearest in composition to the parent metal will usually give the best colour match. However, using matching or closely matching compositions may make it difficult to produce sound welds.
Similar comments apply where welds will be exposed to long-term weathering.
Arc welding aluminium - a guide to best practice
Weldability of aluminium alloys