Anodized aluminum protection

Anodized aluminum has a hard but insulating oxide layer. You have to remove it completely before welding, otherwise you won't get a clean weld and it will spatter toward you. The best way is with sandpaper or a stainless steel wire brush used only for aluminum. After grinding, you must weld the part immediately, otherwise the oxide layer will reform. If you don't remove the layer, the weld will be porous and won't hold.