How To Weld Aluminum Tig Ac Or Dc. DC is used for TIG welding Mild SteelStainless material and AC would be used for welding Aluminium. In a TIGs case aluminum is always welded with AC current because of a special property of aluminum alloy that has a problem with melting point.
Aluminium has a high heat conduction and a great affinity for oxygen these characteristics necessitate the need for an AC current and a high skill level for the TIG welding process. Likewise what polarity do. The positive cycle acts as a scrubbing effect on the surface breaking up oxides that limit weld quality this is what you.
When youre welding aluminum AC welding is the better bet.
You can weld on aluminum foil with the use of an arc or spot weld. How to TIG Weld Aluminum With DC. Aluminum is a unique metal that has a tenacious oxide film on its surface. However there are special situations where a welder may want to consider experimenting with a TIG weld on DC power.