When welding with copper-plated steel wire, stainless wire or aluminum wire, it is necessary to use a shielding gas. Carbon dioxide CO2, argon - carbon dioxide mixture or pure argon are mostly used. It is also possible to use gas-free welding wire, whose special coating forms a gas layer to protect the molten metal of the seam when it melts.
During welding, it forms a protective layer, which must be removed mechanically later.
In this case, the burner wire is connected to the “-” terminal, ground to “+”.