A method of making a spark plug electrode includes several steps. One step includes providing an inner core of a ruthenium (Ru) based alloy or an iridium (Ir) based alloy. Another step includes providing an outer skin over a portion or more of the inner core in order to produce a core and skin assembly. The outer skin can be made of platinum (Pt), gold (Au), silver (Ag), nickel (Ni), or an alloy of one of these. Yet another step includes increasing the temperature of the core and skin assembly. And another step includes hot forming the core and skin assembly at the increased temperature.