Simple Welding rods work best with Aluminum, Cast Aluminum, Aluminum Alloys, Zinc...
They will also work well with Copper, Brass, Pot Metal and most other non-ferrous (non-magnetic) metals.
Simple Welding Rods do work with Galvanized Steel, but they will only bond to the galvanized layer, so the strength will be limited to the strength of the connection between the galvanized layer and the steel.
Simple Welding Rods do work with Magnesium, but we don't recommend doing it, as the Magnesium has a self-ignition point that is relatively close to the melting point of the Simple Welding Rods [883°F (473°C)], so Magnesium auto-ignition may easily happen if you can't precisely control the temperature.
Simple Welding Rods will not work with Stainless Steel, Steel, Iron or any other ferrous (magnetic) metal.