WIRE MIG 0.023 MILD STLse and silicon for a superior weld, even on rusty, dirty steel. Produces a smooth bead which requires less grinding. Not recommended for aluminum engines. Yellow color coding on label. Required shielding gas: Argon/CO2. Recommended Polarity: DCEP Reverse Polarity. Tensile Strength (PSI): 70,000. Wt. 2 lb.