Put on the particle mask. Remove the aluminum from the steel in the area to be welded using sandpaper or a sanding disc. The area will need to be completely free from the aluminum coating before beginning the welding process.
Use the shop towel to remove the sanded aluminum from the welding area. Be certain all aluminum powder has been removed or the weld will not stick.
Put on the welding mask and insulated gloves. Turn on the MIG welder and feed the welding wire until it sticks out 1/4 to 3/8 inch.
Begin the weld by creating a weld pool at the beginning of the weld seam. A weld pool is a puddle of melted metal that will form from the heat of the torch. Once the weld pool forms, drag the wire along the length of the area to be welded until the weld is complete.
Allow the metal to cool. Clean the weld with a stainless steel wire brush to remove any rough areas. Use a shop towel to clean up weld splatter.