How To Weld Cast Aluminium With Mig. TIG welding cast aluminum should always be done with pure argon gas not an argonCO2 mix as is common with MIG welding. Prepare your push-pull wire feed.
The recommended electrode angle of travel is 5 to 15 degrees. This process is a very smooth transfer of molten metal droplets from the end of the electrode to the molten pool. For welds needing deeper penetration an argonhelium mix is recommended.
But If MIG is all you have then you are in the right place.
Cut rotary fileburr preheatweld. Take manifold to a shop with an industrial mig welder preferably a synergic machine. However there are basically two approaches by which you can weld cast iron. Strip rimdrill out holeremove surface skin both sides with Al.