Amen zkling!!!
OK, keyboard welding geniuses..... this is how its done
groove the crack with a carbide burr, in a die grinder on both sides
rinse with lacquer thinner both sides, blow the chips away with an air hose
weld the inside 1st.....notice I didn't say preheat? thats why TIG machines have pedals
now with a die grinder with a SS brush clean all the smegma that came out of the casting....if you need to use the grinder with the burr...use it
now make it pretty on the outside
YES, they MIG aluminum but NOT with box store welders and spool guns
my buddy Josh, the trap shooter, was building bows of aluminum hulled boats out of 2 INCH formed plate and a center insert...
spool gun???? what? change the spool every 3-5 minutes?
NO, a push/pull gun and a 350Amp machine......and a different MIG process too
next project......weld the top of a BMW R1000 4 cylinder case back on, the top engine mounts and the oil pressure relief gallery are broken loose.....
no problem