I have not done the welding yet on the diff,
the pic I have is from a guy in Mexico or South
America, like Brazil, he said since the mod he
has had no problems, so I think he is running
this mod and had no warpage.
I did however weld that custom high angle front
bumper out of .100" Aluminum plate, and some
diamond plate, also aluminum, and did not have
any warpage problems. I don't know how the casting
would hold up, and I don't remember what alloy
the plate I used is, but I did use a MIG welder
with the softer alloy wire, I think it's like 3000
series alloy, I also tried the 5000 alloy wire, which
is much stiffer, but it seems to not be as easy to
weld with. I did get the larger Dia. .035" wire when
I got the stiffer wire, which might be the problem.
I use a small MIG machine, so I pre-heat the thing
I'm working on and that might help to reduce the
warp factor, also I don't think a 110V MIG puts out
over 85 Amps so the heat is not as severe as some
of the high output machines.
I run the welds hot and fast, high wire speed, like around
8 on the 1-10 scale of the Lincoln mini MIG, you know the
ones that about look like a suitcase, great little welder for
light stuff, welds tubing like a champ.