Exhaust manifold welding tips + ceramic coating

[Ameer Antar]

Even though I'm probably going to trash my manifold, I tried to weld up the
cracks in it today. I was using a cheap 120A gasless MIG welder, but I
would notice that eventually that the cracks came back in the same spot.
What's surprising too, is the place where the metail cracked is actually
pretty thick. The crack must be very deep for WD-40 to spray out. Also when
I let the metal cool after welding, I hear this clicking noise from it. Am
I welding this wrong, or are these manifolds really no hope? I see some
repaired manifolds at Dad's and such..are these worth it, or will these
crack soon too? Would a ceramic coating protect it from high heat and
cracking again? Thanks.

-ameer