Welding coated headers?

[SpareChangeRacng]

At the LeDuc swap meet this year I bought some headers for my 4.0 exploder. They looked to be brande new and were just coated (jet coat possibly - looks ceramic to me).
Anyways, after a closer inspection they seemed to have been welded in a few places and then coated to make them look new. The problem is they did not weld one of the cracks fully before the headers were coated. I can see the crach continuing past the weld on the inside, so I want to close it up. My question is - can you weld coated headers? Is it best to sand/grind off the coating and just go for it, or will this ruin the coating? I certainly hope I didn't just donate $225 to a liar.

[ntsqd]

Grind it back only just far enough that it won''t get into the weld puddle. Some of those coatings will actually migrate over time and cover up part of the bare steel.

[hoeker]

run them and if it doesn't leak don't worry about it.

[SpareChangeRacng]

I've got a set on there that are leaking through small cracks right now. I just didn't want to take the time to put the things on and have to pull them off again right away. Since I can see a crack (it goes all the way through) it's kinda preventative maintinence you know.
I guess I will lightly grind/sand it and weld it then. Thanks guys.