Welding on ceramic coated headers

[elacruze]

I need to install O2 sensor bungs on my already-ceramic coated headers. I hope that I can just drill out what's necessary and clean enough metal to TIG the bungs in without totally screwing up the coating.

Anybody done this?

[bull]

Couldn't you drill and use a pipe tap instead? I don't think I'd mess with that coating too much if I could help it. It's just a coating and I think it's a pretty soft one.

[elacruze]

The metal is too thin to give me any confidence that it would stay in place forever.