Welding over header coating.......Can it be done

[wrd1972]

I have a 3 piece coated header y-pipe and it leaks at the seams, therefore I want to weld it up solid and be done with it.

What do I need to do to ensure the weld holds up cause I was told that you cant just weld over coating. Maybe I was told wrong. I have already gone around the seams with a wire grinder with wire brush but I still dont think I have hit bare metal. If I need to I guess I can use a stone or a wheel to just break the surface.

I will be painting the welded areas with POR-15 high temp so I am not worried about the coating around the seams.

I just need to get a heads up before I take it to the muffler shop. I am also open to other suggestions to seal the seams.
Thanks

[fastTa]

You need to get down to bare metal in order to get a good weld. Don't expect rust not be a problem in the near future though.

[Joe 1320]

You need to get down to bare metal in order to get a good weld. Don't expect rust not be a problem in the near future though.

Correct...... the ceramic coatings interfere with heat transfer and won't allow penetration of the metal. It's got to be bare for a weld to take.

[Black97]

I would try to get it sandblasted with fine metal pieces instead of sand. that should take care of cleaning it up for welding.

Knowing what kind of material the Y-Pipe is and then using the proper material welding rod would make a better weld too.