Anyone know for sure the type of metal used for the 'middle layer' of the Renesis exhaust manifold? Not the bolt-on heat shield, but the outer welded layer that's about 0.1" thick. A magnet grabs it tightly, but it doesn't seem to rust, so that makes me think it might be some form of low grade stainless.

I've got some 308L rod that's supposed to be good for welding stainless to itself and to regular steel, but I need to weld an area of the outer metal to itself, & don't know whether to use the 308 or a rod for regular steel.

Thanks,

Charlie