Ronn

what is the midpipe on a 10 gt made of?

dysan

I'm sure the same material as the 05-09, a low grade stainless steel.

10GTSTANG

Mine is plastic!

mapitts

You can do a magnet test on it. If you have a pen magnet, lightly pull it across the pipe. If you "feel" a little pull it is 304-308. Both of those tend to rust over just a tad bit. If you feel no drag, it is more than likely 409.

Ronn

i want to weld in something on the order of the m90's which are stainless so i guess any grade of stainless will work.

mapitts

For exhaust, you should be just fine. If you have it available to you, 308L will do better, but what ever you have will get ti done.