A question for the exhaust specialists out there.....

[darkduke]

Actually, he went over that on the first class. He said 308 works but he prefers 309L as well. He recomended a back purge for SS tubing.

[Ducnial]

Any 300 series will probably work. 3xxL= low carbon. Safe to weld but be aware that in and around the welds will be prone to rusting due to free iron precipitating from the high heat. Be sure to passivate it afterward to reduce rusting.