Weld a Cast Iron Exhaust Manifold

Second repair on Cummins exhaust manifold. Mike used a 130 amp mini welder to make the repair, to demonstrate a worst case scenario for using our electrodes.

A cast iron exhaust manifold from a Cummins diesel truck was headed for the junk pile because the shop did not have a cast iron welding rod to repair it. At a cost of $400 to replace, our 77 and 72 rods were an inexpensive alternative.

We did not preheat the part and experienced no re-cracking when the weld had air-cooled.



  • Always weld no more than 2 inches at a time and let cool for 2 minutes between passes. For some cast irons you may only want to weld an inch or less and let cool 1 minute between passes.
  • Low and slow is the key to a sound weld with cast iron.


NotePlease observe all AWS Safety & Health Guidelines when using Muggy Weld products.