This diesel Yanmar cast iron engine had a large hole in the block, caused by a thrown push rod.
For this repair, the welders at PDX TIG Welding in Portland, Oregon employed a mild steel plate to weld to the cast iron engine block, and utilized 77 cast iron arc electrode, 2% lanthanated tungsten with 17 lbs argon.
After removing the coating from the 77 rod by dropping them in a bucket for a few minutes, PDX used tack welds to secure the steel plate in place before applying 1/2 inch welds throughout the weld area– cooling the part for a minute or two between passes.
This “peening” technique is helpful when welding cast iron, as well as gently heating the block to cool the part slowly.
In this instructional video, cast iron welding tips and techniques are discussed.