During my career in the Nuclear field, I rebuilt many cast iron pump casings and heat exchangers with a type of epoxy metal called Belzona. Very expensive, as it was approved for use in some “Safety Related” equipment, and it worked really well. Belzona had a special release agent ($$$), that I used on the dams to help form the degraded sections. It looked and smelled just like Johnson’s Butcher wax. After running out of that special release agent, I used some Butchers Wax and found it worked exactly the same.
