Alright so I for some reason remembered my copy of American Blacksmithing a few days ago while gluing on hilt components and thinking that one day I needed to start doing some low-temperature silver solder to keep everything together and get rid of little rattles instead of epoxy. There's a page (182) that I've had dogeared for some time now. It gives a recipe for "iron cement" that is "A cement made for stopping clefts or fissures of iron vessels...This will be useful for flanges or joints of pipes and doors of steam engines."
It sounds like fairly tough stuff (especially the steam engine