Stainless Steel boiler. Yes Stainless. This seems to be a topic of great debate and from all the research I have done I cannot find any reason against it, when handled properly. I avoid it myself mainly due to the fact that I can handle brazing copper. Steel is currently out of my scope of welding abilities, and stainless even further. I think a lot of the controversy is the lack of skilled welders that can properly weld stainless and even fewer that are pressure vessel certified. Here is a boiler awaiting its pressure test. The club has several in service all perform flawlessly for many years now.
cheers Ferd