michaellynn2 wrote:Folks , I have no experience with stainless boilers except one. A boiler inspector in the state of VA. told me he would never pass a boiler that he would inspect made of stainless.
I would think that this inspector may need to do some homework. At least he shouldn't make that little mind up so early in the morning.
By 'silver soldering', what is meant is not 'silver brazing'. The eutectic silver containing alloy is not the brazing alloy that is most popular which requires 'red heat or greater than 800°F to flow. There are lower melting 'liquidous' silver bearing alloys made and used with temperatures well above the working temperature of a 100 - 125 psi steam boiler. This solder has been being used for probably 40 years or so. It works with copper, steel, stainless steel and other metals and combinations of them.
Way back when this 304L pipe was purchased for a welded boiler, I was unaware of the pitfalls of the 'heat affected zone' corrosion brought on by the use of cholorinated water for steam production. The decision was made to discard the very idea of a welded stainless steel boiler - even though since, I have read about completely sucessful boilers of 304, 316 and the new on the scene (in other countries) duplex stainless steel. But then it is still unaccepted in the US. Even considering the use of 'silver SOLDER' or the use of distilled water - "there will be no Stainless Steel boilers run on 'my track'" "Let's over build our boilers out of heavy walled welded steel pipe and boiler plate." Most boilers built today could probably be tested to 1000 psi - but then they rust, corrode and deteriorate in a few years so your time, money and energy invested in your 'live steam locomotive' is a waste in just a few years. Welded copper is out - welded stainless is out (rightly so) and silver soldered stainless is out too.
I seriously believe this topic is totally exhausted.... copper is in the works but my wife says go ahead and get the monel 400 for the next one. No discussion required!