I'm in Tennessee as well, some couple hundred miles west of ya. and my interest has been working size boiler builds, something I can run an off road truck/tractor with. Chug around the woods and collect it's own fuel, winter heat for the house, plus wood to make charcoal for biochar and foundry fuel, and whatever other jobs it's good for, like steaming garden beds, maybe even powering my sawmill if I come up with a small steam engine for it. (modified IC engine likely) So with that goal a few years back I got plans for and built to spec an ofeldt water tube boiler rated 15-40 hp. With just an AC arc welder and steel. Bought the seamless steel tubing needed from a Chattanooga supplier, got the 10" sced 40 steel center drum from scrap yard, fabrication job cutoff scrap. Made a tube coiler from odds and ends bolted to a shop support post. The design is rated 600 psi operating pressure. But I found an old westinghouse high speed engine on ebay for a good price and grabbed it, and it's not made for that kind of pressure, (it's size calculates at 15 hp at 100 psi) so I put a 200 psi relief valve on it and set it up for pressure controlled furnace blower with a 2 stage air compressor pressure switch, (mounted on the cold water inlet pipe and air trap so it only sees air, and boiler heat will never get to the switch) set it for around 175 psi. Plus I made it with an aluminum blowout plug for secondary protection. (7/8" hole in the top plate, matching hole in a bolt down cover plate, and small piece of aluminum flashing sheet trapped between the surfaces) I did a cold test with washer pump and it blew the plug at 700 psi. I will do a cold test again every year or so to at least 5-600. It's supposed to have test at 900 psi for running at 600. So I'm running it way under it's capacity. It's taken a number of years a little now and then to get everything set up on the old 4x4 truck frame, but last couple days I've finished up a few details and I think it's ready to start up and drive. I've had no welding training, only 35 years experience repairing and fabricating all manner of stuff. Learned mostly from doing it how to make tight solid weld joints, thin sheet, stainless steel, cast iron, had to figure them all out for various repair jobs. And for the boiler welds I made a used oil torch to preheat every weld joint to dull red heat before welding. Just a simple little mixing nozzle uses compressed air and used motor oil blowing it into a tube to make a very hot blow torch. once it was done and closed with valves and plugs, compressed air and soap water showed where any seeps were, re heated and welded them. Used 6011 rod for it's more liquid bead, and it was also mentioned as good for the job by the man I got the plans from.
Eventually I need a donkey engine/winch for the truck, (electric winch will have to suffice for now) I'm dreaming of eventually making a yarrow type boiler for another steam vehicle, as well as building an engine for it from scrap with charcoal foundry. And maybe a vertical firetube boiler for small stationary use. I will build either one in the same manner, overbuilt and over tested for pressure, with double safety relief. I have to know they are totally safe to be comfortable running them. I do not plan on building a horizontal firetube type. The crown sheet firebox arrangement makes them more difficult, without that they are very limited in efficiency. And they are sensitive to position which I do not like in mobile use in the mountains. Been thinking at times of a custom design for a vertical boiler using combination water tube and fire tube, but that's a remote future project yet. At this point I'd find it easy to weld up a small boiler, make it to hold about 10 times the pressure it would ever see in steam, put the right valves and regulators on it and it's good to go. Always use boiler water treatment in them, with rain water so there's no mineral to make scale, unless yer domestic supply is really low mineral. I even put gutters on my shop and a big stainless tank a neighbor discarded set up at the end on cedar log supports, (a 60's vintage milk truck tank) to have a rain water supply for the boiler, since our spring water is really high in calcium carbonate. Mounted high enough I can fill the boiler and reserve tank with a hose. And I'm using the old poly gas tank on the truck for feed water. a little 12V lift pump pushes water to a pressure washer pump belt driven off the steam engine for boiler feed, and an auto air conditioner electric clutch turns it on when needed. But I think a penberthy injector would be easier to use in freezing weather, a lot less hoses and pipes to keep from freezing. So I may switch it over when I can get one. Put drain valves at every low point for easy complete drain, since I will be using it in winter mostly. The heat of running will make it uncomfortable to run in summer, plus winter is my primary wood gettin time.
That's my setup and doing of it, everything mild steel welded, (except the stainless superheater coil, which I welded the ends with nickel rod) if it's of interest fine, if not forget it and do it some other way. It's just the way I found most affordable and fit what I want to do. But I do find it interesting to be able to pour in the water, pick up wood, light a fire, wait a bit to warm up and away we go, get work done with pretty much zero expense for fuel. Spin a few cast iron wheels and and get to blow off a little steam in the process. My steam interest started about 1978-9 when I was 13 and we visited a man in Chattanooga who had a couple steam traction engines at his place. As well as visiting steam shows a couple times back then. In the years since I've collected lots of info and put together small foundry and machining capacity, but life kind of gets in the way of doing a lot with it, so progress has been slow. And while personal interest is still involved, I probably would never do anything with it unless I can make it practical to help out with necessary work, which is easy enough to do.
