Supporting > Boilers

Small boiler build

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lakc:
 As it so happens, at NAMES in 2013 I bought a PMR #5 engine for the oldest grandson, and as therapy for me as a break from designing my own works. I made rather quick work of that project. and learned quite a bit along the way, but as it was poorly documented on my part, I never offered up a build log.

 Around the July 4th holiday I was starting to actively search my own meager stockpiles of red metals and reading up on various boiler builds and trying to commit Harris's book to memory. While drooling over so many beautiful works of art as various locomotive boilers and several lovely vertical boilers, I looked into my rather empty wallet and sadly realized a piece of 4" or 6" diameter copper pipe of the appropriate thickness and appropriate tube and plate would equal more then a mortgage payment. If I wanted a boiler I would have to do with what was available to me, or affordable with the spare change I find in the couch every week or so.  :wallbang:

 I have always enjoyed metalworking, and coppersmithing is an excuse to work with the most compliant metal there is. About the only useful things I had on hand were a package of copper rivets and some small size copper water pipe. A few questions in a couple of forums, and a bit of cross referencing specs across both oceans confirmed this pipe was at least the correct alloy to use for a boiler.

 Armed with the proper math, I wrote up an excel spreadsheet and started playing with the numbers. The smaller the diameter the boiler, the thinner the copper could be. I couldnt make a 4" boiler like I had originally wanted, I couldnt even make a 2" one, but just a little over 1.5" would be possible. The numbers worked out, it was safe, and I had nothing to loose. Well, almost nothing to loose, as I watched my last $70 fly out of my pocket for a single ounce of 45% silver solder. :facepalm2:

 Having read probably every boiler build thread on several forums by no means makes me an expert, but watching some posters get excoriated for some homebrew designs (most of them rightfully so) has made me quite leery of posting this. I have done quite a lot of research into this, boilers of any size can be disasters in the making. I built this knowing me and my loved ones would be in close proximity to it at working pressures. I am aware as I believe anyone can be on things like hoop stress, creep, hot strength, and hydrogen embrittlement. I am not going to offer this up as a design, I don't want anyone else to try to build it.  I wont mention any specifications, sizes, pressures, etc. This is my first boiler. I have already learned enough along the way to say I wouldn't duplicate this effort again, but the experience has been invaluable. I present this so you can follow along in this journey, and at the very least have something quite different to view for a change.

 Tomorrow, I will start posting some pictures, and building the story up to where I am today. I was a bit too long winded and ran out of evening over here. :(

DavidF:
LOL  well my first boiler was made from a couple old propane tanks with a bit of exhaust pipe passing thru it. Fueled by 3 sterno cans and operated at 150 psi!!  :ShakeHead:  I know better now... Im thinking a forced circulation boiler like a lamont would be intersting to build...

lakc:
Ok, sorry for the delay, on with the show.
As this started out as a bit of an experiment, the very beginnings are not well documented. We started with a few tubes cut lengthwise with a pair of hand shears and hammered-annealed repeatedly until we came up with two half rounds for the main shell. These were single butt joined with a couple of rivets to hold everything in place for soldering. A radius was turned on a piece of round steel for a former and the two end plates were formed with a hammer over the former. Copper is a magnificent metal to work with as long as you pay attention to its work hardening and anneal it often. Shrinking metal, making the lips thicker by hammering the metal back into itself, is probably the most fun you can have with a hammer. :)
Sorry for the lack of pictures up until this point but here is where we begin.

lakc:
Next we needed two parallel tubes exiting the shell. Two holes were bored in a piece of scrap steel to hold the parts and two holes carefully made in the shell to receive the tubes.



Soldering at these sizes was easily accomplished with a MAP torch.

lakc:
Now that we had the tubes, we needed something to stick on the end of them. Holes were carefully made in two tee's for the water tubes.


And then some endcaps for the tee's were made and soldered into place, loosely fit together in this next picture we see it taking shape.

Ill leave this right here for now, have to go to work to make the change that some bits fall into the couch that I can find to buy more tools and make more fiddly bits. 8)

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