Hi Jim, The things you wrote about the Midwest boiler worried me as well, ie: no saftey valve and brass flue pipe. In my attempt to fix these things I noticed areas in which I thought improvements could be made, now mind you this is my first venture into steam. Identifing these inadequacys after purchasing this kit left me with two choices: try to make useable the original bodged up design or scrap it. Since I enjoy the process of discovery during research I chose the former, it is a learning experience for me and one I rather enjoy!
The information gained from discussions such as this one go a long way in helping people (such as myself being new to this hobby) understand the safety and engineering issues that go into a live steam loco, and for this I am grateful :-) A BIG Thanks to all who have contributed !!!!!!! Kindest Regards, PeteH > > That Midwest boiler worries me in that the ones I've seen have no safety > valve - they rely on the plastic steam pipe popping off the stub it fits > onto, if the pressure gets too high. That sounds possible, but sure as > eggs someone will wire or clamp it on, or replace the plastic with brass or > copper soldered on. I know of at least one accident in the USA where a > spectator child was burnt when the steam pipe popped of the engine end in a > model steam boat. The boiler was over filled, and the free end of the pipe > was whipping around spraying boiling water and steam all over. > > The issue of the thickness of the flue pipe wall I think is probably a red > herring - the conductivity across a thick wall will be reduced (VERY > slightly!), but as heat transfer is much more limited at the metal/water > and flue gas/metal interface, the effect of metal conductivity will be > negligible. > > The real problem iwth the Midwest and very many other small vertical > boilers is one of totally inadequate heating surface, combined with > ineffective draft and gas flow arrangements. A Sterno fuel system wouldn't > help either. The proposed three wick alcohol (Methylated Spirit UK) > burner, would help considerably. I'd be inclined to put several more flues > in the thing and use any other way of improving both heating surface and > draft. If this works and you are considering this stage of modifications, > then I start to wonder why persist with the original boiler? It might be > easier to build a right one from scratch in the first place rather than > bodge up the original. > > Jim Gregg. >
