Making a boiler without a lathe

[k4kfh]

Hello,

I am new to live steam (and new to machining) and I just built my first engine, a PM research #3. I got the machined kit as I am a college student and don't have a lathe or a mill right now, only a hand drill and simple hand tools. I saw the 1969 popular mechanics plans to make a pseudo-Babcock style boiler with a 2" diameter pipe nipple and end caps, and I really like this plan because it makes sense to me and I could do it without buying many additional tools. However, I see no good way to add a sight glass if I use this boiler horizontally.

If I could find a way to suspend a 6" length 2" diameter pipe nipple vertically, with a small propane burner underneath, I suppose that could work, but that seems like it would require machining.

I considered making a copper boiler, but I don't have a way to turn the end caps (everyone I've seen hammers the caps out and then turns them down on a lathe). Is there a safety reason that you can't just use store-bought copper pipe end caps and solder them on?

Basically I am looking for an easy, safe way to build a boiler with minimal machining. I know a guy with a lathe but it's a couple hours driving to get there, so the less precision machining, the better.

Advice appreciated!

[neanderman]

Two things come to mind:

• Regarding using ANY pipe, you need to know what the rated pressure is; you don't want to exceed that.
• If using copper, you need to use a high temperature solder. As long as the water level is sufficient, it might not be really likely to melt, but if it ever does...

Others here, with more experience, will know more.

[FKreider]

Quite a few years back I wanted to make a small stationary engine and boiler and at the time I was limited with tools. I came across this great build on YouTube:

https://www.youtube.com/watch?v=WQ_mBwyTaiM

It is made from 2X5" water pipe and as mentioned in the youtube description; plans for this boiler can be found in the February 1963 editon of Popular Mechanics (Copies of Popular mechanics from 1905 to 2005 are available for free on google books and it is very fun to look through old articles.)

https://books.google.com/books?id=R-MDA ... &q&f=false

If I were to build this today, I would probably go with two safety valves - just to be on the safe side.

[James Powell]

Does your collage/university have a shop you can get time in ?

I know U of T Chem Eng used to have a very friendly machinist !

Making a boiler using pre-made copper parts is perfectly fair. HOWEVER, I would highly recommend silver soldering or brazing the boiler together. If you are going to fire with propane, you can use sil phos or similar, low silver containing brazing rod. (not something you can use with coal...)

I don't know that I ever tried to make a boiler without access to a lathe. However, a small lathe should be very high on your list of things to get. It can be done- even something like my Petol would be big enough to build a boiler & fittings with. (IIRC, 2 1/8" " lathe...it fits in a projector box nicely enough).

If you put a location on, then it may well be that there is someone on here who is closer, who might be willing to help !. (I'm on Vancouver Island, for example...so if you were @ UVIC I could help...). Other options are to see what local shops there are- they may be interested in taking on a bit of help for some make-learn. One of my friends got into TRUMF via that route, he's not a HSM type guy, but is definitely in engineering. (in his case, mostly in low-activation materials, at a technologist level position).

[k4kfh]

Thank you all very much for the advice!

Regarding my location, I am in Auburn, AL. The university has machine tools enough to construct a small country, but as far as I know I'm not allowed to use any of them until I take the mechanical engineering elective that teaches me how not to make myself into hamburger with them. Back home (I'm from Huntsville, AL) I had a fantastic machinist friend, so I got spoiled to having easy access to a big lathe and mill. But being in a 3rd floor apartment right now with carpet flooring, my ability to casually sneak a lathe into my room is a little limited...

I had seriously considered the popular mechanics boiler, I am confident I could assemble this and it makes logical sense to me so I would feel safe using it. The only thing I see wrong with it is the lack of a sight glass. Is there any easy way you could fit a sight glass onto it? I looked at PMR's sight glass but it's too long to put on the end, unless I make a sort of extension pipe out the top of the boiler to mate with the top glass fitting, but that seems like a recipe for whacking it and sending glass shards and steam everywhere.

[steamin10]

A "toy" boiler can be built easily with not much more than a hack saw and a set of drills. Copper is the way to go for something small and easy, and you will get into a low pressure deal with a counterweight safty. It will run a demonstrator engine quite well. You will only need about 20 lbs to run on so it is no big deal. As far as a sight glass, you can build one with compression fittings or make a port on the end of the boiler like you see on some Namod products. I have seen all manner of steam sources that work, From converted tea pots to real fire tube boilers of small scale and everything in between.

On U-tube there is a boiler explosion of a model that goes pop and blows a coffee cup of water into the air. The newbie filled the boiler too full and it popped the seam. Small volume, small pop. Keep things in scale and learn. Big machines make for big ouchies. Be curious, be safe. Have fun.

[k4kfh]

Thank you for the information. A few questions:

1. Can I use a store bought safety valve (even one meant for compressed air) as long as it's rated for the correct pressure? I can get one on Amazon for about $10, which is cheaper than I could probably try to make one with a counterweight.

2. I got an idea today for using a PMR sight glass on the popular mechanics boiler. I can use some inexpensive threaded pipe nipples, a coupling, and a 90 degree elbow fitting to make an L-shaped extension out of 1/4" brass pipe out the top of the boiler, which could mate with the top fitting of the sight glass. The bottom fitting could be drilled/tapped into the end cap that makes up the main boiler body. Does anyone see any serious problems with this design? I was concerned about the strength initially because I was thinking of soft copper tubing, but rigid brass pipe with cast elbows/couplings seems fairly safe to me. I like this idea because it doesn't require any soldering/brazing, and it only adds about $30 to the cost of the boiler.

[apm]

Thank you all very much for the advice!

Regarding my location, I am in Auburn, AL. The university has machine tools enough to construct a small country, but as far as I know I'm not allowed to use any of them until I take the mechanical engineering elective that teaches me how not to make myself into hamburger with them. Back home (I'm from Huntsville, AL) I had a fantastic machinist friend, so I got spoiled to having easy access to a big lathe and mill. But being in a 3rd floor apartment right now with carpet flooring, my ability to casually sneak a lathe into my room is a little limited...

I had seriously considered the popular mechanics boiler, I am confident I could assemble this and it makes logical sense to me so I would feel safe using it. The only thing I see wrong with it is the lack of a sight glass. Is there any easy way you could fit a sight glass onto it? I looked at PMR's sight glass but it's too long to put on the end, unless I make a sort of extension pipe out the top of the boiler to mate with the top glass fitting, but that seems like a recipe for whacking it and sending glass shards and steam everywhere.

Go down to the machine shop and introduce your self and start speaking with some of the guys who work in them and see if they have student jobs available. Back when I was in school I didn't know that was available sadly till my senior year. I wound up getting a job in the industrial engineering shop which was not a student shop but I got paid nice money for a student and got to have a lot of fun playing with some great machine tools! I also learned some neat stuff under the wing of one of the professors. That shop used to get research grants with use it or loose it tooling budgets. Imagine if all of us got $5K of play money attached to each job which we just needed to spend in MSC or it disappeared, they had everything and brand new too! What a joy that place was to work in. Talk to some of the professors and avoid the student shops which usually are complete dumps unless someone is there who cares for them.

[FKreider]

Thank you for the information. A few questions:

1. Can I use a store bought safety valve (even one meant for compressed air) as long as it's rated for the correct pressure? I can get one on Amazon for about $10, which is cheaper than I could probably try to make one with a counterweight.

2. I got an idea today for using a PMR sight glass on the popular mechanics boiler. I can use some inexpensive threaded pipe nipples, a coupling, and a 90 degree elbow fitting to make an L-shaped extension out of 1/4" brass pipe out the top of the boiler, which could mate with the top fitting of the sight glass. The bottom fitting could be drilled/tapped into the end cap that makes up the main boiler body. Does anyone see any serious problems with this design? I was concerned about the strength initially because I was thinking of soft copper tubing, but rigid brass pipe with cast elbows/couplings seems fairly safe to me. I like this idea because it doesn't require any soldering/brazing, and it only adds about $30 to the cost of the boiler.

I was going to suggest something similar for the sight glass on the water pipe boiler. I dont see why you couldnt just use the copper but certainly the brass pipe would work as well. For an extra $7 over the amazon one why not go with the PMR safety valve as well? If there is one thing I wouldn't skimp on its the safety valve...just not worth messing with.

[10 Wheeler Rob]

The boiler should not be made from brass, use copper or bronze. The zinc in brass dissolves into the water over time and it becomes porous and weakens. Brass works for piping, tubing and external fittings, that can be easily replaced if they age out.

[k4kfh]

I was going to suggest something similar for the sight glass on the water pipe boiler. I dont see why you couldnt just use the copper but certainly the brass pipe would work as well. For an extra $7 over the amazon one why not go with the PMR safety valve as well? If there is one thing I wouldn't skimp on its the safety valve...just not worth messing with.

The only reason I was scared of using copper tube for that is because I thought it would be too flexible, and that if I bumped it, it wouldn't provide any support for the glass and it would shatter. And I'd like to avoid extensive silver soldering work if possible, so threaded brass pipes seem like a nice alternative to sweated copper stuff.

Sadly I can't use the PMR safety valve because it's locked at 60psi. The $7 one on Amazon is of the adjustable type, so I figure I'll set it to 30psi and test it thoroughly. Plus the cost means I can buy two. If anyone knows a better 30psi safety, I'm open to ideas, but I figure for my first boiler I should stick to 25-30psi. My little mill engine will go into low earth orbit with much more pressure than that anyway, and I haven't gotten around to fitting a proper governor yet.

I figure I can hydrostatic test the whole thing with ordinary household water pressure (I don't have a feed pump, sadly. I might add one later, but I'm trying to keep the cost down). When I do a hydro test, should I leave the sight glass in, or should I completely remove everything except the copper water coil underneath? Obviously I remove the safety valve so it can go to twice working pressure, but beyond that I'm not sure what to take out and what to leave in.

One more question: can I get away with Teflon tape for the fittings on the top of the boiler that are not in direct contact with gas flame? I figure I'll use Loctite on the threads for the compression fittings on the coil underneath, but I like the idea of not having to use a torch to remove fittings from the top of the boiler sometimes. And is there a particular kind of Loctite I need to use, or just Loctite red? I've seen several different kinds used by various people.

[NP317]

Hydro test the boiler with the water glass in place.
You want to know it's equally strong!
I do that with both my steamers, which get annual hydro tests to 220 psi.

Get a steam-capable sealant for threaded fittings. Safer that way.
~RN