home built steamer

I'm currently working with a friend of mine to build a steam engine from scratch. Are we crazy for trying ? Most people say so ,but with a good understanding of the principles of steam generation and with a good safety releif system on board were going to convert an old horizontal shaft lawn mower engine to steam power with an outboard flywheel and drive hub on a seperate shaft connected via a crank rod. were planning on using a few small lp tanks for boilers , propane fired with individual releifs and guaged to run less than 40-50 psi. we just need to build and link the valve assembly.I'm a jack of all trades and so is my buddy and were committed. were on a mission. are we crazy. or are we just in tune with our curious creative mechanical nature? has anyone done this out there? please let us know how you made out?

Sorry if this sounds rude, but I would really suggest you reconsider your boiler setup. There are enough people out there ready to condemn the entire steam hobby without having a Rube Goldberg contraption blow up in someone's face.

What do I suggest? Build from published plans (watch if you resize, physics don't scale), buy a used boiler (make sure it is in good condition) or new commercial made boiler, or even start completely from scratch and do all the ASME calculations.

Remember, from a liability standpoint, it is up to YOU to prove the boiler is safe, and the easiest way is a continuous paper trail.

There..i've heard it again..Rube Goldberg. Well i'ts not like I have'nt been called that before!! Well I dont quite know what to say as well but I guess I'll admit it sounds a little obscure however make no mistake about it, the love and admiration I have for the great designers and builders who set this great country into motion many years ago with the most simplest of means, guided by their dreams and ideas, spun from curiosity and the love they too had for machinery and its great leverage it had on the world as it was. When myself or anyone of us as well watch this simplest of machinery run right before us the effect is somewhat spiritual indeed. I for one have this curiosity and feel that with safety being my most capitol of concerns, and with an understanding of the materials used and mind you keeping this all within a minimal pressure range,and with all regulators in place and tested,when the fire starts to slowly roll from the underside of the boiler, I too will realize the dream. As for the condemnation of this great love of ours all I have to say is if we let the fear of these lower forms guide our future we might as well give up the ship. Steam on friends...Steam on

I really feel an obligation to caution you againt using propane tanks for boilers. 40-50 psi is not low pressure. Over 15psi in public and you maybe in violation of the the law. Depends on the volume involved. As least dont have any friends or family exposed to this risk. Do it by your self and for you own amusemnt.

I dont know where to begin..... It almost crazy to do what you propose with no engineering background. You can learn. You can study some of the old books. Forget ASME, your not even on that planet! At least understand strength of matterials and stresses involved. Study the specs on old boilers. Consider staying under the legal 15psi max. Heck, you might do quite well to fire up an old home steam heating boiler at 15psi. thats simple. Those can be gas, coal or oil fired. often time available as a gift in a home renovation.

Perhaps you would considered attending a few steam engien shows. You can get a lot of support and direction. You will find many guys build thier own stuff and some in a similar manner to your proposal. Perhaps using old air compressors and scrap yard valves. Some are engineers other are gifted mechanics with some good practical understanding. believe me none of these guys would every light a fire under a row of propane bottles. You can get very creative with the engine. I suggest you keep it safe and follow the hard learned lessons of the last 150 years on steam generation.

You may not have heard several people were killed and several dozen more blow off thier feet and hospitalized in a steam hobby accident this year. This guy blundered on a larger scale. Now there is a higher level of safety awareness these days. Its not a personal thing, but people are pointing fingers all over. I have to say, if I see something like you propose -in public, I have no choice but to take action. I am not a state official, but just by knowing what I know. I cannot standby in such a case. Same thing if I see a loaded gun on the ground or suspect a terrorist activity. I may not be very tactful. I dont want to discourage you. Steam is great stuff. Nothing to be afraid of, no more than driving or flying. The atmosphere is less tollerant of ignorance (ie inexperience) regarding steam boilers in public.

At home you can still do pretty much what you want. Please just give some consideration to using a conventional means of steam generation and for god sake forget the propane bottle idea.

good luck guys.

I'm sorry if you were offended by my choice of words. You asked for advice, you got practical, experienced advice, the fact that it wasn't what you wanted to hear is not my concern. Please demonstrate to us some of that native intelligence, and either do all the stress calculations, or turn the boiler construction over to someone who will.

Boiler safety has absolutely NOTHING to do with dreams, and EVERYTHING to do with practical reality...PERIOD.

Is is the word PROPANE that is scaring you. What I see is an approved vessel, of steel construction, able to hold well over my intended pressure use, with an orifice large enough to purge, if needed ,enough pressure, through a spring type relief valve also of large enough volume to releive pressures over my set operating range rendering the unit safe. Eliminate the word PROPANE , and you have a steel tank. As for using a peice of junk from a scrap yard(old compressor tank) I dont consider that sound advice. Can you give me some other reason for not using this steel tank. Also I'm going to take your advice on the pressure. Yes 10 - 15 lbs is more than enough to run this engine, of course i'm going to start as minimal as needed to get motion. I f you still think i'm stupid for trying this please respond and we'll continue.

Please read my reply to Communication Failure. I still cant see, from a practical standpoint, why this steel tank couldnt safely be used. Its like you think it'll be filled with Propane when I fire it up! Please respond...or am I really that stupid?

below is a direct quote from the LP Gas Industry page as follows.

LP Gas Containers

It is important to understand that special containers are required for LP Gas. The pressure in an LP Gas container may vary from approximately 15 pounds per square inch on the gauge (PSIG) to 230PSIG, depending on the temperature of the air normally surrounding the container. LP Gas containers are built to withstand such pressure, LP Gas containers are built strong and safe. LP Gas containers:

1. Are unfired pressure vessels. They are like a steam boiler in that they are designed to handle a product which is under pressure. But, unlike the steam boiler, heat is not applied by means of fire.

2. Are manufactured in accordance with strict codes, which assure the utmost safety in the storage of the product.

3. Are designed for a particular working pressure (shown on the container). The working pressure is well above the normal pressure of the product. The bursting pressure is approximately four times greater than the working pressure

-------------------------------------

this is for reference only, im not trying to sell this idea to anyone.

for viewing go to http://www.lpgas.com/what.htm

[Harry]

"1. Are unfired pressure vessels. They are like a steam boiler in that they are designed to handle a product which is under pressure. But, unlike the steam boiler, heat is not applied by means of fire."

Perhaps the question is, are the construction metals they are made of suitable for building a fire under? Can they take the stresses and aging that would result from such heating and cooling by corrosive combustion gasses over a period of time? Would the water and steam inside them corrode and erode the container from within?

-- Harry

So why are you here? You seem to have all the answers and seem inclined to argue about anyone who sees the folly in your design. I have followed this board and several others for quite a while. About every four or six months, someone comes along to announce that they are going to build this incredible little steam powered generating plant from scrap materials and tell the utilities to get lost. A frenzy ensues with people trying to convince the would-be-engineer that he has grossly over-simplified things and that he is going to hurt himself or some other poor sod. Eventually things die down and he is never heard from again. Since I don't read about a firey death in the papers, I assume he has went back to fantasyland. All of the flowery prose you spew will not change the laws of physics and thermodynamics. Your propane cylinder boiler is going to be so grossly inefficient that it is laughable. Without tubes to increase the heating area, it will have very poor steam output for the amount of fuel consumed. The propane cylinder was designed to work at a relatively slow pressure drop and at ambient temperature. Boilers need to be designed, and are designed, to withstand the increased temperature needed to generate steam, sudden pressure changes and thermal shocks. What about oxygen pitting? You make no mention of how you propose to get feedwater into this boiler, how you intend to monitor the water level inside said boiler or how you know that this boiler is going to have sufficient steaming capability. Your engine is to be a modified lawnmower engine. More details on how you intend to do this would be "entertaining". Yep, a lot of us have heard this all before. If we just take a propane cylinder and a lawn mower engine, we can build a functional steam power plant. Yah, sure. And if my aunt had balls she would be my uncle. If you are intent on killing yourself, do us all a favor and use a gun. The steam hobby has enough troubles without guys who think that the "rules" (physics, thermo, state laws, common sense) don't apply to them.


Darwin Awards

Boy oh boy arent we something. Never meant to upset you kind sir, and never meant to build the most effecient steamer either friend. Just a device to pressurize a piston within a cylinder and turn a flywheel for sImple and safe steam power observation and pure FUN. Cant you see this. Go back to your slide rule clyde, I've got an engine to build.

I thank you for your straightforward contribution.Advice from experience is priceless and yours comes without the negative slander I've been slammed with. I concur with your assessment of the quote and agree with you. This will be an area for study before final consideration.

Thanks again

After reading your reply again Mr Prindle and with just a little rise in blood pressure, I feel the need to add that people like you who puff themselves up like some kind of all knowing entity are going to do more harm to this great interest we all have than good. Im not going to speak my mind here, just let you reply with an apology that i'm sure you and many readers know you now owe me.

Okay, here goes some elementary metallurgy

1. Boiler steel is dead soft by design, so that it will deform (bend) rather than fail catistorphically (crack, shatter) in event of over stress. Also when steel is heated the yield strength decreases at different rates for different alloys. You and I have no clue what kind of steel those tanks are made of.

Also there are certain proceedures that need to be followed when welding boiler steel to minimise the heat affected zone and prevent brittleness (most times welds don't fail, the metal in the HAZ alongside the weldment does). How were the welds on those tanks made?

What is the wall thickness on those tanks? There are calculations used to determine the minimum wall thickness for a given diameter of boiler shell. That is a minimum thickness, it is also rather nice to add some allowances for corrosion.

I can tell you for sure that the ends of those tanks are not stayed in any way, is the area really small enough to not need staying?

Yes, you could probably make an educated guess at all this using a minimum value in the calculations, but why not just do it right?

You, sir, asked for input. You have been given the same advice by at LEAST 4 people and yet you still insist that you are right and everyone else is wrong. If someone lost patience with you for your obstinence, is it really that surprising?

Fact: You are attempting to reinvent the wheel. Rather than pooh-pooh 300 some odd years of accumulated steam knowlege (some of it gained at a very high cost) You should really consider learning and benefitting from it. Its all just for fun you say, and thats fine.... BUT some things (like metallurgy, physics, and thermodynamics) won't change because you find them inconvenient. Look up the Best Friend of Charleston, or the Sultana, the recent incident at Medina, or a thousand other incidents that occured because some bright fellow knew better than everyone else. 3rd degree burns, schrapnel wounds and scalded lungs are NOT fun, and no, you don't really have to experience them firsthand to learn that either.

In my opinion, Mr. Daigle appears to have never been interested in any carefully, qalified, or thoughtful responses to his initial question. Mr. Daigle, in my opinion, appears to be more interested in participating in a raucous smart aleck arguement based on a little truth here and there, seasoned with pipe dreams.

Not that it will be worth a hill of digested beans to Mr. Daigle, but propane cylinders are manufactured as pressure vessels, yes, but not for use in a water environment. They will rust through and rupture in no time when exposed to water, steam, etc. Even using a propane cylinder as a simple air receiver with no heat applied is dangerous because of the accumulation of water over a period of time.

So if Mr. Daigle wants to, on his own, after all this good advice, to go ahead and blow himself up, or badly scald himself, with a hot steam explosion, then that is fine with me. It is the others, the innocent bystanders if you will, who may not have had the benifit to profit from these discussions, that may suffer the same fate as himself that I am concened about.

I 've learned that Mr. Matthews has a wonderfull website , one of the best I've had the pleasure of visiting. He himself gave me enough insite for thought, without dredging himself down into the type of slime some of you people disrespected upon me. When I asked questions I was looking for facts and information on how to base my design. I was'nt looking for gutless losers who at the thought of someone not agreeing with them, lash out with personal slander like any other primal life form. You folks need some therapy on how to get in touch with your manhood. I personally feel sorry for you all. I apologise Mr. Matthews for the kind of comments that have taken place on your site because of an inquiry made by myself about an idea I had. NOT ONCE did I make a personal attack on anyone and did not deserve the type of responses I received. Sure some of your viewers are adept in the mechanical arts but are lacking in their own personal lives, I hope they get help.

"When I asked questions I was looking for facts and information on how to base my design."

You presented a dangerous idea, and were promptly answered with facts AND information. You were not only told WHY your plan was a bad idea but what you needed to do to get a workable one. You then attacked those who offered their insight for petty reasons.

"I was'nt looking for gutless losers who at the thought of someone not agreeing with them, lash out with personal slander like any other primal life form"

Those "gutless losers" are people who have heard the same and similar scenarios proposed every few weeks since the Y2k nonsense first surfaced. And have consistantly given the same advice concerning boilers: Do the calculations, Know your materials, Document EVERYTHING, Do things right, or please don't do them at all. Besides, who will be the biggest loser if you happened to kill yourself? Even if you don't miss living, not only would your family (presumably) suffer, but it could cause irreperable, or at least long term harm to the entire steam hobby if you managed to do it in a spectacular enough fashion.

Just stop reacting emotionally, and think about it

Okay what about the things that you still DON'T seem to know? PLEASE, feel free to prove all these "gutless losers" wrong and answer the following questions:

What is the wall thickness of your cannisters? What material are they made of, and what are its physical properties... how will these change with temperature and pressure? What is the calculated minimum safe shell thickness for that diameter which can withstand your intended operating range with a safety factor of at LEAST 4x? Do you have any corrosion allowance? Will you need to have bushings to maintain proper thickness for any openings? What is the area of your cylinder (boiler) heads? Are they safe at your intended pressure, without reinforcement or stays? How do you intend to clean and inspect your boiler internally? Have you made allowances for these openings in your stress calculations? How do you intend to perform whatever modifications that seem necessary to ensure safe operation? How will you monitor your water level? How will you add water? How will you control your heat input? How and where will you fit a fusible plug? Why? What is your evaporation rate? How will you know that you have an adequate and proper sized relief valve?

And one more just for fun: How much potential energy is stored in that volume of water within your boiler at its operating temperature and pressure that would be suddenly released if the boiler burst? (Just a rough guess is fine)

There is a wonderful reprinted book by James H. Maggard titled "Rough and Tumble Engineering" that should be required reading for anyone interested in steam whether experienced or not. If the facts of live steam don't put a VERY healthy respect for the power of live steam into one, another area of interest should be persued. Anything over 10psi is considered high pressure and one only has to consider the damage a household pressure cooker can cause if the lid should happen to blow. PLEASE do not use anything but a steam boiler as a boiler---for your sake and that of your friend and/or standers by. Just a note: Some of the remarks may seem harsh to you but ALL of them speak facts and truth about steam. I'll not consider the personal references as that is none of my business. However, as I once owned a 60hp Case traction engine and as the president of a local Thresheree club, I am MOST concerned that ANY display of steam by ANYONE be done safely and by a knowledgable operator.