The Stirling Engine, absorb energy from candles, coffee, and more!

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There's energy all around us that's just waiting to be tapped into. Whether it's hot coffee on a cold day, light from the sun, scented candles, waste heat from electronics... there's power to be had! How about we turn it into useful power? Step in the sterling engine.
Ever put a tightly filled balloon in the freezer, then come back and see it largely shrunken? Once you bring it back out into a warm room it expands again. Now what if we could use that expanding and contracting for moving a piston... and you've got the general idea. If you heat the air, it expands, if you cool it it contracts. It's a very simple idea, for a very simple engine.

let's get building!

here' s the video of the build and the engine working!

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Step 1: Materials

Required tools:

utility knife
plyers (long nose)
wire cutters
drill bits 1/16, 5/32, 1/2-3/4
drawing compass

CD and case / large plastic jar lid
10x5 inch piece of steel or aluminum two 5x5 pieces are fine, needs to have some thickness
CD tower (or even better) a LARGE 5 inch wide glass bottle. (see picture)
EPOXY (JB weld/ JB kwik AND regular, cheap epoxy. If it says non shrink, don't get it!)
    *there's been a lot of issue with epoxy, I never realized different epoxies would cause such a difference, so I've added a picture of the epoxy. Here's one place to buy it:  Hopefully this clears up the issues!
wire (welding rod is preferred, Stainless steel is best) 1/16 inch stainless or 1/8 steel - MUST BE SMOOTH and straight!
7 inches of PVC pipe
Foam board (5x10 inches or more, two 5x5 pieces are fine)
3/4" copper pipe

hotglue and glue gun
fan weights
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fdiaz98 months ago
approximately how much power can you get from your engines?
rnewt81 year ago
i'm having some issues with my engine. I have made three different cam shafts at all different depths and i finally found one that runs the smoothest. I'm convinced that it can't get much smoother. I also checked for leaks and i found none except for the little tiny hole on the cold plate where the dis-placer rod comes through. I made my piston with 5 minute gorilla glue epoxy because that was all i had with me. It is very smooth but i had to sand the piston down to get it to that smooth point. those are the only two potentials problems i have. Should i re-cast the piston? Or some how seal up the dis-placer hole? Or both? Besides that my machine looks identical to yours but it just doesn't want to work.
This is really cool.
well done !
very nice project !
engineer#11 year ago
Can I use 6 inch diameter main plates instead of 5 while still keeping the displacer 5? Will it improve efficiency?
akhmad2 years ago
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engineer#12 years ago
I mean loctite
engineer#12 years ago
I used lactate 1 minute epoxy and on the copper tube, I put a little engine oil on the sides and it worked perfectly
micraman2 years ago
GREAT VIDEO! It was very clear and thorough. I love how you used resin to cast a perfect fitting piston! Love it.
ZeroAks2 years ago
Is there a reason that hot glue works better? For me, I've found that it often has trouble adhering to the metal, and breaks free easily.
shiv_rulz2 years ago
i get tht the heat is because of heating it with a candle or something ... but wht about the cooling part ...!!!! is the room temperature enough to cool it..! plz letme knw .. cheers :)
knexfreak322 years ago
f you don't want to spend 10min.-20min. making the wire straight. then chuck it up in you're drill grab the other end with pliers. give it a good spin and there you like a charm.
fastexitbe2 years ago
Thank you for your wonderful Stirling engine instructable. The video was excellent. I am having trouble with the epoxy piston sticking to the copper pipe. I have tried to remove any burrs on the ends of the copper pipe by using a utility knife and have cleaned the pipe inside with Windex as suggested. Then I use one of the following Pam Grilling Spray, Remington Gun oil, or White Lithium Grease to lubricate the copper pipe. I then use either BSI Mid-Cure epoxy (used in the instructable) or BSI Slow-Cure epoxy. The BSI Mid-Cure epoxy refuses to come out of the copper pipe even with the pressure of a C-clamp. The BSI Slow-Cure epoxy comes out of the copper pipe with an insane amount of pressure from a variety of C-clamps, pliers, etc. There does not seem to be *ANY* shrinkage in the epoxy and also it appears to be binding to the copper pipe no matter if I use a little or a lot of the lubricants. I have heated the epoxy as suggested and also tried it cold. The Saran Wrap plastic film works very well. The BSI Slow-Cure epoxy pistons that I was able to get out of the pipe by using extreme force look quite smooth on all sides, however they would never be able to be placed back in the pipe by hand. Any ideas what I am doing wrong?
crockman12 years ago
buy (or make) and heat it with solar magnifying frensel lenses:
tobyscool3 years ago
on the first picture in step one says you need a balloon and a motor ???
ya whats with that?
chimpanese2 years ago
dose it matter the size of the PVC pipe?
one of the best sterling engine makes i have seen
jaipai2 years ago
Very Nice .
Here is some more info on Stirling engines.
A Small Free-Piston S t i r l i n g R e f r i g e r a t o r
A. K. de Jonge
(14th I n t e r s o c i e t y Energy Conversion Engineering Conference,
Boston, Mass, Aug. 5-10, 1979)
x-tian3 years ago
i'm stuck with a pipe filled with epoxy. I think it's bulletproof. (it was 1 minute epoxy btw, it almost burned down my house, but it didn't shrink)
what should i do?
does it have to be cooper on the bottom or could you just use steeal
engineer#13 years ago
I have aluminium in thin sheets does the thickness matter?
kenizl863 years ago
Would styrofoam work for the foam board?
theruss0073 years ago
Instead of using steal or aluminium for the plates, could I use copper instead?
thecheatscalc (author)  theruss0073 years ago
Definitely, Just keep in mid that if the copper plate is flimsy, it'll rob the engine of some of the power, and may mess with the crankshaft.
Can I get away with using 1/2 id copper tubing? Or will I have to make the cam too deep for the motor to run right?
Mckye4 years ago
I am sorry, but I feel that it is a gross injustice that I did not see this comment ten times in the first page. The creation and execution of that video was beautiful in a way that is difficult for an educated man such as my self to put in words. I thank you from the bottom of my soul for making something so incredible in a place so ordinary.
Instructables is no ordinary place. Quite the contrary, Instructables is a haven in an apathetic sea of disposable junk!
Jocieposie3 years ago
This lookes really cool~ Im trying to find a way to use the idea and incorporate it into my science project, but I'm still a little confused on how everything works the way it does. Can I have a little explanation on how this thing functions?[: Thanks.
Google is your friend . . .
Cobalt593 years ago
Awesome! The music and the engine parts that move in time with it make it look like "How it's Made". +1
hippyrob3 years ago
Love the dramatic music. Your video rivals that of Profanisaurus in the awe department. Thank you for posting such a clear instructable on how to make a stirling engine. Your video shows the construction process really well and delivers a solid understanding of stirling engines. (I am making one out of recycled materials.)
hayme3 years ago
uh hey can i use cement, hardening clay or some melted rubber for the piston?
Argon3173 years ago
I casted the piston like you said however it is impossible to push out of the copper pipe. I used this type of epoxy

I realize you said not to use the 5 minute kind, but I did not see any thermal contraction issues when it was setting. On the contrary the epoxy seemed to bond to the copper. Is this because I did not put a sufficient coating of oil on the pipe? I used wd-40. I also pre-mixed it before pouring it in.
Did you use a pipe cutter to cut the pipe?
If you did You need to run a file around the inside to stop the edges catching.
ttbmtk63 years ago
Does anyone think there would be a problem with using a smaller diameter copper pipe, as long as the wire for the piston doesn't hit the side? I'm planning on using some 1/2 inch (diameter from the inside walls; I'm not a plumber!) pipe that I have laying around the house. I actually thought it might increase the pressure on the piston and so lend it some more force, but I'm not a physicist either, just a physics student, so what do I know? :) Any help is appreciated!
Take-Notes3 years ago
Great instructable
polerix3 years ago
Words cannot describe how cool this is.
Dr Qui3 years ago
I bought some epoxy putty in Poundland, 5 times cheaper than everywhere else.

I mixed all of it and packed it into the plastic tube it came in, it does not stick to the plastic and is easy cut out once it hardens.

 The hardened epoxy bar reads 25.1mm on the calipers or 63 / 64 in old money.

I have just bought a mini lathe and the first project I intend to do is a Stirling built from scavenged PC parts.
horshak4 years ago
I'm feeling like a dummy after reading all your comments and seeing videos on your working engines. I used 1/16 th aluminum for my top and bottom plates. I used brass plates for my stand. I have made my crankshaft out of stainless thicker than 1/16th but under 1/8th in My rods and ends are lightweight model airplane parts. .I have tried to cast my pistons twice with quick epoxy and I'm making my 3rd piston out of JB weld. Everything has been made twice with better quality control. It's ballanced and spins freely and looks quite good. Problem, it won't run at all. My wife says I sound like a hamster in a wheel in the kitchen. Please help!
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