Build a fusion reactor in your home

At first we were pretty skeptical of this home made fusion reactor instructable. However, we’ve seen home made fusion reactors before, so it is technically possible, we guess. The construction alone is interesting enough to warrant a few moments of looking.

We’re not experts, so pardon us if we can’t tell you exactly what is going on, but we can appreciate the craftsmanship involved with the build. The vacuum chamber specifically is quite nice.

We know that some of our commenters probably have more experience here. Tell us, does this thing look legit?


  1. Jane says:

    Yep, its legit. Its impressive that he was able to weld the chamber correctly, takes a lot of skill to make the quality of welds required.

  2. Brian says:

    “but we can appreciate the craftsmanship involved with the build.”

    Not to be an ass but are we looking at the same pic? :)

  3. herbicide says:

    Yup – It’s a Farnsworth-Hisrch Fusor –

  4. macona says:
  5. Brian says:

    But how will it fit in the Delorean?

  6. 24601 says:

    The vacuum chamber looks legit, but the rest is awfully messy. To run a fusor requires high voltage. I would not want to be anywhere near that mess of wires while that thing is turned on.

  7. psuedonymous says:

    It’s definitely a Fusor, but the question is whether he’s got a hard enough vacuum and high enough voltages (read: excluded enough non-fusing gasses, and got enough energy into the fusing ions) in order to actually have any fusion occur. He’s picking up neutrons, so there’s a good chance those deuterium ions are whacking together with enough energy to fuse. I’m wondering how he came about his inner grid geometry: it looks like he just went for something that only needed to be attached at the electrode base (i.e. no self-welding), but there may be some more thought behind it.

  8. M4CGYV3R says:

    Building a fusion reactor, especially from as poor-quality a writeup as Instructables provides, is like saying “Please irradiate me!”

  9. Brett_cgb says:

    I don’t think its legit. I was skeptical until they started talking strong vacuums and the necessity of using a ceramic feed-through for the inner grid. I suspect that ceramic feed-throughs are terribly leaky.

    There is also the disturbing lack of any soldered connections – all the connections appear to be stranded wire twisted onto terminals.

    Deuterium gas (D2, or “enriched Hydrogen^2″) is not something that can be easily purchased, and is almost certainly not “off the shelf”. I suspect if you make a serious attempt to purchase D2, someone from the government is likely to be knocking on your door (or worse).

    And finally, while they make references to radiation safety, they say nothing about what to expect, and give no clues regarding what they for shielding. At 40kV, X-ray radiation shielding is necessary, but not much of a problem. Their neutron detectors strike me as bogus.

  10. Jane says:

    If he slapped down the cash for a bottle of deuterium on top of the vacuum equipment, im sure it works. A lecture bottle of deuterium (I think 4L at stp) was quoted to me at $200.

  11. joe kozak says:

    I can never figure out why people put such insanity on flanges for something that only has a ~ -14 PSI pressure differential. How many bolts do you need! half inch — 3/4 inch thick flanges? well polished and true planer surfaces and a little vac grease with no bolts would be just as sufficient. perhaps some paper clips to keep alignment while the pressure goes down.

  12. ragman says:

    Hey, I didn’t know I could use my microwave’s ‘magnatron’ as an oil diffusion pump! Oh and I’d better start earthing the ‘timber’ on all my projects now to protect me from all those leathally high ‘voltages’.

  13. Caleb says:

    did someone say radiation?

  14. fluidic says:


    Yeah, that’s pretty much what I was expecting from the moment I saw the title. Still, the world can always use another fusor build.

  15. joe kozak says:

    I remember a show about the declaration of independence container rebuild and they had a nice presentation of flat polishing to make a mate on an aluminium (ss?) case to a glass panel for a gas seal without gaskets.

    was part of PBS Nova: Saving the National Treasures (2005)

  16. Tyler says:

    I am the owner of this reactor.

    @24601 – Yes, it is quite messy, it has improved over the last year and I used an obsolete picture for the instructable since it has become considerably more complex with recent research and would not be appropriate for that post.

    *Ceramic feedthroughs absolutely keep perfect vacuum. Ceramic is as opaque to gas as stainless steel. Check out products on high vacuum sites if you don’t believe it.
    *Why do I have to solder stuff for it to be legit? Electricity will still flow.
    *Deuterium is not easy to get, I spent nearly an entire summer tracking it down and came very close to requiring background checks but ended up coming out easier due to a lucky distributor find.
    *The neutron detectors are most certainly not bogus, these helium-3 tubes are the best neutron detectors in the world. Also bubble detectors are 100% accurate and are used for personal dosimetry in nuclear facilities. Lead is used for shielding x-rays which are only a risk through viewports at 40kv. When I operate in the 60kv regime, I shield the entire fusor and operate from a distance.

    @Joe Kazok – Large flanges are used for a perfect seal with no rubber. Rubber and vacuum grease are unacceptable in ultra high vacuum and hence the conflat style was invented. A single-use copper compression gasket is used between the flanges and they must be thick since quite a bit of torque is required on the bolts to get enough compression on the copper, and the flanges must not bend or warp or the copper seal could be compromised. You have to realize that a hole a few microns in diameter (hair can be 100 microns in diameter) is catastrophic and makes the seal worthless, this is a very well sealed chamber, not just a bell jar with grease at the seal.

  17. Bill D. Williams says:

    “but we can appreciate the craftsmanship involved with the build.”

    What the…

    Are you kidding me? HAD, but down the bong, dude.

    k thx bye

  18. octel says:

    looks like a meth lab

  19. Eddie says:

    Yeah, that’s what I tell the “revenuers” when they find my still.

    It’s a Cold Fusion reactor. Honest.

  20. Tim says:

    I don’t understand all the hate. This project obviously has a lot of time and money behind it. It seems to me like this is exactly what HaD is about. We don’t all polish our projects so that you think they look pretty, the beauty is in the engineering. I’d still like to see some updated pictures of this project anyway.

  21. Surprisingly, Deuterium is available on eBay.


    More disturbing are the high-count radioactive ore samples…

  22. jkdrum says:

    Crap! Now the Iranians and North Koreans know the secrets! Nice job Poindexter!

  23. Alchemist says:

    Every university which has a NMR uses deuterium oxide aka D2O or other deuterated solvents.

    So the only thing to be done is to decompose these by eg. electrolysis.

  24. jim says:

    Oh man, these things have been cluttering science fairs and garages for fifty years.

  25. jane says:

    that is heavy water, totally useless for a fusor. You need pure D2 gas.

  26. Tyler says:

    D2O isn’t totally useless, as Alchemist stated you can use electrolysis. In fact the first time I got neutrons I was using this method (I had not yet purchased compressed deuterium).

    Also you can use straight D2O vapor, but it is about 100x less fusion at the same power input.

  27. wjp says:

    @ joe kozak
    I know the guy who machined the encasements for the Documents of Freedom. The cases were each milled from a single pieces of Titanium. When he asked why Titanium was required for the construction, the reply was that “Titanium is sexy”. It was built at NIST, however, the person who programmed and machined it now works for a University in North Carolina. Four were built along with several scale models for testing. The models were destroyed after testing. You may be wondering what became of the fourth. It was heavily modified and used as a prop in “National Treasure”. If you saw the film, you saw Nicholas Cage running away with it while using the bullet proof glass for a shield. That encasement had to be lightened significantly for Nicholas Cage to be able to pick it up, much less run with it.

  28. grenadier says:

    Looks legit to me.

  29. tech-no-pest says:

    and with a meltdown gives a whole new level to the saying “there goes the neighborhood”… but still cool…BRING ON NUKE WINTER!!!!

  30. Tom says:

    Deuterium isn’t that hard to get. Couple hundred bucks for a lecture bottle, filled. Return the bottle and get a refill for even less. We use tons of it for hNMR in our lab, I just go to the supplier and pick it up, no questions asked.

    As far as this fusor, you could get almost identical results without the deuterium, minus the neutron production. You’d end up with ion compacting and the neat looking plasma. Probably a better starting point for someone who’s not experienced with dealing with radiation.

  31. Tom says:

    Oh, and sorry for the double post, but as to your defense of the wire wrapping: At least put some wire nuts on there if you want to do it that way, 40kv can arc pretty damn far.

  32. looks cool.
    There are people making “wibble balls” aka bussard fusors at home, as most of the complicated work is just winding the six field coils and shielding them.
    these put out far more neutrons for the same input power than a basic multipactor due to the improved focussing effect of the magnetic fields+electrostatic (sorta like comparing CRTs with scope tubes)

    apparently you can demonstrate this effect using helium at about 0.1 atm (doable using virtually no equipment apart from a cheap aircon pump, He balloon fill gas, field coils, HV supply and a chamber.
    Glass bell jars work well for this, but I do *NOT* advise them for use with lower pressures without a tested, double reinforced blast shield.

  33. strider_mt2k says:

    It all looks pretty well shielded except for that small thermal exhaust port…

  34. Noodle says:

    I don’t know why there’s so much doubt here, everyone in this thread who genuinely understands fusors says it’s legit.

    Tyler, looks fun! On a broader point, good to see the fusor community get a bit more involved with the rest of the hackers these past few years. I think it’s a fantastic introduction to physics, instrumentation and a sense of what’s really ‘dangerous’ and what’s not. Keep on splittin’

  35. bob says:

    Good work. Impressively simple build, too.

  36. argyle says:

    Interesting build! I had no idea that it was possible to produce fusion at home. Not that I’ll be trying it any time soon, but I spent an hour or two reading the instructible and related wikipedia pages.

    Thanks for posting this.

  37. acidrain says:

    this thing might be legit but it is extremely unsafe. there is an article about a young boy-genius in michigan that did something similar to this in his mothers tool shed, he wound up exposing some 4000 people to high levels of radiation… It takes something like 4″ of lead or 4′ of concrete to stop the particles emitted by the fusion process… while i may only have basic knowledge of chemistry and physics I believe it is safe to say that unless you want federal agents beating down your door, it is probably wise not to attempt this particular project… Leave this one to professionals.

  38. ChArLes says:

    Ah, the radioactive boyscout. The most often mis-cited scare story that people with “basic knowledge of chemistry and physics” try to monger fear with, since the public at large doesn’t have *any* knowledge of chemistry and physics. Too bad others take people like you seriously!

    You ought to do some more research and also read what this project is all about, which you clearly have not if you couldn’t tell the difference.

    First off, David Hahn (said man in Michigan) attempted to build a *FISSION* reactor. Fission products are much, MUCH worse than what this simple fusion experiment can produce. That is not legit at all. Yes, Gamma radiation takes lead and concrete to block. But this reactor produces neutrons and X-rays, which are much easier to block and far less damaging overall.

    Do not make “federal agents” jokes so lightly. People with your attitude have contributed the most to the decline of engineering and tinkering as a hobby and pasttime because of the number of things being made illegal based on fear alone.

    I’d advise studying more up on your Basic Knowledge of Chemistry and Physics before trying to criticize this project.

  39. grenadier says:

    ^^ I couldn’t have said it better myself.

  40. Brett_cgb says:

    I _HAVE_ training and work experience in the nuclear power generating industry. I have designed a reactor (as part of a school project, similar to the exercise that EE students go through when designing a large power transformer – which I have also done). I know what’s required.

    Even my handle here reflects that background. B)

    I work as an electrical engineer. I tinker at home, and I encourage tinkering by others. But I’ve found that most people are generally not interested in tinkering, science, or technology. They are “too hard” to hold most people’s interest.

    As for the federal agents joke, what makes you think I’m not mostly serious? In today’s society at large, any discussion regarding radioactive materials (isotopes) invariably brings up terrorism. I don’t know what can be done with D2 gas, but if anyone has weaponized it in any way, I’d sure like to know about it.

    Tyler (the original poster) has corrected me with respect to leaky ceramics (and in hind sight, I should have known this – I’ve worked with ceramic vacuum tubes).

    Twisting wires together for electrical connections works, but it’s a sign of poor workmanship and suggests poor reliability overall. A better sign would be solid connectors of some sort (solder joints, crimped connectors, screw terminals – anything that suggests some thought was given to making the connection easy to make and break with reliability.)

    Tyler confirmed that D2 is not easy to get without background checks (that’s a good thing, and almost certainly requires federal agents to get involved), but that he got lucky finding some. I’m not worried about a couple liters of D2 gas. (How many micrograms of D2 is that?)

    I have only general ideas how to build neutron detectors – I’m more familiar with alpha, beta, gamma and X-ray detectors. The neutron detectors presented may indeed be perfectly valid – I have not researched them.

  41. IJ Dee-Vo says:

    Epic, keep up the good work. It’s easy to be critized by people who don’t know what they’re talking about.

  42. snowdruid says:

    @brett_cg for someone with “training and work experience in the nuclear power generating industry” you know very little about chemistry starting with the fact that not all isotopes are radioactive and D2 can not be “weaponized”. it is regulated because its chemical properties makes it a toxic.and furthermore it is used as heavy water (D2O)in shielding fission reactors.
    im sorry but next time before you post absolute bull please stick to what you know

  43. John says:

    Just a note on Bussard fusion reactors – They’re generally called Polywell reactors, and they use the Wiffle ball effect. The magnetic field lines look a little like a wiffle ball toy.

    The only person I know of who is trying to build a Polywell is Famulus. I think he got covered here a while back.

  44. omgkittenz says:

    Is there any point building this next to because its “fun”? Can you actually use this as energy source for your whole house?
    As I see it cost like 15k to build, thats roughly a yearly electricity bill but if it needs to be maintained too then just doesnt worth it.

  45. Tyler says:

    @omgkittenz – No there is absolutely no power benefit, you put in 500 watts and get microwatts out (it only makes the electrical bill worse). The benefit is half doing it, and half having a reasonably useful neutron flux for nuclear experimentation, particularly element activations.

  46. ChArLes says:


    There is inherent value in building something for fun if it educates you and provides you with new skills and abilities.

    And if it’s awesome.

  47. Kataze says:

    I remember seeing something similar to this a long time ago. The creator of that fusion reactor said fusion was not likely actually occurring due to some imperfection, but it was great at throwing neutrons around, setting off the bubble detectors.

  48. anon says:

    I love when people pretend they know anything about nuclear physics.

    My advice to anyone reading this thread: don’t use it as a primer on anything related to nuclear or health physics.

  49. Whatnot says:

    In a ‘related’ humorous note:

    “An international group of scientists are aiming to create a simulator that can replicate everything happening on Earth – from global weather patterns and the spread of diseases to international financial transactions or congestion on Milton Keynes’ roads.”

  50. IJ Dee-Vo says:


    OH NO! The horror of the idea that anyone would build something for fun or knowlede instead of econimical game! That should be banned.

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