Fusor Forums

I want to build my first fusor, and I'm looking for a simple design that's not too expensive. Today, I've found an article in Make Magazine #36 (the most recent one) describing what they say is a fusor. I don't have a good image of it except what you can see at the top of the front page here:

http://makezine.com/volume/make-36-boards/

It's a glass cylinder, 3 inch high by 3 inch wide, an aluminum disk at each end, the grid connected to one of the disks. It's powered by a 12 kV neon sign transformer. There's a vacuum gauge on top.

Now, I'm obviously not an expert, but there are a few things that don't look right. First off, it's so tiny. Would a fusor this small actually work?

Then, I don't remember seeing any mention of using hydrogen or deuterium. IIRC, it's a low pressure air discharge.

Finally, I don't remember seeing anything about radiation detection. Or any mention that the device might be dangerous due to radiation.

All of the above seem to indicate that this is not a real fusor, but just a glorified neon sign (or rather, "air sign") that happens to look like a fusor. Am I wrong?

This design seems simple enough and fairly cheap, but if it can't produce the radiation signature of fusion, I'd rather not even try to build it.

Looking forward to hear what y'all think. Thanks!

Florin,
Based on the dimensions you have provided, 3 inches by 3 inches, it could do fusion or at least produce a discharge plasma. I would not recommend doing fusion in a glass chamber because of the neutrons and x rays, however it is possible. Correct me if I am wrong but I believe the smallest fusor built here was 1.33 inches. If you search smallest fusor in the search bar you will get results.

Hoped this helped.

Scott Moroch

Not possible to fuse with this as spec'd. Not even a "good" demo fusor.

Richard Hull

Hi,

I also saw this article in Make and had high hopes of constructing a simple fusor. Naturally my searching led me here and one thing that I found frustrating was the lack of a "beginner" section or similar.

Even though I did perform a forum search, I didn't see a matching result for a "Building your first fusor" type article/tutorial. Perhaps one can be written for beginners that would allow an introduction to fusors and that would be deemed as a better design than the one in the Make article.

Apologies if such an article does already exist but as I said, I did perform a search first.

Cheers,

Adrian.

Edit: Also apologies but I didn't see/read the policy regarding user names until after I created an account.

The FAQs are like a beginners "choose your own path" novel. This very sub-forum has lots of beginners FAQs with easy-to-understand block diagrams at the top.

There is no step-by-step "do this" guide. That's because it would be prohibitively expensive to build such a fusor, there is no source for the kind of cheap, easily available parts such as were used in the Make article. Every fusor here was build by extreme scrounging, even the very expensive ones. Like Jedi Knights and their lightsabers..

I think it does make a fine demo fusor, though. Maybe it's not really a star-in-a-jar but it is good-looking and evokes interest. My first exposure to fusors was a similar one made with the pyrex from a lantern mantle (coincidentally, I'm building two like this right now).

From what I can tell based on articles, the Facebook group and the many years worth of postings here at Fusor.net, the number of people who actually build and run a neutron producing fusor are few and far between. The Neutron Club list is quite short for the number of years this has been going on.

There seems to be a big disconnect between the interest/ambition to build a fusion reactor, and the technical/financial/dogged determination to make it a reality. I think much of this disconnect is generated from media hype. It's a great story to tell of a young teenager building a nuclear fusion reactor in his parent's basement.

Take a close look at the plans and results of actual devices built. Most are at what is called the "demo" level. This is a fun project that can be done under reasonable expenses and ability, but is certainly not the fusion reactor that those interested aspire to build. An actual working reactor takes much more expertise and quite a bit more money than is first implied. On top of that you need a neutron detector to prove your reactor is working.

I built a very low cost demo reactor (far simpler and cheaper than what is described in Maker mag). I'm still working on building a neutron producing reactor.

Here are a few obstacles to consider:

Vacuum system: You need a chamber, high voltage and gas feedthroughs, flanges, roughing pump, diff pump, vacuum guage, valves, etc. Even if you get some of these components at a good price, you are unlikely to get all of them at a good price.
Power supply: If you can find a used -40Kv supply, or even a -20Kv, for under $500, you are doing extremely well from my experience. You could build one yourself for less, but do you have the expertise to do it safely?
Deuterium: Good luck, this is a federally controlled substance. You have to jump through some hoops to get some.
Lab location: A fusor is a highly dangerous. The voltages are fantastically high, they produce hazardous radiation, namely x-rays and neutrons. Is this something you want in your basement?

Plus many others. Most people do not have access to a lab or business that might sell or give away some of these items cheap. You can "scrounge" as they say, but that completely depends on your tolerance level for sifting through junk, either actually or virtually as in on eBay. In my opinion, many of the components necessary to build a neutron producing fusor are harder to get than they were even a few years ago due to the popularization of this hobby.

On the bright side, solving these kind of problems is fun to a lot of people, myself included.

Fusion itself is quite easy, scientifically. For the average person it can be quite daunting. If it were as easy as building an old balsa stick and ribbed, paper covered airplane, there would be no challenge and no cache in doing it. All aspects of fusor construction and operation are within the reach and grasp of a truly inspired, tenacious and talented person. To the inspired, obstacles are just goals that must be met, one by one.

Richard Hull

I'm bumping this thread just to show its priority
with respect to today's new thread about the same Make article.

For those with short memories.

Florin: Today's new thread has Make Magazine in its Subject line,
so it'll be more likely to pop up in future searches.
I think your OP doesn't refer to the magazine by name, except indirectly through the link URL.

I applaud your description of the little demo fusor in your own words,
rather than have a post whose usefulness depends strongly on an outside link.

A few years ago, someone showed on this forum a demo fusor
made from a fat and stubby glass tube ( 2" in diameter IIRC ).

-Rich

Mark Scott-Nash wrote: Deuterium: Good luck, this is a federally controlled substance. You have to jump through some hoops to get some.

Try welding shops or Ag. dept. in local highschools, the welding/metal shops there may have some and most ag teachers are pretty friendly.

From the start, I found the term "demo fusor" misleading. Took me a bit of wading through forum info, plus a phone conversation with Carl Willis before I understood that a demo fusor doesn't demonstrate fusion, just a plasma. Still, building one is an essential preliminary step in learning how to use vacuum and high voltage systems. Something I still haven't achieved. Somehow, I got sidetracked with building and studying Geiger counters and scintillation detectors, another important component. One of these days I'll get around to scrounging a vacuum pump. My intention is to use something like a heavy wall Pyrex glass tube in the 2" diameter range, but only for a demo device.

One never gets "sidetracked" studying or investigating nuclear detection schemes. It is all part of making a fusor and just one of the technologies that must be approached in doing fusion.

Richard Hull