Progress on my first fusor project

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Drew Scott
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Progress on my first fusor project

Post by Drew Scott » Thu Dec 10, 2020 3:37 pm

I wanted to have a thread for my project as it progresses. This is my first time trying to build a fusor. I am initially going with a similar design to the Makezine model to use as a demo fusor in my science classroom. Once I get that working well I would like to build a second model intended to actually perform fusion. My biggest hurdle here is available funds. As a public school teacher, these are somewhat limited. So this may be a long-term project, but sometimes the best ones are. I will update this thread only as I get things completed.

Enclosure minus the glass and gasket, The feet are made out of Delrin bar, with 1 inch aluminum top and bottom plate.
KIMG0198.JPG
Grid electrode prior to TIG welding (Stainless Steel TIG rod)
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The grid electrode after welding. My brother did this for me as he is a much better welder than I am and has access to equipment that I do not. He said the TIG approach did not work well for some reason so he used stainless steel MIG wire instead and spot MIGed it. I still have to clean up the welds and attach it to the bolt that will go into the HV feed through.
KIMG0201.JPG
Last edited by Drew Scott on Thu Dec 10, 2020 8:26 pm, edited 2 times in total.
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Quaid Hawkins
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Re: Progress on my first fusor project

Post by Quaid Hawkins » Thu Dec 10, 2020 4:09 pm

A demo fusor is a great starting point while you slowly work up to some better equipment. For anyone with small funds, their best ally is time and patience. Check ebay regularly and for some items set up a notification when things get posted.

Knowing your way around electronics is an indispensable skill. I have found some killer deals on parts that were labeled as 'broken' but only needed a switch replaced or something. Tricky though knowing whether a broken part is truly broken or just labelled as such, never want to waste any of the precious funds.

Anyways, good luck on your efforts!
Quaid
"Get to the reactor!"

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Dennis P Brown
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Re: Progress on my first fusor project

Post by Dennis P Brown » Fri Dec 11, 2020 1:44 pm

A proper vacuum system is the first major sub-system in building for any demo or future fusor. A proper two stage vacuum pump, proper connectors and a micron level gauge are essential. The nice thing about a good vacuum system is that far more can be done with that basic system than just building a fusor. So building a good vacuum system is both useful and a great first learning experience.

Drew Scott
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Re: Progress on my first fusor project

Post by Drew Scott » Fri Dec 11, 2020 6:02 pm

Once I get the fusor chamber somewhat assembled (should be within a week) the vacuum system is my next sub-project! It just so happened that I had easier (and less expensive) access to the materials for the fusor chamber itself first. Maybe some Xmas money will help me along! (Just kidding, who gets Xmas money at 35!? But hey, you never know...)

By the way, what else CAN I do with the vacuum system?
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Dennis P Brown
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Re: Progress on my first fusor project

Post by Dennis P Brown » Fri Dec 11, 2020 10:42 pm

A simple vacuum system can be used to sputter metals onto glass - I did this as a high school student. It can also be used to create plasma glows in tubes - like observing Cook's dark space (of course both these processes require a cheap power supply of a few hundred volts. But those are very cheap and available on ebay.) Most materials will melt at lower temps under vacuum. One can freeze dry specimens/foods under vacuum. If you want to create an ion gun or small low power accelerator the vacuum system is essential. One can use such a system (there is a nice Sci. Am. Amature Scientist piece on this) to liquify some gases or create very cold chambers (again, I did this in H.S. and got to -50C.) One could empty a glass tube, place a feather in it and show that it falls with no air resistance just as fast as a lead shot. A basic vacuum system combined with a high vac pump (i.e. diffusion pump or turbo) can be used to do metal vapor deposition onto glass. Or create a higher power accelerator.

The basic vacuum system is the heart of that more advanced system. And since for a fusor, of course, such a system is required but one must first start with the simple two stage pump and related plumbing/gauges.)

There are a number of more exotic applications one can find besides these - with a NST one could build a very powerful (a few watts) CO2 laser (again, did this in H.S.) Again, the old Sci. Am Amature Scientist has a number of projects that require vacuum systems. All require a basic system - there are other applications but this should paint a picture. Yes, one needs to add various extra parts but all these applications require that basic system.

Cai Arcos
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Re: Progress on my first fusor project

Post by Cai Arcos » Sat Dec 12, 2020 9:04 am

A basic vacuum system and gas management system can also be used to make gaseous radiation detectors. With a pump that could reach about 10 microns you should be able to avoid the worse effects of electron attachment created by oxygen residue. Backfill this with a P10 mixture (commonly available) through a pressure reducer and you can have either a proportional or Geiger tube by operating the contraction at different pressures.
Richard had various posts about homemade Geiger tubes, and all this is explained in various books (Electron and Nuclear Counters by Korff most prominently)

Drew Scott
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Re: Progress on my first fusor project

Post by Drew Scott » Sun Dec 13, 2020 11:55 pm

KIMG0207.JPG
Here is my high voltage feed through. It began as a 6" long by 0.75" diameter ceramic tube. The stainless steel standoff was only 4" long, so I had to cut 2" off the tube. I underestimated how hard this ceramic was. The only diamond cutting device I had was a diamond concrete saw blade for my skilsaw. Well it worked, though not a perfectly clean cut as you can see in the piece that was cut off in the background. After cutting, I ground the hex edges of the stand off down just a bit and epoxied it in the tube, taping over the threaded holes to keep epoxy out of the threads. Next step is to epoxy the feed through into the bottom plate!
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Bob Reite
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Re: Progress on my first fusor project

Post by Bob Reite » Mon Dec 14, 2020 4:12 am

Good luck with your home brew feed through. Did you get the expensive machine able ceramic?
The more reactive the materials, the more spectacular the failures.
The testing isn't over until the prototype is destroyed.

Drew Scott
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Re: Progress on my first fusor project

Post by Drew Scott » Mon Dec 14, 2020 1:28 pm

"The clearest way into the Universe is through a forest wilderness." - John Muir

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Dennis P Brown
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Re: Progress on my first fusor project

Post by Dennis P Brown » Mon Dec 14, 2020 1:46 pm

The feed-thru needs to be vacuum tight; so getting epoxy to seal well is critical; also, these electrode tend to get rather hot so use a grade of epoxy that can handle that.

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