Joe Ballantyne fusor V2. (Low cost fusor.)

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JoeBallantyne
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Joe Ballantyne fusor V2. (Low cost fusor.)

Post by JoeBallantyne »

In line with doing fusion with just a mechanical pump - which reduces dramatically the cost of building a fusor - I decided to try to build the lowest cost vacuum setup that would be capable of doing fusion that I could.

My goals were to build a chamber that was as inexpensive as possible from currently available stock parts that were designed to hold a vacuum well. I also attempted as part of reducing the cost, to minimize the number of parts needed to build the chamber.

Anyone who has read a few of my posts, can probably predict that my low cost chamber would likely use KF parts entirely. They would be correct in that prediction.

Over the last couple of months or so, I bought all of the parts. Late Monday night I finished gathering everything I needed to assemble it, and then spent a little more than an hour plugging it all together.

Yesterday, I connected the chamber up to my Welch 1402 through its test port, and pumped on it for several hours. It ultimately pulled down to about 1.3 microns - which I was perfectly happy with for a first pump down with no plasma cleaning completed. Especially given that my pump will only get down to about 1 micron with nothing but a vacuum gauge connected to it.

Here are a couple shots of the chamber laying on my dining room table.

IMG_20240522_171624171.jpg
IMG_20240522_171743321.jpg

At this point, I have not added a cathode to the sparkplug based feedthrough, but plan on doing that next.

At which point I will connect an HV supply and try to make a plasma and do some glow cleaning of the inside of the chamber.

I plan on posting a bill of materials for this chamber with links to every part that I bought for it, with a grand total of the cost. I'm pretty sure that it will come in under $500 total.

I will post about my attempts to do fusion with this chamber, as it should be fusion capable.

Hopefully other folks who want to do fusion on a tight budget, will consider building a chamber similar to this one.

The purpose of this thread, is to make it easy for anyone to do so.

Joe.
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Richard Hull
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Re: Joe Ballantyne fusor V2. (Low cost fusor.)

Post by Richard Hull »

I never did fusion using a spark plug, though I started out with one on the first iteration of fusor III. Ultimately, due to breakdown around 23kv I replaced the plug with a more suitable insulator. I did fusion with this new version of fusor III with no secondary pump. My neutron detection methods were poor, at best, in 1999 and it took just over 30kv to move the needle up scale on my Eberline rem ball and get a good statistical grip on my effort with the Bicron BC210 scintillation system to max out at 150,000 n/s on that first true fusion system. Before moving to fusor IV, sporting a nice diff pump, in 2003, I had fusor III touching the 240,000 n/s at 33kv.

I am sure that with your plus ultra, Multi-atmosphere 3He system for neutron detection, you will see fusion at a lower voltage with your mechanical pump only system.

The fly in the ointment is how many folks can brandish such a neutron detection system? A few can and will, I am sure, using the money they save to instrument up properly.

All the best with your effort we look forward to your reports.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
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Rich Gorski
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Re: Joe Ballantyne fusor V2. (Low cost fusor.)

Post by Rich Gorski »

Interesting thought you have... low cost fusor that can produce real fusion events... for those on a budget.

Love those 1402s. I have one as well that I've been using for about 20 years. They last forever and I've seen mine get down into the single digit micron range while connected to a fairly large ISO160 chamber and through a turbo pump (turned off). If you can get the cathode to 20 or 25kV with that spark plug feedthrough at say 15 microns you should see an unmistakable neutron signal. I've seen a few hundred CPM at 20kV in my ring accelerator and just below 100 at 15kV. This was measured with my old GE B10 detector tube.

Did your estimate of $500 cost include the neutron detector?

Rich G.
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Re: Joe Ballantyne fusor V2. (Low cost fusor.)

Post by JoeBallantyne »

Rich, my $500 upper bound estimate was just for the vacuum chamber parts only, and also excluded that fancy MKS901p with a screen.

I'm pretty sure the chamber parts will total up to about $400. The Kozyvacu TA500 pumping solution with adapter and good oil is about $200. A Mark Rowley 30kV precipitator supply should add another $50 or so. A Mark Rowley style Horizon based heavy water D2 supply should add another $100 or so. A standard KF16 MKS901p another $125. That should bring it up to about $875.

Given what Ludlum 3 meters are going for now, and those GE B10 tubes on eBay, it is probably at least another $350 - $500 for a decent neutron detection setup.

So the whole setup with instrumentation is very unlikely to come in under $1000, which is too bad, because that is a nice even number. But hey, thanks to the FED and rampant federal spending, inflation is BACK baby. We're pretty much stuck with it now.

I will try to get the chamber BOM posted soon, with its total. And plan to do the same for each other subsystem. (Pump setup, vacuum gauge setup, gas supply setup, high voltage setup, neutron detection setup.)

We will find out together what the whole thing totals out to. The goal is to do each subsystem as economically as possible, while still enabling a real fusing system.

It will be fun.

Joe.
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Dennis P Brown
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Re: Joe Ballantyne fusor V2. (Low cost fusor.)

Post by Dennis P Brown »

Lets not forget that oil companies and food companies are at record profits - so, inflation is driven more by what they can force us to pay rather then the government spending (which is small compared to the entire economy).

The price of used equipment, of course, isn't inflation driven. More to do with supply and demand. And certainly the older equipment available has been getting bought for years; so, there is only so much out there to sell and working equipment will command a higher price now since fewer such pieces are available anymore.

Then there are the Chinese tariff's (which we solely pay) that a previous administration imposed and the current is maintaining; all those inexpensive vacuum components and electronic parts/devices are much more expensive. That has hit people trying to build inexpensive vacuum systems especially hard.

I do think that someone with access to machine shop type equipment & the skill to use it, that can weld, has advanced electronic skills and waits on deals could possibly do fusion under $500. As you certainly proved with vacuum pumps, those under $200 can work for fusion and no need for a high vac system or related gauges.

For instance, using a drill press, and a (use to be ) cheap Chinese hole drill bit, also a small telescope glass blank, I built a high voltage feed-thru for under $100. I did have to bore and machine (with an o-ring) a metal plate on a lathe - not something many would be able to do in order to save $$$. Later I did buy a very nice 35 kV HV ceramic feed-thru with KF type vacuum plate for a little over $100 but I got lucky on e-bay.

The real issue would be a neutron detector. While BF-3 tubes can be had still at decent prices, the black box is not something that can be easily built - again, ebay is the best chance but frankly, good deals are getting very rare.
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Re: Joe Ballantyne fusor V2. (Low cost fusor.)

Post by JoeBallantyne »

Here is the bill of materials for the low cost KF fusor pictured earlier. All of these parts were purchased from eBay, and most of them were new, not used. I have included the effective price I paid including shipping but excluding tax and rounded to the nearest dollar, as well as a link to the item.

Note that some of these items I made offers on for less than the listed price, and I generally bought 2 or more of each part. Thanks to Joe Gayo for pointing out the KF25 to M14 threaded part, as well as the Champion spark plug that uses those same threads.

His post about it is here: viewtopic.php?p=82078#p82078

(1) KF50 to KF16 reducing cross
$39 https://www.ebay.com/itm/394680512034?var=663248147708

(1) KF50 to KF25 conical reducer
$15 https://www.ebay.com/itm/225861830998?var=524953863097

(1) KF25 to female M14 thread (sparkplug compatible blank)
$23 https://www.ebay.com/itm/322480729252

(1) Champion J99 599 copper spark plug
$14 https://www.ebay.com/itm/364585272888

(1) KF50 viewport
$139 https://www.ebay.com/itm/314790356190

(1) KF16 metering valve for D2 gas supply
$70 https://www.ebay.com/itm/392897293381?var=661806839535

(1) KF16 tee for connecting vacuum gauge
$8 https://www.ebay.com/itm/124843333338

(1) KF16 butterfly valve for throttling vacuum
$68 https://www.ebay.com/itm/386784786621?var=654046922550

(1) KF16 bellows 24 inches long to connect vacuum pump
$28 https://www.ebay.com/itm/125055927265

(6) KF16 clamps and centering rings
$11 https://www.ebay.com/itm/114332165849 https://www.ebay.com/itm/114340869927

(2) KF50 clamps and centering rings
$8 https://www.ebay.com/itm/114332162449 https://www.ebay.com/itm/124600141899

(1) KF25 clamp and centering ring
$10 https://www.ebay.com/itm/394784183709

The following are not absolutely required, but are good to have so that you can seal off any combination of components and test them for vacuum tightness. I bought them, and think anyone who builds this setup should buy them too. The price I listed below was my effective price as I bought a larger quantity of each type of blank.

(2) KF50 blanks
$8 https://www.ebay.com/itm/394616940146?var=663168181770

(2) KF16 blanks
$4 https://www.ebay.com/itm/394616940146?var=663168181752

(1) KF25 blank
$2 https://www.ebay.com/itm/394616940146?var=663168181758

This totals out to $447 excluding tax. I excluded tax, because the sales tax you pay depends on where you live. I get the wonderful privilege of paying a tad over 10.1%, so with tax, my total for this setup was $492. Almost exactly the $500 upper bound I threw out without calculating, and well over the $400 I thought it would total out to. But that is very typical. It ALWAYS costs more than you think.

Joe.
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Dennis P Brown
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Re: Joe Ballantyne fusor V2. (Low cost fusor.)

Post by Dennis P Brown »

Again, you are really making extremely useful posts that really address cost issues for fusors. The work with pumps was something that really was impressive especially considering you also addressed the issue of whether a high vac system was even needed. That post should be in the FAQ section
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Re: Joe Ballantyne fusor V2. (Low cost fusor.)

Post by JoeBallantyne »

Thanks Dennis. I am working on the single mechanical pump FAQ post. I do have a draft in progress and hope to get it posted in the next few days.

Joe.
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Re: Joe Ballantyne fusor V2. (Low cost fusor.)

Post by JoeBallantyne »

So spent some time the last couple of days working a bit more on this low cost fusor. Today I got first plasma in it.

Yesterday, I put together a cathode for it. It was as simple as I could make it. I used a single 3mm to 3mm brass "drive shaft" coupler made in China for model car use I suppose, as well as a 1.2 inch diameter stainless wire shaker ball for mixing protein shakes. Both of those were purchased a couple years back as part of lots of several of each.

I bent one end of the shaker ball wire so that I could directly clamp on it with one side of the coupler, and the other side of the coupler I directly attached to the end of the spark plug electrode. I didn't bother making an extension to place the cathode lower in the fusor. I wanted to keep it as simple as possible, with fewer parts. So just one coupler to directly connect the cathode to the spark plug center electrode which is about 3 inches long.

Unfortunately I didn't take a picture of the cathode setup after putting it together, but here is a picture of it inside the fusor with a plasma.

The harbor freight meter in the photo is measuring the current, I do not yet have voltage metering on this setup.

IMG_20240605_171044793ds.jpg

Here is the list of parts for the cathode.

(1) 3mm to 3mm brass coupler
$11 for 8 couplers + set screws + allen wrench https://www.amazon.com/gp/product/B07VFFJBVH

(1) 1.2 inch shaker ball
$7 for 8 balls 3 different sizes https://www.amazon.com/Shaker-Stainless ... B0CMCCRNBD

Joe.
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Re: Joe Ballantyne fusor V2. (Low cost fusor.)

Post by JoeBallantyne »

Last night and today, I put together a low cost power supply for the fusor using a 40kV Chinese precipitator supply similar to the ones that were extensively reviewed by Finn Hammer (30kV) and Mark Rowley (60kV). I chose the 40kV supply, because it easily puts out enough voltage to do fusion (>30kV), and its maximum current is decent (10mA), and it costs MUCH less than the 60kV supply. Only about $40, instead of more than 3x that much for the 60kV supply. Plus for me, the primary goal for this fusor is fusion, not activation. So 60kV is overkill.

I spent a bit of time looking on Amazon for an optimally sized oil container for this supply. I wanted a container I could fill with oil that was about 1 inch larger in each dimension than the supply itself. I needed a container about 7 inches wide, 10 inches long, and 6 inches tall. A found some, again on Amazon that were cheap. $25 for 6 of them. And I must say the container is just about perfect for holding these supplies. It is a 6 liter plastic storage container with a lid that can be clamped on, and with the supply inside it takes about 6.5 pints of mineral oil to completely cover the supply, and leave a half inch or so of space under the lid.

I used a couple of 2 wire extension cords that I bought used from Habitat for Humanity to wire up the 220V supply for it. I cut the triple 2 prong receptacle ends off of the cords, and used them only for the plug and the wires. It is not pretty, but it works very well. I use 2, because I need to pull line voltage from 2 different outlets I have upstairs, which are on different phases of my house supply. That way with another long extension cord, I can get 220 without having a 220 outlet upstairs. Plug one cord into one outlet, plug the other cord into an extension cord plugged into a different outlet with the opposite phase line, and wire the hot from each up to the supply. I used the neutral from one for grounding the fusor through the Harbor Freight meter, so that I could monitor the cathode current. The meter I used had already had one of the probes disconnect from its wire, so I just removed the probe from the other wire, stripped the ends, and directly connected the meter wires into the circuit. All the low voltage electrical connections were made using wirenuts.

Here is the list of supplies for the 40kV 10mA supply.

(1) 40kV 10mA precipitator power supply
$38 https://www.ebay.com/itm/313119408064?var=611839114176

(1) 6 liter plastic storage container
$26 for 6 containers which are perfect IMO for the above supply https://www.amazon.com/dp/B0CBWH5B5L

(7) 16 oz bottles of mineral oil from Walmart
$15

(2) used 2 wire extension cords from Habitat for Humanity
$6

(1) Harbor freight multimeter (Cen-Tech 7 function digital multimeter Item 69096)
$7 (pretty sure I got mine free several years ago when they still gave them away with a coupon and a purchase)

(3) large wirenuts
$4 for a package of a few from Home Depot

So the total expense was $96. Although when I looked right now on eBay it seems the price on the 40kV supply has gone up a lot since April when I bought mine.

Here is a picture of the supply in its oil filled and wired up container.

IMG_20240605_165345944ds.jpg

The supply seems to work just great. I use a long screwdriver to adjust the voltage pot which you can see in the picture.

I got a plasma at about 30 microns pressure, and with the supply voltage at its lowest setting the current was 6.3mA.

I have not yet pushed the supply, as at this point I am just trying to make sure that things work, and don't really want to risk blowing it up yet.

It drove a nice plasma inside the fusor for about 15 minutes, at pressures ranging from 30 microns up to 50 microns.

So far so good.

Joe.
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Dennis P Brown
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Re: Joe Ballantyne fusor V2. (Low cost fusor.)

Post by Dennis P Brown »

Great post and break down - again, your providing essential information for new fusor beginners.
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Re: Joe Ballantyne fusor V2. (Low cost fusor.)

Post by JoeBallantyne »

For the vacuum pump on this low cost fusor, I am using the Kozyvacu TA500 with a KF16 adapter, setup using the process described in the following FAQ post.

viewtopic.php?t=15463

The total cost before tax (excluding DOW Corning vacuum grease) was $173. Which with sales tax for me totals out to $190.

Just now, the Kozyvacu took 5 minutes to pull the chamber down from 86 torr to 10 microns. It took 27 minutes to pull the chamber down to 7.5 microns.

Joe.
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Re: Joe Ballantyne fusor V2. (Low cost fusor.)

Post by JoeBallantyne »

After a little over 2 hours of pumping (2 hours and 8 minutes), the Kozy pulled the chamber down to 6.1 microns. I think that with a better butterfly valve or bellows valve between the chamber and the bellows going to the pump, the vacuum would not rise as much in the chamber when valved off and shutdown, and it would be quicker to get the chamber down to 6 microns or so. My other fusor generally gets up to a few torr over a long period of time, but this one went up to 86 torr in a day or so. So not as good. The low cost butterfly valve I got for this chamber is definitely not as nice or as vacuum tight as the 1/4 turn MDC, Huntington, or Lesker knurled knob KF butterfly valves that cost much more. Might be better off using a bellows right angle valve that uses a screw mechanism to open and shut the valve instead of this particular butterfly valve.

Joe.
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Richard Hull
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Re: Joe Ballantyne fusor V2. (Low cost fusor.)

Post by Richard Hull »

I have always despised butterfly valves. I found them tricky to control with far too large of a circumference, as opposed to a smaller viton rubber seal and seat in a bellows valve. I rely only on a new or warranted rebuilt and tested bellows valve.

Richard Hull
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Fusion is the energy of the future....and it always will be
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