FAQ - Make your own deuterium from heavy water!! The video

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Richard Hull
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Re: FAQ - Make your own deuterium from heavy water!! The video

Post by Richard Hull » Mon May 10, 2021 2:18 pm

We ran these calcs way back. We determined you get a lot more D2 via electrolyzation per unit dollar spent than tanked gas. A 50 liter tank can cost over $350 now with about $100 being the disposable, non-refillable tank. So in a large tank 100 liters might cost $500 in bulk. This is opposed to about $80-100 for D2O with similar gas capability and a lot of electrolyzation passes. The sole advantage to the tanked gas is you avoid a bit of a hassle every time you want to do fusion and have to be very mindful of not running out of D2 at a critical moment of operation. Obtaining some of those larger capacity storage cells for the electrolyzer would help obviate this though. I note Mark's process seems to warrant only pure D2 gets into his fusor. This is very important and demands evacuation of the lines which require a bit of forethought in construction design if you plan on getting your gas this way. This isn't present with tanked gas as you are constantly connecting and disconnecting you gas bottle, (syringe) if you electrolyze.

Mark seemed to do OK for his runs with just a 100ml syringe once he got his operation down to a routine.

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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Re: FAQ - Make your own deuterium from heavy water!! The video

Post by Jim Kovalchick » Mon May 10, 2021 2:43 pm

I have been using a 150 ml syringe, but I usually fill to 120. I have found that with my leaky 6 inch tee chamber running at 0.01 mbarr, and around 40 kV and 10 mA, I use about 60 ml before my chamber gets too hot to keep neutron numbers from falling. This is usually 15 minutes.

With regard to shuttling syringes and the resulting need vent and purge, I will be adding fittings and clamp valves to eliminate the need to separate the tubing.

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Frank Sanns
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Re: FAQ - Make your own deuterium from heavy water!! The video

Post by Frank Sanns » Mon May 10, 2021 6:23 pm

Anybody know how the Hydrofill PEM unit gets the pressure in the Hydrostick canisters up to 400 psi? Whatever THAT is would solve all the problems for a reasonable compact storage reservoir.

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Re: FAQ - Make your own deuterium from heavy water!! The video

Post by Mark Rowley » Mon May 10, 2021 9:25 pm

Frank, hopefully Andrew Seltzman sees this post. After all the work he’s done on the little cylinders I’m fairly sure he has the answer.

Regarding the need for such a big reservoir I think we should ask ourselves a few questions…

How many folks build neutron capable fusors that go anything beyond “the big win”?

Out of that tiny fraction that do, how many get their systems efficient enough to begin activation work?

Out that smaller fraction, how many people add the necessary cooling to keep “activation capable” neutron output sustainable past 20-30 minutes?

In reality, we’re only talking about the rarest of rare occurrences. Being as such, it appears there are only three situations where a large reservoir would be needed:

1) a fusor capable of very long operational periods

2) a fledgling fusor builder who is still learning the ropes of gas handling and throttle efficiency. With certainty, I can say I wasted quite a bit of gas when I was getting my system off the ground. However, if I had a big reservoir, maybe I wouldn’t have focused as much as I have on gas use efficiency. Regarding that phase of learning, the occasional re-filling of the syringe was of no consequence.

3) a large chambered fusor

As discussed before, most if not all Fusors are as unique as a fingerprint. Gas effeciency will greatly depend on chamber size and the type of secondary pumping system one uses (not to mention smaller factors like needle valve types and such).

As long as ones system is small (cube fusor, 2.75” type, my cylinder system, etc) and cooled, making a 100mL syringe last a full hour at the mega n/s mark is attainable. As of now the best I’ve done is a bit over 45 minutes. My only limitation was a psu issue several months ago which has since been fixed. There was more than enough gas left in the syringe to take it home.

My main point of all this is of course directed to the newbies and rookies. For them, a PEM cell and syringe is all they need. It’s important to highlight, especially in a FAQ which is mostly frequented by the new folks.

Mark Rowley

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Frank Sanns
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Re: FAQ - Make your own deuterium from heavy water!! The video

Post by Frank Sanns » Tue May 11, 2021 2:02 am

My chamber is one of the larger ones at over 22 liters. As such, outgassing is a big issue so it takes gas. Normally I run a heavy deuterium stream to keep the chamber flushed of any outgassing. The ruddy color disappears in an hour or so with a good deuterium stream. That is for those of us that are not running everyday or like me, opening it up often to run different geometries and shell configurations. .

The large chamber has way more surface area to dissipate the heat. So a big chamber is good and a big chamber is bad. Still, in 20 years, I am only on my second cylinder. In my area, cylinders are hard to come by to purchase. The local dealers want you to pay a monthly leasing fee. No go for me as it takes me a long time to use a bottle. Some out of state suppliers will sell then there is the hazardous shipping charges.

I have a couple of PEM cells and have wanted to use the deuterium from them as the flush gas and the gas to bring it up to higher pressure between runs. I just don't want to dawdle with it every time I want to flush. It would be great to get enough to be able to sparge with no mind to how much is being used. I may just run my high vacuum pump and pull down a container and back fill it with electrolyzed D2. Running at some pressure would be a win. Hopefully Andrew can shed light.

For the new people, more gas makes getting to neutrons a little faster, especially in a less refined chamber or with little experience.

Just some thoughts from another angle.

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Re: FAQ - Make your own deuterium from heavy water!! The video

Post by Andrew Seltzman » Tue May 11, 2021 5:10 am

As far as the Hydrofill units go, I believe they just use back pressure from the fuel cell to achieve the high pressure. There are no active compressor components in the system, the H2 or D2 output of the cell goes through some sort of moisture separator, thorough a molecular sieve canister to trap any additional moisture and to the metal hydride cartridge fitting (in parallel with a pressure switch/sensor). The molecular sieve canister is regenerated by occasionally purging D2 from the metal hydride back through the sieve and out to the atmosphere. The fuel cell is backed by a hefty 1/2" thick aluminum backing to withstand the pressure.

I made two youtube videos on the Hydrofill units
https://www.youtube.com/watch?v=7tC-uMBQv4g
https://www.youtube.com/watch?v=N-WEIwiA3Co

I'm pretty sure the hydrofill units run a Pressure Swing Adsorption cycle for hydrogen purification:
https://www.peakscientific.com/discover ... n-methods/
Andrew Seltzman
www.rtftechnologies.org

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Re: FAQ - Make your own deuterium from heavy water!! The video

Post by Richard Hull » Wed May 12, 2021 2:26 am

I find Mark's reasoning quite sound. The DIY in-it-to-win-it types are best served by syringe fed electrolizers. Those few long term fusioneers might wish to invest in either tanked gas, if they can obtain it, or try out the Hydrofill tanked system. Mark, once he got his operation down, notes that the 100cc syringe works great for him. Guys with Mastodon sized fusors are pretty much doomed to tanked systems that can supply large volumetric gas flow rates over sustained operational periods. Again, sustained operation periods it seems tend to demand active coolant systems. This is especially true for activation work on elements of the activation isotopes sought with half-lives on the order of many minutes to a few hours.

Note: Tanked D2 can now be obtained easily without much hassle, if you have the money and desire from the suggested vendor in the trading post section on prime resources.

viewtopic.php?f=75&t=13889

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
Retired now...Doing only what I want and not what I should...every day is a saturday.

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Re: FAQ - Make your own deuterium from heavy water!! The video

Post by Mark Rowley » Wed May 12, 2021 2:57 am

As a final installment to the PEM video series, I made an unboxing vid to compliment Richards recent post about the kit.

https://youtu.be/dGlxx4_Ov0g

Richard, maybe this is something you can add to the first post under the other videos. That way they’re all together for easy initial access.

Since this new cell is defined for long term storage, I elected to vacu-seal it. As stated in the video, Horizon used to have them vacu-sealed but it seems now they’re just kept in a ziplock. Kinda odd since Horizon originally recommended against unsealing the cells until ready for use. Being as such, I decided to lightly vacu-seal it. I avoided a hard vacuum as there was concern about damaging the membranes.

Mark Rowley

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Re: FAQ - Make your own deuterium from heavy water!! The video

Post by Frank Sanns » Wed May 12, 2021 3:23 pm

Andrew and Mark.

High pressure coming from the blue PEM cells is not possible. They will blow out at very low pressures. The membranes are delicate and cannot take 4 psi let alone 400. Either the PEM cell is vastly different in the HYDROFILL unit to achieve the 400 psi or the adsorption of the hydrogen onto the metal hydride takes place at a very low pressure yet gives the volume of hydrogen (deuterium) that would be equivalent to an open cylinder at that pressure.

As for finding the original Horizon cells, yes there are far fewer of them but they have been replaced by this other ones, also from China, for around half the cost. I have no idea of their quality but at $30 a piece, it looks to be a good unit consider maybe. They are all over eBay.

Mark, It might be good to add all of your links to your original thread starter here so people do not have to read through all pages to find them.
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Re: FAQ - Make your own deuterium from heavy water!! The video

Post by Mark Rowley » Wed May 12, 2021 5:02 pm

Frank,
I’ve seen the Chinese versions before but elected not to get one due to the month long shipping times. But you’ve convinced me to give it a shot. Ordered this morning so it should be here by mid to late June. Total cost inc shipping was $34. It’ll be a worthwhile comparison for the community… especially if they work equally well!

I added the unboxing vid to the original post on page 1.

Mark Rowley

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