DarrellTaylor's Fusor Build Thread

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darrelltaylor
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DarrellTaylor's Fusor Build Thread

Post by darrelltaylor »

Hi All,

I'm new on here and i've not done much lurking - so if i'm not using the forums as accepted then point me in the right direction....

I decided to build a fusor a while ago - I enjoy physics, i'm working towards a Bsc in the evening and weekends (around work) but I have a long way to go still. This project will hopefully compliment my studies and feed my practical appetite when trawling through endless theory books.

I would like to achieve fusion really but i read that a demo fusor is a better starting point to learn from, so rather than rush in and get disheartened when it gets difficult I decided to make a demo fusor first - I was hoping this thread would be my 'build and progress' report - if no-one minds.

Im sure many of you are fed-up with this link, but its the design I decided to do..... http://makezine.com/video/nuclear-fusor-star-in-a-jar/
I think its neat, understandable and is a good learning journey. Its not the cheapest and ive spent approx. £575 to finish my fusor, but that includes a protective screen and a few additional extras - I think I could have finished this fusor for £450 - but I like to do things a little bit my way.

I hope to turn the fusor on for the first time in the next couple of weeks, its basically built and im waiting for the screen to arrive. I was given advice to use a safety screen in case the glass breaks in the vacuum chamber and I will heed that advice.

I have not written everything up, I don't have a report to paste as such but over the next week or two I will write-up the components, build and then results once turned on - with pictures along the way.

Any help or advice is welcome

My updates wont come through thick and fast - I might be slow to update but I will get it all on here :-)
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Re: DarrellTaylor's Fusor Build Thread

Post by darrelltaylor »

Component Information

This is a list/ write-up of the components I used, how much they cost and where they came from (mostly ebay for convenience). I thought this might be boring/ useless for many of you experienced people but it might be useful for new people - if nothing else people can critique what I have done so others can learn from my mistakes!

List

Nylon Legs – cut 4 sections from solid nylon bar 16mm x 300mm that I bought of ebay and drilled the centre out on a pillar drill. Bought from ‘diamondengineeringsupplies’ for £3.25.

Ceramic Stand-off – I contacted a company called Ceramic Substrates www.ceramic-substrates.co.uk and told them what I needed, they were kind enough to send me one for free. I found it difficult sliding this through the hole in the lower aluminium plate as the hole was the same diameter & there was little relief/room to slide. I drilled out the hole again (same size) and filed it to help the stand-off pass through but I did damage the end of the stand-off through this process a little bit. I would advise getting a few stand-off’s if you are heavy handed & lots of patience.

Aluminium tube for the centre of the stand-off – from ‘forwardmetals’ on ebay, £8.00.

Threaded bar – I bought threaded bar from screwfix to use from the bottom of the wooden base to the top of the vacuum chamber. I bought 4 stainless steel bars in 30cm lengths for about £10.

2-Pack Glue – Bought from B&Q for £8, it is a two pack glue that uses a syringe to mix the parts as they travel down the syringe. I bought the pack that claimed high temperature resistance. I glued the ceramic stand-off into the lower aluminium plate on both sides and I repaired the damage I caused to the stand-off when sliding through the aluminium plate. I also put glue in the middle of the aluminium tube that ran through the centre of the stand-off to seal the vacuum if there is a leak past the thread of the two bolts at either end.

Nuts and Bolts – I used nuts, bolts and screws from assortment packs I already owned to fit the parts together. I did buy some extra wing-nuts and tee-nuts for the bottom of the wooden base plate from ebay and screwfix for a couple of quid per pack.

Rubber feet - £1.79 from ‘fullspeedit’ on ebay. 22mm x 10mm (I screwed them in with short wood screws that I had).

Caps for the rectifier – I used 2 pairs of “silicone hose intake vacuum end cap bung plugs” from “autoperformanceonline” on ebay, £8.90. They were a good fit and look fine. Jubilee clips stopped any mineral oil leaks.

Base plate – I had a bit of wood in the garage that was suitable. I just sanded it and stained it with some stain that I also had sat on the shelf. I think it was an off-cut piece of pine that was left over from some shelving I put up.

Aluminium plate – Luckily for me, a friend supplied the 2 cuts of aluminium bar for free. I drilled the 11 holes and tapped 2 of them with an NPT tap which I bought – as it’s a tapered thread it was not easy to cut. To cut the thread I used some cutting fluid and worked the tap down a bit at a time, tightening and untightening over and over again until the tap reached the other side of the aluminium plate. I regularly removed the tap to clean out the swarf as the thread cut.

Rubber washers – cut from rubber sheet from ‘cisonline11’ on ebay, £2.10.

Borosilicate Glass Tube – I bought from www.glass-solutions.co.uk, I purchased 5 to get the price down at a cost of about £110, I sold one on eBay and have 4 left (included the one fitted). A lady called Helen @ Glass Solutions was very helpful, they cut the tube to the dimensions I specified, wrapped them and delivered them quickly and well. They offered ground or rounded ends, I chose ground to help the seal in the vacuum.

Pressure gauge – I bought the pressure gauge from a bloke called Len at www.pressuregauge.co.uk. It was about £25, seems to work ok. The only thing I would do differently is add a swivel joint so that I can tighten the thread into the aluminium plate and then turn the gauge to face me (if such a thing exists).

Plastic fittings – for the rectifier. I used leftover parts from a kitchen installation I did a few years ago as clips to hold the rectifier in place. The clips I used are normally used to hold kick-boards to the legs of kitchen cabinets.

Rubber hose (thin and thick) – I bought this from ebay – “autosiliconehoses_outlet” and “racespecperformance”. It was inexpensive £2.65 for one length, £3.47 for the other. One hose is 16mm ID and has not collapsed under vacuum so far.

Brass fittings & Reducer/Expander for hose – bought from various ebay stores to suit my hose sizes and vacuum pump connection. ‘qualityparts09’ £4 & context-pneumatic-supplier-cpm’ £12.

NPT thread tap – bought from ‘drill_taps_uk’ on ebay for £5

Jubilee clips – I bought some for the rubber hoses from ebay (racebikebitsuk,£3) and I had some already that I used to help seal the oil in the rectifier.

Dow Coring grease – bought from severnvacuumservices on ebay for £14, nothing bad to report

High Voltage cable – from ‘high-voltage-hv’ on ebay. Took weeks to arrive because it came from the far east (by sea I think). 10ft, 30kV, 18AWG. Should be fine, I did use most of it as I used it for the earth cable too. Only cost £8.00.

Cable connections – I have used a variety of ring terminals and fork terminals that I had in my garage, previously bought for automotive wiring (assortment packs). I have crimped all wires in place, only soldereing the wires in the rectifier.

Diodes – I struggled to find these, I think they were £20 from the USA for 4.

Solder & Flux – for the Diodes. I bought “Electronic Solder Flux Paste 35g + 3m Fine low melting pt solder wire” off ebay for £2.50. It was rubbish and I really struggled with soldering the diodes together. That said, I’m not good at soldering, I don’t know how to use the flux properly, I have very little experience, my soldering iron is wobbly, etc….

Inner grid wire – I got given this from a friend, who acquired it from where he works. Apparently it is typically purchased in large quantities and can be difficult to source smaller lengths. I believe the thickness of the wire is slightly out but ‘would be close enough’…… time will tell….

High Temperature Silver Solder & Flux – 2x 600mm lengths of solder and 100g of flux powder from eksupplies2009 on ebay (£19). Good service from seller and excellent solder. I enjoyed the soldering using a MAPP blow torch and this good quality solder and flux.

Emergency stop switch – bought from ‘getitconnected’ on ebay for £11.

Vacuum Pump – Edwards EDM2 - 2 stage vacuum pump. I approached a seller on ebay of an item that didn’t receive any bids. I paid £50 (I think) for a reconditioned pump and collected it from 20 miles away – I think it was used at a university and then replaced with newer equipment.

T-piece for rectifier – A piece of plastic plumbing pipe bought from B&Q for a couple of quid.

Mineral oil – White Mineral Oil Carrier Oil – 100% Pure – 500ml. I bought this from an ebay shop called mysticmomentsuk, all good and £8 delivered.

Variable Transformer – 1A, 240V, Open Type Variac bought from Wattbits ebay shop for £55. The manufacturer is Ravi Electricals, model 1F-1. The only downside is the 1A variac has no earth, so on my fusor the earth cable will bypass the variac – not ideal but also not a deal breaker. Also the mounting style is less ideal with no ‘frame’ – to mount it you must remove the knob, use threaded two holes inside the dial and then refit the knob –again its not ideal but not a deal breaker.

Junction box & Connector blocks – I used a junction box and connector blocks inside to wire the variac to the main 3-pin plug. It wasn’t necessary but it’s a bit neater and allowed me to branch off my earth cable directly to the NST in a neater fashion. I had these bit already in the garage so no additional cost.

Polyacrylate Sheet – I bought the Polycarbonate Sheet for the protective screen from www.plasticsheet.com, 4 sheets (front and top, LHS & RHS) were about £75 delivered. I ordered 5mm thickness which I hope will be enough in case the borosilicate tube collapses under the vacuum.

Aluminium channel for screen – I had some aluminium channel that I have screwed to the worktop where the fusor will be set up. This is just for the screen to locate into, to keep it secure and in position. I think this is a good idea but not necessary – I only did it because I had the channel lying around in my garage, Its “W” section, about 1” tall.

Plastic angle for screen – I bought a few 1m lengths of white plastic angle, ½” by ½” to use along the corners of the polycarbonate sheet safety screen. I plan to rivet the plastic to the sheet to hold the screen together. Each length was approx. £2 from my local B&Q store.

NST – I bought a Jefferson NST, no GFCI, 12,000V, 30mA from California, USA (via ebay) for approx. £100 delivered. The seller was “myroxyrose”, seemed very knowledgeable in the product description. Feedback was low for a ‘shop’ at only +150 but the NST worked perfectly, arrived earlier than shipping suggested and was in good condition – I would use this seller again!
Tom McCarthy
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Re: DarrellTaylor's Fusor Build Thread

Post by Tom McCarthy »

Hi Darrell,

Great progress, you'll most likely need to change out your chamber for a metal one when it comes to doing fusion, but what you have should do for demo.

May I suggest that you move your progress to the "Images Du Jour" forum - it's situated at the bottom of the main page in the "Miscellaneous" section and is the appropriate place for progress reports.

Best of luck,
Tom
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Re: DarrellTaylor's Fusor Build Thread

Post by darrelltaylor »

Tom McCarthy wrote:Hi Darrell,

Great progress, you'll most likely need to change out your chamber for a metal one when it comes to doing fusion, but what you have should do for demo.

May I suggest that you move your progress to the "Images Du Jour" forum - it's situated at the bottom of the main page in the "Miscellaneous" section and is the appropriate place for progress reports.

Best of luck,
Tom
Hi Tom,

Thanks for the advice.

Can a 'Mod' move this whole thread to the 'Images Du Jour' forum please? Images soon to follow!
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Re: DarrellTaylor's Fusor Build Thread

Post by darrelltaylor »

image.jpg
Basic frame & easy bits
image.jpg
Now with ceramic stand-off and glass
image.jpg
1st grid
image.jpg
Grid installed and hose added
image.jpg
Inner grid v2
image.jpg
Inner grid v2 with flash
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Re: DarrellTaylor's Fusor Build Thread

Post by darrelltaylor »

image.jpg
Rectifier, gauge and vacuum pump added
image.jpg
Nicer inner grid fitted, drawing a reasonable vacuum
image.jpg
1st HV wire fitted and Variac in place
image.jpg
More wires fitted and NST added
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Dennis P Brown
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Re: DarrellTaylor's Fusor Build Thread

Post by Dennis P Brown »

Very nice design - I'd think it will work well as a demo.
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Richard Hull
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Re: DarrellTaylor's Fusor Build Thread

Post by Richard Hull »

I am sure you know that the gauge you are using is intrinsically valueless in determining your real vacuum level. A thermocouple gauge is really needed.

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
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Re: DarrellTaylor's Fusor Build Thread

Post by darrelltaylor »

I've had it running tonight, sorry for the low quality pictures (iPhone 4, boo), I will try to get some better ones over the weekend!
image.jpg
image.jpg
image.jpg
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Richard Hull
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Re: DarrellTaylor's Fusor Build Thread

Post by Richard Hull »

You have bugle jets showing and that means you are in the 100 micron range with your vacuum pump.

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
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Re: DarrellTaylor's Fusor Build Thread

Post by darrelltaylor »

I'm chuffed to bits! A good vacuum and some good pictures!

It is plasma isn't it?
smaller P7304148.jpg
smaller P7304146.jpg
smaller P7304142.jpg
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Richard Hull
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Re: DarrellTaylor's Fusor Build Thread

Post by Richard Hull »

Darrell, I have placed your name in the Plasma Club listing.

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
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Re: DarrellTaylor's Fusor Build Thread

Post by darrelltaylor »

Does anyone have any advice on how to create a nice 'star mode'?

Also, how can I read the temperature in the plasma, what type of meter/ gauge would be most suitable?
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Re: DarrellTaylor's Fusor Build Thread

Post by John Futter »

Darrell
The plasma temperature is worked out from the number of eV you have put into the plasma roughly 11,000 degrees kelvin per eV

so for a 20kv fusor the max temp of the plasma is 220,000,000 degrees kelvin
Plasma temperature is the equivalent temperature you would have to raise the gas to to equal what the electrical discharge is doing for you.
It is not real temperature as it refers to the electron temperature equivalent only
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Richard Hull
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Re: DarrellTaylor's Fusor Build Thread

Post by Richard Hull »

Check on the FAQ on Temperature. You should have already consulted the FAQs in this forum.

viewtopic.php?f=24&t=9223

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
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Re: DarrellTaylor's Fusor Build Thread

Post by darrelltaylor »

Thanks for the info.

I'm actually curious as to the actual physical temperature of the plasma in the centre of the vacuum chamber. Its just for my curiosity really - but if I was to hypothetically stick a thermometer into the centre of the plasma, how hot would it be?
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Re: DarrellTaylor's Fusor Build Thread

Post by Richard Hull »

That will not tell you the temperature of the plasma as a thermometer is a solid mass and the bombarding particles would heat it and it alone to real world temperatures and not the thin plasma particles relative kinetic energy equivalent temperture, which is in hundreds of millions of kelvins. Perhaps you still don't grasp the relationship in the plasma energy-temperature equivalences. Such actual glowing plasma measurements are often measured with an optical spectrometer looking at doppler broadening of deuterium wavelengths.

Even a demo fusor, not doing any fusion and running at 10kv, might be expected to have a high end plasma temperature of 100 million kelvins. But the bulk of the particles in the plasma will be on the order of 1-10 million kelvins or so.

Work is afoot here using a special infrared camera system to measure the bulk temperature of the plasma. Find that thread and you will understand, perhaps.

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
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Re: DarrellTaylor's Fusor Build Thread

Post by darrelltaylor »

Hi again.

I have a couple of questions after a few runs of the demo fusor.

Firstly there is a bright white glow at the exit point of the chamber where the vacuum hose is attached. What causes this? Is this ionisation of the brass vacuum fitting atoms? I have done a quick search and found nothing - but I will search some more on the forums because im sure im not the first to notice this.

This white glow slightly increases its size upto approx. 12kv at which point it jumps from the size it has reached to a smaller size and back to the 'fully grown' size, flickering like a lightbulb (so to speak).

I have attached a couple of photos of the glow that im referring to along with a close-up of the fitting from the outside:-
P8104181 small.jpg
P8104192 small.jpg
P8104193 small.jpg
The other question that I had was about the colour of the plasma. The colour is very violet - although a friend described it as blue - I see more purple. The camera catches a more blue light. Either way, what dictates the colour? Is this directly related to the predominantly Nitrogen atoms in the vacuum?

Thanks in advance for any pointers or advice on finding the answers that you can give.
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Re: DarrellTaylor's Fusor Build Thread

Post by Richard Hull »

Vacuum leaks where air is flowing into the chamber can create glows at those points. The whitish glow at the vacuum port can be oil/air mixtures ionizing at a circular sharp edged gradient point. I have seen glows moving into a transparent vacuum pump hose towards the pump, even! A really great pump never has these issues. Pumps that are struggling and back streaming oil after long operation periods are often the cause of these glows.

The color of all glows are a combination of visible colors emitted by various ionic recombination of elements. In a good pumped chamber, in theory, the glows are due to nitrogen and oxygen. If doing fusion and in a rather pure deuterium gas environment, the glow will be a ruby red.

Bluish, purple-violet is the norm for air.

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
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Re: DarrellTaylor's Fusor Build Thread

Post by Rich Feldman »

What happens to the upper glow when you connect a wire directly between fusor end plate and the vacuum pump?
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Re: DarrellTaylor's Fusor Build Thread

Post by darrelltaylor »

Thanks for the replies......

I'm planning to upgrade the demo fusor because I want to achieve 'star mode' but I have in the back of my mind my plans to build a fusion fusor, so I want to try to update the demo fusor with parts that I can re-use for the fusion fusor if that makes sense.

To improve the vacuum performance and reach a deeper vacuum I was planning to add a foreline trap with a bellows value either side, and use solid pipe (as per the plans for a fusion fusor). Do you think this will improve the depth of vacuum that I draw or should I start directing these questions into the vacuum dedicated part of the forum?

Of course, I will also ditch the vacuum gauge in favour of something useful. I'm undecided if I should replace like-for-like with a range of 0-100 micron or change to a thermocouple. I think the thermocouple would be more appropriate for the fusion fusor but a like-for-like switch would fit the demo fusors design......

And thanks for the colour explanation - I found the same answer through further re-reading of the FAQ's last night too :-)

Rich - im not sure I follow your logic. The chamber end plates are earthed (via the NST), and the vacuum pump is earthed through the standard UK 3-pin plug. I can happily connect a wire between the fusor chamber end and the vacuum pump and see what happens, im just not sure what it might do?
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Re: DarrellTaylor's Fusor Build Thread

Post by Richard Hull »

I would get a thermocouple gauge ASAP so that you will be able to know your vacuum level. It can help find leaks, too.

The general rule is to ground all touchable metal objects in any system. Your system uses the end plates as a substitute for the outer grid normally placed in all demo systems. This is a less than perfect scenario. You have no real outer grid entirely surrounding your central grid. The pump, the chamber body or in this case, the end plates, etc., must be grounded. You are working from the "Make" article and not the recommended path shown to be the normal demo fusor here. "Make" magazine or their website does not do fusion or know much about it. We do.

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
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Re: DarrellTaylor's Fusor Build Thread

Post by Rich Feldman »

darrelltaylor wrote:Rich - im not sure I follow your logic. The chamber end plates are earthed (via the NST), and the vacuum pump is earthed through the standard UK 3-pin plug. I can happily connect a wire between the fusor chamber end and the vacuum pump and see what happens, im just not sure what it might do?
Sounds like you got it right, Darrell, assuming a proper 3-pin plug on your NST.

I suggested the experiment because it's trivial to perform. Any change in the "top" plasma would show that your electrical connection between fusor and pump has room for meaningful improvement (in its DC or AC impedance).

Here's an alternate approach. Instead of adding a fat wire, you could start by measuring the DC and AC voltage between metal parts at the two ends of your vacuum hose. Should be less than 1 volt.
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Re: DarrellTaylor's Fusor Build Thread

Post by darrelltaylor »

Rich Feldman wrote:
darrelltaylor wrote:Rich - im not sure I follow your logic. The chamber end plates are earthed (via the NST), and the vacuum pump is earthed through the standard UK 3-pin plug. I can happily connect a wire between the fusor chamber end and the vacuum pump and see what happens, im just not sure what it might do?
Sounds like you got it right, Darrell, assuming a proper 3-pin plug on your NST.

I suggested the experiment because it's trivial to perform. Any change in the "top" plasma would show that your electrical connection between fusor and pump has room for meaningful improvement (in its DC or AC impedance).

Here's an alternate approach. Instead of adding a fat wire, you could start by measuring the DC and AC voltage between metal parts at the two ends of your vacuum hose. Should be less than 1 volt.
I see. The electrical connection is provably less than ideal. Thanks Rich, it gives me another direction to follow-up!
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