FICS Fusion...early stages

[Steven Sesselmann]

Hi guys,

I received the first parts for my next project

Those of you who have been around the forum for a while will remember my early STAR experiments, I built a series of four different versions of STAR, some which did not work at all, and some which produced a measurable amount of fusion. Fortunately these experiements were not a complete waste of time, as I learned a lot about how plasma behaves and about the apparatus that I had built.

The next experiment is called "FICS" (Fusion Induced Charge Separation), and I am pretty confident that this one will FICS the energy problem.

I will reveal more about this experiment as it comes together, in the mean time we shall just look at the bits...

Stage one is to build an accellerator tube. I have 10 water cut glass discs (10 mm) and 9 machined aluminum discs. I will attempt to laminate these using Latex glue, as suggested by John Futter. It will be tricky, as I can't spill any excess glue inside he tube. the latex glue is waterbased, and I imagine it will be slow to dry. Before I glue the discs together, I will drill and tap a small hole in each of the aluminum discs, into which I can connect a chain of 64 M ohm resistors. If anyone has any helpful suggestions, now is the time to speak....

Steven

[ScottC]

You can polish the glass edges with a belt sander using fine grit (800 - 2000) sand paper (preferably wet). You could also mill o-ring grooves in the aluminum discs to seal them.

Scott

[Chris Trent]

May I recommend a UV Cure glass adhesive instead.

There are various manufacturers, LocTite, Dymax, SuperGlue even makes one. You will likely find some at your local automotive store, though you might want to test the auto store version before use.

Get everything lined up and simply expose to sunlight for a few minutes. Novelty black light bulbs work as well, but take longer.

[Chris Bradley]

If the surfaces are flat enough, would vacuum grease not serve your purposes just as well, and be easily reversible for disassembly?

[Steven Sesselmann]

Chris,

I really like the simplicity of your suggestion. These discs are a very good fit, and your idea is plausible. The trick is to get the right amount of grease. A syringe might be able to lay down a nice bead of even thickness. definitely worth trying.

Steven

[DaveC]

Steven -

I think you will find the grease is drawn in by the pressure difference, unless it is the merest wipe, and the surfaces are very flat. Bell jar gasket seals, when greased, have a very thin film, no appreciable thickness and of course use the elasticity of the lip seal to work.

The suggestion to use O rings might work....depending on the voltage gradients.... after sufficient outgassing has occurred. This concept will certainly work wrt to vacuum, but the local outgassing could affect the longitudinal withstand.

Surface field (longitudinal) limits are generally an order of magnitude lower that bulk or transverse electric strengths, except if the surfaces can be made extremely clean. For many dielectrics there is also the issue of secondary emission from impact bombardment.

I was wondering how will you would maintain axial compression on the assembly, in either case (grease or O rings) ? It seems the full voltage would be across this clamping piece, whether inside or out.

Dave Cooper

[Steven Sesselmann]

Dave,

I intend to have a flange at either end, and six threaded nylon rods, that will clamp the stack together. The aluminum discs are beautifully machined (almost look like the disk in a hard drive). It is tempting to try the grease idea, but as you suggest, the grease might be drawn into the tube, ....not so good.

Plan B is be to use Latex glue. last time I visited John Futter's lab, we had a good look at the spare VanDeGraaf tubes he had, and these were assembled with Latex. Apparently they take 14 days at 120 C˚ to cure. Not sure what 120 celcius will do to the nylon rods? . I did find a supplier of glass reinforced nylon rods.


Steven

[John Futter]

Steven
your constructing I'm destructing
You are making an acceleration tube
mines now in bits

[Steven Sesselmann]

John,

That one should come together nicely after you have cleaned it.

I notice the class discs appear to be ground, do you think the latex will bond better, if the surface is a bit rough?

Steven

[John Futter]

Steven
I think the glass discs were ground to make them perfectly flat as the discs are cast.
I going to use PVA glue for the first try.

If that doesn't work I'll try natural latex and if that doesn't work I'll mix in a little ZnO and sulphur and vulcanise the whole thing @ 170 degrees celsius

[Jerry Biehler]

Can you use indium alloy to solder the glass to the aluminum? Though that might be a bit expensive. Heck, for that matter is indium vacuum compatible?

[Steven Sesselmann]

Jerry,

Indium wire is quite often used as vacuum seals, and it works quite well. I have a small coil of indium and have used it before. the main problems are that you need quite a lot of clamp pressure to make it flow, and that could be a problem with glass, as it might easily crack.

Steven

[Richard Hull]

Pure indium flows pretty easily and well, unfortunately like teflon, it has a continuous creep characteristic under pressure and that is where the high clamp pressure comes in. It also has temperature limits and creepage rates go up with temperature.

It is totally vacuum compatible and has almost zero vapor pressure far past its melting point. This last wonderful characterisitic is why it is often used in vacuum work.

The Indium Corporation has voluminous app notes on cold welding Indium to create near perfect seals for lower temp apps ceramic to metal or glass to metal.

Indium is one of my favorite metals.

Richard Hull

[derekm]

my suggestion would be to maximise the clampling force provided by atmospheric pressure by creating a seal near the outer periphery of the disks. I would achieve this by using a viton gasket or o ring with an inner plastic or glass annullus thinner than the gasket between each glass and metal disc.

what size is the radius on the outer edge of the disc? larger is better but then whats the disk to disk potential difference?