Flashlamp Video

[Draco]

I found a cheap compromise, corrugated plastic panels, it gives me the space i need and they are dirt cheap, Lowe's has them and i think some hobby stores sell them, they dont have much for breakdown voltage but they make up for that with the air gap that's inherent in there design, made like card board but out of plastic so for non critical stuff they should work fine, like separating the caps, i am not seeing the full voltage on the case of the caps so for that gap it needs to withstand only a few hundred volts at low current

[Draco]

I think I misinterpreted your use for the plywood, did you mean to use that as a stand for the lamps? rather then a high voltage insulator? If so i think they would work well as long as it's sitting on something non conductive. I have used polymer clay (oven baked plastic) with good results, i made spacers with that stuff for a plasma globe driver, they keep the ground and high voltage lines an inch apart and add just a tad of capacitance and the results worked very well, i was able to get it into the right resonance point for the globe and it takes higher frequency ac fairly well.
I also found a local source for the thoriated tungsten rods. here is a pic of the ignition coil driver i built too, the FET is an IRF640, it was a rats nest as i had the FET off the board until now.
I am also thinking of adding a voltage meter inside the case for my voltage dubber as i have a few spares not doing anything, it may be redundant but for stuff like this i like redundancy

[Draco]

Planters, quick question on the needle values, i find a whole host of ones to pick from, any recommendations on one that i should go with given the specks your have generously provided for the lamp style i am constructing?
This and the silicone tubing for the brass electrodes are now the only thing i need at this point. and i find the needle values are cheaper then i had thought so they should be in budget.

I am so glad i found the tungsten locally, they where a bit more then say from ebay but i like supporting a local company as much as possible, they supply my argon as well but did not seen to have the needle valves and ones for plumbing water i don't know if they would work for this

[planters]

You need a really small port. A typical needle valve for commercial applications will flow too little or too much to adjust the pressure around several thousand volts breakdown. I've gone through a few. The one I am using in my laser now is:
http://www.mcmaster.com/#flow-contro...alves/=10bqjka

#7832k21

These are not cheap, but they work very well. These will only get more expensive if you look at lab grade valves from companies like Swagelock.

McMaster Carr also has the silicone tubing.

http://www.mcmaster.com/#silicone-hose/=10bqm9i

Get the very soft, opaque white variety.

[Draco]

Thank you, i will need to save some funds for that right now but the tubing is very reasonable
I stopped but a "hobby lobby" store while up north and found .05 thick non branded Lexan in large enough sheets with out special order, i was surprised that they had it in a sheet of about 2x3 feet at 7 bucks each, much cheaper then acrylic that i could find so that will be used to enclose the caps, for added air gap i am going to use the 3M VHB so it should withstand much more then the 5kv of my system. when all the home improvement and other hobby stores failed i was shocked i found it at a hobby lobby store.

I am going to go with your idea with plywood for the lamp stands on an acrylic base, a friend gave me an end mill bit so i may skip the oven bake plastic or try both. the set bake plastic can be machined as well, it does shrink when baked by a little bit so i would make a sheet and mill it to the shape i need
I got a quadra copter for Christmas but it has a rather heavy foam guards so after i learn to fly it an going to vacuum for a dome for the electronics not that i have a reliable source for the lexan so aside from the needle value i can begin lamp construction, i have enough quarts tube to make two tubes now

Please let me know if my math is off on the lexan, the .05inch is listed at 56kv per mm, so 67kv, that sounds really high to me, the VHB adds some air gap as well and of course i will need to over extend that it the edges but since it should see only 5 kvdc at the caps that should be more then enough.

I really under utilize McMaster Carr, The corning press I use for making my own black powder came from them, the Delrin piston for the thing was not cheap but they where the only ones i found that would cut a custom length and the cylinder was overs 100 bucks plus the acrylic tube for the outside but it has to tolerate nearly 4 tons of force, with it i can bake black power nearly as good as commercial stuff like Goex that costs a bloody fortune these days, that and for rockets i use a slightly different formula, rockets and canons,... allmost as fun as lasers lol, while legal neighbors really don't like the noise

I wanted to thank you again as this project would not be possible for me with out your help

[planters]

I wanted to thank you again as this project would not be possible for me with out your help

No problem. 56kv/mm does sound a bit high. The rating on most plastics that are in the bulk range ie many mills thick is in the 300-700V/mil or 12-28kV/mm and I would stick with these numbers.

If the cost of the valve is high you can substitute the flush and evacuate cycle to fire these tubes. While this limits the control you would have, to time the discharges that a trigger gives, this is very simple and eliminates the need for the trigger circuit as well. You can always add the valve and trigger later, but you will be able to get some discharges going right away.

[Draco]

i did find some nylon ones in flebay but have my doubts as the specs are lacking,
I could salvage a needle valve from a camping stove fuel control as well, the one i have that still works has a brass needle and multi turn i wonder is that would work as i could solder other fittings to it and it was free, i was going to use it for a patio fireplace that i have, i burn my sensitive mail but i went with a propane system instead, i wont have the fine control but what would think of using that? it would have poor control but that may work as well.

Now if i understand you right i would use the regulator on my argon tank at a very low setting? I will keep looking on ebay as well, i see the style that you listed but some are plastic.
This was just an expensive month

about the plastic, i thought that was too high of a rating as well, when i made caps from glass sheets i had use much thinker glass then the math and charts called for and still had one fail, spectacular failure though

oh and Happy new year!, i never make new years resolutions but i think i make one, not getting electrocuted sounds like a good one

[Draco]

i think i just came up with a way to test the crappy needle valve i have on had from the stove, my idea was to pump down the tube to self conduction with a high frequency supply and open the valve and see if i can keep it at the edge of conduction, latest till i can afford a real valve, i think i can do that with out wasting argon

[planters]

Good idea, but don't use argon. This is a weird gas. It has a very flat Paschen curve and you can get discharge at very low stand off voltages and then large changes in pressure produce small changes in voltage. The vacuum pump can have trouble keeping up at reasonable voltages(energies). Just use air. Nitrogen is even more predictable and helium can be the best, but has other problems that you might not want to tackle.

[Draco]

I had forgotten that argon will self conduct at a lower voltage, it's the only gas that i have so air it is then. My trigger i will directly control from the fleabay timer's relay, i can cut the power to the triggers timer or use it to ground the gate of the FET with a pull down resistor with out damage, other people have tried Arduino but with out isolation they would get unpredictable operation or blow the processor on the Arduino, I doubt they had any kind of isolation to protect the Arduino from the back EMF even with diodes