Combustion circuit from scratch (need help)

Boom! The classic potato gun harnesses the combustion of flammable vapor. Show us your combustion spud gun and discuss fuels, ratios, safety, ignition systems, tools, and more.
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)DEMON(
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Wed Mar 21, 2007 7:35 am

I would like to make a combustion circuit. I don't know if it is possable though. I have thought about it and from what I understand a camera flash circiut is just a power source, a capacitor and a switch to discharge the capacitor. With resistors and so one.

Couldn't I make a simple circuit that will make a spark to ignight a combustion mix? I don't think I need multiple sparks.

Although if it is this simple would it not have been done already?

So if I could do this, having all the tools, what would be on my 'shopping list'?

Could a timer also be added to the circuit? An electrical chip or something that delayed the discharge after the switch is closed?

I would appreciate some help as I don't know exactly what I am doing. :P
Forever dreaming...
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deusXmachina
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Wed Mar 21, 2007 2:09 pm

I've experimented with camera flash circuits, and while they are a blast to trick your friends into grabbing and zapping themselves, I've had a lot of trouble using them to draw a spark.

If you're not going the stun gun route, I would suggest getting your hands on a neon sign transformer and/or automotive ignition coil. You could also try building a voltage multiplier that runs off of 60Hz 120VAC (wall outlet).

http://en.wikipedia.org/wiki/Voltage_multiplier

You might need to get some high-voltage capacitors and diodes, you can find them quite easily on the net if you look.
"On a scale from 1-10, I hope you fall in front of a bus."

:white stuff pours out of piston: "What is that? It looks like milk."
"....<i>Well...</i> it's not milk."

YAAAAAAAAYYYY WE'RE DOOMED!
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Wed Mar 21, 2007 4:51 pm

How about using a barbacue ignitor to ionize the air so the camera cap can strike wouldn't that work.
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Wed Mar 21, 2007 5:03 pm

:lol: :lol: :lol: :lol: I know but.... it still would make the cap go off.
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Bubba05
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Thu Mar 22, 2007 6:10 am

better off useing the BBQ ingniter!! sounds tricky but it could work. seen sillyer things out there. the trick would be getting a big enough spark outa it. get it to arc properly and it should to the trick. 2 gold plated amp plugs would do a treat. i have seen ignition coil set up that use an actual spark plug to get the spark. this also requires a car battery to fire but they go pritty good!!
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deusXmachina
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Thu Mar 22, 2007 1:09 pm

The BBQ ionization trick works pretty well, although it has a lot of reliability issues. I'm still a big fan of high voltages, they do the job nicely.

If you have a metal chamber and want something SUPER reliable, you can make a dead man's switch with the ends wrapped with steel wool and connected to a wall plug via switch. Nothing initiates combustion like burning steel fibres :-D
"On a scale from 1-10, I hope you fall in front of a bus."

:white stuff pours out of piston: "What is that? It looks like milk."
"....<i>Well...</i> it's not milk."

YAAAAAAAAYYYY WE'RE DOOMED!
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Thu Mar 22, 2007 2:47 pm

Yeh, I forgot to mension that I wanted to make this for my combustion paintball grenade, thats what the delay is for.

Right now I am leaning into a pneumatic but that will mean a mechanical delay valve. I am having trouble designing a mecanical valve, that is small, reliable and tough. I could make a sprinkler valve grenade but that will be bulky and fragile.

Back to the drawing bourd I guess.

(lol, if someone can design a simple mechanical, high pressure, reliable, re-usable, small valve, that has a few second delay can have all my spudbux :P )
Forever dreaming...
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Scope
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Thu Mar 22, 2007 4:46 pm

if you are confident enough with your abilitys make a flyback transformer.
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Thu Mar 22, 2007 5:26 pm

Demonm use a simple 4 dollar clock/watch the a wires for you ingition system switch hooked up to it so after you turn on the clock/watch it ticks down to detination.
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Bubba05
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Thu Mar 22, 2007 7:08 pm

I like the clock/watch set n forget!! sounds kewl!!
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