Multiple Cannon Ignition

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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brplatz
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Mon May 19, 2008 6:38 pm

I was wondering if this would work.

A stun gun or electric grill igniter through a selector switch an on to however many cannons or ignitions you need.

The pic isnt great but it should make sense.

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jrrdw
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Mon May 19, 2008 6:42 pm

It should work as long as you wire it rite. The stun gun would probly work better, more power!
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mark.f
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Mon May 19, 2008 6:50 pm

I dunno. Depending on the type of switch current may arc across the contacts when open, allowing for inconsistent selection.
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brplatz
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Mon May 19, 2008 7:05 pm

i thought about that too. when soldering to the contacts possibly it will jump there instead since electricity chooses path of least resistance, the contact points or the switch itself could possible be that path. any ideas on good insulation on the contact points?
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jrrdw
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Mon May 19, 2008 7:11 pm

Shrink tubing insulates well.
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brplatz
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Mon May 19, 2008 7:14 pm

Ok i have a ton of shrink tube in Patriotic colors :) Good ole red white and blue. Do you think it might jump inside of the selector switch itself? Cause that could be a problem
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jrrdw
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Mon May 19, 2008 7:16 pm

Only one way to find out. How heavy is it?
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daxspudder
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Mon May 19, 2008 7:17 pm

For it to work you need a mechanical selection switch, something that will maintain a good size gap between your contacts... i dont think you can buy one, so you could just make one!
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brplatz
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Mon May 19, 2008 7:33 pm

@jrrdw

how heavy is what? the cannon?

@dax

i thought about that, hopefully can find a workable one first
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jimmy101
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Mon May 19, 2008 7:37 pm

The switch will be a problem.

If the gap in any open switch branch is less than the gap in the currently selected branch then the spark will jump inside the switch to another branch. So, if gun one has two 1/16" gaps and gun two has a single 1/16" gap and the spacing between the contacts in the switch is less than 1/16" then the spark will ignore gun one and spark to gun two even when gun one is selected.

You might have to fabricate the switch from scratch so you can keep all the parts well separated. It wouldn't be too difficult. Your contacts really don't have to carry any power and heck, they don't even have to actually contact, just get close enough to spark.

BTW, you don't have to connect both wires to the switch. No reason all the guns can't share a common return wire.
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jrrdw
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Mon May 19, 2008 7:48 pm

How heavy is the selector switch. Maby a board with nails in it, about 2 inch's apart???
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brplatz
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Mon May 19, 2008 7:50 pm

ok so maybe here i can still use a purchased switch

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jrrdw
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Mon May 19, 2008 7:56 pm

Like jimmy pointed out, if the switch contacts are closer then the ignition points in the cannon, it will arc in the switch.
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brplatz
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Mon May 19, 2008 8:01 pm

crap i understand but there has to be a way!!! lol aside from making my own switch
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jrrdw
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Mon May 19, 2008 8:13 pm

Use indivigaul power supplies on the cannons and a relay set up. That way all the heavy current is only on the cannons, and light current through the selector switch. Like a cars wiring system.
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