Right Fuel Mixture

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.
Rogue
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Sat Nov 10, 2007 3:12 pm

Grrrr... i made a ghetto combustion earlier today. everything is dry but i can get the fuel mixture right. Noooo!! this is what i am using for a chamber: Imagewith a lighter piezo in the cap. i am also using a piece of 2ft.long 1" pvc.


i have tried using a 5 sec. spray of axe.

and a 4 sec. spray of butane.


help?!?!?!?!?[/url]
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BC Pneumatics
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Sat Nov 10, 2007 3:41 pm

5 seconds is way too long.
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jimmy101
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Sat Nov 10, 2007 3:42 pm

You are using an isopropyl alcohol bottle as your chamber? Not sure I would trust it to handle the pressure. As a closed chamber it will probably explode.

Number one cause of no-ignition is too much fuel. If that really is your chamber, then the volume is 1 pint (29in<sup>3</sup>, 473cc)? I would think that four seconds of butane would be too much. Try one second. If it doesn't fire, than add another second, etc.

Poor mixing will also make ignition difficult. Try adding a packing peanut or other small object to the chamber. Shake it a while to get the fuel to mix.
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Sun Nov 11, 2007 4:10 am

You have sprayed way too much. try 2 sec butane and 1 sec axe. Then it might work. 8)
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spudgunnerwryyyyy
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Sun Nov 11, 2007 4:14 am

Use like denatured alcohol. It works great for smaller combustions. Put it in spray bottle and use 2-3 sprays.
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