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Why the #@$% isn't my potato cannon igniting?

I can see a spark, but can't get it to ignite. I have tried using hairspray and Lysol, and have tried different amounts of both. I also tried wiping off the screws for a better spark (which actually seemed to help, but still no ignition.)

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Tom Savage3 years ago

the reason that your potato cannon isn't lighting is the amount of O2 (oxygen) that is in the chamber. by blowing on the end of the chamber for about 1 second after you have put in the propellent add the cap and fire quickly

try using an electric grill ignitor, i use one on my propane powered cannon and it works wonders for me
I have never had much luck with bbq lighter ignition, I use a coleman lantern flint/twist ignition on all of mine. but one may also use propane as a fuel which is 100% success or gasoline via fine mist spray bottle(not as reliable as propane)
Vyger6 years ago
It's possible the stuff you are using is not reaching the correct fuel to air density which will make it flammable. Or the spray isn't flammable to start with. Butane or propane is a good explosive gas. Some aerosols use propane as a cheap propellant but companies have been looking for a less flammable and environmentally friendly propellant. They used to use freon until they discovered it was destroying the ozone layer. So, maybe what you are trying to use won't even catch fire.
log63 (author)  Vyger6 years ago
Yeah, you're right about not all aerosols bring flammable. I tried cheap hairspray, lysol, and spray on axe, and axe was the only one that gave me that "flamethrower" effect. Maybe I need something more flammable, but pure butane/propane seems pretty dangerous to be using in a pvc potato cannon.

As for the fuel to air ratio, I have tried spraying the stuff in and then blowing in there a little to try to make sure there is still some oxygen in there. I just can't see how it could be that picky. I should have just stuck with a pneumatic design.
Twi7ch log635 years ago
I have 3 cannons 2 of which are the spray type. The one thing I learned is use way less spray. Seriously like a second is better off since too much will cause it to fail. Besides that Id say stick with body spray. After a few shots the threads get all nasty and everything is sticky from hair spray. With these less is more for fuel.
plotkiller5 years ago
The way I solved my hairspray to air mixture issue is with tin foil and cardboard. I cut a piece of cardboard to fit in the center of my 3 inch combustion chamber leaving about 8 inches from the barrel and about 2 inches from the bottom plug. It isn't attached at all, just loosely lodged in there. My igniter is in the end cap but when I spray into the chamber I only do it on one side and it seems to flow through the foil cover cardboard seperated chamber and mix perfect. I have been using aquanet extra hold which sends the spud about 800 or so feet with a 6 mississippi count spray into the 3 feet long 3 inch combustion chamber. If I had rigid foil like the stuff they use in a fire barrier wall, I'd ditch the cardboard!
log63 (author)  plotkiller5 years ago
The only thing I would be worried about is the cardboard blocking the airflow from the explosion chamber to the barrel, but I will give it a try! Thanks a lot!
zack2476 years ago
well im not sure, but try a few different hairsprays, if not Tag.

i have some dollar store hairspray that is extremely flammable, i havent used it in a potato gun or cannon yet, but ive used tag and it works.

with these full size potato cannons, a common length of spray into the chamber is 3 seconds, but i would start at 5 seconds, and quickly close the chamber after you spray the aerosol in, you would be surprised how much floats out in a second or two.

if it doesnt ignite at first, open the end cap and close it, dont bother blowing into the cannon, the suction from the end cap being pulled off should be enough of a difference, otherwise, just blow a tiny bit, im not sre what the ratio is, but its a tad precise.

also, double check your seals on the cannon, if it isnt sealed well that could be your only problem.
log63 (author)  zack2475 years ago
Thanks a lot. I will definitely check out Tag and try spraying for five seconds.