First Combustion Cannon\Gun (Some Questions)

[stavcas]

So hi,my name is Stav and i'm from Israel...
First of all i'm sorry for my bad english.
I have few questions to ask you guys:
1. I all the stuff you can see in the image below:

I wanna build my first successful Spud Gun with this stuff please tell me how to do it...(i wanna build a mid size gun 12 MM barrel as show in the picture above)
2. On the last three days i was reading some of the articles in the Wiki
about venting the chamber With a CPU Fan or About Iginiting the fuel(in my case Adam Basics) and when i tried to build my own Gun i could shot with it some times and times not...my problem was the iginiting and venting...
if you guys can help me with this gun ill be very happy...
Thank u , Stav

[bigbob12345]

Are you useing the bottle for the chamber? If so I would recomend one used for soda as they are made to hold pressure and have a much less likely chance of blowing up on you.
It looks like you do have everything you need in the picture and if you are useing the hot glue to glue the barrel to the bottle, dont it is not meant to hold any pressure and may blow off. Use epoxy it is some of the most useful stuff for spudding.
Other than that it looks good and should get some reasonable power especially since you have a chamber fan they really do help power and consistincy a lot.

[stavcas]

ok now i can get the fan in chamber without any leaks??

[TurboSuper]

File the edges down until it fits snugly, then run the wires through the chamber wall and plug the hole with epoxy.

[stavcas]

ok... and what can ido with the iginator??
some time its iginites and most times its not but i have spark...
my spark gap is 9 mm or 10 mm...
what can i do??
and i put the right amout of gas...

[Maniac]

Use the syringe method to in sert the exact amount of gas needed insret a syring into a hairspray can (im assuming it hairspray deoderant sprays work better.) and pull up on the syringe and the spray it back into the chambe i cant tell you how much fuel you need because i dont know the volume in side your chamber.

[stavcas]

ok... but can i use syringe to measure gas??
after i put some amout of gas in the syringe it turns to liquid
and in the chamber i need it as gas...

but what is goin with the igination??
sometime it iginite and most of time its not,and yes i got spark every time i push the bbq sparker...

[Maniac]

No hen you extract the syringe all thats in its is gas. Also what are you using for fuel. The Ignition does not work because there is either to much gas (not enough oxygen for it to ignite.) or to little gas.

[jimmy101]

ok... and what can ido with the iginator??
some time its iginites and most times its not but i have spark...
my spark gap is 9 mm or 10 mm...
what can i do??
and i put the right amout of gas...

Your spark gap is pretty big. 1mm will be more consistent and works fine.

The most likely cause of "failure to ignite" is too much or too little fuel. Poorly mixed fuel can also be a problem.

So, that bottle is your chamber? Kind of hard to get a fan into it. You might try just droping a couple "packing peanuts" into the bottle and shaking the thing after fueling. Like others have posted, you probably should use a bottle from a carbonated soda, it'll have a much higher pressure rating than the Gatorade like bottle in the photo.

The barrel looks pretty small for the chamber volume.

[Ultimate Weapon]

No, Gatorade bottles are stronger than most soda bottles. I used to make aluminum foil and toilet cleaner bombs all the time, the caps on the Gatorade bottle blows before It can blow the bottle up. But, I would rather use a soda bottle because the caps on those are better. And don't worry about it blowing up with just combustion, 2 liter coke bottles blow at 150 PSI and I hear combustion doesn't go more than like 80? Besides that, even if it did blow up you would be just fine.

[stavcas]

ok so after all i decided to buy some pipe and i built my first good spud cannon

please give your opinion
damage pics soon...