Newbie help & ignition coil system clarification needed

[Ramla]

Hello all spudders. I recently built my first potato cannon but had little luck with it. With the Finnish coal barbecue culture we don't have spark BBQ lighters (at least not in every automarket) so I ended up getting a piezo igniter from a long nosed butane lighter and hoped it'd work. At least it sparked.

For fuel I thought I had WD-40 but it was with the new CO2 propelling and therefore didn't work, so I tested my cannon with 95 octane gasoline. BTW is it not suitable fuel for cannons as nobody else seems to use it? Too combustive or not at all? Going to buy a bottle of butane anyways so no biggie.

Anyways, I used small amounts of fuel (maybe 5-10ml) since I had no idea how much I should, and I only got it fire a few times. I did wait for the fuel to vaporize but the spark wasn't good enough.

Now that I even broke the ignitor I thought of moving into proper systems right away. I was thinking of an electric ignition which could be done even with remote control if I some time am going to use excessively combustive fuel mixtures in the chamber and want to preserve my arm for another load. Stunguns seem very easy and cheap but they are illegal to buy for private use here so it's a no go, but car ignition has the system all ready why not use that. I've read a few websites and come into conclusion of picking up the following stuff from a scrap yard:

- an ignition coil
- a spark wire
- a spark plug.

Now, I only have a problem of not knowing how to actually connect these and whether to use a capacitor (and how) or not. I have here two sets of instructions on the subject but can't figure them out.

http://www.geocities.com/ResearchTriang ... #sparkplug
http://www.sentex.net/~mwandel/cannon/sparky.html

EDIT: Oh well. Just as I submitted this I had a quick glimpse on both sites and figured the circuitry now.

Now, the latter page says 8 AA batteries are enough to create a spark. I suppose it means a voltage of 12. Does it matter if a 9V battery or 8 AAs are not capable of the same amperage as a lead acid battery when it comes to the ignition power of the spark?

Some of you have used ignition coils in your spud guns. I would be more than happy to hear what power supply and such you have used, and how it has worked.

[Agent Orange]

i havent used ignition coils, but i know you can generate a pretty sizeable spark from a television flyback transformer. you can get a good 30 volts out of these things if you wire it right. theyre not too hard to come by either, but you'll want to read up on it a bit if you arent too familiar with electronics. but if you can find a tv you can put one together for around $5. i have one or two that make some nice sparks, but they havent been hooked up to launchers because stun guns are legal where i live. check these sites out for details.

http://www.powerlabs.org/flybackdriver.htm

http://www.angelfire.com/80s/sixmhz/flyback.html