help-ignition ideas?

[salasd]

hi, for like the past week ive been working on my first spudgun and ive just been wondering, what do i use for the ignitor? i heard bbq lighters were crap and i cant seem to find flint ignitors yet,plus, stun guns are illegal in ny state.

are theyre any alternatives? i was thinking if you drill a hole in the combustion chamber,could you just put a lighter up to the hole for shooting like an old fashioned cannon?
thx and happy new year!

[FishBoy]

Peizoelectric barbecue ignitors certainly are not crap. I have two that have lasted for a long time and have endured a lot. Plus they're cheap and easy to hook up.

[salasd]

thx i was just wondering because i did some research on way to ignite combustion spud guns and i hear that the piezoelectric ones broke easily.

[LCTChamp]

As fishboy said bbq ignitors are very reliable once you get the spark gap set. I have an ignitor that is over a year old and still gives a spark every time. You certainly could hold a lighter in front of a hole, but flame will shoot out possibly burning your hand. Also you will lose pressure through this hole which will cause it not to shoot very far.

[salasd]

thx guys next time i get the chance ill go to the store and get a bbq ignitor. cheers!

[Xxplosive42o]

Go for a bbq electric ignitor if you can or research flyback ignition. In either case like lctchamp said, make sure to ajust your spark gap properly.

P.S You building an advanced cannon?(chamber fan, spark strip, propane/mapp propellant) or a basic one?

In any event, I'm sure it will turn out great! Enjoy building! 8)

Cheers!

[salasd]

its a basic one, but i plan on making a more advanced one soon.
also, for a spark couldnt you just hook up a capacitor to a little transformer if you were going to make a spark strip or so?

[jimmy101]

its a basic one, but i plan on making a more advanced one soon.
also, for a spark couldnt you just hook up a capacitor to a little transformer if you were going to make a spark strip or so?

Nope. The "little transfomer" needs to generate at least 5,000 volts (and 10,000 volts would be better). If it is powered from a 1.5V battery that's a step up transformer with a turns ratio of 1:3333. Not exactly a common transformer (most transformers have turns ratios in the 1:1 to 1:10 range). Even if you start with 120 volts AC you still need a 1:20 or more transformer. Plus, with 120VAC there's a good chance of killing yourself if you don't know what you are doing.

The flash circuit from a disposable camera takes 1.5V from a AA battery and steps it up to 300V and ~5,000V. These can be used as ignition systems but they are probably more work than they are worth since you also need a automotive ignition coil to get the necisary ooomph out of it. It'll end up costing more unless you have a spar ignition coil laying around.

There are a fair number of web postings saying that piezo BBQ igniters don't work well. Take it from folks who have used piezos, lantern (flint) igniters, stunguns etc. The BBQ igniter is usually the cheapest and easiest method of igniting a 1X combustion spudgun.

One serious problem with flint ignitors is that they take all of one hand to operate. That only leaves one hand to hold and steady the cannon. Piezos are trivially easy to build into a pistol grip so that both hands can support the gun.

[psycix]

There are multiple kinds of piezo ignitors.
The tiny black things which are inside lighters are crap.
The big red pushbutton BBQ sparkers are very good.