So I did drill and tap on the barrel down at the base for venting and also fueling.

Thanks for the quick responses. My boy so wants to see it fire.

I viewed the spark plug in action before putting fuel in .... I am a mechanical engineer and so now what is safe.

I built up the following spud cannon ... http://24.22.111.106/wordpress/?s=spud Just installed a 100kv stun gun and when you look down the barrel you can totally see a spark at the spark plug. I tried to spray some starter fluid in but not ignition. Do I need to have a potato installed? How long sho...

Built up an aluminum spud gun out of spare material. Tapped the end plate for 14 mm spark plug and wired a BBQ light to it.

It is sparking but no combustion for some reason.

Any thoughts .... the BBQ lighter was one of those cheap disposable ones ($1) at walmart.