SpudFiles

Ok, I've built a spark rail for my first combustion cannon but it seems when i try to test the whole rail together it doesn't work.
I have 3 spark gaps on it.
I'm using a wooden dowel with 3 small PVC rings attached to it. (Each ring has a spark gap)
I'm using screws for the prongs and some small wire to connect each gap and the ignition source.
My ignition source is a simple click BBQ igniter (non-electric)

The rail sparked fine when i connected the ignitor to each gap individually, but when I wired them all together and tried to spark them all together they dont spark.

I have it wired correctly, im damn sure of it but I think its because my ignitor doesnt have sufficient power to light all three at once. I think it might be the size of the gaps thats the problem. They are 4-5 mm apart each.

If anyone could help me out I'd be very appreciative. Thanks

I'm no expert but I believe your spark gap has to shrink when you make multiple gaps. try shrinking that gap? If that isnt it perhaps some pics and/or diagrams are in order?

Your gaps are definitely too far apart. Just find the max spark length that your ignitor will do, and divide it by 3 to get your gap size for each individual spark. For most ignitors, you will get a total of about 1/2", so your gaps should be 1/6".

Here's my PVC "rail". Gaps are as small as I could get them with a dremel cutting wheel, roughly 1/16" each.

First, take the cannon into a dark room and trigger the sparker to make sure there are no shorts outside the launcher.

If there are none, then shorten the spark gaps.

4-5mm each, 3 gaps? Too large.
That comes down to 3x5=15mm
A good spark system has less then 5mm in total.
Make sure that every gap is 1mm or less and it will spark just fine.
The shorter the jump distance, the better.

ok thanks all of you for helping, I just have to find the correct lengths of screws to put into it

hopefully, you'll use propane as a fuel, hair spray and deoderants have water in them and would foul those tiny gaps over time. maybe later you could move up to a stun gun ignition system.