Bbq Lighter?

[Reaper1232]

Hi,
I am currently constructing my first potato cannon and am having some difficulty. I purchased a standard BBQ Lighter to act as the igniter in the chamber. My chamber is very large so i thought it would be best to have it set up to spark at 3 different points. I drilled in 3 pairs of screws and i tested the pairs individually, each time they set off a spark inside the chamber.

However once i connected the 3 pairs into a sequence, none of the points ignited. Is this because the BBQ lighter is not strong enough to do a triple spark? How would i go about giving it extra power?

Cheers..
-Reaper

[Hubb]

The points need to be closer together. Check out spark strips in the wiki.

[jimmy101]

Hubb is correct.

The total gap length needs to be less than the maximum length of a single gap.

If one 1/4" gap fires consistently then each of the three gaps will need to be 1/12" gap or less. Add a bit of windage, and figure the individual gaps need to be 1/16" or less.

[Reaper1232]

Ah k thankyou.. This is a problem though seeing as I would need to unscrew the screws then screw them all back in. Probably weakening the pipe in the mean time by doing it. Oh wells..

Cheers

[starman]

Unless you're prepared to do some more precision work getting these gaps narrowed, it will not work properly. Maybe you should consider scoping down to 2 or even a single gap. It also may require a chamber rebuild to do correctly and safely.

[Eddbot]

just disconnect the other two gaps from the circuit, you can just leave the other screws in, that shouldn't affect performance or safety

[nibbler125]

ya youre gaps need to be closer no biggy just add some soder or a hunk of wire to the end of the screws to make them closter together

[explsvcookie257]

You could try wrapping tin foil around the ends I did that it also keeps the screws from getting gunked up but I use carb cleaner now in my combustion and dont have that problem. Also I have had the same peice of tinfoil there for like over 50 shots and its doing fine.

[Reaper1232]

The tinfoil or wire idea sound good.. Although as this was just my first cannon i got lazy and didnt cut the pipes down. It was just an experiment till I build a more advanced one. So the chamber is about 1 metre long. Might have trouble reaching down to the front screws to wrap foil around them haha

But I shall try that. Thanks heaps.