SpudFiles

This is just weird. I can't get ignition with my little spud gun.

The chamber is a 1" iron pipe. I am using a camera flash for ignition, after having tried piezos without success. The spark from my camera is very solid.

I am using butane, but I have also tried a mix of combustible gases.

Any idea what might be wrong? I never had this much trouble with ignition with my first spud gun.

How long is the 1" iron pipe?

If it is fairly short, you will probably have a bit of a hard time getting a good mixture without something like a syringe.

EDIT: sorry, I mean 50mm long, not 80

Yup, I would work on a more accurate way of fueling your gun. A small syringe to fill with butane should work.

1" ID x 2" long?
Chamber volume is just 1.57in³.
4% is 0.062in³ (1.0cc).

1cc isn't very much. Probably need a 10cc or smaller syringe.