How do you make a basketball cannon work?

I made a basketball cannon out of ten inch pipe that is about three feet long and then made a little ledge inside for the basketball to sit on, put a bottom on it and drilled a hole at the bottom. I am spraying ever clear inside and waiting a little while for it to vaporize and then lighting it with matches in the little hole at the bottom. It is shooting it about a foot up. What am I doing wrong? Did I make it wrong? Or why is it not working?|||not enough seal around the ball or your ignition hole is to large... pressure = further distances... low pressure like you have is going to give you nothing. Increase the pressure.