Yeah I've been doing research on mixtures and you are right about pressure in the PVC, I will use a normal air/propane.

Also, how would be using butane instead of propane? does it has a significant difference?

K thanks for the advice, you are rigt maybe a balloon is too small for a moderate power, to meter the mix I thought on using 2 small pressurised tanks (propane and oxygen) and try different mixtures and volumes. Thanks for the advice, and that cartridge is pretty cool indeed I will try that

Greetings, I'm new to this forums, I found it while looking on the internet spud cannon designs. I joined and I've found it very useful. Also I'd like to introduce a new model I've been think of and will begin in a few days, I have designed other pneumatic spud cannons before but until now im gettin...