i think i understand, but thanks heap for your help mate!

if i had to make one know with yuor advice id probably get a 2L coke bottle make some holes up the top for the pipes and drill a hole in the bottle top for the C.P. (or make a larger one that fits without the lid) and make sure everything is completely air tight.

Would a shotty be necessary? i'm guessing it would to clear the chamber out..