I'll second what jsr said, you're still going to be quite safe for those pressures with pn12 (so long as you are not planning on hitting your gun against a wall or putting it in a freezer before use) Also, I have a feeling that those garden mate sprinler valves from bunnings are only rated to 175psi...

How coincidental, just yesterday I was wondering exactly the same thing. I solved my problem a little differently though. I had to cut an o-ring slot in a couple of 25mm pvc sections so I found some smaller diameter pipe and slid the ring of pvc that i wanted to cut into around that. The ring was no...

yup! that's me: Hook, line and sinker (and wallet to a sizeable extent...) @cannon monkey, I've had a pissed off neighbour but not cops (although there is one that lives up my street though) I was first planning to make a ballista to throw golf balls around untill I stubled onto spudfiles and since ...

Thanks for the tips inonickname and -_-, I think i will fasten the barrel to the chamber before I get those Damage pics because I don't want my cannon to break (or explode) due to the stress of the recoil.

Yup you guessed it I'm actually from Queensland too. It was really hard to persuade my dad to let me put the stubbie holders to a better use but I eventually won him over. Shame about the laws though, I usually disassemble it and then take it into a big patch of bush right next to my house so that n...

Thanks for that Technician, The chamber does have some sections of some stubbie holders in it but I thought it needed a bit more cushioning. As for the piston itself, I think that I will have to glass over the back of the piston to give it a bit more area for the force of the collision with the bump...

hey sparkie, the accuracy isn't so good because golf balls and marbles tend to spin off in odd directions sometimes but the power is really good and the recoil with a golf ball at 120psi is kinda scary when your not ready for it. covey12, I actually had white and red primer and blue and green glue s...

Firstly, I'm a new user to this site and I've been looking around on it for help on how to go about just building a stock standard barrel sealer as my first proper cannon. I just have to say that it was very helpful to be able to see such a range of designs and discussions on them and that this is b...

Are we allowed to use more than one potato as the chamber?