SpudFiles

My next project is a high pressure co-ax. My chamber will be galvanized steel, but my barrel will be pvc. At 300psi is there any chance of my barrel imploding. Thanks in advance!

how much the thickness of the pvc barrel ?

Details please! What size pipes and thickness etc.

Highly unlikely, tubes tend to be much stronger when subjected to external pressure. I've used unrated 20mm PVC electrical conduit as a barrel in a coaxial at 400 psi and never had even a hint of failure.

I haven't done 300 PSI so this may not apply, but 2 inch cellular core ABS DWV takes 100 PSI just fine. Same with sched 40 1 inch PVC.

The test of the ABS is covered in my Celluar core ABS test thread. The 1 inch was tested in my Mouse Musket, a 1 inch coax. Sorry I don't have tests at higher pressure.

Assuming you'll have equal pressure on all sides of the barrel (yes), the pipe will hold at least the rated pressure if not significantly more.

Even so, if for some reason it did fail inside the chamber, it would experience a fairly "controlled" decompression out of the barrel.

The circular shape of the section subjet to pressure gives it strength, it has been know for centuries now, in construction manner, an ogival or circular handle can hold tremedous amounts of weight.

So I guess you'll be fine, and remember, if you always follow safety rules about your guns, there should be no, or very minimal problems if something were to fail. Point your gun in a safe direction when you pressurize is, and perform some pressure testing before you actually use it. As a matter of fact, the motion the projectile will take when forces apply to it will undoubtly deform the barrel by a small amount, making it more likely to fail. So, test it and be safe ^^

Proper PVC will most likely stand up to a lot of external pressure.
However, I do remember to have seen one or two cannons which did implode the barrel.
Good supports may help. If the barrel goes bending/vibrating it will go wrong faster.

Ok, thanks guys thats all i needed to know.