SpudFiles

Actually i just want a high pressure one to pilot my qev.

Your pvc chamber would be more likely to break before your blowgun would

MrCrowley wrote:I would assume it is perfectly safe at 125PSI but seeing as I don't know what kind of blowgun it is I can only speculate. If it's made of metal, it wont fail catastrophically at 125PSI; worse that will happen is the seals will fail and your cannon would fire without warning.

i use my blowgun thats rated 90 psi at 100 - 125 psi

I found one that was rated to 150 and I'm going to put that one on my gun as soon as possible.

mr.potatohead wrote:

MrCrowley wrote:I would assume it is perfectly safe at 125PSI but seeing as I don't know what kind of blowgun it is I can only speculate. If it's made of metal, it wont fail catastrophically at 125PSI; worse that will happen is the seals will fail and your cannon would fire without warning.

i use my blowgun thats rated 90 psi at 100 - 125 psi

I know most blowguns can take well over 125PSI but my point was that we didn't know what kind of blowgun he was using

If he's using the typical Home Depot silver blowgun with red handle, people have taken them well past 450PSI without them leaking. If that is indeed the blowgun he is using, I can say with a high degree of confidence that they should be safe at 125PSI assuming safety procedures are always in practice before, during and after firing the cannon. This includes things like loading the projectile before filling the chamber with compressed air and insuring that the barrel never points towards something that you do not want damaged while the cannon is loaded and pumped up. If the seals fail on the blowgun (this could even happen at the rated pressure of the blowgun), the gun may discharge and shoot the projectile when you're not expecting it.

Like I said, the blowgun is safer than the chamber and 9 outta 10 times the pvc would fail before the blowgun. I would be more worried about that if anything.

how much dammage would an exploading pressure tank do if ithad 100 psi in it

mr.potatohead wrote:how much dammage would an exploading pressure tank do if ithad 100 psi in it

Not much damage to a concrete wall but it has the potential to be fatal if you're standing next to it.

You might not get injured at all or it might cause enough damage that it ends up killing you. Can't say much more than that.

mr.potatohead wrote:how much dammage would an exploading pressure tank do if ithad 100 psi in it

how old are you? If you cannot answer the question you just asked I dont think you should be making cannons. Not tryin to be mean, just stating the obvious. Compressed air is extremely dangerous and should be handled with extreme caution.

ouch, but i thought they make the pvc, so that it splits down the side when it explodes, so it doesnt hurt anyone

I believe that is ABS that is made to tear when it fails. PVC is more like a shrapnel bomb when it fails.

edit; ninja'd.
Those metal tanks seem to have pretty good failure characteristics. You definitely wouldn't have any ear drums left, but they seem to more or less stay in one piece. Out of curiosity, anyone ever heard what it takes to pop one of those 3 - 5 gallon portable air tanks?

mattyzip77 wrote:

mr.potatohead wrote:how much dammage would an exploading pressure tank do if ithad 100 psi in it

how old are you? If you cannot answer the question you just asked I dont think you should be making cannons. Not tryin to be mean, just stating the obvious. Compressed air is extremely dangerous and should be handled with extreme caution.

i knew an estimate of how dangerous they are but i was just asking to see what other people thought

I wonder why many generic blow guns are often labeled as "90 PSIG max"? Usually a pressure max is given for safety reasons, not because the device leaks at higher pressures.

The generic one;

http://www.harborfreight.com/rubber-tip ... 68263.html
I've seen rated at 90 and 150 PSIG. The harbor freight data sheet says it is chrome-plated zinc and doesn't list a pressure rating.