Do PVC guns become unsafe over time?

[bode713]

My friends and i have made about 7 guns, starting out with combustion ABS guns, and then we moved on to pnematic PVC guns. We have a 2" Sch40 PVC gun that we pressurize to about 100 PSI. We have been firing this gun for about a year and a half without any problems. However, I was recently chatting with the plumbing guy at home depot who was telling me PVC was unsafe for pressurized air (it also says this on the labels for PVC pipe fittings), and i was wondering if this is true. He told me over time the PVC breaks down from UV rays, cold temperatures, and constant air pressure, and eventually explodes.. Is there any truth to this? If so, how long before a PVC pnematic gun becomes 'unsafe'?

[draculon]

PVC technically is "unsafe" for pneumatic guns because compressed air holds more energy than compressed water, and PVC was never intended for air in the first place.

As long as you keep it out of the sun, and away from the cold... it should last you a long time. It's more likely that a valve or something will fail before the pipe actually ruptures.