Old PVC

[TheTrooper]

Hey, i have a question. My friend has some great varieties of Pressurized PVC pipe, unfortunately its been in his attic for a long time (I do not know exactly) i will only be using the PVC pipe for a barrel so do you think it will be okay? Yes, i searched.

[benstern]

If it is not discolored, it should be okey. However you should hydro test it.

[TheTrooper]

Hydro test? Sorry but i do not know what that is.

[SpudUke5]

test it using water pressure (like using a hose to fill the chamber with water), hence the word "hydro". You will need an appropriate hose fittings for this.

[ALIHISGREAT]

its where you fill it with water and pressurize it, its far safer than using air because it won't blow up and stick shards of plastic in you.

[TheTrooper]

Thanks so much, i'll make sure to check if it doesnt have any color.

[f.c]

youre looking for a yellowish tinge.

[iknowmy3tables]

but remember if it's cpvc then the yellow tint is normal, cpvc also uses a diffrent sizing from pvc so pipe sizes are narrower than their pvc equivalent

[MikeNice]

I would find out how old is the pipe you're considering using. Materials that have undergone many heating / cooling cycles (expansion / contraction) have a tendency to become weakened. I honestly don't know if this would hold true with pvc or not, but if it's really old I wouldn't use it. Just me though, I'm usually over-cautious. Just a thought.

[Maniac]

if you use find another piece of pvc you can slevee it in and youll be fine

[DYI]

A better barrel choice would be ABS. Although PVC is often pressure rated, it usually has a low impact resistance, which is the main criteria for a barrel material. ABS is cheap, available, and can be used as barrels on launchers using hundreds of psi.

Barrels are, however, usually subjected to the least stress of any part of a launcher, so unless the PVC is in incredibly bad condition, or you plan on using upwards of 500 psi, it really should be fine. A little eye protection never hurts though. And neither does a trip to the hardware store.

[TheTrooper]

"And neither does a trip to the hardware store." Hey i dont want to buy more, because i dont want another 10 foot piece in my garage (And PVC cant be glued to ABS, and it cant hold hundreds of PSI, not pressure rated.)

[DYI]

I have personally used large bore (over 1.5") ABS barrels to well over 400 psi on many occasions with pneumatics, as well as on an Oxy-MAPP hybrid, with no failures whatsoever. Also, if ABS does rupture, it only tears open, with no shrapnel. I wasn't recommending using non-pressure rated ABS for a pressure vessel, I was recommending it as a barrel material. As for bonding, that's what threads are for. If you permanently glue your barrel to the chamber, you can never use a different barrel, so threads really should be used anyway. Never use old plastic pipe as a pressure vessel.

[spudgunnerwryyyyy]

Listen to dyi he's the man, abs rocks cus its so soft, get a 3"x1' piece and try to break it. compare to pvc and you will be amazed.

[DYI]

I've taken 1.5 " ABS and crushed it in a vice until it was completely flat. Try that with PVC and it will shatter. This is what makes it such a good barrel material. There are obviously limits, but it can survive repeated spikes to pressures well over its burst pressure.

This is also the reason behind the fact that pressure rated ABS is the only kind of plastic pipe that building codes allow to be used with pressurised gases without a shrapnel-proof housing. Non pressure rated ABS is the same thickness, just minus the quality control. Not to be trusted with continuous pressure, but ideal for barrels.