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Strength of PVC?

Posted: Sun Feb 17, 2008 2:40 pm
by Monkey621
I found an 8 foot piece of 3" diameter (rated) PVC behind my garage. It was inside of a 4" piece of DWV which is probably why I hadn't seen it before (stumbled upon it when firing another gun). It had some muddy water inside of it and it wasn't exposed to direct sunlight due to the other piece of pipe protecting it. It has some slight discoloration near the end (a light greyish/yellow) but I think thats due to the mud it was on top of. Will it be safe to pressurize up to 80 psi if I make a cannon?

Posted: Sun Feb 17, 2008 2:53 pm
by psycix
Depends on what text is on the pipe.

If its said to be pressure rated >80psi, use it.

Posted: Sun Feb 17, 2008 3:04 pm
by Monkey621
Ok, its rated up to 260 psi I was just wondering if its exposure to water might have affected its strength.

Posted: Sun Feb 17, 2008 3:21 pm
by MaxuS the 2nd
What do you reckon they use rated PVC for in the first place?

Posted: Sun Feb 17, 2008 3:24 pm
by potatoflinger
MaxuS the 2nd wrote:What do you reckon they use rated PVC for in the first place?
Owned!

Posted: Sun Feb 17, 2008 4:14 pm
by Monkey621
Never mind then... :D

Posted: Sun Feb 17, 2008 4:25 pm
by Pete Zaria
Personally, just out of paranoia, I'd consider cutting off the discolored part. I can't tell you exactly why, but that's what I'd do. Just seems like a good idea.

Peace,
Pete Zaria.

Posted: Sun Feb 17, 2008 5:03 pm
by rna_duelers
Cut the discoloured part at the end off.The exposure to the sunlight has weakened and degraded the PVC polymer,which in short...IS bad.

Posted: Sun Feb 17, 2008 5:49 pm
by dongfang
Hi,

For the almost FAQ about sunlight discolored PVC:

I found this (in Danish) at
wavin.com

The link at the bottom of the page.

Translation:
Q: Does it make any difference if the PVC pipe is discolored by sunlight?

A: Within the first one year, PVC pipe's measurable properties will not change because of sunlight. The bleaching of the pipes by sunlight only has cosmetic significance.
Over longer periods, the impact resistance of pipes may be affected. Only an impact resistance test in each specific case can accurately determine the extent of the change.
We can inform that we in have performed several impact resistance tests on pipes that had been stored (used?) outdoors for 8-10 years, and that those pipes still fulfilled the governmental requrements for impact resistance.

Regards
Soren