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New Member


Monday, June 2nd 2008, 12:12pm

Capping off 3/4 inch pvc under high pressure - Need Help!

In my backyard, I have a 3/4 inch pvc pipe coming vertically out of the ground. The original owner had placed a hose nozzel on top of the pipe which I never used, but I managed to knock this off after using a weed eater while doing my yard.

All I wanted to do was cap this pipe off but I'm having a lot of problems.

First, I turned off the sprinkler system and returned to the pipe but found it still had some pressure. I then turned off the main located where my sprinkler system is located and returned once more - still some pressure. Finally, I had to shut off the water main to the entire house which worked. I used fine sand paper to clean pipe. I used the typical purple primer with some pvc cement made for wet conditions (blue). I placed the cap on and let it set for 15 minutes and then turn the water back on. POP - off the cap went.

Using the above steps as before, I let the cement cure for 1 hour and then turned the main on without turning on the sprinker system. I then waited 24 hours and turned the sprinkler system on and it held. I then went on vacation and 1 1/2 days later the cap popped off while I wasn't at home flooding the entire yard until a neighbor shut it off.

I know I made a couple of errors in doing this...1) I sanded the area of the pipe which someone told me not to do since they need to be tight fitting. 2) I put the cap on without having twisted it as per the directions.

So I went to Home Depot and got Christy's Red Hot glue and put a new cap on. It's been 24 hours and I'm so worried that I'm going about this the wrong way. I did notice that originally the pipe had what looked to be like gray cement used. Are there any high pressure cements out that are gray in color? Am I going about this the wrong way? What am I doing wrong?

Any tips would be greatly appreciated!!!!!


Supreme Member

Posts: 482

Location: Houston, Texas


Monday, June 2nd 2008, 4:58pm

I understand your pain.
I am going to assume that each time the cap got blown out that you cut a little bit lower on the vertical pipe to get a fresh seal. If you did not make a fresh cut, you may have an issue.

You should make a fresh cut and don't sand the pipe like you mentioned. Use some primer and Christies Glue. Glue both the inside of the cap and the outside of the pipe, and Twist the cap forcing it downward. You may hold it in place downward for 30 seconds (sometimes the fitting will float up or out a bit).

Wipe up any excess glue.
Let it dry for atleast an hour. When you turn on the water do it slowly don't turn it on fast at all. Slooowly and leave a hose bib open. After the water is on slowly close the hose bib. Slowly.
Good Luck.
A side note: Start this in the morning you will sleep better.
:thumbup: :thumbsup:
LI0006121, BPAT0011021, CI0009500


Supreme Member


Tuesday, June 3rd 2008, 7:35am

See response at No luck with capping off a 3/4 inch pvc pipe - advice needed., (but it's basically just what todd said here).

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