SPRINKLER TALK FORUM - You Got Questions, We've Got Answers

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!!!!!