questions re: pvc piping fitting, etc

[tenax]

well,it seems i need pvc assembly school. fortunately, i'm on an installation test run as i'll need to redo some of it when i get my new heater, pump and autopilot..meanwhile, some tips please.

here's what i've been doing with about 80% success (80 percent being how many joints don't leak, 20 that do!) small leaks, but still leaks.

my first mistake maybe? is i made an assumption that grey pvc is like white pvc..both being whatever 40 pipe..i am now thinking that given grey pvc is actually for electrical conduit rather than water, it doesn't have the fitting tolerance that white pvc does? 2 of my joints have slip on greys and both are leaking a bit so..that's my first guess..confirm anyone?

now,if only it were that simple i have a few white pvc joints with white pvc fittings that are leaking a bit too..here's what i did:

-cut pipe,filed any burrs down in and outside the pipe..they never were cut completely straight, but judging by the prior pool dudes my cuts were straighter than theirs, and theirs didn't leak!

-used the purple primer on both ends of the joint to be made.

-let it dry for a few minutes

-pretested fittings..made sure pipe went all the way to the "stop" in the slip on joint pieces. no problem.

-put pvc to pvc glue all the way around inside of the joint, making sure not to puddle..i would say all areas inside were wet from the glue , but a bit thinner in some spots then others. right away, put the pipe in..made sure it was down to the "stop" and gave it a few twists..let it dry for 15 minutes before running any pressure through the joints.

in hindsight after my white pipe leaks anyway, i'm wondering if i should have put glue on both ends of pipe? sealed the gap around the edge somehow? (with more pvc glue?) i note that the glue they used was not grey it appears as is the stuff i'm using (which is the same the pool guys are using now) and it appears like it filled the gaps all the way around where the pipe goes in on their fittings..mine didn't..should i have used enough to push out the ends?

i applied the pvc glue in proper operating temps.i've tried to seal with exterior waterproof silicone but where they leak,they seem to find another little hole to come through. i did all the pipes with the same method so i'm scratching my head on why it worked most times, but not all the time!

thanks for help in advance!!!!

[Poconos]

First, you should apply glue to both of the mating pieces. Push the joint together and twist some. Usually a 1/4 twist is OK. I twist back and forth a few times. Don't skimp on the glue. Note that for some reason, you push the joint together and before the glue sets the joint seems to want to separate. Keep pressure on it to keep it seated until the glue sets. Usually about one minute should be OK. Schedule-40 is the typical white pipe/fittings. The grey stuff is usually sched-80 but the same glue is used. I used the same glue (Oatey green can) on the S-80 fittings to S-40 pipe for my heater when I had it. The sched-40 pipe and fittings are used for pressure applications and the unions, 90's, etc have about a 1.25" seating depth for the pipe. From what you describe I'm betting you just didn't use enough glue. Hope this helps. At least the stuff is cheap when you goof.
Al

[mas985]

I am not sure about the grey to white but I don't think it is a good idea. Anyway, what I normally do with usual success:

1) Fit all pipes before prime. Priming softens the PVC so you do not want to disturb the pipe after priming.
2) Prime both parts. I found that waiting to glue is not necessary.
3) Glue both parts. I apply glue on the male side first and then the female side but I do not redip the applicator so as not to get a lot of glue on the female piece.
4) Insert pipe but do not turn more than 1/4 turn.
5) Do not stress too much before 15 min. and pressure test after 2 hours.


Good luck

[tenax]

thanks a bunch for the quick reply gents..the common thing seems to be that i didn't put glue on both sides so it sounds like i got lucky on some joints, likely just happened to smear enough for it to work on some..i'll know better next time..as always a great forum and in the short time i've been here..it's become a favorite!

[cygnusecks]

Yes, it's not "glue" it's "solvent" - and you are not gluing PVC together, you are actually *welding* them together. Yes, there's a difference :-) glue is adhesive (e.g. sticks stuff together without penetrating the stuff). PVC cement is actually "melting" the pvc during the join/weld. So it's important to use glue on both pieces, so that the solvent has several seconds to start melting the PVC so that when you push them together both sides are squishy and slightly melted.

[tenax]

well, now that makes a bunch of sense..who knew..oh..you guys did

[Waterworks]

Here is a link to a great video that I train all of my staff with. It goes something like this:
Cut the pipes, debur inside and outside edges, check the fit (male fitting pushing 2/3 of the way into the female is perfect), primer onto female side, primer onto male side, glue onto male side, glue female side and glue male side, push fittings together and 1/4 turn. I just finished a commercial plumb job with 700 connections and didn't have a single leak using this method. You shouldn't have a problem using the grey electrical pipe and the white pool pipe.

http://www.ipscorp.com/weldon/howto.html

Brad
Waterworks Pools