how to seal copper to PVC threaded joints?

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Old 07-06-09, 09:20 PM
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how to seal copper to PVC threaded joints?

I am putting in new pool pump. the pump is plastic-not sure what kind, but it does say to use teflon tape. The plumbing is all 2". so I used regular white teflon tape on the male PVC adapters with two full wraps at end then continued wrapping down the threads so probably has 3-4 wraps near end and everyplace else has at least 2 wraps. the discharge will be short run then into the brass valve. it already has a piece of copper pipe on it that was attached to the old pump. I cut the copper and need to go from this to the PVC. I plan to sweat a 2" male adapter onto this copper pipe, then thread this into a female PVC adapter that has slip joint on other side. I ran out of teflon tape and while at store, I noticed that the white and pink tape both said only for use up to 1 1/2" pipe. Not sure what I was to use? I did buy some rectorseal 5 that does say can be used to 2" (says that for 2" and under at less than 100psi can be used immediately) I did note the other thread on leaking brass/copper joint. should I use the locktite? Once this is together, if it leaks, I am screwed and will have to take it all apart and throw away pieces and start over as I don't have room to work.

another thing-any advice on sweating 2" pipe? I have done some 1/2" before, but I am not great at it. I eventually get the job done but would really like to get it on first try since failure means throw out several pvc fittings and plex flex pvc pipe. this adds up in cost.
 
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Old 07-08-09, 08:29 PM
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I'll let someone else comment about the rectorseal versus teflon tape... though in my experience, rectorseal works well for 1.5" PVC to Copper.

As for the worry about taking apart the system, I would seriously consider installing a union, either on the PVC or the copper side. This will allow you to pull out a section and replace it if needed... in case you mess something up, or if something breaks down the road.
 
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Old 07-09-09, 09:50 AM
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If I were you, I would prefer sweating a female copper joint and a male threaded PVC. Perhaps an irrational fear, but seems to me it is better if the female is made out of the stronger material. It seems to me a female PVC would be more prone to cracking over time than a male PVC.
 
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Old 07-09-09, 11:46 AM
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I do intend to put in a union when I get a chance to dig out an area and put the pump in its final place. but this is temporary. If I put in a union, I will not be able to reuse it since there is not enough room to cut it out and then glue it onto another piece.

I could be wrong, but I think I read somewhere in pool plumbing website that if you have copper/PVC joint, you want the male side to be copper?
 
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Old 07-10-09, 03:45 PM
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Copper To Pvc

(ThomasE) Is right, it is better to use a female copper adapter and a male pvc adapter to prevent splitting the pvc.
 
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Old 07-10-09, 08:00 PM
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too late now. I soldered the joint, used rectorseal Tplus2 on the copper threads, and put it together. started up pump and it didn't leak. got it on first try! I did have a very minute leak at the pump outlet (a pvc male adapter screwed into the plastic pump. after about 8 hours it seems to have sealed as I don't see any more water there. I will have to remember the male/female, pvc/copper thing when I redo the plumbing after I get some excavating done and am able to move everything to its final location.
 
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Old 07-11-09, 07:30 AM
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I want to add one small point to the thread.The OP used the term "locktite" in the original post.Locktite is not a plumbing thread sealant.Locktite is a "threadlocker" for bolts etc. and is designed to keep those types of items held together so that vibration etc does not loosen a nut on a bolt etc.It is a series of products but all are designed for that purpose.If you go in a store and ask for locktite you will not be given a sealant for plumbing use.
 
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