Hi all. I have seen bits and pieces to the answer to my question in other posts, but not sure I have the complete answer, so I will ask it directly...

Transitioning from copper to (C)PVC, are compression junctions adequate and/or recommended, or is it advisable to use soldered connections?

Just to clarify (and probably state the obvious) I am talking about the copper end of the junction. I know that the "plastic" end gets glued.

Thanks all in advance,
G-

PaulC

Dependson the application, if it's DWV then just glue a male adapter on to the pvc side and use a female adaptor in copper and tighten them up.

labman

If you are talking about adding a threaded adapter to copper, I would solder I it. I installed a water heat and water softener last summer needing to have to run some new pipe for both. I mostly used CPVC compression unions. They are cheap and easy to work with. They are not 100 % safe from the pipe pulling out. I back them up by wiring the 2 pipes together. I also used a Shark's Tooth tee in one critical spot. $9 for a 3/4'' tee, but the quickest and easiest reliable connection.

speedball1

While solder is the most reliable , compression fittings are the easiest to install for a DYSer. Your choice,( although I recommend solder if you have the tools and experience.) Solder a male threaded adapter on the copper pipe and prime and glue a female threaded adapter on the plastic pipe.
Good luck, Tom

PaulC

Again what is the application, I'm a plumber for 25 years.

Do you know what male and female adaptors are? If it's DWV ( Drain, waste and vent) than follow the directions I gave you the last time, or explain what it is your doing.

solder a small piece of pipe on the adaptor before threading it together.

Paul

speedball1

Welcome to the plumbing page Paul, Paul gave you excellent advice when he advised, "solder a small piece of pipe on the adaptor before threading it together." If you attempt to put heat on a copper adapter after it's threaded in to a PVC fitting the heat will melt the PVC fitting threads. As far as DWV or pressure the drill's the same. You solder a male threaded adapter on the copper pipe and prime and glue a female threaded adapter on the plastic pipe. Good luck, Tom

labman

Thinking about this some more. Again you buy 2 threaded adapters, you are going to have much of the price of a Shark Tooth adapter. Only problem is that a 3/4'' PVC pipe is bigger than a 3/4'' copper and won't fit. Solution? A PVC/CPVC adapter and a short length of CPVC. I used a bunch of them on my projects last summer. Found them at Lowes.

As I said, the Shark Tooth couplers are the easiest way to join 2 pieces of pipe, just push the plain ends of each pipe into it. It can also be easily removed.