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PEX to Copper fittings

I blew out a threaded 3/4 valve connecting my water tank to the house plumbing (it was something like 20 years old, in an unheated crawlspace in upstate New York). I used it to shut water off to the building when the house was not in use in order to drain the pipes.

While trying to replace the copper valve, I managed to undo a solder joint about five feet away from the valve. So now I'm sitting with a bunch of loose copper pipe, and no water in the house.

Plumbers are not easy to come by in this area. The nearest one is 30 miles away.

Rather than go thru the exercise of learning how to solder and then trying to figure out how to seat the valve, this is what I'm thinking I might do: run PEX from the solder joint to the copper valve, and fit the PEX into the valve.

Question: what would I need to connect the PEX to the 1/2 copper solder joint and the 3/4" threaded valve? I remember Rich did a segment on connecting PEX to copper on ATOH a while ago, and I think I see the video on the site, but I want to make sure I have the right fittings.

Re: PEX to Copper fittings

You're still gonna need to solder. You need to solder a fitting that has the female sweat on one side with the PEX nipple on the other that you will crimp the PEX tubing to.
Same onto a valve unless you buy a valve that is a PEX valve and has the nipple on it already you can crimp the PEX to.


If you really don't wanna sweat anything you can always spend a few more bucks and buy all compression fittings and forget about the PEX.

Re: PEX to Copper fittings

There are approved plumbing fittings that fit copper, pex, and CPVC so you do not have to solder. These fittings have a variety of options to get you to most any fitting that you need. They can be put on and off by holding the retaining ring. Also there is a chemical compound (also approved) that bonds copper in the absence of air. Clean the pieces as if you want to solder, apply the compound (its liquid) and put the pieces together. Before you can blink you will not be able to pull them apart. This also works when you have a slow leak and cannot get the get the heat up to soldering temperature. These fittings and the chemical compound (2 sizes) can be purchased at many hardware stores.

Re: PEX to Copper fittings


Shark Bite fittings will do what you are asking....
See the above link. I believe they are now available in the local big box.

Re: PEX to Copper fittings

I may be old-fashioned but soldering copper tubing still has many benefits and is a rather simple process to learn.

The fittings and components needed are low-cost & an excellent seal is obtained.

Copper sweat fittings, in particular, remain much lower in cost than the alternatives for this application.

A quick cleaning of the surface of the tubing to be soldered with fine sandpaper or emery cloth, application of a thin coat of flux paste and a small propane torch with lead-free solder, then a wipe with a cotton cloth is all it takes to get the job done.

All of these items can be bought at the big box stores for $30 or less.

Be careful where you point the propane torch flame; remove any flammable items from the immediate work location; it won't hurt to have a small fire extinguisher at your side.

Try to find sites that have pictures of how to solder tubing; books at the local library tend to have this in the 643.7 numbering section.

Google such phrases as "tips on soldering", "soldering copper tubing", "soldering tips", etc. (google these phrases with and without the quotes).


Re: PEX to Copper fittings

Thanks, all.

I guess it looks like either Shark Bites or some other form of compression fitting.

Jack, the only reason I'm hesitant to go back to copper pipe is the configuration of this particular section of plumbing: the solder joint is about a quarter inch from a joist and butt up against the fibreglass insulation (another topic for another day), plus it's not a straight run to the valve, but is actually offset by about six inches to get around a PVC drain pipe.

You can imagine why I'd want to use PEX in this instance and avoid soldering. It is doable (there hasn't been water in the pipe for something like six months now), but if that's the only solution, I'd rather call a pro.

Which is itself a bit of a hang up. If I'm calling to call a pro, I might as well have them come redo the entire plumbing system, and at least make it worth their while.

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