PEX 101

dbsoccer

My main water line decided to spring a leak - after close to 40 years so I'm luckier than my neighbors. Mine was soft copper so I was surprised. Anyway…….on to today's question.

With my new line I have a copper-PEX adaptor in straight line with the path of the new PEX water line. I'm using Uponor PEX with expander fittings. I only have two connections to make so it should be easy. I have an expander tool.

The demos I've watched using the expander tool, etc show a plumber using a straight piece of PEX, in free space, and pushing it onto the fittings (after expansion) without any obstructions, turns or twists. The PEX I got came in a roll meaning the material is not straight. I'm concerned that by not being straight I could end up with a less than ideal joint. Is there an acceptable way to straighten about a foot of the end of the PEX so I'll be pushing a straight piece of PEX onto the fitting thus eliminating the joint to get twisted or torqued before the seal is made? My experience with PEX is zero but I'm trying to avoid getting a bad joint and having to start over.

Larry Weingarten

Hi, I'd start here. A straight cut, properly expanded and then pushed fully onto the fitting is what works. Hold it snugly in place without moving, for roughly thirty seconds to be sure. https://www.uponor.com/getmedia/b88822e9-e713-432b-a495-d54bab71a37c/uponor-piping-installation-guide.pdf?sitename=USA

Yours, Larry

hot_rod

This is not for an underground water line, is it?

You can straighten pex by warming it with a blow dryer or heat gun.

In fact with "A"pex that is how you remove a kink.

dbsoccer

No it's not under ground. Thanks for both bits of feedback.

mattmia2

Make sure it can move as it expands and contracts like not completely constrained at a corner or something like that. I uncoiled it around a couple things in my yard and let it sit in the sun for a couple hours to help straighten it.

dbsoccer

I got this 60+ feet of 3/4 pulled through the soffits and framing of my house yesterday. Took about 2 hours. I had access holes cut in the dry wall at key spots/corners but ended up cutting a couple of more. I had one helper, an 86 year old ex-gymnast from the gym I go to every morning. I has expecting more help but they didn't show up. We did fine and it went along better than I thought.

I bought an extra fitting or two and some extra collars just to practice. I didn't want my first PEX connection to be on the expensive pipe I'd just spent two hour pulling through the walls. Everyone said it was easy. A Youtube by the folks at Supply House was very good. And it was easy. I used a heat gun and my wife's hair drying to relax the tube in a couple of places and I feel that worked well.

Bottom line is we are back in business with our own water line. Thank to all for your support. PEX is easy but I still like copper. I'm old, however. It would have been a major project to make this run in copper, I can see that so I appreciate the new technology.

mattmia2

You can expand the tube and jam it on a fitting back in some dark corner you can barely reach. You can't solder something in a situation like that. You have to work out something with a subassembly you jam in and connect to someplace more accessible or use a union or threaded adapters or something.

There are bend braces that snap over the tube that can hold it at a 90 degree bend.

psb75

I can usually straighten a given length of pex pipe just by manually flexing the pipe by "back-bending" a curved section a few times. Its easier in warmer temps of course.