This has been in the back of my mind for some time and thought someone through personal experience might have noticed the nice fit between pex pipe and cpvc and glued it with cpvc glue just because it was all being used at one time.Well i did and it seemed to glue rather well.Someone on the web said it melts the pipe,isn't that the process of welding plastic piping to fittings.I know were suppose to use what the manufacture imply s or else were liable and the fact that their two dissimilar materials. Just wondered if anyone has tested it for a length of time.

you are joining polyethylene (cross linked) to poly-vinyl chloride plastic

? suitable solvent cement ?

your guess is as good as mine, but, why are adapters made ?

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"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

there are lots of proper ways to join those 2 pipes BUT gluing the pex is a NO-NO..

This comment has been removed by Plbg.com staff.

Thank you, staff - it most likely WAS out-of-line.



Edited 2 times.

I'm aware of a bath addition that was plumbed with polybutylene piping and cpvc fittings. It was glued using cpvc glue. It has been in use over 20 years with no leaks yet. It is on a gravity water supply with a pressure of approximately 20 PSI.

quote; Just wondered if anyone has tested it for a length of time.

You are kidding, right? We would NEVER "test it" for ANY length of time. Our insurance company would go ballistic because of the liability when it DID fail. IF it worked it was only because the glue is "packed" in the fitting and pressure has not been able to push it out "yet".

I have seen PVC systems installed without primer last for 20 years, but eventually some of the joints started to come apart.



Edited 2 times.

quote; You are kidding, right? We would NEVER "test it" for ANY length of time.

A test is not to install in a house,testing is undergoing a pressure test in a setting where a valve would shut it off if it blows.
I did write a liability issue would ensue if this was method was practiced. I just found it unusual that the two pieces glued and cant be pulled apart. I had a call last week to repair a small crack in a pex pipe nexto the ring and I cut out the whole foot section from sidewalk to house entry.The last repipe installer created a C loop because both ends were not vertical.I wont accept the ring installation,and the C loop was pointed towards the sidewalk.converting 3/4 pvc to pex in one foot of pipe with a brass shutoff is a challenge.I had a pvc female adapter at the concrete walk so it got me thinking about how nice it would be using a cpvc 3/4 male adapter if pex was easily adaptable. Dont worry I used a 3/4 shark bite male in the shut off and a S Bite 3/4 90 to the building.Had just enough room to make it work in a foot with the brass,pvc,and pex adapters.
Im also a state registered Adjuster but it doesn't keep me from wondering why or what if

quote; testing is undergoing a pressure test in a setting where a valve would shut it off if it blows.

And what would be "any length of time" for a test like this? In the first place, we would not even make the test because WE know the two materials are incompatible for that type of connection.

Quote

I'm aware of a bath addition that was plumbed with polybutylene piping and cpvc fittings. It was glued using cpvc glue. It has been in use over 20 years with no leaks yet. It is on a gravity water supply with a pressure of approximately 20 PSI.

polybutylene is NOT polyethylene

PEX = polyethylene cross linked

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"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

I think he knows that, he was just giving another example of some DIY or handyman, screwed up installation.

Yea we do know they are incompatible,its the ingredients in the glue that makes the chemical reaction and adherence of pipe and couplings.

Nobody would ever "pack" a fitting with glue since you cant even fit a piece of paper between the fusible area of the fitting and pipe in all plastic pipe installations.

I understand your point From an insurance claim angle and performing per manufactures instructions of installation, that's a given in the book of doing the right thing. My intent was to draw information on why the two parts fused ,will it hold water pressure hot and cold, and for how long. Why? I dont like the crimping method, seeing more of pex, repairing or adding on to pex re-pipes, having to use threaded adapters and shark bites. Wondering if research was ever done by manufacturer of gluing pex even if it had to be a special formula.

Note: You may temporarily affix adhesive tape to PEX
tubing or EP fittings during installation. However, to
protect the integrity of the system, the tape should not
be permanent. Remove the tape and residual adhesive
after completing the installation.
--direct from the Uphonor installation instructions
[www.uponorpro.com]

They don't want anything that could compromise the integrity of tubing applied to it, even tape adhesive.

Alexander,

based upon your 'paper will not fit in joint' comment you may be unaware as to exactly why fusion solvent welding works for *VP piping


the fittings are TAPERED forcing the 'melted' (wrong term) plastic together under pressure for about 1/3 of the fitting depth

the real strength is at the BOTTOM of the fitting 'well'

if done 'book perfect' and 'sectioned' for examination this area will be actually seen to have become a solid piece with NO SEAMS WHATSOEVER or visible primer/glue

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"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

quote; Wondering if research was ever done by manufacturer of gluing pex even if it had to be a special formula.

How many times and ways do we have to tell you that NOBODY IS GOING TO DO IT, PERIOD!!!!!!!!!! Only an "@#$%&" would even try and there is absolutely NO WAY to tell how long it would last or when it will fail. IF you insist, go ahead and when it does fail, tell us how long it lasted. IF IT WERE POSSIBLE, they would have started selling the glue decades ago.