How to mate brass valve to plastic pipe

[piikoiCoder]

Short Question:

Where can I find the correct plastic pipe to mate with a 1/2" compression nut on a BrassCraft under sink water cut off valve?

And the little metal insert needed to safely use a compression fitting on plastic pipe … (I don’t know its name?)

It seemed an easy question that I should be able to answer for myself. But I guess it’s such a dumb thing to do no search turns up an answer.

Long Sad Story: (And why it’s not my fault. Some previous licensed, but I guess not professional, stuck me with it.)

The goal was to swap out a dripping under sink valve. The surprise was to find the valve was on the end of a plastic pipe whose other end now disappears into inaccessibility … I hadn’t noticed the contractor who modified the sink cabinet snuck plastic into our originally all-copper pluming.

Complication: Unfortunately the main1/4-Turn cut off valve has always continued to dribble
… not fast, but steadily when off.

Not enough for major repair yet, because it’s never been a problem when swapping out other under sink valves on that line, but …

The leaking valve’s 1/2” compression nut was screwed down on the plastic pipe without the little metal insert, which I discovered meant …

The compression ring gets sunk so deeply into the plastic it can not be removed (and in this case refused to be resealed) so …

With the main line still dribbling
… and no working under sink valve
… I had to cut the pipe to get a clean end which meant …

The new valve’s compression nut is now too far behind the back of the cabinet wall to get the two wrenches needed to compress it enough to seal without snapping the plastic, which meant ...

I had to do emergency surgery on the back cabinet wall, which …

Left me with another compression ring sunk into the now shorter plastic pipe without the little insert which meant …

To seal it without the insert, I had to crank it down so tight it again sunk
the new ring forever into the pipe which means ...

Means I need to eventually cut it off again and then glue an extension on to the old plastic pipe before I can
a) make a proper connection, and
b) repair my surgery on the back wall of the cabinet.

Help would be much appreciated.

Oh ... and no. I can't replace the plastic pipe entirely, because the other end is too far behind a new wall that I'd have to rip open again to get to it.

 

[Chris]

What type of plastic pipe is it?

 

[SHEPLMBR]

Probably cpvc

 

[piikoiCoder]

Hi ShePlmbr,

I believe you are right. (Grin … And based on your picture, I’m not going to argue.)

It feels like regular pvc pipe. However, all I know for sure is it’s hard, white, plastic.

That’s because all I have left showing is maybe 2" … with no markings I can read.

And the more I look the more it is obvious the guy just used a piece of scrap pipe he took from his junk pile. The stub is far too scuffed, and scrapped, and dirtied to have been new when added.

I know how dumb I sound, but here’s the Long Sad Story I hope explains why I’m so stuck:

We live in a high rise condo, and the unit’s entire outside wall is floor to ceiling glass. Not ideal in a WC.

So they added a false solid wall in the WC that’s set back maybe 6 " from the outer glass wall.

And in that 6” space behind the hole in the cabinet, and the window wall, there’s a metal frame.

It’s like aluminum studs, but much cheaper metal. They needed a frame to support all the pipes, because they obviously can’t be hung on brackets screwed into a glass wall. And, of course they ran all the pipe on the other side of that metal framework. Window side I can’t see. Not the WC side I can see.

Therefore, all I can see (without high tech flexible video cable) is about 3 “. That’s from the back side of the sink cabinet wall … to the front side of the metal framework.

And of course, I was dumb enough to not keep the piece I cut off.

My only excuse is I was in a hurry to stop the main line’s continuing dribble. And heck … I just assumed I could get another piece from Home Depot or Lowes later.

For anyone who lacks the pleasure of working with water in a high rise condo, at that point the main line’s dribble was dribbling into the space behind the cabinet’s back wall and the outer wall … so only God would know where it would have gone from there on its way to earth – through the 35 units beneath us – if I didn’t quickly stop it.

But now I discover Home Depot and Lowes has no help.

The valve’s compression nut expects a 1/2" copper input pipe. And when I measured another one, it looks like that means about 11/16” O.D. I guess that’s standard?

But I can’t find plastic pipe with that O.D.

And after reading why plastic would need a metal insert before using a compression nut, I can’t find that either.

I’m doing something very wrong. Just don’t know what it is.

I mean this is should be a simple problem.
Find the pipe. Glue on an extension. Find the little metal sleeve … ferrel? Add the valve. Repair the cabinet.

But I can’t get past the “Find” parts.

Thank you for any advice.
glb

 

[Chris]

What about glueing a male adapter and a threaded valve, or another length of pipe on? I hope it is not regular PVC? I don't know of any interior uses for that. I only work with larger sizes of CPVC that are Grey in color with a yellow stripe but I thought smaller CPVC was not white so you don't get it confused with regular PVC?

 

[phishfood]

You really need to know what kind of pipe it is.

CPVC is a yellow/cream color. It is really stiff, has almost no flex to it.

PEX can be any of lot of different colors, but white, red, and blue are the most common. It is relatively flexible.

Not to be mean, but with 35 floors of units below you, do you really want to be the one financially responsible if something bad happens? I would try to find a REAL professional to come deal with the problem, and let their insurance be responsible.

 

[Mr_David]

Most PVC is bigger in diameter ( 1/2" with an OD of about 7/8") than copper tube unless you have copper tube size pvc which is not very common here. Pex pipe OD is the same as copper tube. 1/2" copper would be 5/8" outside diameter. That would be 10/16" pretty close to 11/16"
Compression type stop valve are normally 5/8" compression. So if you are using a compression on pipe coming from wall it is most like pex you have.

AND you really should not use a brass ferrule/olive on plastic

Can you cut it with a razor/utility knife? then you have pex.
That's why it's soft and crushing with a compression nut.

Try a Sharkbite fitting. Lot of guys here don't like them. I don't use them but I have never run into one that leaked.
You can use copper ( recommend type "L") in one end and pex in the other to extend it out of wall.

 

[piikoiCoder]

Thanks to all for the insight. It helped.

I’ve decided I don’t need the little insert.
I need to eliminate any use of compression fittings till we have another reason to renovate the bathroom and can tear out enough wall to remove all the plastic,

That means I have find a matching plastic fitting I can glue on the end of the current plastic pipe.
So I can transition to a permanent threaded metal fitting.
So in the future I can swap the under sink valves … that never seem to last forever … without such heroic effort and help.

Which means I still need to find out what I have (it is definitely not PEX).

Details in no particular order.

… This is definitely not PEX. I know what that looks and feels like. And no it isn’t easily cut with a blade. I cut it with a standard little copper pipe cutter (a little tool you can clamp on the pipe with a cutting wheel you can tighten down, turn a few times, tighten down bit more, turn, etc. It cut well and cleanly.

(Note also: The pipe is hard enough so I could crank down enough on the nut to reseal the connection … as it was the first time. It’s just that that being plastic the olive gets driven into the plastic. Not enough to clearly see … maybe only a 32nd inch or so. But just enough so it can never be slid off the end again.)

… It also seems definite I don’t have PVC. It just isn’t manufactured with an O.D. that would match the hole of the compression nut on the half inch side of a BrassCraft valve (that’s clearly marked as having a “ 1/2 inch ” input and 3/8th output). Again best I could measure them, the pipe’s O.D. and Compression nut’s I.D. are 11/16ths.

… So maybe all I need to do is search for cpvc instead. I mean someone once made the stuff I now have, because I have it still mated with the original hot water valve and it was mated to the cold water valve I replaced.

… Yes. The idea of sticking the problem with a reputable firm’s insurance sounds great. But as you might expect, that has also occurred to such firms.

So most will not touch any job that is non-standard in a high rise. And if you read the very fine print in the contracts of those that do, it’s more difficult and costly than you would expect to leave it with them if anything goes wrong. Especially in my case, where to getting rid of the entire problem would mean pulling out the false wall for about 6 feet to get back to the next access point in the original plumbing … which I’m not prepared to do. I.e. they’d just be adding to a non-standard installation, not fixing it back to its source. So they are willing to try … but if it goes bad it’s still your problem

… And of course, it was a licensed plumber that left me with the problem in the first place. He was hired by general contractor LLC formed to build the building 18 years ago. Who was hired by the developer LLC, both long since gone. [I mean, aside from this surprise, the building was exceptionally well built … which is why I guess the developer lost his backer’s shirts. I’m sure neither the Developer or General weren’t aware that one of the subs doing the last minute pre-closing modification cut corners. And I’m sure they’d take responsibility … if they still existed. But they don’t.]

Thank you for any help.

 

[Mr_David]

If the pipe is the same size as the copper tube then look for
" FlowGuard Gold " That is copper tube size CPVC

 

[piikoiCoder]

Thanks to all who helped.

-- I have the parts.

-- CPVC does come in off white with a yellow stripe. Which is what I have ... not PEX

-- So I finally found a dusty old 10' 1/2" cpvc pipe at Home Depot (after hunting down an employees till I found one who knew what I was looking for and where they had some. Cpvc is is obviously not a big seller.)

-- And HD had some glue-on couplings that transition from plastic to a threaded brass female connector. Which means valves now are easily removable & replaceable pretty much forever.

-- All that's left is to buy a new valve with a threaded male 1/2" input and 3/8" compression output which seem pretty standardly available.

-- This weekend I'll get pictures of the fittings to post here in case anyone else ends up traveling down this path.

GLB

 

[Chris]

Did you get cpvc glue?

 

[piikoiCoder]

Hi,
Attachment shows the parts it was easy to find once I realized I was looking for 1/2" CPVC pipe.
A coupling that can be glued on the pipe that transitions to treaded metal connector. Then a valve with matching threaded connection.
No more use of compression rings on plastic that can only be removed and replaced by cutting the pipe.
Thank you to all for patience and help.
glb.

 

[WyrTwister]

And to repeat , did you get glue made for CPVC ? Primer ?

I have done PVC but never CPVC .

As long as it does not freeze , I really do not know why you seem to be bothered by the presence of plastic pipe .

Yes , copper is nice , but it does not last forever , either . I had to re-plumb much of the hot & cold piping under the house ( pier & beam ) . I used copper which may or may not have been the wisest move . Many peop;le advised me to use PEX .

Then I had to replace the 3/4" copper line from the alley water meter to the house . I did use 1" PEX for this .

So , each to his / her own . Best of luck .

Wyr
God bless

 

[mrfixitplumbing]

This was a really helpful thread for me. Thanks!

 

[piikoiCoder]

Glad it helped. The string helped others. sure helped me.

And yes. Using primer AND glue was most emphatically stressed by Home Depot guy.

As for the problem with plastic it is that compression fittings sink the little olive so deeply into them it can't be removed. So pipe is fine ... unless and until some day when you replace a valve and the #!&%@# thing will not reseal as mine didn't when I replaced the valve ... had to cut the pipe ... that shortened the stub sticking out of the back of the cabinet ... that required cutting a hole in back of cabinet ... and so forth as I whined about in detail above.

Many thanks