Have you ever used this funky style 2" PVC sliding pipe connection

Thanks for being patient with the explanation.

I understand the key point, which is you make a temporary double-ended "slider" out of the repair 5-3/4pipe, where it fits inside the 6" opening, and then, while the glue is still wet, you slide the still-wet couplings (before they have set) out to meet the old pipe on both ends.

This is ingenious!

The only problem I have is with the math on the initial length of the

(I'll take up the length clarification separately.)

Drat. Every once in a while, my newsreader hangs and sends the same message out 3 times! Sorry about that.

Message-ID: Message-ID: Message-ID:

I'm sending this via a different news server.

I know, mine is installed exactly like that and hasn't leaked. I was just pointing out the obvious

I took both apart to visually analyze how they work:

Laying them side by side, the o-ring is in a different position:

Each o-ring seems to be blocking flow slightly differently:

DD_BobK says he knows exactly how they work so I'll let him explain as they seem to work slightly differently, admittedly to my inexperienced eyes (having never even seen the telescopic coupling before).

I love the procedure; I just have a problem with the math, and, since I plan on trying it out, the math matters.

The problem I have is that the coupling seems to have an internal stop at about 1-1/4 inches inward as shown in this photo:

Given that, the repair pipe is extended by the remaining amount on both sides, which is about 1-1/2 inches on each side including the stop itself and a bit of slop (for a total of 3 inches of length extension).

So, given a six-inch opening, if I subtract those extra 3 inches, that would make a repair pipe of about 3 inches.

If I then subtract the 1/4 inch from those 3 inches, I get the following dimensions & procedure for the repair pipe:

1. Cut a 2-3/4" repair pipe
2. The total length including the two couplings would be: 2-3/4" pipe + 1-1/2" coupling + 1-1/2" coupling = 5-3/4"
3. That should easily fit in the 6-inch opening.

a. Prime everything & put glue on everything b. Place the couplings on the pipe ends (all the way) c. Insert the pipe in the opening, and slide the couplings outward

This math, if I work fast, should fix this hole, if I cut out six inches of pipe. Right?

PS: I changed my newsserver because aioe is posting in triplicate.

Good luck with any of that. The glue bond (not totally set) is enough to freeze the piece you slide into position. You can't reslide it anywhere. On top of that a standard union cannot be slid "all the way on".

Perhaps there is a "repair union" that does not have that center ridge preventing sliding it but even then the glue bond prevendts any "sliding" more than inserting the first section on more than the normal length. That glue bond even prevents removing a misfitted joint after more than a few seconds.

Your 'prime glue all fitting then insert won't work. Time you fit one the fitting on the other end has 'glue set" too stick to insert.

Harry K

I suggest you try a 'dry run' of fitting two couplings to a repair section, glueing up both ends and then try putting a sub of pipe on each end. First one will go but if you delay more than a second or two the other one won't got, glue will have set too much already. At least with all the glues I have used. Trying that procedure in the bottom of a hole isn't going to work.

Harry K

Same here. I'll be looking the next time I'm in a good hardware store.

Harry K

That's a good idea!

The PVC "cement" is so very fast, that there are only seconds to spare before it "sets".

I'd guess I have about 10 seconds, maybe even fewer.

OooooooooooooooHhhhhh!

Now I understand *why* trader said to cut the original pipe to

If the coupling did *not* have a center ridge, then the math does work out because you *can* slide the couplings all the way onto the 5-3/4" pipe!

Now I at least understand what trader was suggesting!

Unfortunately, all the couplings I bought have a center ridge, so you *can't* slide the coupling all the way onto the pipe.

But, if I remove 3" from that 5-3/4" pipe, the math *does* work. With 1-1/2" of coupling added to the center 2-3/4" pipe, that center pipe becomes the 5-3/4" trader theorized.

The only problem is that it will take practice and skill to glue everything, and then slide the two couplings onto the

I suspect I have about 10 seconds, and maybe even about half that in warm conditions such as now, so, as Harry wrote, I'll need to practice ahead of time (or eat my mistakes).

Thank you Harry for explaining that because I couldn't figure out what Trader was suggesting (math wise) until you mentioned that a coupler might exist that doesn't have a center ridge.

All mine have a very definite center ridge, which prevents any pipe from going into it past that ridge.

I guess I could file out the center ridge - but it seems easier to just compensate for that center ridge by subtracting roughly two times 1-1/2" from the repair pipe initial length.

Traders kindly suggested solution seems ingenious.

The only problem is *technique* (as that "glue" sets awfully fast)!

PS: They should make all glues this fantastic! (yes, I know it's a 'weld').

Having stared at the two fittings side by side, I'm scratching my head to find the real *value* of the telescopic fitting over the union (other than the installation process is a bit easier):

Telescopic PROS:

- Telescopic makes measuring easier on the installer

- Telescopic slider *may* handle length fluctuations better

- It's slightly lower in height (for space-challenged locations)

- Telescopic doesn't need a "repair pipe" (it only needs a coupling)

Telescopic CONS:

- Telescopic cost about 50% *more* than the union did for me

- Minimum repair is larger with the telescopic than the union

- Telescopic will leak *differently* than does the union (if it leaks)

- Total cost is (far) higher with telescopic than with union

Hi Oren,

That's an interesting suggestion. You're always helpful, and I appreciate that.

Googling, I see this slow set "216 PVC Cement" sets in hours:

It seems that the "gray" cement is the slow setting stuff:

Interestingly, I could have used that thicker cement when doing my oversized couplings over the existing Jandy valves. "This cement is ideal for joining large diameter PVC pipes & fittings where the gap between pipes and fittings is large."

The "cure time" is roughly about 2 hours (give or take); but I wonder what the "setting time" is, as that is more important than the final strength.

That's because the coupling you have is a regular coupling, not a REPAIR coupling. The one you have has those stops for convenience when working with pipe where you have room. The repair coupling has no stops so you can use it for a "repair", per the above procedure.

Given that, you need a repair coupling.

the repair pipe is extended by the remaining amount

You can't make up 3" of missing pipe with couplings.

Yeah, it will fit. I'm not going to do the math, but how much pipe do you then have inside the coupling? Answer: very little, not enough to make a sound PVC connection.

No, per above.

That is the difference. A repair coupling does not have the stops inside. It will slide all the way on.

No, the problem with that is there is so much pipe missing that little if any pipe will be inside the coupling. If you take any coupling, the pipe is designed to go about half way in from each side. With the above method, it won't be in anywhere near that far.

You don't have much time, that's true. Also, you can forget about the suggestion of dry fitting. With PVC unless there is glue, it's nearly impossible to assemble the parts, that is to get the pipe anywhere close to how far into the socket it needs to go.

What I mean is that it might "harden" in, say, 15 seconds, such that it's almost immovable - which is really what matters. Not how long it takes to get to full strength.

As a (longer time) analogy, concrete will set in, oh, I don't know, about a half hour where it's no longer workable - yet it would take much longer to cure to full hardness (which is about a month I think).

So, to me, the time of importance is how long the glue allows movement. I assume it will give us the 30 seconds we need to position everything.

If we get those 30 seconds, then we're fine. I've just never used the stuff - and - I don't see that "setting time" number anywhere.

Hi Trader,

My mistake. I had not even realized that a "repair coupling" even existed.

All I knew was a coupling, and all mine have a center ridge (because they're *not* repair couplings).

So, thanks for letting me know. The math is much easier with a repair coupling. All you do is subtract 1/4" from the length of the opening (as you had said twice). I'm sorry for not getting it until today.

Googling for "Lowes repair coupling", it's funny what came up:

Heh heh... Not *that* thing again! :)

Apparently they're *both* called a "repair coupling"!

Anyway, googling some more, I find this nice diagram showing what you were kindly explaining in words for me:

Thanks for the ideas!

This is true. I've gotten them 'stuck' on a few times dry, and even then, they only go about half way.

It's amazing that they slide fully on once the primer and glue are there.

PVC is an amazing glue system!