Best Way to Couple PVC Pipe to Plastic P-trap?

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SteveHGraham
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Best Way to Couple PVC Pipe to Plastic P-trap?

Post by SteveHGraham »

The jobs just keep coming.

Today I found water under my bathroom sink. It taught me that it's a smart idea to store toilet paper there, because instead of standing on the wood and ruining it, the paper soaked it up. You never know what you're going to learn.

Anyway, the pipes down there are plastic. There is a 1 1/4" PVC pipe coming out of the wall horizontally, and it goes into a flexible coupling (rubber with two hose clamps) which goes to a plastic P-trap.

The main leak was from the top of the P-trap, and I think I fixed that by tightening it, but there is some corrosion by the flexible coupling, so I want to fix that, too. Obviously, a little water has escaped there in the past. It may have happened while I was plunging the sink, so maybe it will never be a problem during ordinary use, but I want to fix it anyway.

What's the best way to join the P-trap to the horizontal PVC?

I am thinking I may just remove the flexible coupling, paint the inside generously with plumber's grease, and reinstall it.

I don't know a whole lot about these couplings, but it seems like installing one dry would be a bad idea, because it would resist going onto the pipe, and it might get abraded. It might not seal as well without some kind of lube. Therefore, I thought grease or pipe dope might be helpful.

Comments? Suggestions? Non sequiturs? Abuse?
Every hard-fried egg began life sunny-side up.
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warmstrong1955
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Re: Best Way to Couple PVC Pipe to Plastic P-trap?

Post by warmstrong1955 »

I've never used a flexible coupling. Sounds like a cheater.....usually means it's easy, but maybe not so reliable.
I just measure things up, and buy what I need.
I do use the adjustable traps, which takes care of the vertical most of the time. Never had a problem with any of them. They are inexpensive by the way....like 8 bucks.

I use glue on PVC to get the outlet pipes where they need to be to fit the trap.
For the thread on trap, I assemble dry. Just keep it clean.

I assume you have rust on the sink basket?
Also cheap. 15-25 bucks will get you a good stainless steel one.

Bill
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hammermill
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Re: Best Way to Couple PVC Pipe to Plastic P-trap?

Post by hammermill »

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SteveHGraham
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Re: Best Way to Couple PVC Pipe to Plastic P-trap?

Post by SteveHGraham »

That flex coupling looks more or less like the one the contractor put on the sink.

The pipe that goes to the trap is like this one; maybe longer:

http://www.homedepot.com/p/Everbilt-1-1 ... /205153709

The leak is at the top.

I am not in love with this flimsy stuff. Seems like sink disasters are bound to come eventually.

The sink doesn't have a basket. It's just a regular old bathroom sink with a stopper on a lever.

I read that pipe dope eats rubber, so I guess that idea is out. I do like the grease idea.

Plumber's grease is sold in tiny tubes. I'm thinking I should go to the drugstore and get a big tube of K-Y instead. Same thing, probably, and it would give the clerks something to talk about.
Every hard-fried egg began life sunny-side up.
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warmstrong1955
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Re: Best Way to Couple PVC Pipe to Plastic P-trap?

Post by warmstrong1955 »

You can buy the heavy duty stuff. It just costs more.
Pics are of the kitchen sink when we remodeled a few years ago.
ABS, one PVC tee.
Again, I used no grease on any of the connections. Never have.
I guess if it's compatible with whatever material of trap & pipe you get, it doesn't matter, so long as it doesn't cause you to over-tighten something. It's just unnecessary.
100_1349.jpg
100_1351.jpg
I used the flimsy cheap stuff, like you sent a link to, when I put a sink in my shop. Still working fine. That was 8 years ago.

Bill
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Russ Hanscom
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Re: Best Way to Couple PVC Pipe to Plastic P-trap?

Post by Russ Hanscom »

Years ago there was a comic strip called Little Abner? One of the characters was a downtrodden fellow with a name like Bxrhvwzjg (all constanants) who always had a little black cloud hanging over his head.

Any relation of yours?
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warmstrong1955
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Re: Best Way to Couple PVC Pipe to Plastic P-trap?

Post by warmstrong1955 »

Steve Graham......or Joe Btfsplk?
Joe Btfsplk.jpg
:)
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TomB
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Re: Best Way to Couple PVC Pipe to Plastic P-trap?

Post by TomB »

30 or 40 years ago they use to sell both PVC and ABS pipe and fittings. The black stuff was ABS and it required a different glue. Your's may be PVS that is colored black but I doubt it as getting PVC that black would likely require a lot of colorant.

Having water leak from the top of a trap indicates the drain pipes downstream of the trap are not flowing correctly. I would have a knowledgeable septic system contractor check the system. If you are on a septic tank you may be getting into a problem.

Tom
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SteveHGraham
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Re: Best Way to Couple PVC Pipe to Plastic P-trap?

Post by SteveHGraham »

I got it fixed. It's all polypropylene.

The contractor did a number of things wrong. Not surprising. This is a person I would put high on the list for involuntary sterilization. If you want to ruin someone's home, let me know, and I'll provide his contact information.

He didn't install the flexible coupling all that well. I took it out, cleaned it up, and reinstalled it. I should have gotten a new one, but I didn't realize they could get crusty. The old one had scale on it, and chemicals wouldn't touch it. I ended up sticking it on my drill chuck, inside-out, and using the drill to turn it while I sanded the crap off. It will do for now.

The polypropylene fittings were not installed all that well. I cleaned everything up and put it back in. I sanded some burrs off the parts that are supposed to mate up smoothly.

When I got it all put together, there was a leak at the bottom of the metal pipe that attaches directly to the drain. The contractor left it one turn too loose! I put dope on it and tightened it one more turn, and now it doesn't leak.

I am happy about the plumber's grease. It made things turn and slide past each other without binding or making me crazy. I don't think I overtightened anything.

The drain is still a little slow. I snaked it out, but it needs work. The contractor installed the toilet, shower, and sink with pretty much no slope on the pipes leading to the drain pipe, so eventually I'm going to have to pay a real plumber serious money to take all that out and do it right.

The stories I could tell you about that contractor. He painted my windows shut.
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rudd
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Re: Best Way to Couple PVC Pipe to Plastic P-trap?

Post by rudd »

Painting windows shut is SOP around here.
I had a dickens of a time with the tail of the trap getting unsealed from the pipe going into the wall in the house I am in now, I bought it as a forclosure, the bank had had some real jacklegs come through and "spiff the place up" - i.e., they installed a new gas heat air handler, and just moved the vent from the gas water heater to the furnace, so the water heater could vent directly into the living space. :shock:
They replaced the countertops and used too deep of a sink, which caused the problem with the tailpiece on the trap. And the original sewer line from the sink is pretty low slope, less than the 1/8" per foot recommended minimum.
So when I got the plunger after the clogged up sink, well, it drained, right into the cabinet. And then it did it again un-aided. And again.
One of those rubber Fernco connectors and a bit of "customization" on the end of the P trap put an end to it. That and getting under the house, finding the cleanout for the kitchen line and rodding that nasty thing out.

Just for general knowledge, civil engineers use Fernco couplers to connect downspouts to the soil lines on big time commercial and institutional buildings. The bands are stainless, should last a long long time even buried in the earth.
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neanderman
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Re: Best Way to Couple PVC Pipe to Plastic P-trap?

Post by neanderman »

I've never had to use any grease or putty or anything connecting p-traps. Either the rubber or tapered plastic gaskets are all I've ever needed. I do like the threaded rings with the 'wings' on them -- they are a lot easier to get a good grip on to tighten them (which I've never had to use a wrench for). The telescoping fittings are nice provided you don't cut them too short.
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TRX
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Re: Best Way to Couple PVC Pipe to Plastic P-trap?

Post by TRX »

I recently put all new drain piping in and under my house. Local code permits rubber couplers, and I used them liberally, planning ahead for the possibility of future repair.

As an example, the bathtub drain to the main stack was about five feet; I have a rubber coupler at each end. And I also welded up a couple of nice steel supports to hold the pipe up. If the pipe ever needs to come out, like to replace the bathtub, just unscrew the stainless clamps and slide it off. Well, probably pry, curse, and eventually cut the rubber couplers with a knife, but it *will* come off...
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