Drain pipe broke after kitchen sink p-trap


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Old 08-11-09, 02:07 AM
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Drain pipe broke after kitchen sink p-trap

Something fell in my garbage disposal and I couldn't fish it out, so I had to remove the garbage disposal to get it out (turned out, it was a quarter). When I went to unscrew the collar on the end of the P-trap to remove the garbage disposal, the threads to the drain pipe that leads into the wall just crumbled. I'm glad it happened when I was working on it instead of when I was draining the sink, but now I need to fix it.

I've already had the pipes under the bathroom sinks replaced with PVC, but my old plumber has gotten too busy to make service calls to my town any more. I don't think it could be too tough to replace the plumbing with PVC, but I wanted to look into it first and see if there are any "gotchas" that I need to worry about.

Here's what I was planning to do:
1. Saw off the downward bend at the end of the wall pipe, leaving me with a good 4" of straight pipe coming out of the wall
2. Scrub out the metal pipe coming from the wall with a wire brush
3. Get a piece of PVC whose outer diameter is about the same as the inner diameter of the wall pipe
4. Use plumber's cement to install the PVC inside of the metal wall pipe
5. Replace the other couple short pieces of pipe up to the garbage disposal (including the P-trap) with PVC and get the right fittings/collars to hook them all together

Is that all I need to do, or is it more complicated than that? For example, will the smaller inner diameter due to PVC inside of the metal pipe noticeably lower the drain's capacity? Is the rest of the metal pipe coming from the wall likely to corrode all the way through? Should I remove the existing horizontal metal pipe and tap new PVC pipe directly into the vertical drain pipe in the wall? Is there anything else I should be aware of?
 
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Old 08-11-09, 05:26 AM
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Simpler then that. Just cut the old nipple off enough to get to solid pipe, probably just behind the threads, and use a Fernco coupling to connect the trap. Size will probably be 1½" pipe to 1½" tubing. Looks like a piece of hose with a worm gear clamp on either end. One end large enough for the pipe and one end small enough for the P trap.
 
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Old 08-11-09, 03:35 PM
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LOL just don't do #3. Bad idea. Like the other post said use a fernco to convert to pvc and just rebuild the rest.
 
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Old 08-12-09, 05:23 PM
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Hey, that almost sounds TOO easy. Is the fernco considered a permanent fix?

SDplumber: after I wrote #3 I started to wonder if that was a really bad idea.
 
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Old 08-12-09, 05:58 PM
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Yes Ferncos are a permanent fix.
 
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Old 08-12-09, 06:46 PM
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Just make sure the pipe isn't rotted out all the way or likely to do so in the near future.Examine it very well with a flashlight and look for extreme rust build up etc.Cut behind anything that looks iffy.

You don't want to put a fernco on and forget it only to have it crumble further back.The alternative to this fix is replacement of this pipe and you don't want a situation where just rings off if you try to remove it down the road.
 
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Old 08-15-09, 01:15 PM
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I picked up a fernco the other day and went to work, but ran into a snag. The pipe was really corroded, so I had to cut off about an inch or two. There was also a good quarter inch of sludge built up all the way around the inside of the pipe. The remaining pipe isn't as bad as what I cut off, but it's still pretty thin.

I think it will be okay for a while now, but eventually I'm pretty sure I'll have to replace this pipe completely. What's the best way to go about doing that?
 
 

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