OT: any plumbers around?

[fmradio516]

Soooo I signed up to help my friends mom do some plumbing. Not gonna give the backstory because its long and not important, but one thing let to another and now I need to replace the bathroom sink drain and while im at it, the P trap.

Well whatever the hell plumbers putty they used in the 60s to secure the drain in the sink turned super hard, and even after undoing the drain nut, it wouldnt come out. I had to dig the hard silicone stuff out little by little using a pick, and kept hitting it with a hammer to try to break it free. Eventually had to torch it in order to get it to free up and thats what did it.

Well after some hammering, I noticed something in the back developed a very slow drip. I investigated it and its the connection from the P trap to inside the wall. Low and behold, the cast iron was so rusted that all the hits/twists must of caused it to finally give out.

I need to find a way to connect a new P trap(maybe PVC) to the rear facing drain that goes into the wall.... without using the rotted threads. Are there any neoprene-type adapters w/hose clamps that I can use to mate a new P trap to the rotting cast iron drain?

See pics below. Thanks!

[dgauthier]

It's time to call a real plumber.

[jimcav]

but i successfully tied into old iron drain at our (former) house from the 1920's using a fernco donut fitting. You need to find a good plumbing supply place (here in san diego that is Ferguson). I believe you can also order from them online--you might call them and discuss (not sure if that is 1.5 inch drain)--if the iron is 2" it should be easy to do (I believe that was the drain size I had), if it is 1.5, not sure there is a donut that will work to allow typical sink drain to mate into the donut. If that is the case, then you can use a flexible coupling, which are also made by fernco, and are available in all sorts of sizes. You just need enough straight pipe on the iron side and on the pvc side so the band clamps get a good seal. Should work.
example search:
https://www.ferguson.com/search?q=1-...head-suggested

[RAS72]

Yeah, finish removing the p-trap, cut the threads off (you still have enough stubbed out of the wall), and use either a no-hub coupling or a compression coupling to transition to pvc. Just don't over-tighten.
In plumbing a proper fit is way better than over torqueing.

[Peter P.]

You'll have to cut off the threads before installing a Fernco fitting as the threads will interfere with providing a water tight seal.

Of course, measure the diameter of each mated piece before buying the proper fitting.

Although dguarthier has a wise solution as well because at this point it is beyond homeowner level.

[Hilltopperny]

Originally Posted by RAS72

Yeah, finish removing the p-trap, cut the threads off (you still have enough stubbed out of the wall), and use either a no-hub coupling or a compression coupling to transition to pvc. Just don't over-tighten.
In plumbing a proper fit is way better than over torqueing.

+1 not a plumber, but have done a lot of general contracting over the years. Jimcav has good advice as well.

[rwsaunders]

Images of what others have offered.

https://www.familyhandyman.com/proje...ld-metal-trap/

[Mikej]

That male threaded pipe coming out the wall is galvanized and likely well past its usable life - its rotted from the inside out, as are all of the original drain pipes in galvanized in the house. Since the crack is on the downstream threaded side of the p-trap, if you don't seal it properly you will have a possible sewer gas escape route - you may not ever see a water leak due to the drain not being under pressures, but the circumference can still leak gas above the water flow line. Also, those c-clamp type connectors are not allowed past a wall surface (behind), and most likely not at all to code. They are not a suitable long term fix. The real fix is to take out the threaded pipe behind the wall to the stack, which is most likely beyond your abilities, but can be done - be careful of the cast iron pipe stack. Sorry.

[General69]

I just did a job this weekend. All that galvanized pipe is rotting and probably full of rust. Replace back to cast iron stack. Vents from other locations can remain as seen in this pic of my second floor bathroom.

[mnoble485]

Originally Posted by rwsaunders

Images of what others have offered.

https://www.familyhandyman.com/proje...ld-metal-trap/

Wait, isn’t this why you use a great subcontractor?

Mike

[Tandem Rider]

The waste stub coming out of the wall should be 1 1/2" pipe thread, NPS. If you can unscrew the trap from the stub without breaking it or destroying the threads, you are good to go. Clean up the threads either with a die or a wire brush if they aren't too bad. Get a modern p-trap waste assembly and install it. You may have to use a big half round file to clean out the stub enough to get the waste arm to slip inside. The nuts that the kit comes with are NPS thread. Unlike your old trap, the threads are not what keeps the seal, they enable enough pressure on the gasket to make the seal. A little plumber's grease on the threads goes a long way towards making life better.

If the stub is damaged, you will need to unscrew it out of the sanitary tee on the stack, make a new one out of pvc or abs using a short piece of pipe, a male adapter and a waste adapter to screw into the stack. Inspect the stub carefully, they will sometimes split from torqueing on them and I have seen the threads break away from the rest of the pipe.

Good luck!

[fmradio516]

Originally Posted by Tandem Rider

If the stub is damaged, you will need to unscrew it out of the sanitary tee on the stack, make a new one out of pvc or abs using a short piece of pipe, a male adapter and a waste adapter to screw into the stack. Inspect the stub carefully, they will sometimes split from torqueing on them and I have seen the threads break away from the rest of the pipe.

Good luck!

Thanks, but it you look at the first pic where the stub connects to the p trap, the threads already started crumbling. This has turned into a mess. I dont know what things look like behind the wall, so i dont want to touch the stub. Was hoping to connect something to it as is to convert to a PVC p trap

Moral of the story: Dont offer to help anyone. Ever.

[clyde the point]

Don't hit if it doesn't fit. I guess you've figured that out by now. Good on you for trying, I would turn that over to a pro.

[fmradio516]

Originally Posted by dgauthier

It's time to call a real plumber.

Originally Posted by clyde the point

Don't hit if it doesn't fit. I guess you've figured that out by now. Good on you for trying, I would turn that over to a pro.

Thanks, yeah its not going as well as it could have, but its just a drain pipe, so I should be able to get through it if the local store has the Fernco adapter that people suggested.

A couple years ago, had a water SUPPLY line burst in my basement. Didnt have thousands to hire a plumber, so I wound up fixing it myself by re-doing all the copper plumbing that supplied water to the rest of the house. Wasnt too bad once you learn everything you need to.

[Gsinill]

Timebomb without completely replacing that rotted iron pipe IMHO.