[Dan1973]

I plan on gutting my 1961 bathroom this spring. The vanity drain pipes in the wall are galvanized and obviously I will be replacing with PVC. It connects to cast iron that is in good condition.

I have a choice as to how to handle this and wonder which is the better way:

Option A is to cut the galvanized where indicated in the picture and use a shielded coupler to connect new PVC to the that last little bit of galvanized. Downside to this option is it still leaves some galvanized pipe and it would be better to have it gone.

Option B is to attempt to unscrew the galvanized from the CI, then use a PVC male threaded adapter screwed into the CI. This gets rid of all CI, but I'm a little nervous about attempting to unscrew the existing pipe from the CI. Not sure how difficult it will be. I don't have a pipe wrench but will borrow or buy one. Main thing I'm worried about is damaging the threads making it difficult or impossible to screw in the PVC male threaded piece.

This is a double vanity so there are 2 places where I need to do this but both are the same issue. I do have plenty of room to work as all the plumbing is exposed in the basement.

 

[TarheelTerp]

Option B is to attempt to unscrew the galvanized from the CI...

Hire it out if you're this unsure about things.

 

[Dan1973]

Of course hiring it out is an option, but since this is a DIY forum...

 

[mark sr]

I'd cut the galvanized pipe closer to the middle and then work at unscrewing it at the coupler [either side]

 

[huesmann]

If it's me I'm pressing the easy button and cutting the galvanized, connecting the PVC to galvanized with a Fernco coupler.

You say you're replacing the galvanized with PVC in the wall—how will you be accessing that? Will you be cutting the wall?

 

[rjniles]

I would try to unscrew the galvy from the cast.
Use plenty of penetrating oil for a few hours. If the elbow unscrews from the nipple, install a PVC female adapter to start the transition.

Sent from my Moto E (4) Plus using Tapatalk

 

[SeniorSitizen]

I'm a little nervous about attempting to unscrew the existing pipe from the CI. Not sure how difficult it will be. I don't have a pipe wrench but will borrow or buy one. Main thing I'm worried about is damaging the threads making it difficult or impossible to screw in the PVC male threaded piece.

A little nervous about attempting that pipe in the position it's in and you should be. I learned a inexpensive valuable lesson with PVC female screw fittings years ago and avoid those like the plague, unless they are specifically reinforced for threaded application. Do a shielded coupling.

 

[Dan1973]

I hear ya, but I'm talking about male threaded PVC, not female. I understand that using female threaded PVC has the potential to be split by the metal.


*edit - I jumped the gun and see you were replying to the suggestion to use female PVC. I will not be doing that.

 

[Dan1973]

You say you're replacing the galvanized with PVC in the wall—how will you be accessing that? Will you be cutting the wall?

I'm completely removing the existing vanity and at that time will have access to open up the wall. New vanity drains may need to be in a specific position (it's a floating vanity with drawers not cabinet so there is not as much wiggle room for where the drain can be) so I have to open the wall anyway and will run new PVC at that time.

 

[SeniorSitizen]

I can say with certainty you aren't going to like plan B. The only way i would attempt that, with it being up near the floor joist, is if everyone of those screw connections were assembled with Teflon tape. And they weren't because it appears that job was done before TT tape was invented.

 

[Dan1973]

If I were to attempt Plan B, I would first cut the galvanized off and only try to unscrew the last bit that is threaded into the CI.


I'm definitely leaning toward option A and making sure I put a cleanout to make it easier to keep the last little bit of galv clear in the future.

 

[SeniorSitizen]

If I were to attempt Plan B, I would first cut the galvanized off and only try to unscrew the last bit that is threaded into the CI.

To attempt that i guarantee you will egg the nipple. To prevent egging with a pipe wrench is to leave the 45 ell on, OR force a socket wrench into the nipple tight OR if space allows use an internal pipe wrench, OMGAWD. Another option is to split the nipple with a saw blade and peel it out, but like previously mentioned you won't like the position ( angle to do that ).


If you can get that short nipple out of the cast, then by all means replace it ALL with PVC.


EDIT: EDIT:

 

[TheEplumber]

To attempt that i guarantee you will egg the nipple. To prevent egging with a pipe wrench is to leave the 45 ell on, OR force a socket wrench into the nipple tight OR if space allows use an internal pipe wrench, OMGAWD. Another option is to split the nipple with a saw blade and peel it out, but like previously mentioned you won't like the position ( angle to do that ).


If you can get that short nipple out of the cast, then by all means replace it ALL with PVC.


EDIT: EDIT:

Spot on and I'd go with this.
Your nipple may be super thin from interior rust. Who's to say it won't rust through next year or develope a hole when you cable through that new cleanout.... Then you will be replacing it for sure

 

[SeniorSitizen]

Your nipple may be super thin from interior rust.

I could never be that lucky so it could just be peeled out.:smile:

 

[Dan1973]

I once went to a bar called The Rusty Nipple.

 

[SeniorSitizen]

I once went to a bar called The Rusty Nipple.

Ours is the Galvanized Palace. :vs_laugh:

 

[Dan1973]

I heard you could get your nipple egged there.

 

[Biscuits]

That galvanized drain pipe most likely has another 50 years of life left in it.

If it's location is not moving, I would not mess with it.

 

[Dan1973]

My understanding is that galvanized has a 50-70 year lifespan. Other drains in the house that have already been replaced prove this out. These drains are coming up on 60 years old. I'm leaving the CI, though, as that is still good.

 

[Ghostmaker]

Unscrew it out of the cast that way you are not leaving a future failure.