Drain pipe 1-1/2" threads rusted bath sink drain---want to rethread--How do I do it?

[surfsalterpath]

.....what a pia! Bathroom redo in a 1960's built house. Of course, the 1-1/2" bath sink drain pipe is cast iron and the pipe sticks out of the wall under the bath sink about 5". The threads have gunked up somewhat and I cannot get either of the 2, pvc/plastic nut to screw on nor a galvanized cap (thinking I could use this to clean up the old threads). Questions ....is HOW to REFRESH the threads on this OLD pipe cleaned up to ACCEPT a new screw on adaptor?? Thanks in advance!!

 

[Gary Swart]

Your best bet is to use a no hub connector. This is not a rubber sleeve with 2 clamps.

 

[Sponsor]

 

[hj]

A plumber would remove the nipple or use a die to rethread it, but, I do not know what your capabilities are or what tools you have to work with. A wire brush wheel in an electric drill may clean them up.

 

[surfsalterpath]

....i heated the pipe then used a wire brush all around the threads and some pb blaster "lube oil" than I filed down and chipped off the corrosion where the threads start. Finally I got the galvanized 1 1/2" threaded cap to start screw on. Could only screw it on a couple of turns and very resistant. What is the best penetrating oil to use the might cut the corrosive material in the remaining threads? I sthere stuff plumbers us called "monkey oil" and how is it sold? Brand name? Thanks guys for the tips. Guess I will try re heating the pipe and wire brushing a little more so I can get a good (non-leaking) bite on that old pipe!

Thanks Gary for the advice on the "no hub connector." That will be my last resort as the pipe is substantial and solid. I'm trying to attach a pvc adaptor on it so there will be no future connection issues and easy to fix in the future. Fingers crossed.

 

[Standardairconditioner]

The whole point of rubber couplers is for situations like this. No need for a no-hub connector, those are mostly for larger diameter mains.

This repair can be completed in 30 mins. How much time have you already spent?

It's not like this repair is going to be buried. You'll be able to keep an eye on it over the years, and I doubt a repair will fail.

 

[Reach4]

I think Gary was suggesting a metal-banded rubber coupler. Click Inbox.

 

[hj]

you do NOT want a PVC adapter/coupling, You want a brass female threaded trap adapter.

 

[Jadnashua]

Female pvc connections tend to split after awhile. As they age, the plastic gets brittle, and the tapered pipe threads are constantly applying pressure. This is why a metal fitting is safer.

Code does NOT allow the all rubber connector to be used except underground where both ends of the pipe can be supported. It is a hack solution. A banded coupling, on the other hand, is code approved, and the metal provides the strength to keep the ends of the pipe aligned.

 

[surfsalterpath]

??what is the brass looking fitting on the end of the supply line valve?

The whole point of rubber couplers is for situations like this. No need for a no-hub connector, those are mostly for larger diameter mains.

This repair can be completed in 30 mins. How much time have you already spent?

It's not like this repair is going to be buried. You'll be able to keep an eye on it over the years, and I doubt a repair will fail.

 

[Standardairconditioner]

I have no idea.

These are just pics that I find with google that I feel best associate with what I may be writing about.

Pics in this forum really help, posters should be encouraged to use pics when possible.

 

[Gary Swart]

No need to follow code? The rubber Fernco is intended to be buried. When not buried, the approved connector is the no-hub type. Sure, the rubber one would work and probably last a life time in this application, but it isn't code approved.

 

[Standardairconditioner]

 

[hj]

Those brass fittings are "Add-a-Tees" to run supply lines to another sink.

 

[Jadnashua]

You can buy lots of plumbing things in the store, but that does not make them code compliant or prudent to use!

 

[Terry]

This nipple was threaded into a copper DWV santee. It's missing a lot of threads.