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michael76 03-09-2008 02:06 PM

Backing off OLD galvanizd pipe...& PVC to cast iron
This is what happens when you decide to make the extra effort and paint a closet. you find things...

Our 2nd-floor tub drains into 2" galvanized (I think) pipe, which connects to a 4" cast iron stack. Where they were once threaded together has completely corroded away...due to electrolysis I was told. So far, I have opened up the wall and, with limited access, cut out part of the 2" galvinized pipe. The plan is to remove the section of 2" pipe back to its next threaded end (accessible) and then replace from the remaining 2" pipe (horizontal) to the cast-iron stack (vertical) with PVC.

- I cannot back off the remaining 2" pipe out of the female end it is in. These are old pipes, obviously...Any advice on how to get these apart? I have tried heat and muscling it with a 14" pipe wrench? Or is it better to not break the bond and tie the PVC into the existing pipe with some kind of no-hub coupling?

- The female receptor (for lack of a better word) on the cast-iron stack looks pretty messy, and I'm not confident that the PVC with tread in all that well, if at all. Has electroylsis eaten the iron too? Can I still work with this and somehow complete the bond between the 2 materials with an epoxy or something (a JB Weld type of thing)?

Thanks for any info/advice,

michael76 03-09-2008 02:22 PM

Update: PVC does not fit in cast iron
Portions of the old, correded pipe are firmly stuck in the threads of the cast there a way to reduce PVC fittings to get in there, then complete the bond with application after install (like the JB Weld I mentioned in the first post)?

Thanks again,

Jack A. Trades 03-09-2008 04:41 PM

I am not a plumber.
But, if I needed that done in one of my houses, I would use a rubber coupler with hose clamps to make the connections.
I have no clue if that is up to code in your area, but it seems to make a good, leak-free repair.

Marlin 03-09-2008 06:51 PM

A picture would be nice. From what I can gather you should cut the galvanized 2" short of the cast iron hub. Use that 2" to transition to PVC with a no hub clamp. Cut as much of the galvanized out as possible. If you can't get it all out use a no hub clamp on the other end as well to transition to PVC. Use banded no hub clamps, they will have a solid metal band all the way around them. Do not use the type with two hose clamps.
It is possible the hub is damaged or that you damaged the lead joint by applying heat and torque to the soil adapter. Their is no way for us to tell without looking at it though.

Old galv. pipe almost never backs out, when it does it usually takes a combination of 24" or larger pipe wrenches, heat, a hammer, and a good bit of luck.

michael76 03-09-2008 08:09 PM

Pictures of pipe
2 Attachment(s)
here are some pics...i did this quick and hope you can see everything (some copper pipes are in the way.

thanks again,

justdon 03-09-2008 08:22 PM

I would tear out enough wall or whatever it takes to get the whole chunk of galvinized out of there,,,its just the first sx of total failure,,,try taking the lead joint off the cast stack and Ferco doughnut it to the plastic and run plastic all the way,,,it is probably lost its drain from hair,rust and soap scum inside anyway!! Replace the trap with a plastic one also,,,they dont rust thru!!

Might as well take any metal tailpeices off the tub while your at it,,,plastic dont rust thru,metal does,,,OR you will be back tearing this apart NEXT year,,,or sooner!! While your at it you may as well somehow make a plumbing access in this closet for this whole thing!! Paneling,plywood,or similiar with removable screws is nice.

Ron The Plumber 03-09-2008 08:25 PM

1 Attachment(s)
I posted the picture for you.

What you need to do is remove the existing pipe that is inside that cast hub, it will be leaded in, hammer, screw drivers, anything you can use to dig the stuff out with, it will come out of there, then go to a supply house and ask for a 2" tight seal, a rubber seal that will allow you to insert abs or pvc pipe into that existing hub, giving it a water tight seal, then use a fernco coupling to reconnect back onto the galvi pipe you see to the left.

You may have to open wall up more to be able to work in that area.

USP45 03-09-2008 08:38 PM

Ron, are you referring to the same type of gasket that is used in cast iron floor drains? If so may I suggest that he bevel the edge of the PVC first, then rub some "Duck Grease" on the gasket to make the pipe slip in easier? This is what we do when inserting PVC into those cast iron floor drains with those rubber gaskets, otherwise we kill ourselves trying to get it in.

Ron The Plumber 03-09-2008 08:44 PM


Originally Posted by USP45 (Post 105970)
Ron, are you referring to the same type of gasket that is used in cast iron floor drains? If so may I suggest that he bevel the edge of the PVC first, then rub some "Duck Grease" on the gasket to make the pipe slip in easier? This is what we do when inserting PVC into those cast iron floor drains with those rubber gaskets, otherwise we kill ourselves trying to get it in.

Yes thats what I'm talking about, I'll slap some pipe dope on the pipe so it will slip in easy. I was trying to find a picture on the net, but not sure of the name, we call them tight seals.

It has tapered ribs inside the seal.

USP45 03-09-2008 08:48 PM

Thats what I thought. I can not remember what we call them and what I want to call them I can not say here!
Also if you use a twisting motion will help set the pipe too.
Have you ever had to do that with 4" pipe? talk about a bad hair day!

Ron The Plumber 03-09-2008 08:54 PM

I had to with 3" came down to a block of wood and a sledge hammer to get it seated, that sucked big time.

Double A 03-10-2008 12:09 PM

Know as a Ty Seal. Not sure of the proper generic name.

But, I'm afraid that is a threaded tee, and not a bell fitting.

I think that tee will need to be cut out, or the old male pipe threads cut out and the female threads chased with a 2" die. That is going to run you $120.00 - $150.00 to buy if you can't rent one, not to mention trying to get it started straight so it follows the old threads.

Marlin 03-10-2008 03:54 PM

Double A is right. That isn't a hub on that tee so a dual tight will not work. The best thing to do is get that tee out of there and put a PVC tee in it's place.

Another idea I have, wait for another opinon on this one though. A 4" x 2" no hub clamp may fit on the outside of the fitting though. Measure the outside diameter of the tee then ask to see a 4" x 2" cast iron no hub clamp and a 4" copper by 2" cast iron clamp. If they don't have a 4" x 2" adapting clamp ask to see a 4" copper by 4" or 3" (preferably) clamp. The copper clamp will be tighter than the cast one and may fit better.
If the copper one is the better fitting one and they don't have a 4" CU x 2" CI use whichever one they did have with a short piece of 3" or 4" PVC then a PVC reducing coupling to get you down to 2".
Cut everything off flush with the cast iron hub and clean it up well. Then smear a thin coat of silicone on the face of the tee and apply a bit to the bottom of the 4" side of the no hub clamp, you don't need to do the sides or the 2" side.
Go with whichever one is closer. You can stretch the clamps out a little bit if need be, better to be a little tight then really loose.

A 4" x 2" fernco will defiantly work to get you back in business temporarily if you have no shower at this point. The fernco is not a perminant solution, it will cause clogs and cause the cast iron to rot over time.

4just1don 02-17-2009 11:18 PM

whats on top of this tee yet?? and whats below it? feet? fittings? IF there is ANY way you can get the whole mess outta there and redo with plastic,,,you will be so much happier down the road,,once these start its only a matter of time for another to sprout a leak!! Replacing a few wall sections of drywall or patching what needs to be,is a far less evil that that alligator waiting to bite you in the butt AGAIN!! Otherwise take out from tee up at least.

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