Cast Iron Drain Pipe

[AlanB]

I am doing an old bathroom. Have to remove the toiled flange and first length of pipe. It is old cast iron.

I do not see any threads etc, just looks like a wax seal of sorts between the pipes. How do I seperate them?

 

[gordon21]

It is most likely a lead seal. Many years ago the joints were sealed with molten lead. The flange was laid over the pipe and molten lead poured between them to create a seal. It is not wax. There might be a film of toilet wax ring coating the lead. Dig down and scrape. You will probably find the lead under the wax.

The modern day fix for this situation is to drop in a specialty 3" plastic self tightening toilet flange into the cast iron pipe which is probably about 4" OD. The special plastic fitting drops into the pipe and it expands to tighten and lock itself in place aagainst the inside of the cast iron pipe.

If you are really really lucky and can find an old time hardware store, you might be able to find another ring designed to work with the cast pipe. You could then reseal it. The replacement would be brass.

 

[California]

Mom had a similar replacement done in her old (1920s) house last week. Some leaded joints were rusting through and leaking.

The plumber cut the 4" cast iron pipe a few feet beyond the project area. He used modern 4" plastic sewer pipe to build a new assembly with the flange at the top then a basin line and the vent coming in a few inches lower down the vertical run. Then an elbow and another couple feet of 4" plastic going horizontally. The whole thing was then spliced to the remaining cast iron using a 'no-hub coupler' which is a rubber sleeve inside a sheet metal sleeve, with screw clamps.

If I were doing this project, that's how I would do it.

 

[CurlyDave]

The plumber cut the 4" cast iron pipe a few feet beyond the project area. He used modern 4" plastic sewer pipe to build a new assembly with the flange at the top then a basin line and the vent coming in a few inches lower down the vertical run. Then an elbow and another couple feet of 4" plastic going horizontally. The whole thing was then spliced to the remaining cast iron using a 'no-hub coupler' which is a rubber sleeve inside a sheet metal sleeve, with screw clamps.

If I were doing this project, that's how I would do it.

I second California on this method.

As I recall, cutting that pipe is easier said than done. I did it with a Sawzall type saw (mine was a Makita) with a 6" bi-metal blade. I used lots of cutting wax (much better than oil, stays in place longer) and it took quite a while to make the cut.

Re-apply the wax every minute or less, try to do it in a comfortable position because you will be there for a long time. Change blades as necessary.

Think about supporting the cut-off section of pipe -- it is heavy.

Measure the diameter of the cast iron pipe carefully after it is cut off. It is a different diameter than the 4" ABS pipe, and there is a glue-on piece of ABS you can buy to make the diameters match so the no-hub connector will work.

 

[AlanB]

Going out too look at it today again, and the other piece of advice I was given, was as long as it is not broken, just rebuild your floor under and around it. I don't think it is broken, so I may try that, I was thinking that it would be easier to get it out of the way, but everything I have read or heard says that it is no easy feat to cut and work with it.

So, some cleaning is in order and then an evaluation. If I cannot just use it as is, and rebuild the floor around it, I think the cutoff, and no hub connector is what will happen.

Will know more tonight.

 

[kmdigital]

I would remove it if you are to that point, assuming the pipe is easily accessible below the floor. The plastic is much easier to work with, and more forgiving.

The castiron toilet flanges are still readily available if you want to go that route, but to remove the old flange you need to use a 1/4" to 3/8" drill bit to drill out the lead between the old flange and the cast iron pipe.

The way this was put together is that flange was installed on the pipe, and then oakum, a material that looks kinda like old fashioned roap, but isn't twisted and is soaked in oil is tamped down into the bottom of the space between the flange and the pipe to create a tight seal up to about 3/4" from the top of the flange. Then molten lead is poured into the remainder of the space and peened around the inside and outside edges with special tools after it has hardened to create a liquid tight seal. To remove the flange you need to drill out this lead enough that you can pull it out and then dig out the oakum under it. After this the flange will lift right off.

If you go to plastic pipe, use Fernco adapters instead of nohub adapters. They are similar, except they are thicker rubber and have SS clamps on each end and no metal over the whole thing. They work much better for connecting cast iron to plastic then nohub couplers, because you will find that 4" plastic is about 1/4" larger in outside diameter than 4" cast iron due to the thicker walls. Fernco's work much better for bridging this difference than nohub couplings becasue they are longer and more flexible.

Also, you can get 3"x4" Fernco's so you could easily reduce the 4" cast iron pipe down to 3" plastic, which is easier to work with and gives you much more flexibility in tight spaces where every inch counts. Also, 3" works better in creating a good wax seal between the toilet and the flange, and works better with modern ultra low flush toilets. That is why I would go to plastic, and reduce it to 3".

Also, the easy way to cut cast iron is with a special tool you might be able to rent. It is a snapper, and will cut the pipe in a matter of seconds. It works by wrapping a special chain with sharp points in direct line with each other around the pipe, and then tightening it until the cast iron breaks, which it does very suddenly as the chain is tightend. Much, much easier than a sawzall, if you have enough room to work.

 

[AlanB]

OK, I sat and looked at it closely today, and when I thought about taking a picture, the camera was in the truck that had went to get lunch, yeah, likely story I know.

Tomorrow, tomorrow, theres always tomorrow....

Anyway, so the flange looked like crap, I thought, well, they told me about some repair parts, so I reached down and touched it, and the ears were just falling apart. OK, so grab the hammer (beat it too fit, paint it too match) and tap on it gently. The closet flange tapped off nicely and left a nice round expanded portion of the pipe there. I think it had to be made in two pieces that way.

So I was at Lowes tonight buying new electrical panel etc. etc. (Hey this is getting expensive) and I go look at the closet flanges, and it looks like they have a 4 X 2 cast iron adapter ring that looks like the piece that is gone to crud on mine. SOOOOOO, with any luck, that is how I will go.

Will try and remember to grab pictures tomorrow, but tomorrow is also new Electrical box day, so it may be a LOOOOONNNNGGGGG day, or I may catch a break

 

[AlanB]

Can the Fernco or no hub connector be put on horizontal runs or do they need to be on a vertical run of pipe?

Will try and grab a picture today, meant to yesterday.

This is what you guys are saying correct?

Fernco, Inc.

 

[California]

That looks about right but I was just watching a professsional, not doing it myself. The connection was horizontal, 4" new plastic to 4" old (80 years old) cast iron.

 

[toolaholic]

I'm a Gen. contr. that does all His own plumbing. Have all the tools snap cutters, pipe threaders ect. Sounds like you're over your head on this work. You'd be best getting a plumber. Here's what I'd do ,use a BANDED metal coupling and do A B S OF THE CAST. Chances You don't hace a swivel snap cutter. A hand metal grinder will cut the old cast fine. Use goggles,ear protection and dust mask. Sparks will start fires! use sheet metal deflector or hardy board. Keep water bucket handy! good luck