[billwill]

Well, I have dug out to the cast iron connection outside my stem wall and the concrete pipe seems to be cemented to the cast iron pipe. Any tricks to get this cast iron pipe cleaned up so I can connect the plastic pipe to it? Could I use a small chisel and chip away carefully so as not to break the cast iron pipe? I have some time... :-)

[InfoJunkie4Life]

Yeah, chipping it away shouldn't be too much of a problem. Depending on the thickness of the cast iron pipe, they do tend to crack easily. Be careful not to hit straight down on the pipe as to cause a crack. You don't need to be overly gentle with it if it is thicker.

[KISS]

Rent a snap cutter and cut the cast iron pipe. Then use a Proflex band connector.

Ridgid 34403 Press Snap Press Snap Soil Pipe Cutter Kit

Fernco P3000-44 Proflex 4 Inch Coupling #9063348 at HardwareAndTools.com

[Milo Dolezal]

... or, you can cut of the joint and connect to clean pipe. What exactly are you doing ?

[billwill]

Replacing the broken section of concrete pipe with pvc...


Just taking out the section of concrete pipe back to the cast iron pipe by the stem wall. So, if I am careful I ought to be able to get the concrete pipe off and clean off the iron pipe for the coupling. Cutting is the quick efficient method and fairly easy to do with the right tool whereas "scraping" or gently chiseling the concrete of a bit more labor intensive and time consuming.

[speedball1]

There are several ways to go about this. How I would do this is first take a cement saw and cut out the affected concrete pipe. Yo can now remove to old concrete pipe from the bell of the cast iron. Here's where your options come in.
1) You can insert a donut gasket, (see image) in the hob and insert a piece of PVC in the cast iron hub. Using a shielded No- Hub Band, (see image) to connect back to the concrete pipe, **OR**
2) you could cut out both the bad piece of concrete pipe AND the cast iron hub and use shielded bands on both ends, Good luck, Tom

[billwill]

Thanks to everyone. I appreciate your comments.



This is where I am at now. It looks like I can get the concrete pipe off now pretty easy. Is there a trick to separating the concrete pipe joint on the other end? Thanks again for all the input. (I have not figured out how to click on all the buttons, yet!)

[massplumber2008]

Hi Bill

Your picture didn't show up, but if this was me I would recommend cutting the concrete pipe using an angle grinder with a diamond blade... cut just behind the hub or a foot or so after the hub. Here, you'll install the diamond blade and then cut all around the pipe... this means digging a little deeper under the concrete pipe so you can get the angle grinder under the pipe. Be sure to wear safety goggles! You could also rent a gas cutoff saw and make a nice straight cut that way... Just FYI.

Then I would recommend using a reducing FERNCO clamp of the correct size to connect this all back up again. Here, you'll measure across the pipe to determine the correct sizes needed for the clamp. The only place you will find these sized for this application will probably be at a local plumbing supply store... but hard for me to say because I simply do not know the size of the pipe we are talking about at this time. These fernco clamps are the only clamps that can transition between concrete pipe and cast iron or PVC pipe using only one clamp... ;)

Let us know if you would like to discuss further... OK?

Mark

[billwill]

OK. I know what a gas cut off saw is. I used one to take off the patio built over this line! :-) I have a question that might help me in my low tech pursuit. At the joint of the concrete sections of pipe, how are the pipes joined? Are they cemented? Could a person chisel out the pipe from the joint? Very gently? I do see a problem with doing that in that the cement pipe is brittle but my real question is how are they typically joined? I will eventually find out, but knowing ahead of time is useful. Thanks.

[massplumber2008]

Most likely you'll find an oakum (fibrous/stranded.. see image) material under a layer of concrete to join the pipes.

You could try to use a carbide tipped drill bit and see if you can work the old concrete out. Then you could use a long screwdriver and pry/remove the oakum strands. Most likely this will not end successfully, but could be worth the effort.

If successful, then you could pack some oakum back in around the new pipe in the concrete hub and then you can push in some SOIL SEAL to finish the job... sold in cans at most home supply stores (see other image). DO NOT use cement to rejoin the pipes. The stuff is pourous (roots can enter easily) and gets brittle over time.

Back to you...

Mark

[TXhomeowner2010]

What size angle grinder is best for cutting concrete pipe?