Hi; I have a vertical 2 inch cast iron vent pipe that I need to remove to install a medicine cabinet.
I have cut it in one spot with a sawzall, but there is also a joint in it where I would like to separate it. The joint appears to be poured with lead. If I heat it with a propane torch to get it hot enough to melt the lead, the lead may spill out into the framing inside the wall. At 600 some degrees, I am concerned that it would cause a fire. There is no room to get a roller cutter on it.
Any ideas?
Thanks, Ken Wallace, San Diego

Hi Ken,
To remove a poured lead and oakum joint take a 3/8" drill bit and drill a few holes down past the lead and into the oakum.. Push a screwdriver under the lead ring and lever it up. Once it's free you can began to peel the lead ring out. Now pick out the oakum and you can pull the joint apart. Good luck, Tom

Thanks Tom;
The top of the joint where the drilling would be done is not accessible without breaking into the wall. I can only get at the bottom of the joint. Perhaps I could drill some 3/8 holes through the cast iron and the lead.Then, maybe I could then get a drift punch to catch the edge of the lead and drive it up out of the joint.
Do you agee that the heat of melting the joint is dangerous? Or, is this done routinely? I can put some sheet metal around the pipe to shield the drywall and stud from the torch. I also wonder if I am applying a bending force on the joint as I heat it, if it won't start to soften when it gets to the melting point so I can pull it apart before it really melts?
Thanks, Ken Wallace, San Diego

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Originally Posted by kwallac2

Thanks Tom;
The top of the joint where the drilling would be done is not accessable without breaking into the wall. I can only get at the bottom of the joint. Perhaps I could drill some 3/8 holes through the cast iron and the lead.Then, maybe I could then get a drift punch to catch the edge of the lead and drive it up out of the joint.
Do you agee that the heat of melting the joint is dangerous? Or, is this done routinely? I can put some sheet metal around the pipe to shield the drywall and stud from the torch. I also wonder if I am applying a bending force on the joint as I heat it, if it won't start to soften when it gets to the melting point so I can pull it apart before it really melts?
Thanks, Ken Wallace, San Diego

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Hey Ken,

As you've found out when you cut the 2" cast iron, cast iron's very tough to machine so I wouldn't attempt to drill any holes. I worry more about the heat from the torch. I always have a bucket of water handy when I use a torch inside a wall. Do you have to save the hub? Before I advise you to break the hub off I need to know how you wosh to congigure the 2" pipe after the cabinet's installed. Offset around it? What fuction does the 2" perform? Give me more details on the job so I can aqdvise you better. Regards, Tom

Thanks for your help Tom;

I drilled a 3/8 hole up through the bottom of the hub. Then I drove a rod through from various angles. It came through the lead, but the lead did not come up.
Then I sawed a cut through the wall of the hub and drove the tip of a cold chisel into the slot until the hub cracked. This broke off about 180 degrees of the hub so I could pry most of the lead out. It was then loose enough to get off. I have to say that this cast iron plumbing is very impressive. This is what them mean when they say "built to last".

Thanks Again, Ken Wallace