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How To Separate Cast Iron Pipe Joints

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When your home has old plumbing or drainage, you’ll often have a cast iron sewer pipe, cast iron plumbing stacks, or other pipes you need to remove. Most old cast iron drain pipes and cast-iron plumbing are sealed using lead and oakum.

Oakum, a tar-coated hemp material placed into the joint to seal it, where the oakum swells and thus seals the joint. The oakum is held in place, and the pipe joint is strengthened by casting a 1′′ thick bead of lead around the pipe inside the hub/socket.

Fortunately, both the lead and the oakum can be removed if you need to preserve one side of the pipe. However, when you wish to install a new bathroom, it takes some skill and effort to separate an old pipe because if you use too much force, you could break the side of the drain line you want to remain in position. (Learn How Hot Does A Chimney Flue Get)

In our guide, to help you know about replacing 2 cast iron plumbing stack and other oakum-filled pipes, we show you all the way and means you need.

By the end, you’ll know all you need to smash the pipe with a hammer if you don’t need the pipe or how to remove cast iron drain pipe and other pipes for your new connection.

Guide To Separate Cast Iron Pipe Joints

How Do You Take Apart Cast-Iron Pipe Fittings?

The question most often asked is how to repair a cast iron pipe joint? Here are the steps needed to remove one piece of pipe while protecting the other side.

Depending on the replacement, you may have to dispose of cast-iron pipes with fittings
and couplers, so you need to know how to remove cast iron pipe safely.

You can save money on transport by disassembling the pipes and separating them into manageable sections.

The method requires a cast-iron snap cutter and a few hand tools.

  1. Install a 1/4-inch drill bit in a drill
  2. Drill holes 1/2 inch apart around the lead seal fitting of the two sections where the pipes meet.
  3. Use a flathead screwdriver to pry and remove the lead. To pry out the lead, gently tap the screwdriver handle using a hammer to force the tip into it.
  4. Next, use your old screwdriver and pry out the oakum packing underneath the lead.
  5. Pull both connectors apart.
  6. Repeat on any other lead and oakum-connected pipe joints.
  7. To cut your cast-iron pipe into shorter sections, you can use a reciprocating saw or an angle grinder with a cutting wheel.

If you need to repair a joint and don’t need to remove part of the main drain.

Remove any corrosion from the lead joint if you have a leak or can smell a foul odor.

Tap the old molten lead back into the cast pipe joint using a cold chisel and hammer. Next, you need to fill the joint using cast-iron pipe repair paste.

If you spot any holes, fill these around the joint of your cast iron drain.

Note: a reciprocating saw is the best tool for cutting cast-iron pipes in the ground or under a concrete slab. (Read Running Pipes In Stud Walls)

When making a cast iron repair on your drain pipe, you may need to locate and cut out any damaged cast-iron pipe and replace it with a new PVC pipe.

With such a cast-iron repair, you need all your parts beforehand, as you can’t cut cast-iron pipe and leave it open as you visit the hardware store.

What is Cast Iron Soil Pipe?

In an older US house built before the 1980s, it’s typical to find black metal pipes under floors, walls, and roofs. This cast iron pipe was used to create plumbing drain systems for years.

Cast iron can rust and rot, and you find this more with horizontal pipe sections than vertical sections. However, vertical sections collapse, especially under kitchen sinks where you could spill chemicals.

Cast iron was also used in yards and under concrete floors, which can also fail. Repairing or replacing cast iron in the ground or under concrete requires uncovering it, then replacing the soil and concrete.

Before cutting any cast-iron pipe, you need to decide if you’ll replace the entire thing or just one or two sections and replace damaged materials.

Tips to Join PVC Pipes and Fittings

How to Join PVC Pipes and Fittings

You can use a rubber coupling to join cast iron to a PVC section, and you’ll need PVC glue to glue the PVC pieces together.

Because a good fit between pipes and fittings is essential, you need to cut your sections of the pipe clean and straight.

How Do You Remove Cast-Iron Pipe Lead Joint?

Here you can find the steps to remove cast-iron plumbing.

  1. Plug the hole in the soil pipe.
  2. Remove a small part of the soil pipe with an angle grinder or a soil pipe cutter.
  3. Because the pipe usually is empty, you can cut a small section without damaging the entire stack.
  4. After removing this section, quickly fasten it. As the stack slides from the wall, there’s a good chance you’ll create debris, which will be costly to remove if it goes into the drainage system.
  5. The first method is to use brute force using a lump hammer to smash the wastewater drain pipes before you pull them off the wall.
  6. However, it is better to remove soil pipes using a grinder or pipe cutter.
  7. In the underground drain system, your iron waste pipes eventually connect to clay soil pipes. So, connect directly to this clay pipe.
  8. The clay pipe connection requires digging despite being only a few inches deep. Allow enough room to cut the iron-clay joint and not clog drainage systems neatly.
  9. Now that your home is free of old pipes, you may plan your new plumbing stack.

Remove Old Lead And Oakum Joints

How Do You Remove Old Lead And Oakum Joints?

Here’s how to remove melted lead and oakum joints in your CI pipe?

If the lead and oakum joint was far from wooden structures, you could melt the lead and oakum from your drain pipes in a couple of minutes, making removing cast iron pipe far easier.

Such a task is challenging in your home and for the everyday handyman who lacks accessibility to tools and working area. (Learn How To Get Rid Of Rats Under Concrete Slab)

Here’s how to replace the cast iron pipe or sewer line fittings with plastic ones.

Two methods for physically removing lead are drilling lead every 1/4′′ or so to separate it and then to chip off each piece with a 1/2′′ or 1/4′′ chisel.

If you want to re-use the main pipe rather than replace the drain, it will take a long time and a lot of patience and effort.

If you don’t have complete access to the joint between joists or studs, you’ll need to use a right-angle drill.

  1. Using a reciprocating saw to cut around the entering spigot end of the pipe you’re replacing, trim it about 1/2 inch away from the hub.
  2. Consider whether you genuinely want to keep the joint or replace it entirely. For example, rather than removing more drywall panels to gain full access to complete the job, it may be easier to cut the pipe or sewer line and remove it to a flexible connection.
  3. When compared to meticulously chipping away at the lead from one of these junctions with a drill bit, changing drywall is simple and offers you more job access.
  4. Of course, breaking cast-iron pipe neatly may require you to hire a specialized pipe breaker tool.
  5. Choose the cheapest drill bits if you must save and re-use the joint due to space or other constraints.
  6. This isn’t the time to break out your expensive titanium carbide drill bits. Steel drill bits should be tougher than lead while remaining soft and non-brittle.
  7. Otherwise, if you drill lead and apply any sideways pressure to the drill bits because of their extraordinary hardness, they will shatter.
  8. This leaves a solid chunk of hard metal in the lead seal around your cast iron drain pipe, challenging to remove.
  9. Don’t rely on a drill bit; instead, use a reamer. After chipping away enough lead to remove the inner pipe, the interior of your hub will still have a thin lead ring all the way around.
  10. Remove all oakum using pliers, scrapers, or a cutting wheel on an angle grinder. Be cautious as oakum could catch fire if it gets too hot and is exposed to air.
  11. You can use a small blowtorch and carefully melt the remaining lead.
  12. Use the torch on the inside of the pipe when lead drops fall from the ring and have a fire extinguisher and a bucket of water handy.
  13. The lead that encounters the cast iron pipe will eventually melt.
  14. With a screwdriver or chisel, pry the entire lead ring out of the pipe.
  15. You will have a clean hub connection, thus making fitting your donut or Fernco coupler easier. Check the fit and make sure everything is in its proper place first.
  16. Put some cooking oil in the cast iron pipe hub to make it easier to hammer in the Fernco connection.
  17. Apply a bead of silicon caulk around the donut’s circumference.
  18. Pound the donut into place with a strong hammer. The PVC pipe can now be chamfered to make entering the seal/donut easier.
  19. To check the length inside, make some inch markers on the length of your PVC pipe.
  20. Add more cooking oil on the inside of the donut, a bead of silicon caulk around the PVC pipe, and hammer in your new pipe.
  21. To reach your drain, all you must do now is glue one fitting to the next with PVC solvent and cement.

How Are Cast-Iron Pipes Joined?

Oakum is a tar-coated hemp substance used to seal the joint. When oakum is moist, it swells to the maximum point and seals the joint and every small hole between the fittings.

The oakum is held in place, and the pipe joint is strengthened by a 1′′ thick bead of lead they cast around the pipe inside the hub/socket. (Learn How To Fix A Squeaky Refrigerator Door)

In many home remodels and retrofit projects, contractors are replacing old cast-iron pipes and vent risers with ABS plastic pipes.

How To Separate Cast Iron Pipe Joints