Skip to content

How To Remove Cast Iron Pipe From Hub

  • by

For homeowners, old cast iron pipes might be scary. However, most people disregard them because they were trouble-free for such a long time. But you risk doing so because a cast-iron pipe can fracture and leak. When this happens, the cast-iron joint and weakened lead solder are frequently the leak sources.

Most cast-iron pipes are joined at bell-shaped hub-and-spigot joint, which are sealed with molten lead seal and a substance resembling rope called oakum.

In our guide, you can learn how to remove cast iron drain pipe from cast iron hub and spigot; cast iron hub connection can be tough, but with any pressure, and cast iron hubs and lead joint can break unpredictably. By the end, you’ll see the right ways to go about removing old pipe from a hub using various methods. (Learn How To Trim Laminate Countertop End Cap Without A Router)

cast iron pipe

How To Disconnect Cast Iron Joints

It is possible to remove the lead and oakum. After you have gotten all the lead out and cleaned up the hub, you can place a donut (also known as a compression joint seal) in the hub of the cast iron pipe to adapt it to PVC, such as a Fernco coupling.

It is worth noting that donuts are only usable on non-pressurized pipes, such as waste/drain lines. The recommendation is to cut the pipe somewhere other than at the lead & oakum joint and then use a Flexible Coupling to join it to your PVC Fernco coupler etc., for most applications.

How do you remove the melted lead and oakum joints in your CI pipe? Cast iron pipe removal would be made much easier if the lead and oakum joint were located far from wooden structures, causing a fire hazard.

In minutes, you could heat and melt the lead inside and burn the oakum from your drain pipes. Such a process is challenging to complete at home and for the average handyman who lacks easy access to tools and a workspace.

Here’s how to replace the cast iron fittings for plastic ones in sewer or pipe systems.

  1. Drilling lead to split it at intervals of 1/4′′ or so and then chipping each piece off with a 1/2′′, or 1/4′′ chisel are two techniques for physically removing lead from the fitting.
  2. It will take a long time, a lot of patience, and a lot of work to re-use the main pipe rather than replace the drain.
  3. You must use a right-angle drill if you don’t have total access to the joint between the joists or studs.
  4. Trim the pipe you’re replacing by about 1/2 inch from the hub using a reciprocating saw to cut around the spigot end at the entrance.
  5. Think if you will re-use or replace the joint. As an illustration, it might be easier to cut the pipe or sewer line and remove it to a flexible connection rather than removing more drywall panels to have full access to finish the job.
  6. Changing the drywall is straightforward and gives you more task access compared to painstakingly using a drill bit to chip away at the lead from one of these junctions.
  7. Of course, you might need to hire a professional pipe breaker instrument if you want to break cast-iron pipe precisely.
  8. If you have to store and re-use the joint because of limitations in space or another factor, pick the cheapest drill bits.
  9. Do not use your pricey titanium carbide drill bits at this time. Steel drill bits should be softer and less brittle than lead while still being more durable.
  10. Due to their extreme hardness, drill bits will break if you drill lead and apply lateral pressure.
  11. This leaves a substantial piece of hard metal that is difficult to remove in the lead seal around your cast iron drain pipe.
  12. Instead of using a drill bit, use a reamer. The interior of your hub will still have a thin lead ring all the way around after chipping away enough lead to removing the inner pipe.
  13. Remove any oakum using pliers, scrapers, or a cutting wheel on an angle grinder. If oakum gets too hot and is exposed to air, it could catch fire.
  14. The leftover lead can be carefully melted using a little blowtorch.
  15. When lead drops fall from the ring, use the torch on the inside of the pipe, and have a pail of water and a fire extinguisher close by.
  16. The lead will eventually melt when it comes into contact with the cast iron pipe.
  17. To remove the entire lead ring from the pipe, use a screwdriver or chisel.
  18. Your hub connection will be clean, making inserting your donut or Fernco coupler easier. First, make sure everything is in its proper location and that everything fits.
  19. To make it easier to hammer in the Fernco connection, add some cooking oil to the hub of the cast iron pipe.
  20. Apply a bead of silicon caulk around the donut.
  21. Use a heavy hammer to pound the donut into place. The PVC pipe can now be chamfered to make entering the seal or donut easier.
  22. Make some inch markers and place them along the length of your PVC pipe to check the interior length.
  23. On the inside of the donut, add more cooking oil. Then, wrap the PVC pipe in a bead of silicon caulk and hammer it into your new pipe.

cast iron fittings

How To Take Apart Cast-Iron Pipes From Fittings?

How to fix a cast iron pipe joint without calling a plumber is the most typical question. Plumbers take the actions of removing one pipe while you, as a DIY plumber, safely support the other connected pipe. (Read Door Sticking After Painting)

Note: Cast-iron pipes with fittings and other material will have to be disposed of. Therefore understanding how to remove cast iron pipe securely is essential. By disassembling the pipes and dividing them into manageable portions, you can save money on transportation and what you would have spent on a plumber.

One way you could do it is to hit the pipes with a hammer until they are in small pieces and chuck them in old buckets to transport them. Cast-iron snap cutters and a few hand tools are needed for the procedure.

  1. Put a 1/4-inch drill bit in your drill.
  2. Around the lead seal fitting of the two parts where the pipes meet, drill holes spaced 1/2 inch apart.
  3. To pry and remove the lead, use a flathead screwdriver (use an old screwdriver as it may get damaged).
  4. Use a hammer to press the screwdriver’s tip into the soft lead to pry it out of the connected pipe fitting.
  5. Next, pry the oakum packing positioned beneath the lead with your previous screwdriver.
  6. Pull apart the two connectors.
  7. Do the same on any additional lead and oakum-filled pipe joints.
  8. You can use an angle grinder with a cutting wheel or a reciprocating saw to cut your cast-iron pipe into smaller pieces.
  9. If you can, remove a joint without removing a section of the main drain if possible.
  10. Remove any corrosion from the lead joint if you notice a leak or an unpleasant smell.
  11. Tap the old molten lead back into the cast pipe joint using a cold chisel and hammer. The joint must next be filled using cast-iron pipe repair paste.
  12. Fill any holes you find near the cast iron drain joint you find.

Remember that a reciprocating saw is ideal for cutting underground cast-iron pipes.

Also, it is worth noting that you may need to replace the broken cast-iron pipe and remove it before replacing it with a new PVC pipe.

It would help if you had all your parts in advance for a cast-iron repair like this since you can’t cut cast-iron pipe and leave it open in the ground while you head to the hardware shop. (Learn How To Remove Glue From Engineered Hardwood Flooring)

cast iron fittings with lead joint

How To Remove Cast-Iron Fittings With a Lead Joint?

A soft material is coated in tar called oakum; an old plumber used to seal the joint. Oakum seals the joint, and each slight gap between the fittings when damp to the utmost extent.

Plumbers are used to seal this inside by heating and melting lead with a flame torch and dripping this in the final gap to stop leaks and offer support. In many home renovation and retrofit projects, contractors are replacing outdated cast-iron pipes and vent risers with ABS plastic pipes.

However, to do this yourself, you may not be able to get sufficient heat or have good enough access to use a flame torch to melt the lead. Besides this, even if you could, the lead is inside a hole, and you would struggle to remove it.

The procedure to remove cast-iron plumbing is provided here.

  1. Fill the dirt pipe’s hole.
  2. Remove a tiny section of the soil pipe by using an angle grinder or a soil pipe cutter.
  3. You can cut a tiny part of the pipe because it is typically empty without harming the entire stack.
  4. Remove this portion, and then swiftly fasten it. Unfortunately, there’s a considerable probability that as the stack slides away from the wall, you’ll produce debris, which, if it enters the drainage system, will be expensive to remove.
  5. The wastewater drain pipes are initially pulled off the wall by brute force by being smashed with a lump hammer.
  6. However, a grinder or pipe cutter is preferable to remove soil pipes.
  7. Your iron waste pipes finally connect to clay soil pipes as part of the underground drainage system. So, join this clay pipe immediately.
  8. Even though the clay pipe connection is only a few inches deep, digging is necessary. First, cut enough space to obstruct drainage lines while cutting the iron-clay joint neatly. (Learn How To Unfreeze Water Line In Refrigerator)

Now you can fit your donut inside the hub; just check the fit and alignment before following these few steps:

  1. Spray cooking oil inside the cast iron pipe hub to make it easier to hammer in the donut.
  2. Next, caulk the donut to avoid any leaks.
  3. Now chamfer the PVC pipe to make it easier to put into the seal/donut.
  4. Mark your PVC pipe inches to see how far it’s gone into the seal. Spray cooking oil inside the donut, caulk your PVC pipe, and hammer it in.
  5. Glue PVC pieces together using PVC solvent and cement to reach your drain.

How To Remove Cast Iron Pipe From Hub (1)