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Preparation and Safety — Break and Remove Old Cast Iron Flange

Intermediate

Part of project

How to Replace a Cast Iron Toilet Flange with PVC · Step 3 of 10

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In this video

Begin by identifying the cast iron hubs that need to be removed. Gather all necessary tools and safety equipment. This includes an acetylene torch, a flathead screwdriver for picking out the lead, a hammer, channel-lock pliers, and safety glasses. Critically, if working on a vertical pipe stack, stuff a rag down into the pipe below the joint to catch any falling debris or molten lead, which could cause a serious blockage. It is also wise to have a fire extinguisher and a spray bottle of water on hand for safety.

Goal: Prepare work area and gather tools

  • Failure to place a rag in a vertical pipe can lead to molten lead creating a permanent blockage further down the line.

Used in this video

  • Acetylene Torch (brand: Unspecified, Tool Type: Specialized tools, Power Source: Fuel-powered) — Heating and melting the lead seal in the cast iron hub.
  • Flathead Screwdriver (brand: Unspecified, Tool Type: Hand tools, Power Source: Manual, Screwdriver Tip: Flathead) — Picking and scraping molten lead and burnt oakum out of the pipe joint.
  • Hammer (brand: Unspecified, Tool Type: Hand tools, Power Source: Manual) — Tapping on the pipe stub to loosen it after the lead has been melted.
  • Channel-Lock Pliers (brand: Unspecified, Tool Type: Pliers, Power Source: Manual, Pliers Jaw Type: Groove Joint) — Gripping, wiggling, and pulling the loosened pipe stub out of the hub.
  • Safety Glasses (brand: Unspecified, Tool Type: Safety equipment) — Protecting eyes from sparks and potential splatter of molten lead.
  • Fire Extinguisher (brand: Unspecified, Tool Type: Safety equipment) · optional — Extinguishing any accidental fires, as an open flame is being used near wood.
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FAQs

How difficult is replacing a cast iron toilet flange with PVC, and how long should I expect it to take?

This project is rated as intermediate. While it doesn't require specialized plumbing skills, removing the old cast iron and lead/oakum seal can be physically demanding and time-consuming. Expect it to take anywhere from half a day to a full day, especially if you encounter unexpected issues like a stubborn old flange.

What specialized tools are absolutely essential for removing the old cast iron flange and its lead/oakum seal?

Beyond basic household tools, you'll definitely need a cold chisel and a hammer for breaking up the old cast iron and carefully removing the lead/oakum seal. A shop vacuum is also crucial for quickly cleaning up debris and ensuring the cast iron pipe is spotless before installing the new flange.

What are the most important safety precautions I should take when demolishing the old cast iron flange and seal?

Always wear heavy-duty safety glasses to protect against flying fragments and a respirator (like the Honeywell R95) to avoid inhaling dust and potential lead particles from the old seal. Heavy-duty gloves are also essential to protect your hands from sharp edges and the demolition tools.

What's a common mistake when installing the new PVC compression flange, and how can I avoid it?

A common mistake is not thoroughly cleaning and deburring the inside of the cast iron pipe after removing the old flange. Any rough edges, rust, or debris can compromise the compression seal of the new PVC flange, leading to leaks. Ensure the pipe's interior is smooth and completely clean for a watertight fit.

Transcript
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good knowledge to know. I got my safety glasses here. I got my acetylene tank with the turbo torch on it. I got a screwdriver to pick the lead out. When you do a horizontal, obviously the lead is going to fall out on the floor. When you do a vertical, lead is just going to sit in there. This is open from letting it go down. So you got to kind of kick it out as you melt it. You got to brush it out. So you can use a flathead cleaning brush. Now the lead is dirty like you're in a trance or something. You got to use a cleaning brush. You got to clean that dirt off. The lead for some reason doesn't know as well. It takes forever. But we're not in a trance. It's above ground. One thing I will say if you're on a vertical piece like this, I'm not too conservative. Anything drops down into the pipe. I can just reach my hand in and grab it out. But if let's say we're on the second floor, you know, the first floor, I'm melting the hub out from there. I'm not going to be able to reach down and grab it. You got to put a big rag in down there to stop anything from dropping down. I've done it where I've taken the cast iron out and the lead is still hot and liquidy. And I pulled the cast iron out and the lead dropped down into the pipe. And I was going to go crap and I'd fix it. But basically all you do is take the torch to it and you melt it out. If you want, you can wear a mask. I just wear glasses because lead, especially those water around them. If water hits hot lead, it kind of like pops. It explodes kind of.

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