Said It Here

How to cut a cracked cast iron pipe without breaking it

Using a chain soil pipe cutter on a cracked cast iron pipe risks shattering the entire section if the fracture compromises the pipe's structural integrity. Beginners often worry whether a mechanical cutter is safe to use or if they should switch to a reciprocating saw to avoid a messy disaster.

What people tried

Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.

  1. 1
    Using a reciprocating saw (sawzall) instead of a soil pipe cutter
  2. 2
    cutting and replacing the damaged section of the stack

In their words

Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.

r/Plumbing2 people · September 2026

“I need to cut out a split section of cast iron vent stack pipe.”source ↗

“I’m wondering if the cutter is ok to use on split pipe or if I should just bite the bullet and use the sawzall.”source ↗

“My concern is the cutter might not cut cleanly since there is a crack present.”source ↗

“I haven’t cut cast iron before and am hoping to avoid a possible disaster.”source ↗

torribul · r/Plumbing · 5 upvotes

“Are there any remediation options besides cutting it out? It seems like cutting could be a pretty extensive job.”source ↗

glassengineer123 · r/Plumbing · 2 upvotes

Where this came up

People with this problem also raised