Cut Out Damaged Pipe Section — Support the Pipe
Part of project
How to Connect a PVC Drain to a Cast Iron Pipe · Step 3 of 9
In this video
First, protect the lower drain by plugging the openings with rags and plastic to catch debris. Using a reciprocating saw equipped with a specialty blade for cutting cast iron, make a straight cut through the upper section of the pipe, above the damaged area. Then, cut through the lower section of the main 4-inch stack and the connected 2-inch vent pipe to completely remove the broken piece. To ensure a straight cut on the lower section, a piece of wood can be braced across the opening to serve as a guide for the saw.
Goal: Remove the broken cast iron section
- Wear safety glasses and heavy-duty gloves. Cutting metal creates sharp edges and can send small particles flying.
- A cast iron specific blade (often diamond grit) will cut much more effectively than a standard metal blade.
Used in this video
- Reciprocating Saw (brand: Milwaukee Sawzall, Tool Type: Power tools, Power Source: Battery) — To cut through the thick cast iron pipe.
- Cast iron cutting blade (brand: Diablo, Tool Type: Power tools) — To effectively cut through the cast iron.
- Safety Glasses (brand: Milwaukee, Tool Type: Hand Tools) — To protect eyes from flying debris.
- Work Gloves (brand: Unknown, Tool Type: Hand Tools) — To protect hands from sharp metal edges.
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FAQs
What are the most important safety precautions when cutting cast iron pipe?
When cutting cast iron, always wear 3M Professional Chemical Splash/Impact Safety Goggles, MCR Safety BearKat Safety Glasses, and a 3M P100 Household Respirator to protect against dust and debris. Cast iron is heavy, so ensure the pipe is well-supported with 2 in. x 4 in. dimensional lumber before and during cutting to prevent injury or damage.
Do I need a special blade for cutting cast iron with a reciprocating saw?
Yes, a standard reciprocating saw blade will not work effectively on cast iron. You will need a Milwaukee 12 Amp SAWZALL Reciprocating Saw equipped with a DIABLO 9 in. Diamond Grit Reciprocating Saw Blade for Cast Iron Cutting. This specialized blade is designed to cut through the hard material efficiently and safely.
How do I properly support the cast iron pipe to prevent it from falling after I cut it?
Before making your cut, use 2 in. x 4 in. dimensional lumber to create temporary supports on both sides of the cut line. Secure these supports to a stable surface, ensuring they can bear the pipe's weight and prevent any movement, cracking, or collapse during the cutting process.
Why is a shielded flexible coupling recommended for connecting PVC to cast iron, and how do I install it correctly?
A shielded flexible coupling creates a durable, leak-free seal between cast iron and PVC, accommodating slight differences in pipe diameter and vibration. Ensure both pipe ends are clean and deburred before installing the coupling, then tighten the stainless steel bands evenly to the manufacturer's specified torque using a TEKTON 7/16 in. Nut Driver.
Cut Out Damaged Pipe Section — Support the Pipe
Part of project
How to Connect a PVC Drain to a Cast Iron Pipe · Step 3 of 9
In this video
First, protect the lower drain by plugging the openings with rags and plastic to catch debris. Using a reciprocating saw equipped with a specialty blade for cutting cast iron, make a straight cut through the upper section of the pipe, above the damaged area. Then, cut through the lower section of the main 4-inch stack and the connected 2-inch vent pipe to completely remove the broken piece. To ensure a straight cut on the lower section, a piece of wood can be braced across the opening to serve as a guide for the saw.
Goal: Remove the broken cast iron section
- Wear safety glasses and heavy-duty gloves. Cutting metal creates sharp edges and can send small particles flying.
- A cast iron specific blade (often diamond grit) will cut much more effectively than a standard metal blade.
Used in this video
- Reciprocating Saw (brand: Milwaukee Sawzall, Tool Type: Power tools, Power Source: Battery) — To cut through the thick cast iron pipe.
- Cast iron cutting blade (brand: Diablo, Tool Type: Power tools) — To effectively cut through the cast iron.
- Safety Glasses (brand: Milwaukee, Tool Type: Hand Tools) — To protect eyes from flying debris.
- Work Gloves (brand: Unknown, Tool Type: Hand Tools) — To protect hands from sharp metal edges.
Frequently Asked Questions
What are the most important safety precautions when cutting cast iron pipe?
When cutting cast iron, always wear 3M Professional Chemical Splash/Impact Safety Goggles, MCR Safety BearKat Safety Glasses, and a 3M P100 Household Respirator to protect against dust and debris. Cast iron is heavy, so ensure the pipe is well-supported with 2 in. x 4 in. dimensional lumber before and during cutting to prevent injury or damage.
Do I need a special blade for cutting cast iron with a reciprocating saw?
Yes, a standard reciprocating saw blade will not work effectively on cast iron. You will need a Milwaukee 12 Amp SAWZALL Reciprocating Saw equipped with a DIABLO 9 in. Diamond Grit Reciprocating Saw Blade for Cast Iron Cutting. This specialized blade is designed to cut through the hard material efficiently and safely.
How do I properly support the cast iron pipe to prevent it from falling after I cut it?
Before making your cut, use 2 in. x 4 in. dimensional lumber to create temporary supports on both sides of the cut line. Secure these supports to a stable surface, ensuring they can bear the pipe's weight and prevent any movement, cracking, or collapse during the cutting process.
Why is a shielded flexible coupling recommended for connecting PVC to cast iron, and how do I install it correctly?
A shielded flexible coupling creates a durable, leak-free seal between cast iron and PVC, accommodating slight differences in pipe diameter and vibration. Ensure both pipe ends are clean and deburred before installing the coupling, then tighten the stainless steel bands evenly to the manufacturer's specified torque using a TEKTON 7/16 in. Nut Driver.