How to Switch from Cast Iron to Copper Piping

What You'll Need
Red brass (85% copper, 15% nickel) piping, 12-foot lengths
Friction wrenches and clamps
Standard pipe wrenches
Pipe hacksaw
Acetylene welding torch
Face mask
Threading dies
Brass couplings

Switching from cast iron to copper piping for residential hot water can be done by the home handy-person. Copper piping retains heat and resists corrosion much better than cast iron. Follow these steps to replace cast iron piping with copper.

Step 1: Cut Copper Pipe to Size

Clamp the copper pipe with friction clamps so 6 inches protrudes. Cut the copper pipe sections to the sizes you need.

Step 2: Weld the Copper Pipe at Joints

Determine where right-angled joints are needed. Cut pieces of copper pipe to make the joints and weld these pieces on with the acetylene torch.

Step 3: Thread the Copper Pipe Fittings

Use the threading dies to thread the copper pipe at section ends to make the fittings.

Step 4: Ream the Pipes

Use the reamer to remove all metal burrs at the cut pipe ends before adding couplings. Attach the brass couplings at the threaded fittings to join pipe sections

Step 5: Remove the Cast Iron Pipe

Use the standard pipe wrench to release the cast iron pipe couplings and remove the pipe. Replace the cast iron pipe with your prepared copper piping.