Yes, you can connect iron pipe to copper pipe, but it requires a special fitting to avoid corrosion.
The Problem: Dissimilar Metals
Connecting iron pipe (specifically galvanized steel) directly to copper pipe creates a situation where galvanic corrosion can occur. This happens because iron and copper are dissimilar metals, and when they are in contact with each other in the presence of an electrolyte (like water), one metal will corrode more rapidly than the other. In this case, the iron will corrode, leading to leaks and eventual failure of the connection.
The Solution: Dielectric Union
The recommended solution to this problem is to use a dielectric union.
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What it is: A dielectric union is a specialized fitting designed to connect dissimilar metals.
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How it works: It physically separates the two metals with a non-conductive material, preventing the flow of electrical current and minimizing corrosion.
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Construction (According to Reference):
- One end of the dielectric union features a threaded steel female pipe fitting. This connects to the male threads of the galvanized steel pipe.
- The other end includes a female copper hub fitting. This slides onto the copper tubing.
Example Connection
| Step | Description |
|---|---|
| 1 | Ensure the iron pipe is clean and has properly cut threads. |
| 2 | Apply pipe joint compound or Teflon tape to the threads of the iron pipe. |
| 3 | Screw the steel end of the dielectric union onto the iron pipe. |
| 4 | Solder (or use a compression fitting, depending on the type) the copper end of the dielectric union to the copper pipe. |
