You’re probably wondering why a blog on energy efficiency is writing about rotten pipes. I’ll cover pretty much anything related to things going wrong in a home, so feel free to ask questions!
Pipe corrosion is a real issue. Even long time plumbers can’t seem to get it right. The reason pipes like this corrode is simple – when you connect two different types of metals together, they act like a battery and one side will be sacrificed to the gods of “galvanic corrosion.”
This is a given. It’s physics and chemistry and it happens. So what went wrong in this picture?
The plumber had an issue – they wanted to connect a 3/4” copper pipe to a 1/2” brass pipe. So they reached in their toolbox and pulled out a steel adapter and screwed it in. In the process, they created a battery that started eating away at the steel adapter. Once it reaches this point, that $1.49 adapter now costs you several hundred dollars because the plumber is going to have to cut the pipes apart and find a new way of connecting them. And you know what? They’ll probably do the exact same thing again. It makes my head explode!
Repeat after me – corrosion is not caused by leaks, it’s caused by electrical interactions!
You must never let dissimilar metals come in direct contact with one another! Keep in mind that some are similar enough, like brass and copper. They won’t destroy one another. Steel and iron are basically the same. But copper and steel is a no-no! Stainless steel and copper will also cause problems.
How do you fix this? You buy a $10 piece called a dielectric union. This electrically isolates the two metals, letting you connect them without problems for years.
Rather than duplicate what’s been described hundreds of times around the web, I’ll just point you to a great article on Hammerzone.com.
Feel liberated now. You probably know more than your plumber. And don’t believe it when they try to tell you that they can connect copper and steel. It just ain’t right!