Remember soaking a penny in vinegar? It gets super shiny, right? That’s because vinegar dissolves the patina. You’re not making it clean; you’re stripping its protective coat. Leave it in too long, and the penny starts to dissolve completely.
So, yes, water can eat copper if you’re nasty enough. But under normal conditions—a lake, a pipe, a rainstorm—copper holds its ground. It’s like that friend who gets a tan instead of sunburned.
Here’s the punchline: Copper is mighty. It’s why we’ve used it for roofs and plumbing for thousands of years. It doesn’t rust. It just gets prettier with age.
Okay, but what about “copper rust” products?
You might see “copper rust” spray paint at the store. That’s a marketing lie. They’re selling a fake iron look. Real copper never goes that nasty orange-brown. It goes green, black, or blue.
And if you see a copper pipe that looks flaky? That’s usually galvanic corrosion. That’s a fancy science fight where copper touches a different metal (like steel) in water. It’s not rust; it’s a metal divorce.
Copper Corrosion In Saltwater
Also, hard water? That leaves white chalky deposits, not rust. That’s calcium saying hello. Copper just blushes under it.
