I want to know the answer to the following question:
What's the minimum amount of copper a layer in a PCB can have to be considered "heavy copper"?
All the background I'm provided with is that "The printed circuit board industry defines heavy copper as layers exceeding three ounces of copper, or approximately 0.0042 inches (4.2 mils, 105 μm) thick.". Is that enough to answer the question?