I built a large digital circuit on multiple breadboards. It runs at 5V and 8MHz, and I imagine it puts out a lot of EMI. I was planning to enclose it in a box made of copper sheet, since it looks cool. My questions are related to this enclosure. What is the minimum thickness this copper should be? I figure the practical range is .016" - .032". Thinner sizes get really expensive. But would there be any difference electrically? Also, should I connect the shield to the circuit ground? The 5V power comes from a USB battery.