I can’t ever leave things well enough alone, so while working on Veronica’s input system, I decided to really push my PCB etching. I wanted to see if I can find the boundaries of what the process is capable of, and perhaps identify the weak points.
One of the key elements of the process is that I print the UV exposure mask on to two transparency sheets, and double them up. I’ve been assuming that one layer of printer toner probably wasn’t enough to completely block UV. Ultraviolet light is sneaky stuff, capable of going right through blue tape, for example. However, doubling up the masks introduces a tricky element to the process- alignment. The two masks need to be lined up very very precisely, and this is difficult to do perfectly. So, it would be nice if I could skip this step. Can I?