Well, after experimenting with CNC milled PCBs I decided to give etched boards a ago. As I have a “UV exposure box” (i.e. a cheap eBay thing for drying dragons’ fingernails) for the soldermask, I decided to try photoresist board. Odd then, that I found this was far too stong for the PCBs. Even a minute would appear to give a good exposure when I started developing the, but it turned out to be so overexposed I stripped all the resist off the boards. An expensive way to end up with plain copper boards.
Etching the boards was also not as simple as I thought. Sodium Persulphate seemed useless. Using Freeic Chloride and a sponge seemed too rough for the delicate photoresist. Sloshing Ferric Chloride didn’t do much until I heated it up – by putting the containing (including PCB) in the microwave. Anyway, enough of my woes and failed attempts.
When I eventuallly got a combination that worked this is what I came up with. This is the board post-etch. It’s not quite as good as I hoped but definitely good enough for the MPS430 microcontroller (TSSOP) and the 0805 LEDs, resistors and capactiors.
I’m hoping I don’t ruin it when I come to try surface mount soldering…