By mixing CuCl4 into CuCl2, I was able to etch a 1 oz copper-clad FR4. With a very unusual setup, I was able to prototype an industrial-type etch with an agitator. According to the research and test trial, it takes 20 minutes to fully etch the copper on the side facing down. If you keep it in the bath for 40 minutes, you begin to over-etch the copper on the PCB. Therefore, the solution is strong between 20 and 40 minutes. The first test was conducted on a 0.8″ x 0.25″ blank PCB. Then the PCB test became my name tag. The agitator ran at 62 Hz at 24 volts (the agitator was an air assist for the laser machine).
Build Notes:
- 1x- 3 volt operation on CR2450.
- 1x- 100 Ohm resistor.
- 3x- Forward voltage drop on led is 1.7 volts at 20miliamps.
- 1x- polarized film 90 degree for contrast.
- 1x- smd mini-switch.
- 1x- CR2450 smd battery holder
