9. Etching the PCB

After I managed to get my prototype breadboard running successfully some sample g-code I went on to create a PCB.
Never have done such a thing before but I am a  chemical laboratory assistant and chemicals do not raise fear in me.

Again I used Groovers lasershield layout. It comes in EagleCAD format.

I mirror printed the layout on ordinary paper and glued it to a photosensitive copper board and used my dremel clone to drill the holes. As I do not have a fancy exposure timer I took some alcohol and removed the protective varnish.
With a overhead projector pen and a ruler I traced the layout by hand. This pen gave a very nice shiny trace.
I also tried to use a thin permanent marker (acid-resistant / Edding 400 in Germany) but the result was a thick ugly line.
Although with the overhead pen I just needed to draw the trace once and not several times to get a nice coating.

To etch the layout I used Fe(III)Cl. Don’t like the other stuff that is available. They could vaporate, they stink and stuff that contains peroxid can explode when kept in sealed bottles. So Fe(III)Cl is the most convenient solution to store and dispose.

Nevertheless : !! Don’t pour it down the drain !! It is going eat your drainpipe if it is made from copper and it will definitely kill all the little usefull bacteria in your local sewage disposal facility.


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