Homebrew PCBs

I've just done a bit of experimenting with the HCl I bought earlier, and
some 20 Vol (6%) H2O2 from the local Boot's emporium.

A couple of small pieces of PCB material about 1.5 cm in area etched
completely in about 5 minutes at room temperature, with continuous agitation
in a small container. I used about equal quantities of the 32% HCl and 6%
H2O2. The resultant solution is now green, indicating that there are plenty
of cupric ions present. If I re-use the solution, adding some H2O2 from time
to time when it goes blue (excess CuCl2), I should end up with a reasonable
concentration of CuCl3 that I can use. I think that some PCB manufacturers
who use CuCl3 monitor the etchant by measuring the colour continuously and
oxidise it automatically.

Leon
--
Leon Heller, G1HSM
leon_heller@...
http://www.geocities.com/leon_heller