JanRwl@... wrote:
> Can someone here PLEASE outline the procedure and chemistry to use for this
> etch-method? I have never seen ANYWHERE a list like,
> "1. Boil the bare blank in swamp-water;
> 2. Incant;
> 3. Swish the board around in a 30% CuCl solution over 80°C for 15 minutes;
> 4, Etc. etc."
>
> With FeCl, you can omit steps 2. and 4., and the result is fine, but messy.
>
> Please?
>
>
There's two main approaches to chloride etching chemistry.
1) CuCl2 + HCl + H2O2
2) CuCl2 + HCl + O2
Method 1)is much faster than 2). I use 2) at room temp, which is about 2
to 3 times slower than FeCl3 at same temperature. For 1) you don't
actually need CuCl2, but helps, and its a byproduct so you get it for
free. Most reliable determination of CuCl concentration is by density
measurement, and should be 1.30 to 1.45 g/cm^3, yes, very concentrated
solution needed for method 1), or else its too damn slow. HCl should
also be > 1 Molar (4% wt) for speed. Ball park figure of HCl content is
easily found by taking a 1cm^3 graduated diabetic syringe filled with
1.0 cm^3 of 40g/Liter NaOH. Add drop wise to small clear jar filled with
1.0 cm^3 sample from etchant + 1 table spoon of water. When copper
hydroxide precipitate forms, stop, stir, and continue additions if
precipitate redissolves. When precipitate stops dissolving then HCl
concentration = X Molar, where X is cm^3 of NaOH solution added. You
need access to some scales measurable in gram units in order to prepare
40g/L NaOH solution.