Homebrew PCBs

The clearest etchant I am aware of is ammonium persulphate (AP).  As
it gets consumed, it turns a rather pretty shade of blue but is still
clear enough to see through.

The next clearest is CuCl as stefan mentioned.  I have used it but
found it to be difficult for me to use and recently switched back to
AP.  Even though it isn't opague, I have to disagree with stefan on
the clearness aspect.  It turns an emerald green (also quite pretty)
and unless your etch tank is fairly narrow, it is hard to see through.
  My CuCl tank is about 3 inches wide and I had to lift my boards out
to determine progress.  CuCl also stains though not nearly like FeCl.
 it is also much more agressive to some plastics than the other 2
etchants - probably due to the HCl.  I also was not able to get better
than 30 minute etch times vs 10-12 with AP.

FeCl, which I think you used, is completely opaque and a totally
horrible substance...

I've used all three and much prefer AP even with the disposal issue. 
CuCl is cheap to make if you have an inexpensive source of hydrogen
peroxide but I don't.  Also, with CuCl, you don't have a huge disposal
problem.  AP is the priciest of the bunch (3X CuCl, 2X FeCl).  If I
was making a lot of boards per month, I'd probably go back to CuCl
because of the cost even though I'd have to play chemist.

--- In Homebrew_PCBs@yahoogroups.com, "lcdpublishing"
<lcdpublishing@y...> wrote:
> I looked through the files section and didn't see what I am looking
> for (it may be there, I just don't know one chemical from another).
> 
> I am looking for an etching solution that I can get or make from
> common materials (hardware stores, etc.) that works good and is also
> clear.
> 
> The stuff I have used so far came in the Radio Shack kit and was dark
> brown in color - made it very difficult to monitor the etching
> process. Others here have mentioned some chemical that is clear and
> works good.
> 
> Hope you can help!
> 
> Chris