[sdiy] PCB etching re-revisited

[aankrom]

OK. Lots of good tips. Now all I need to know is ideal bath temp for 
FeCl3 etching bath & how long to expect a typical etching to take. Is it 
better to etch a large board or a small board? Oh and you print on the 
dull side for PnP Blue? Now it feels like I had anothr question...

Does FeCl3 work for etching Al sheet & die cast Al? Also brass? This is 
how I want to make the control surface markings for my projects. I 
wondered if a very very dilute solution of HgCl2 might work for aluminum 
or if the Al would all just eventually crumble from oxidation.

Anthony