Homebrew PCBs

Volkan Sahin wrote:

> Hi Simao,
> Thanks a lot for your reply. It contains full of information. I tried
> phosphoric acid + ammonium per-sulfate it works fine. It didn't etch
> the tin plated side of the copper. The problem is ammonium per-sulfate
> is very slow etcher and tin becomes black.  I'll try Adam's wet
> lamination method, I think it will  reduce pressure change inside the
> holes.

I was to say something more about tin compatible etchants, since is also
in my interest that you success in this, but it has the good answer
already. You will find better expertise and greater methods in Adam
Seychell writings than i found using 75K eur off bungard equipment. 

And this should be corrected. Dry film MSDS and wikipedia says something
like Acrilics and benzophenone, which i sadly mentioned. But only very
specific and odd compounds will work in low concentrations and sensitive
enough. 
Knowing the top plastic film in dry film function as oxygen blocking,
avoiding it's inhibition, I should never consider similar things as
liquid in free air. 
Thanks for your sharing, 
Sim�o