Homebrew PCBs

On Mon, 5 Jan 2004 16:01:49 +0000 (GMT), Udara Dewamuni 
<dewamuni@...> wrote:

> Hi guys,
>
> I going to do an experiment with Etching
> chemicals.  What is the best etching chemicals u guys
> recomand for PCB etching except Ferric Cloride?
>
> Cheers,
> Udara
>
>

my personal choice is HCl and H2O2.
this gives kind of CuCl etchant but faster regeneration.
there are etchants based on sulphuric acid too.

these combinations are reuseable, regenerable nearly forever.

ferric cloride and ammonium persulphate are the more common etchants
for electronic work, though i don't see any disadvantage of what i use.
you get them at electronics stores.
they are not or only difficult to regenerate.

ferric cloride is a real mess, but cheaper and more environmentally 
friendly
then ammonium persulphate. A.P. is clear, so you see the etching progress 
through it.
it also isn't staining everything like fe3cl.


it depends on how often you want to use them.
for only one or two pcbs the "standard" methods with fe3cl and a.p.
are ok, however, i found it more convenient and cheap to use HCl.

it also depends where you do your shopping, if muratic acid (HCl) is easy 
to come
by where you are and you can get H2O2 somewhere is most likely the cheapest 
method.


there is at least one person here using the listed etchants, so it should
be no problem to get help with whatever you select.


also keep in ming that not every resist is compatible with every etchant.
same for equipment you are using (plastic is compatible to everything, 
stainless steel only with sulphuric things i think)

(is it possible that i have seen a tank for ammonium persulphate with 
aluminium pcb holder?)