Homebrew PCBs

Definitely too strong! :)  

The Muriatic Acid from the Hardware store was 31% and the Hydrogen 
Peroxide from a beayt supplies store was listed at 40 volume.

I got the formula proportions from googling. I'll eat my own words, 
so much for accurate info when when googling.

Fortunately, there was very little chlorine gas. I'm familiar with 
the odor, the bubbles were probably oxygen from them excess peroxide.

I've already diluted the solution and it has stopped bubblng.

A six or seven minute etch from the reference in the files section, 
seems a lot more reasonable and controllable. I remember reading the 
about acid etching in the fioes section, a while back, before I was 
actually interested in trying it. Thanks for the reminder.

I'll try it the 'right' way next time.

And yes, I had goggles and gloves on while working with it.

Myc



--- In Homebrew_PCBs@yahoogroups.com, "Stefan Trethan" 
<stefan_trethan@...> wrote:
>
> Congratulations, you have just produced some chlorine gas.
> 
> Your proportions are wrong.
> There should not be any bubbling if the proportions are right.
> 
> Your acid is probably way too strong (how many % is it?), and too 
much  
> H2O2 too.
> In short, way too much of everything ;-)
> 
> You should at least dilute the acid down to 10 or 15% with water 
and use  
> only small amounts of H2O2 just to keep it bright green.
> 
> If it still bubbles, maybe dilute, and get some ventilation going. 
Don't  
> let get too hot!
> 
> Read the links in the links section about CuCl, although most are 
more  
> complicated than need be.
> 
> ST
> 
> 
> On Wed, 08 Feb 2006 22:31:47 +0100, mycroft2152 <mycroft2152@...>  
> wrote:
> 
> > I just tried the HCl/Peroxide etchant solution. 1.5 parts 40 
volume
> >
> > Hydrogen Peroxide to 1 part HCl (Muriatic Acid)
> >
> >
> > WOW! A very active etch. Took under 1 minute to etch a 2 sided 
board.
> >
> > The solution went from clear to bright green and bubbled 
furiuosly.
> >
> > After 20 minutes its still bubbling.
> >
> >
> > If anyone has experience with this etch solution. Does it stop
> >
> > bubbling? Is it storable? Were my proportions correct?
> >
> >
> > I never was worried about undercutting , but with this etchant, 
I will
> >
> > definately be concerned.
> >
> >
> > TANSTAAFL!
> >
> >
> > Myc
> >
>