I use both FeCl3 and Acid/H202 etchant. Each has its good points as
well as its hazards. In either case, protective safety equipment must
be used.
FeCl3 is a "milder" and "safer" etchant to handle. Yes, it does stain
just about everything, but there is usually very little serious
damage. On the other hand, Muriatic acid / H202 is extremely damaging
to just about everything, including skin.
We all tend to become a little too familiar with the process and get
sloppy. I have had my share of stains and burns too. I definitely
prefer the FeCl3 stain.
When I do an acid etch, I wear goggles and rubber gloves. I have the
etchant tank in a second containment tray. I also have a half kilo of
baking soda handy as well as running water. After finishing, I dust
everything with baking soda and keep adding baking soda to any spots
that fizz. Then carefully wash everything down.
The acid etching process does generate heat and bubbles. There can be
a mist of etchant that is almost invisible. You will notice the
effects, if not immediately, but in a very short period of time. Acid
burns cause intense pain and heal very slowly. Fabric distegrates.
Do not underestimate the danger. Having a little "experience with
acds and bases" in high school, does not adequately prepare you for
proper use.
Be safe!
Myc
Industrial Chemist for 30 years
--- In
Homebrew_PCBs@yahoogroups.com, "Stefan Trethan"
<stefan_trethan@...> wrote:
>
> On Sun, 25 Mar 2007 13:30:24 +0200, sam_jfs <Samuel_joao@...>
> wrote:
>
> > I use Muriatic acid and H2O2 ( medical grade 3% too ) with good
> > results. The only problem is, after some days i can´t really
etch with
> > it, i must throw it away and make a new one, i don´t know why, i
don´t
> > understand chemistry ...
>
>
> The reason is that the H2O2 is not stable in the etchant, it
dissipates
> into the air.
> You can rejuvenate the etchant with fresh H2O2, but the problem
with the
> 3% stuff is you would add too much water.
> If you can get 25 or 30% H2O2 you can use the same etchant forever.
>
> ST
>