Hello Group,
I've been following this discussion with interest and would like to move away from etching pcb's with ferric chloride.
I live in the UK and wonder if anyone knows of a supplier of the muriatic acid and hydrogen peroxide to home users. My local chemist was no help at all and didn't have a clue.
Any help greatly appreciated!
Steve
----- Original Message -----
From: Michel Baguet
To: Homebrew_PCBs@yahoogroups.com
Sent: Tuesday, May 20, 2008 5:05 PM
Subject: Re: [Homebrew_PCBs] H2O2 + muriatic acid etchant?
I'm using HCl for a years. 700cc of distilled water, 270cc of HCl highly concentrate (you can see smoke when the bottle is open) and 30cc of H202 at 30% concentration.
The only problem with this etchant is that H2O2 decompose with heat and light and if you etch another board a few days later, you don't know what part of H2O2 is still in solution. So I put the board to etch in the tank and take it out to see the color of the copper. If there is still enough H2O2, it must turn brown immediately.
If not, I add 10cc and son on but never more than 30cc (obvious !).
But the cost of HCl, H2O and H2O2 is so cheap that I often replace the etchant, to always get accurate results with small traces. A 200cm² double sided board with 35µ copper take between 4 to 6 min. in bubble etch tank @ 45°C.
clintonlcorbin <clcorbin@...> wrote: Folks,
First, I want to say "Hi". I just recently started making my own
single and two sided PCBs and even more recently joined the group.
There is a lot of great info here!
The question I have regards the etchant I have been using: 1 part
muriatic acid and 2 parts H2O2 (hydrogen peroxide). I found the
formula on a web page about (what else) DIY PCBs. As I was wanting to
try making my own PCBs and the materials were easy to obtain and low
cost, I decided to give it a try.
All in all, I have been quite happy with the results so far. I
haven't tried any real fine line etching yet and the smallest SMD
devices are 0603, so they are pretty big. The etchant is clear, so it
is very easy to keep your eye on the board during the etching process.
Plus, I have been doing all my etching at room temperature with no
heating at all. It generally takes about three minutes to fully etch
the small (2x3" are the largest so far) boards I am working with.
So the questions are:
1) How does this etchant compare to more traditional etchants?
2) Does it have over etch / under etch issues with finer lines?
3) Anything else I should be aware of?
4) Anyone else used this etchant along with the others that can give
a pros/cons?
Thanks for the help and all the info in this group.
Clint
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